The increasing availability of gene sequences of prokaryotic species in samples extracted from all kind of locations allows addressing the study of the influence of environmental patterns in prokaryotic biodiversity. We present a comprehensive study to address the potential existence of environmental preferences of prokaryotic taxa and the commonness of the specialist and generalist strategies. We also assessed the most significant environmental factors shaping the environmental distribution of taxa.http://metagenomics.uv.es/envDB.We used 16S rDNA sequences from 3,502 sampling experiments in natural and artificial sources. These sequences were taxonomically assigned, and the corresponding samples were also classified into a hierarchical classification of environments. We used several statistical methods to analyze the environmental distribution of taxa. Our results indicate that environmental specificity is not very common at the higher taxonomic levels (phylum to family), but emerges at lower taxonomic levels (genus and species). The most selective environmental characteristics are those of animal tissues and thermal locations. Salinity is another very important factor for constraining prokaryotic diversity. On the other hand, soil and freshwater habitats are the less restrictive environments, harboring the largest number of prokaryotic taxa. All information on taxa, samples and environments is provided at the envDB online database, This is, as far as we know, the most comprehensive assessment of the distribution and diversity of prokaryotic taxa and their associations with different environments. Our data indicate that we are still far from characterizing prokaryotic diversity in any environment, except, perhaps, for human tissues such as the oral cavity and the vagina. The patterns of species distribution and diversity, which are fairly well-known for macroorganisms, are not altogether understood for microorganisms. Some ecological trends that have already been observed for macroorganisms, such as taxa-area or distance-decay relationships , and espEscherichia coli), or to separate organisms with an almost identical gene complement (as in the genus Bacillus). The ongoing debate on this topic includes the proposal that similarity in lifestyle, and not just in genes, is the best approach to classify microorganisms [The study of ecological trends in microorganisms has been traditionally hampered by different factors. First, the methods used to catalogue microbial diversity (mostly based on sequencing the 16S rDNA gene) are expensive, time-consuming, biased and inadequate for massive screening, although technologic advances in DNA sequencing technology can change this picture dramatically -10. Anotrganisms ,13. Simirganisms . Polypharganisms , includirganisms .Also the massive number of existing species makes cataloguing microbial diversity difficult . Most saFurthermore, knowledge about the most determining factors that shape the distribution of bacteria in the different environments is still limited. It is quite usual to ascribe whole bacterial clades to a single environment by identifying them as for instance, marine or terrestrial. Should we make this simple categorization? Could this not be a consequence of our incomplete and biased knowledge of the different environments and taxa? To study ecological trends, it is important to count on an accurate description of habitats and, accordingly, it would be most helpful to adopt standardized descriptions for the environmental characteristics of the samples. An interesting initiative in this direction is being carried out with the development of the MIGS/MIMS (minimum information about a genomic/metagenomic sequence) specifications by the Genomic Standards Consortium .Nowadays, however, there are a big number of studies inspecting the presence of particular taxa in different environments. The analysis of the presence of taxa in different environments for which many samples are available is a valuable approach to in part overcome some of the limitations pointed above. The use of these data may allow to obtaining conclusions on how environmental features and taxa-specific properties influence the patterns of microbial distribution.In this study, we present a comprehensive analysis of the relationships between individual prokaryotic taxa and different environments, in an attempt to cover two main objectives: firstly, to describe the environmental distribution of taxa, in order to explore the existence of environmental preferences for taxa and the commonness of specialists (environment-specific species) and generalists , at different taxonomic levels (from phyla to species); second, to describe environmental variation according to taxa distribution in an attempt to ascertain common features between different environments and to determine the most significant environmental characteristics. In both cases, we show the most remarkable trends that could orientate future studies on these issues. Although partially similar studies were performed in the past , this isPrevious references have attempted to characterize the patterns of distribution and diversity of some taxa by proposing, for instance, the existence of environment-specific taxa, or even whole clades ,21. But It is sensible to think that patterns of ecological and metabolic diversity may depend on the specific level of taxonomic and environmental resolution. In this study we have considered all possible taxonomic ranks, from phyla to species, in order to explore how the trends change with taxonomic resolution . Likewise, we have created a novel classification of environments composed of three nested levels of environment classes with increasing resolutions Table . Each saProchlorococcus marinus and Pelagibacter ubique. These taxa are thought to be amongst the most abundant microorganisms in the Earth [First, we determined the abundance of each taxon in all the environments, to study the patterns of specificity and cosmopolitanism. The results are shown in Figure he Earth , but at he Earth . The gasIt must also be remarked that for environmental subtypes, the most detailed level of the environmental classification, specificity is almost inexistent at any taxonomic depth Figure . The relWe can define a cosmopolitan taxa as having five or more observations in 90% of the environments . While the upper taxonomic ranks can be considered as eurioic (tolerant to highly diverse conditions), that behaviour does not necessarily hold for their constituents. This trend can indeed be appreciated in Figure Clostridia (Lachnospiraceae and Oscillospiraceae), and the gamma-proteobacterial family Succinivibrionaceae, all of them specific for the gastro-intestinal tract of animals , Thermoactinomycetaceae (soil), Sulfolobaceae , Oscillospiraceae and Lachnospiraceae (gut).Cosmopolitanism and specificity patterns can also be revealed by inspecting the evenness of the distribution of a particular taxon in the different environments. This can be done by calculating biodiversity indices. For a particular taxon, high diversity values indicate both presence in more environments and a well-balanced distribution across them, as expected for ubiquitous families, while low diversity indicates preference for some environment(s). The results , or in association with human tissues . Here, 180 of the 211 families  show a high affinity for at least one environmental type, and 52 (25%) do for just one. This does not imply environmental specificity but does, undoubtedly, indicate a clear environmental preference.It is apparent, however, that even in the absence of total specificity, some taxa show a marked preference for some environments. For instance, some archaeal clades have been found mostly, but not exclusively, in thermal samples. To quantify these preferences (affinities), we used a Bayesian hierarchical statistical model for detecting differences between the observed and expected distributions of abundances of the taxa in the environments, under the assumption of statistical independence between taxa and environments. The results are presented in Additional file Proteobacteria, such as Xanthomonadaceae, Comamonadaceae, Pseudomonadaceae and Burkholderiaceae, but also the archaeal Methanosarcinaceae and the Clostridia Peptococcaceae families.The families that are present in many environments, but not showing relevant affinity values for any of them, may be considered ubiquitous. Amongst these we mainly find Clostridia clade harbors cosmopolitan families, such as Peptococcaceae, and environment-specific ones such as Lachnospiraceae or Oscillospiraceae. This indicates that phylogenetically close families can show strikingly different environmental preferences and distribution patterns, which at least for some cases, questions the validity of the proposed relationship between phylogenetic distance and environmental preferences [It is interesting to note that the ferences ,27.Taxonomic distributions can be used to explore the characteristics of the environments themselves. Grouping environments according to similarity in their taxonomic profiles can help us to understand the main environmental features at play in selecting prokaryotic diversity. To assess the relationship between environments and taxa, we clustered the different environmental types according to the affinities of their different taxa Figure .The environments are separated into five different groups. The first one is associated with animal tissues . These habitats clearly differ from the rest, and some of the prokaryotes living there do not thrive in other locations . Thus, hThe second group to segregate is composed of thermal environments , and also shows a clearly distinct taxonomic profile. Both environments are separated by long distances in the dendrogram, which indicates significant differences between them. The absence of oxygen and light in hydrothermal locations accounts for the presence of some anaerobic methanogenic archaea in hydrothermal, but not geothermal sources, or for some photosynthetic cyanobacterial families that are located only in geothermal spots where light is present.The third group comprises saline environments, and is represented mainly by heterogeneous marine samples which show quite similar profiles. Athalassohaline waters of saline inland lakes  also cluster within this group, showing that salinity as a whole, and not salt composition, is the determinant ecological factor. This is related to osmotic adaptations of the organisms. The fourth group contains terrestrial samples from soil and plants. Finally, the last group is dominated by freshwater samples. It is very interesting to note that freshwater samples are more related with terrestrial samples than with marine ones. This indicates that salinity is a very important selective factor for the composition of prokaryotic communities, and more relevant than the apparently loose distinction between aquatic and terrestrial media, as was also described by Lozupone and Knight using a strictly phylogenetic approach . Many prActinobacteria), and is in accordance with previous studies [When performing the analysis for environmental subtypes, the trends above are shown again, but new details emerge , a well-known multivariate technique traditionally used in ecology to explore patterns of variation in community data matrices. Figure A measure of the complexity of the composition of the different environments can be obtained by means of the diversity indices calculated from the abundance of taxa in the samples from these environments. Low diversity values for a given environment indicate that some taxa are highly prevalent (appear in most samples from that environment) and dominate, while high diversity represents less dominance and a more balanced composition. The values of the Shannon's index of diversity for the different environments are displayed in Additional file Finally, we are interested in exploring how complete our knowledge is about the richness of species in the different habitats considered in this study. By using the distribution of sequences and OTUs in the samples of a given environment, we derived a collector's curve which illustrates the rate at which new OTUs are found as more samples are sequenced. This curve indicates the present coverage of the environments and the completeness of the current knowledge about the abundance of OTUs, thus also providing a comparison of the richness of the different environments. The curves Figure  show thaIt is also important to notice that most curves show no saturation . Therefore, we can conclude that there is still a long way to obtain a complete description of species diversity for almost any environment. The only exceptions may be human tissues  where their respective curves show a relative saturation, thus indicating that we have already observed the majority of the putative species in these habitats. The curve for gut does not show this clear saturation, and one reason is that it includes samples from very different animals (not only humans), thus making it more heterogeneous than the samples from the rest of human tissues.In short, our results indicate that most taxa can be found in many different environment types. Environmental specificity is not very common, although clear environmental preferences exist. The most selective environments, where more specialist taxa can be found, are animal tissues and thermal locations. Salinity also emerges as a very important factor in shaping prokaryotic diversity. These results are in accordance to previously described patterns . The speBacillus is the second most abundant genus in this dataset, only after Pseudomonas. This could be a general case for prokaryotic communities, which may be composed of "core members" , five in Lake Cadagno (Switzerland), and four in Lake Kinneret (Israel), which differ among sampling times. Therefore, it would be possible to address the temporal variation of the microbial composition in these sites. But it is very difficult to discriminate between temporal and spatial factors. In this particular case, all these lakes display different types of vertical stratification, and the microbial communities found at different depths could vary and be influenced by the mixing regime. A temporal analysis should therefore be performed with sets of samples where all environmental features have been well characterized. And also, as above, the heterogeneous sizes of the samples and the existence of different niches can be misleading and complicate the analysis.As far as we know, this is the most comprehensive assessment of the distribution and diversity of prokaryotic taxa and their associations with different environments. We expect that this and further studies can help to gain a better understanding of the complex factors influencing the structure of the prokaryotic communities.We collected 16S rRNA gene sequences from the environmental section of GenBank database, comprising the results of many different 16S rRNA sampling experiments. After discarding short (less than 250 bps) and long (more than 1900 bps) entries, we have obtained a data set of 399.098 16S sequences of variable length from bacterial and archaeal species. Each sampling experiment is identified by its reference (title of the study and authors), and the individual sequences are assigned to their original sample. A total of 4.334 samples were identified, that reduced to 3.502 when we eliminated those with less than five sequences. It is important to notice that the original source can describe each sample exhaustively, listing each sequence found, or rather enumerate just the different genotypes by removing the identical sequences. The second case is the most common one, in which no information about the abundance of individual genotypes is present. In these instances, we can obtain information about the richness (number of genotypes) of each individual sample, but not about its diversity (abundance of each genotype). For normalizing the minority of cases in which some of this information is present, identical sequences were eliminated by using cd-hit  with ideWe have derived a classification of environments to categorize the collection of samples. The environments are classified in 5 supertypes, 20 types and 46 subtypes, as can be seen in the schema shown in Table We have used a semi-automatical text-mining procedure for classifying the samples in these environmental categories . The perIn some instances, a single sample is composed by different individual sampling experiments, which have been merged for submission to the database. Usually this is not an obstacle for classification and for the final objective of describing taxonomic diversity of the different environments, because all individual samples come from the same or very similar environments . In the few instances  in which the individual samples come from diverse environments , they have been classified in all of these environments, thus reflecting the multiple origins of the sequences. The results were unaltered when we repeated the analyses excluding these 43 samples.We have grouped closely related sequences into OTUs using cd-hit , clusterhttp://greengenes.lbl.gov, collecting the bit-scores for the five best hits belonging to each taxa, and finding the taxa with the best average score and a fixed difference to the second best. This procedure assigns 90% of the sequences to phyla, 81% to classes, 72% to orders, 65% to families and 47% to genera. At family level, 85% of the assignments are coincident between both approaches.Each of the sequences was assigned to a reference taxon by using RDP classifier , consideOTUs were classified by extracting a consensus from the taxonomic assignments of their individual sequences. The objective was to find the taxon that dominates at the lowest possible taxonomic rank, fulfilling the following criteria: having more than five sequences in the OTU, and being the only taxon with at least 25% of the sequences of the OTU assigned to it. The usage of either RDP or Greengenes assignments produced coincident assignments for 91% of the instances, and does not alter the results significantly. Unless stated otherwise, the results shown correspond to RDP assignments.To create collector's curves for the distribution of OTUs in environments, a single metasample was created for each environment, pooling together all the sequences from the samples corresponding to it. We simulated the sampling of the metasample by picking up individual sequences randomly, with non-replacement. To produce the curve, we checked whether another sequence for the corresponding OTU had already been seen or not. The simulated sampling continued until no sequences were left. The full procedure was repeated ten times, and the individual curves were averaged to obtain a final result.We computed a two-way table with the number of different OTUs per taxa and environment. To assess the level of bacterial biodiversity of the different environment types and the degree of ubiquity of the taxa considered, we computed Hill biodiversity numbers  using thExploratory data analyses revealed that those environments with more samples tended to have more OTUs. To remove this 'size' effect, we transformed the data by dividing the frequencies in each column by the number of samples in that environment, thus creating a community matrix which contained the average number of OTUs per sample for each taxa and environment type. We then carried out a Detrended Correspondence Analysis (DCA) to explore the variation in the transformed abundance matrix.ij observed in the taxonomic family i and environment type j. The mean of this distribution is assumed to be λijEij, where Eij is the expected number of OTUs under the hypothesis of independence between the distributions of taxa and environments, and λij is the under- or over-presence of family i in environment j. The values of λij > 1 indicate the affinity of the family for the environment, whereas the values of λij < 1 suggest a lack of affinity. In the second layer, the 'affinities' λij  are decomposed into the taxa and environment main effects plus an interaction: log λij = α + θi + γj + νij. The main effects of taxa and environments can be interpreted as surrogates for the unobserved variables that associate to each one. The interaction terms  can be seen as an adjusted affinity, that is, the part of the over- or under-presence that cannot be accounted for by the factors linked to the taxa or environment.We also fitted a Bayesian hierarchical model to the original community matrix in order to quantify the affinity between taxa and environments. In the first layer, our model assumes a Poisson distribution for the number of OTUs Yhttp://mcmc-jags.sourceforge.net, a free-license software for Bayesian inference. The outputs from this analysis were samples from the posterior distribution of the model parameters. We then represented the posterior median of the affinities between taxa and environments using a heatmap; we chose a dichromatic scale from purples to oranges. The former represent low affinity values (meaning an underpresence of the taxa in the environment), whereas the latter represent affinity (overpresence). We used standard hierarchical clustering with Euclidean distance to group the environment types according to the values of their taxa affinities . The resulting cluster dendrogram is displayed next to the heatmap to make visualization and the interpretation of the results easier.Statistical inference was performed under the Bayesian paradigm, which implies assigning prior distributions to the parameters. We chose normal distributions for each of the main effects and a mixture of two normal distributions for the interactions. One of the components of the mixture is intended to pick up noise, whereas the other aims to pick up true departures from the main effects. We implemented the model in JAGS http://metagenomics.uv.es/envDBWe have created envDB, a mySQL database containing all the data associated with this work. The user can perform queries on sequences, OTUs, samples and environments under a flexible and user-friendly interface. The database will be updated regularly and its capabilities are described elsewhere . The datJT and AM conceived the study. JT and JJA designed the methods. JJA performed all statistics. MP created the database. JT, JJA and AC analyzed the results and extracted the conclusions. All authors drafted, read and approved the manuscript.Table S1. Dominant environments for taxonomic families.Click here for fileFigure S1. Specificity and cosmopolitanism plots (see figure Click here for fileTable S2. Biodiversity indices for taxonomic families.Click here for fileFigure S2. Affinities of the taxonomic families for the different environment types, depicted using the same diagram as figure Click here for fileFigure S3. Heat-map showing the relationships between environment sub-types and with taxa.Click here for fileTable S3. Biodiversity indices for environments.Click here for fileFigure S4. Diversity plots showing the taxa ranked by their presence in the samples from each environment. The distributions are used to calculate diversity according to Shannon's index.Click here for fileFigure S5. The first two components of a DCA of the experiments-taxa community matrix.Click here for fileTable S4. Distribution of the number of OTUs in the clusters.Click here for fileFigure S6. Specificity and cosmopolitanism plots (see figure Click here for file


Tobacco use became an ingrained habit in the United States (US) following the First World War and a large proportion of physicians, similar to the general population, were smokers. The period from 1949 to 1984 was a pivotal era of change however, as the medical profession, like the society it served, became increasingly aware of the dangers that tobacco incurred for health.An extensive review targeted all manuscripts published in academic journals between 1949 and 1984 that related to tobacco smoking among US physicians. The study was undertaken in 2007–08 with an internet search of relevant medical databases, after which time the reference lists of manuscripts were also examined to find additional articles.A total of 57 manuscripts met the inclusion criteria. From a research perspective, the methodology and coverage of smoking surveys ranged from detailed national investigations, to local medical association surveys, and journal readership questionnaires. From a historical perspective, it can be seen that by the 1950s many US physicians had begun questioning the safety of tobacco products, and by the 1960s and 1970s, this had resulted in a continuous decline in tobacco use. By the 1980s, few US physicians were still smoking, and many of their younger demographic had probably never smoked at all.Although the quality and coverage of historical surveys varied over time, a review of their main results indicates a clear and consistent decline in tobacco use among US physicians between 1949 and 1984. Much can be learned from this pivotal era of public health, where the importance of scientific knowledge, professional leadership and social responsibility helped set positive examples in the fight against tobacco. By this century ,4. Vario century , althoug century ,7. By th century , where iAlthough all health professionals can contribute to tobacco control , physiciHow this situation came to be reveals an important period in the history of tobacco control, as physicians progressed from being cigarette smokers themselves, to quitters and then to anti-smoking role models. Although many investigations have looked at the progression of smoking in the general American population, few historical studies have specifically reviewed the changing nature of smoking habits among US doctors. Given that physicians have been largely absent from direct tobacco-related advertising since the 1950s and that the prevalence of smoking among US adults has almost halved since the 1960s , it can Medline® database incorporating all years between 1949 and 1984. The Medical Subject Headings (MeSH) of 'smoking', 'tobacco', 'physician' and 'United States' were initially used, followed by the use of additional keyword variations such as 'smoke', 'doctor', 'America', and so on. The reference lists of all manuscripts located using these initial search criteria were then examined to find additional publications that may not have been listed on modern search engines. A large proportion of manuscripts were eventually located using the latter method. Manuscripts were initially arranged by location , and then in descending order, depending on the year in which the survey had been undertaken. All articles were assigned a reference number based on the abovementioned criteria. As the results of some investigations were published over more than one journal article, some studies have two to three corresponding references. Investigations that had clearly divided their data into different groups, either by location or by year of study, were separated into multiple sections.This study was conducted as an extensive literature review of all manuscripts relating to tobacco smoking among United States physicians that had been published in peer-reviewed journals between 1949 and 1984. Unpublished articles were not considered, and for consistency, only English-language reports were included. The literature review was performed in 2007–08 with an internet search of the National Library of Medicine's All data was placed in a table and arranged as follows: author of study, year of publication and reference number as used in this manuscript , year in which the study was conducted , state in which the study was undertaken , from where the participants were sourced (using terms as described in the manuscript) and whether their medical specialty was listed . Smoking status was defined as per the original manuscript and categorized (when available) with all smoking rates rounded to the nearest whole number and listed by gender, where possible . If the type of tobacco smoked by physicians was not clearly defined, or if the smoker was a current smoker of pipes or cigars or both, this was indicated on the table. As some manuscripts listed only raw data or figures, certain smoking rates were calculated by the author and indicated as such on the table.Survey response rates were rounded to the nearest whole number, and where multiple methods were used to follow-up initial non-responders , this was indicated on the table. Unlisted response rates were calculated by the author, where possible. For physician's data that had been sourced from national surveys, the overall response rate of the entire survey is listed, and if the exact number of participating physicians was not listed, then the total number of participants in the study was indicated. National survey study codes were as follows: ACS = American Cancer Society, HIS = Health Interview Survey, NHIS = National Health Interview Survey and NORCS = National Opinion Research Center Survey. If the response rate of the survey was not specified and could not be manually calculated, this was indicated on the table. Additional information from the study , were also displayed.An extensive literature search eventually located 57 studies  which met the inclusion criteria, as shown in Table S1 in Additional file Sample sizes ranged from 45 to 56004, with state medical associations appearing to have had some of largest returns. Overall response rates ranged from 40% to 90% among the single state surveys, although for the majority of multiple state and national investigations, a response rate was not listed by the authors. The determination of absolute tobacco smoking rates was somewhat complicated, due to a lack of standardisation regarding the definition of 'current smoker' and a lack of consensus on exactly what product they smoked. Although most authors referred to their subjects as being either current smokers or non-smokers, the type of tobacco they smoked was classified in many different categories such as cigarettes only, pipes only, cigars only, pipes and cigars, pipes or cigars, cigarettes or pipes or cigars; and so on. This lack of standardization in tobacco smoking research has previously been noted among studies conducted with physicians , dentistDespite this fact, a large proportion of studies had listed the cigarette smoking prevalence rate among the physicians they surveyed, and much can be learned from the data. Firstly, from a summary of the retrieved manuscripts, it can be seen that absolute smoking prevalence rates declined from around 40% in the 1960s to less than 10% by the 1980s. Refer to Figure th century [once!" . Furthermore, if physicians then failed in their own quitting attempts, they should then "forget about it" (p.408) [On January 11, 1964, the Surgeon General's Advisory Committee on Smoking and Health released a groundbreaking report  where, a century  had actu century . In thei century , it was  century  and 1958 century ,32, had  century . Further century  reported century . The smo century , that ci century  for exam century  stated t (p.408) .Some of the earliest research to look at smoking among US physicians appears to have been published by Vaillant and colleagues , who conThirty seven percent of Swedish physicians were smoking in 1972 , with 35Not all studies on US physicians' smoking habits examined their data by medical speciality. Of those that did, a few interesting and inconsistent trends were observed. In Massachusetts during 1954 for example, Snegireff & Lombard  reportedpulmonary physicians by Sachs [Somewhat surprisingly, a study of smoking among by Sachs ,79 reporby Sachs , reporteby Sachs  reportedby Sachs ,66,82-85th century it was further demonstrated that US physicians tended to marry other physicians. Three studies of medical school graduates for example [A physicians' spouse may be an important influence on whether he or she actually smokes, and women's medical auxiliaries in New York were becoming increasingly active in smoking-related matters by the 1970s . A physi example -91, founFrom a purely longitudinal perspective, this review has clearly demonstrated a consistent decline in the smoking habits of US physicians occurring since the mid 1950s. Similar trends have also been demonstrated in other countries. Perhaps the most famous of these, the British Doctors' Study, began in 1951 , and folEncouraging physicians who currently smoke to quit their habit remains a contentious issue for tobacco control. On one hand, the British Doctor's Study revealed that quitting smoking at any age is clearly effective at reducing the loss of life expectancy due to smoking . On the th century, tobacco use became steadily less common over time as the medical profession, like the society it served, became increasingly aware of the dangers that smoking incurred for health. Physicians have always had an important responsibility to convince their patients not to smoke, as they are generally viewed as exemplars by the community, and also serve as providers of support, information and encouragement in helping patients to achieve such a goal. Although once used for cigarette advertising, US physicians were largely absent from tobacco-related advertising after the 1950s and the Surgeon General's Report of 1964. As such, it can be assumed that this time period represents the beginning of a major change within American society. By the 1950s US physicians had begun to question the safety of tobacco products, and by the 1960s and 1970s this had resulted in a continuous decline in their use. By the 1980s, as this review has shown, few US physicians were still smoking, and many of their younger counterparts had probably never smoked at all. Nevertheless, the fact that any physicians continued to smoke is still unfortunate, given their undoubted status as role models. Either way, much can be learned from this important era in tobacco control, and as such, it is important that physician's smoking in the US, as elsewhere, continues its decline so that the medical profession can remain at the forefront of tobacco control programs and continue to lead the way as preventive medicine exemplars.Overall, it can be clearly seen that 1949 to 1984 was a pivotal era in the decline of tobacco smoking among US physicians. From being an ingrained behaviour in the mid 20The author declares that they have no competing interests.Results of Tobacco Smoking Surveys Conducted among Physicians in the United States between 1949 and 1984 (Arranged by Geographic Location and Date of Survey)Click here for file


The "right to health," including access to basic healthcare, has been recognized as a universal human right through a number of international agreements. Attempts to protect this ideal, however, have relied on states as the guarantor of rights and have subsequently ignored stateless individuals, or those lacking legal nationality in any nation-state. While a legal nationality alone is not sufficient to guarantee that a right to healthcare is accessible, an absence of any legal nationality is almost certainly an obstacle in most cases. There are millions of so-called stateless individuals around the globe who are, in effect, denied medical citizenship in their countries of residence. A central motivating factor for this essay is the fact that statelessness as a concept is largely absent from the medical literature. The goal for this discussion, therefore, is primarily to illustrate the need for further monitoring of health access issues by the medical community, and for a great deal more research into the effects of statelessness upon access to healthcare. This is important both as a theoretical issue, in light of the recognition by many of healthcare as a universal right, as well as an empirical fact that requires further exploration and amelioration.Most discussions of the human right to health assume that every human being has legal nationality, but in reality there are at least 11 to 12 million stateless individuals worldwide who are often unable to access basic healthcare. The examples of the Roma in Europe, the hill tribes of Thailand, and many Palestinians in Israel highlight the negative health impacts associated with statelessness.Stateless individuals often face an inability to access the most basic healthcare, much less the "highest attainable standard of health" outlined by international agreements. Rather than presuming nationality, statelessness must be recognized by the medical community. Additionally, it is imperative that stateless populations be recognized, the health of these populations be tracked, and more research conducted to further elaborate upon the connection between statelessness and access to healthcare services, and hence a universal right to health. The "right to health" has been recognized as one of a set of basic human rights for at least the past half-century, since the adoption of the Universal Declaration of Human Rights in 1948. Currently, the "right to health" has been formally recognized by 56 national governments, in the form of constitutional or statutory provisions [Despite a general awareness within the scholarly community that the right to health may not be available universally, investigations of this right have in large part been limited in scope. This has two particular manifestations. First, debates frequently center on the structure, elements, and functions of health systems located within nations, thereby defining the state-centric platform from which citizens can access a right to health. An implicit assumption of this discourse is that the nation-state is the guarantor of first resort for the social rights of its recognized citizenry, either through state action or through the promotion of such efforts in the private sector. This assumption is codified for health rights by Article 12 of the International Covenant on Economic, Social and Cultural Rights (ICESR) [medical citizenship, or the fulfillment of their right to health. Medical citizenship may be characterized as a subset of the larger category of social citizenship, through which basic standards of social welfare are enforced for a citizenry. Those without nationality cannot access institutional health provisions that are regularly secured by those recognized as belonging to a nation-state.By contrast, individuals with no legal nationality - the right to reside somewhere and to be able to move freely - often have no venue in which to make claims to rights of health. In order to examine this issue we consider the case of statelessness, which has been defined as the condition by which someone "under national laws, does not enjoy citizenship - the legal bond between a state and an individual - with any country" . The OffA central motivating factor for this essay is the fact that the concept of statelessness is largely absent from the medical literature. Even a systematic review specifically of the effects of statelessness upon health or access to healthcare is challenging; entering the term "stateless" into PubMed, for example, yields only 23 results in total, and only four from the past decade that are directly applicable to healthcare -9. The gIn order to illustrate this connection between nationality and medical citizenship we will first offer brief reviews of the right to health and the concepts of statelessness and nationality. Following this discussion, we then proceed to briefly illustrate selected instances of the effect of statelessness upon access to health. We will then conclude with recommendations for future action on this front.The legal basis for the right to health is found within international law and agreements. The 1948 Universal Declaration of Human Rights (UDHR) contends in Article 25 that "everyone has the right to a standard of living adequate for the health and well-being of himself and his family," including medical care. Article 27 adds that everyone has the right to "share in scientific advancement and its benefits" . More rerespect the right to health by, inter alia, refraining from denying or limiting equal access for all persons, including prisoners or detainees, minorities, asylum seekers and illegal immigrants, to preventive, curative and palliative health services; abstaining from enforcing discriminatory practices as a State policy; and abstaining from imposing discriminatory practices relating to women's health status and needs," and Paragraph 43 describes the core obligations of states to ensure the right of access "to health facilities, goods and services on a non-discriminatory basis, especially for vulnerable or marginalized groups." Finally, Paragraphs 46 - 51 describe various acts of commission and omission that may be applicable to stateless populations.Article 12 of the ICESR [General Comment 14 applies the tenets of Article 12 to stateless populations in several ways: it specifies duties and obligations of states to provide access to healthcare; it identifies the need for the distribution of the underlying determinants of health in an equitable and non-discriminatory fashion; it draws special attention toward vulnerable and marginalized populations; and it proscribes acts of commission  and/or omission  that may lead to statelessness. The right to health, therefore, has a strong legal basis in international law originating in these and other provisions. The question for stateless populations, however, is not whether they have the legal right to health or healthcare; but, rather, whether institutional safety nets enforce the legal articulation of these rights. Statelessness may therefore present a practical and fundamental paradox: in order to be able to exercise right to health accorded to them by international law, stateless persons must receive forms of political recognition from states that many states are often unable or unwilling to grant.Despite solid legal underpinnings the medical citizenship actually available to individuals varies widely and depends upon a range of variables. Although some version of a "right to health" is perhaps the least normatively contestable social right, the specifics of what that right should or does entail are often difficult to determine. A right to health can include a number of components including: access to health services, resources necessary to achieve health, medical self-determination, the ability to resist conditions or policies that endanger health, health information and transparency, informed consent, and even a right to decision-making and accountability for health programs and policies . The rig...the right to health is closely related to and dependent upon the realization of other human rights, as contained in the International Bill of Rights, including the rights to food, housing, work, education, human dignity, life, non-discrimination, equality, the prohibition against torture, privacy, access to information, and the freedoms of association, assembly and movement. These and other rights and freedoms address integral components of the right to health.In short, the right to health cannot be realized in the absence of substantive and effective protections for a host of other human rights. As we discuss in the next section, of particular importance to stateless persons is non-discrimination and movement.In response to concerns about indeterminacy and accountability, transnational actors have introduced new standards for advancing health as a human right and for specifying what this right confers. Advocates of health rights - which include professional associations, intergovernmental organizations, networks of patients and human rights organizations, and prominent individual activists such as Paul Farmer - combine protections of the person  with social rights (such as the right to be provided the highest level of care attainable within one's society) . The WorThis framing of health as a universal right, like all human rights, imposes three obligations on states. First, states must respect this right; states may not interfere with the enjoyment of the right to health, either directly or indirectly. Second, states must protect this right by taking measures to prevent private persons and businesses from interfering with the right to health. Third, states must fulfill the right by facilitating and promoting medical citizenship . HoweverIn the aftermath of two world wars and the consequent dissolution and realignment of states, the Universal Declaration of Human Rights was established in 1948 . Article• The 1951 Convention Relating to the Status of Refugees extended protections to stateless refugees, including the right to asylum;• The 1954 Convention Relating to the Status of Stateless Persons extended some protections to stateless individuals who were not refugees; and• The 1957 Convention on the Nationality of Married Women, Article 1, protected a woman's citizenship in the event of divorce or marriage to a foreign national.The most influential piece of international law related to statelessness, however, was the 1961 Convention on the Reduction of Statelessness. In Articles 1-4, the Convention attacked the problem of statelessness at birth by requiring states to grant nationality to all children born in its territory who would otherwise be stateless. Article 5(1) attempted to eliminate change of status - such as marriage, divorce, and adoption - as a cause of statelessness, and Article 8(1) sought to contain discriminatory denationalizations that gave rise to statelessness. Article 10 afforded some protection from statelessness arising out of transfers of territory. However, the Convention took a full thirteen years to garner the necessary number of ratifying or acceding states in order to enter into force, with Walker noting that the slow pace of ratification probably reflected "the reluctance of states to give up a measure of sovereign autonomy over nationality within areas of domestic jurisdiction" [An important reason for addressing statelessness stems from the connection between rights protections and nationality. Writing after World War II, Hannah Arendt criticized conceptions of human rights for their inability to protect those who lacked citizenship and the protection provided by a nation-state, noting that "it turned out that the moment human beings lacked their own government and had to fall back upon their minimum rights, no authority was left to protect them and no institution was willing to guarantee them" . More reThe community of European states has attempted to eliminate these rights inequalities through the creation of the European Court of Human Rights, as established by the European Convention on Human Rights (ECHR) . The ECHth century, the trajectory of which culminates in the braiding together of civil, political, and social rights. Over the past half-century, this process unfolded in international law courts and venues. Civil rights preserve individual liberties such as contract, property, speech, conscience, while political rights ensure representation and participation. Social rights exist to prevent the worst effects of capitalism from rendering civil and political rights meaningless. Social rights such as pensions and welfare protect people's rights to a decent standard of living, for example, while education allows people to gain the enlightened understanding required for self-representation [de facto as well as de jure rights in piecemeal fashion, it is often empirically the case that those without legal nationality  do not have, or cannot access, even limited packets of rights on the local or national level, despite international recognition and pronouncement of basic human rights and right to a nationality.This disconnect between human rights law and protection not only leaves millions of people stateless, but also threatens the right to health and a variety of other rights as outlined in international law. Ultimately, the relationship between health rights and legal nationality is framed by the larger concept of citizenship. Citizenship is an omnibus term comprising legal rights, status, and activities associated with formal political membership. T.H. Marshall's work provides the starting point for most contemporary discussions of citizenship . In his entation . The socentation . Semi-ciMarshall was relatively inattentive to matters of place and the questions raised by displacement and immigration. Thus rights associated with legal nationality did not figure in his triad. Yet in today's increasingly mobile world these rights are not only as important as civil, political, and social rights but, in some circumstances, they will also govern a person's ability to access the rights Marshall considered fundamental to citizenship. Despite the development of limited free-movement zones, in general nation-states still monopolize the conferral of documents such as passports and greencards/work permits that in turn allow people to live within a set of borders, as well as documents such as visas that permit people to cross borders. Formal, state-issued documents are often utilized not just for internal or external mobility but also for general identification. This was apparent in the 2003 decision by the ECHR in Smirnova v. Russia, in which a Russian citizen had her passport revoked, and could not receive health services without this document . AlthougThe consequences of the connection between legal nationality and medical citizenship are wide-ranging and deeply consequential. Non-nationals are often denied access to healthcare, or provided lower standards of care as compared to their citizen counterparts, and research suggests patterns of barriers and limited access to care for undocumented noncitizens. In California, for example, undocumented Latino immigrants have significantly worse healthcare experiences than their documented and US-born counterparts - including fewer sources of usual care, more difficulty understanding medical information, and a belief that they would receive better care if they were a different race or ethnicity . In addipossibility of attaining such equality. This concept has been central to theorists of citizenship for at least the last half-century. Theories of rights and citizenship formulated by scholars such as Marshall [Although citizenship alone cannot guarantee equal standing within a society, legal status is nonetheless a prerequisite for the Marshall  and RawlMarshall -34 are bMarshall ,36 repeaMarshall . HerselfMarshall . Walker Marshall .Although there is a growing body of international law, as described in the preceding sections, that articulates fundamental rights that ought to be enjoyed by stateless populations, the language of these documents  acknowledges that the nation-state remains the most effective enforcer of even international human rights, a fact also noted in the academic literature by postnationalists such as Soysal  as well Legal nationality fulfills the "right to have rights" . That isAcademic discussions of the human right to health often assume that every human being has legal nationality. Largely absent from such discussions is a consideration of individuals who have no nationality claims anywhere: stateless individuals who lack any legal relationship to a nation-state. These individuals are deprived of nationality as a result of a "bewildering series of sovereign, political, legal, technical or administrative directives or oversights," including: arbitrary deprivation of nationality by the state, conflicts of law, procedural problems such as excessive fees or unrealistic deadlines, and failure to register a child at birth . WhereasEveryone is entitled to all the rights and freedoms set forth in this Declaration, without distinction of any kind, such as.... national or social origin... birth or other status.In Article 2.2 of the International Covenant on Economic, Social and Cultural Rights, states commit to guarantee the Covenant's rights "without discrimination of any kind," including discrimination based upon national or social origin, or birth status.However, the UNHCR's own studies of the efficacy of its human rights doctrines, and in particular the UDHR, have repeatedly demonstrated the difficulties associated with the special case of the stateless. For example, UNHCR's "Report on the Implementation of the 1954 Convention within the European Union Member States" formulated recommendations for harmonization, indicating that:...most States have not put in place specific mechanisms which will allow the identification and recognition of stateless persons...The possibility for a stateless person to secure residence will often be the necessary prerequisite for him or her to exercise the rights provided for by the Convention, which for the most part are only applicable to persons lawfully staying in the country. States are therefore invited to introduce mechanisms to promote the acquisition of lawful stay in appropriate cases for recognized stateless persons, in particular for those who have no other option.Signatory states remain unable to identify stateless populations, as most states do not have mechanisms that effectively identify cases of statelessness within their own borders . This, cIn addition to the status of nationality, individuals also generally require documentation of nationality in order to claim an array of human rights, including the right to health. For stateless persons, acquiring such papers is often impossible. Politics is increasingly governed by "documentary nations," or document-requiring societies which require papers such as passports and identity cards to access social goods ranging from education and healthcare to entertainment and mobility . Sometimad hoc fashion to ameliorate the immediate or long-standing consequences of displacement. However, there is little or no discussion of remediation via the recognition of a standing right to health, and the consequent responsibility of the host nation to provide such services - in effect, to recognize the medical citizenship claims of such groups. In the next section we present three brief case studies that illustrate the potentially direct connection between legal nationality status and access to healthcare: the Roma of Europe, the hill tribes of Thailand, and Palestinians in Israel.Despite these connections between nationality and the right to health, the medical community has largely overlooked the problem of statelessness. There are numerous clusters of stateless populations around the globe, including clusters in Côte d'Ivoire; Sahrawis taking refuge in Algeria; the Banyaumulenge in the Democratic Republic of Congo; Eritreans in Ethiopia, Nubians in Kenya; the Rohingya in Burma; ethnic "hill tribes" in Thailand; Bhutanese refugees in Nepal; Palestinians, Kurds and the Bidun  throughout the Middle East; the Roma in some parts of Europe; Meshketians in Russia; a variety of other groups throughout former Soviet republics; and numerous ethnic groups across Africa and, to a lesser extent, Latin America . In manyThe Roma, a linguistically and religiously diverse population that migrated to Europe in several waves from northern India over the past millennium, represent a major stateless population throughout Europe, particularly in the former Soviet bloc states. Although information on Roma populations is often limited and varies by country, many  Roma lack legal nationality . In manyThe consequences of Roma marginalization  certainly contribute to severely compromised health outcomes in essentially all Roma populations ,48-50, bThe combined effects of these issues, which essentially deny nationality to many Roma, have downstream effects upon the right to health. For example, Boika and colleagues conducted a qualitative study of Roma healthcare seekers and policymakers in Bulgaria, and found that changes in one's place of residency and/or a lack of identity documents resulted in the inability to register with a physician in order to obtain health services . The EurSimilar problems facing Roma populations are prevalent throughout Europe. In Macedonia, for example, many Roma are explicitly excluded from Macedonian citizenship, and hence from state health insurance . In RomaThe stateless population of Thailand is currently estimated to number 2 to 3.5 million, despite efforts on the part of the Thai government to grant nationality to some members of "hill tribe" ethnic minorities. Part of the cause of Thai statelessness lies in other policies that contradict the nationality-granting efforts. As noted previously, policy decisions to not register the births of hill tribe children thwarts recognition of the existence of these individuals, and hence makes granting of nationality all the more difficult . AdditioLack of nationality and the resulting absence of documentation prevent stateless persons from accessing affordable healthcare in Thailand. The government introduced a subsidized "30-baht plan" in 2001 with the intention of universalizing access to healthcare. In order to take part in the program, individuals must present identity documents to local administering officials in order to receive a "gold card" that ostensibly allows them to obtain basic health services for a fixed fee of 30 baht, or roughly US$0.88. The program has covered nearly 14 million people who were previously uninsured , yet rouWhile there is no established causal relationship between statelessness and poor health in the Thai population, it is probable that lack of legal nationality stands in the way of access to health services and coverage . As natiConflict within neighboring Burma has also contributed to the troubled health situation of hill tribe members in northern Thailand. Members of the Shan minority, for example, have been driven across state lines as a result of widespread abuses by the Burmese military regime. Denied refugee status or nationality in Thailand and often recognized only as enemy "insurgents" in Burma, these stateless individuals are often forced into exploitative situations (such as the Thai sex industry) and are simultaneously denied basic healthcare services. Data on stateless Shan migrants in Thailand indicates that this group bears a disproportionately high burden of infectious diseases, especially HIV, tuberculosis, lymphatic filariasis, and some vaccine-preventable illnesses. Not only does this situation undermine the right to health, it also undermines Thailand's ability to control many infectious diseases that may spread throughout broader populations .The complicated case of Palestine is a further illustration of the relationship between legal nationality and the right to health. Palestinians, who represent the world's largest stateless population with more than four million stateless people located throughout several countries , often sStateless individuals in Israel have severely compromised and irregular access to national health insurance and social services. Although Palestinians residing within the 1967 state borders usually retain Israeli nationality and are able to access rights, permanent residents residing in the outskirts of Jerusalem and Palestinians living in the occupied territory do not have such state protections ,61. TheyAlthough standards of health are generally higher in the occupied Palestinian territory than in several other Arab countries, they are substantially lower than in Israel . Health Many Palestinians rely on only six hospitals for routine, emergency, and specialized treatments. Yet, the difficulties in securing necessary travel permits to drive to those hospitals have led to reductions in patient admissions by 50 percent . ResearcAs this brief discussion has illustrated, legal nationality serves as an often unstated prerequisite for accessing medical citizenship and the human right to health. Those lacking legal status - including Roma populations throughout Europe, hill tribe members in Thailand, and stateless Palestinians in Israel - frequently face an inability to access the most basic healthcare, much less the "highest attainable standard of health" outlined by the ICESR. Although the right to health is outlined as a universal standard by international laws and agreements, current discussions of this concept presume nationality and ignore the vulnerabilities of the 11 to 12 million stateless individuals living worldwide. For those lacking legal status, along with its resulting documentation, medical citizenship is often an impossible goal.Although framing access to healthcare as a human right is a promising step toward achieving equality, we cannot ignore the importance of nationality as the "right to have rights." In order to move toward universalized access to the right to health, the concept of legal nationality must be considered by scholars, policymakers, and bioethicists. Rather than presuming the existence of nationality, discussants must consider stateless individuals, who have no place to lodge claims for social rights, including the right to health.While this paper began as a systematic review of the literature on statelessness and its effect upon access to a supposedly universal right to health, we quickly found that the term, and the concept, is widely absent from the medical literature despite being recognized by human rights specialists as a persistent global problem ,35,36,64Once statelessness is recognized as an issue that may impact individual and population health, the global health community ought to conduct a great deal more health service research into populations that have been specifically marginalized and excluded from nationality. There is suggestive evidence from NGO field reports, human rights organizations, and limited formal health literature that statelessness is a problem that affects the medical citizenship of individuals around the globe. We hope that those engaged in related research will seek to thoroughly document the problem.Once identified as a truly significant variable affecting access to healthcare, statelessness must become a priority for the community of global health practitioners, NGOs, and human rights organizations to address directly, alongside acute health crises caused by war or natural disaster. Added advocacy for the healthcare access of stateless persons should also be on the docket. It is one thing for states to recognize a universal right to healthcare by granting such care to their recognized citizens; however, for such a right to be truly universal, nation-states must also grant medical citizenship to those who are presently denied access due to a lack of legal nationality.The authors declare that they have no competing interests.LNK is an interdisciplinary social scientist and a topical expert on statelessness. She was the primary writer of the initial draft of this paper, and participated in all subsequent revisions and discussions. EFC is a political theorist who specializes in citizenship and immigration, and was the primary contributor of the theoretical presentation of citizenship and nationality included in the background sections. She also participated in revisions and discussion of all sections of the manuscript. CPM conceptualized the essay and the need for it in the medical literature. He also contributed content expertise in health policy, and participated in all revisions and discussion of the manuscript. All authors read and approved the final manuscript.The pre-publication history for this paper can be accessed here:http://www.biomedcentral.com/1472-698X/10/11/prepub


Occupational injuries have received limited research attention in the Southern African Development Community. Much of the published data come from South Africa and little has been reported elsewhere within the region. The present study was conducted to estimate the prevalence rates of occupational injuries and compensation; and to determine factors associated with occupational injuries and compensation.Data were obtained from occupational health and injury questions added to the Zambian Labour Force Survey of 2009 by the Work and Health in Southern Africa programme. Logistic regression analyses were conducted to determine the degree of association between demographic, social and economic factors on one hand and injury and compensation on the other.Data on 61871 study participants were available for analysis, of whom 4998 (8.1%) reported having been injured  due to work in the previous 12 months to the survey. Of those injured, 60.5% reported having stayed away from work as a result. The commonest type of injury was "open wound" (81.6%). Male gender, being married or married before, being a paid employee, working for a private company and household were positively associated with serious injuries. Injuries also varied by geographical area. Factors positively associated with receiving compensation for work-related injuries were: male gender, Copperbelt and North-Western provinces, and unpaid family worker. Employer/self employed and having less than 5 employees in a workplace were negatively associated with compensation.The prevalence of reported injury and its association with a significant level of absence from work, indicate that occupational hazards in Zambia have significant health and economic effects. Female workers should equally be compensated for injuries suffered as their male counterparts. The Central Statistical Office (CSO) estimates that of all persons employed in Zambia, 72% are engaged in the agriculture sector; 83% are engaged in the informal sector and of all persons engaged in informal sector, 77% are in informal agriculture sector, mainly subsistence farming . Common Zambia is a major producer of copper in the world, and the mining sector employs about 15% of formally employed workers . People The law is in place in Zambia for workers injured at workplaces to claim compensation. Zambia ratified in 1964 the following International Labour Organization (ILO) Social Security Conventions: Convention No. 12 ; and in 1965, Zambia ratified Convention No. 18 . The Employment Injury Scheme in Zambia is administered by the Workmen's Compensation Fund Control Board; and the Ministry of Labour and Social Services generally supervises the fund [Research on occupational injuries and the pursuit of improved occupational health has largely been conducted in high- and middle-income nations. Routinely collected occupational health data using information systems from low-income nations are often unavailable or incomplete and unreliable. Much of the data on occupational health and safety from the Southern African Development Community (SADC) which comprise of Angola, Botswana, Democratic Republic of Congo, Lesotho, Madagascar, Malawi, Mauritius, Mozambique, Namibia, Seychelles, South Africa, Swaziland, Tanzania, Zambia and Zimbabwe are from South Africa. There is a paucity of data from the rest of the region. Hence the negative impact of poor work conditions is unappreciated and the scientific basis for interventions and policy formulation is to a great extent absent in this region.What data there is in Zambia often arises from research done on selected work force populations: in a most recent paper on occupational injuries limited to persons working in mines in Zambia, Michelo et al  reportedInformation on compensation as a result of work-related injury was not covered in the 2005 Labour Force Survey (LFS). Furthermore, no analysis to characterize persons who reported injury was done. Identification of factors associated with injury is important in the design of interventions to control injuries. Hence, using data from the most recent 2009 LFS, we carried out this study to determine the prevalence rates of occupational injuries and compensation; and to establish factors associated with occupational injuries and compensation.The Zambia LFS is conducted, as a nationally representative survey using a series of cross sectional studies over time. It was designed to measure the labour market and to provide key indicators of the labour market such as unemployment, underemployment, and hours of work.The Work and Health in Southern Africa (WAHSA) programme was a 4-year, Swedish-Southern African OHS programme. Among its objectives was the profiling of occupational health and safety (OHS) in the region and, for this purpose, the generation of data to supplement the scarce data available. By an agreement between WAHSA and CSO, a set of OHS questions was added to the 2009 LFS.The LFS aims to enroll 8000 households countrywide and the sample size is determined in such a way as to have adequate power to produce estimates for the entire country, urban and rural areas, and for each province. Zambia has nine provinces which are: Central, Copperbelt, Eastern, Luapula, Lusaka, Northern, North-Western, Southern and Western , identified from a sampling frame compiled from the 2000 population and housing census. In the second stage of sampling, households are systematically sampled in each selected SEA and stratified by urban and rural areas.The composition of the LFS questionnaire varies from survey to survey. In 2009, CSO incorporated OHS questions in the questionnaire on: health outcomes, work sector and conditions, work place facilities, work-related injuries and history of compensation as a result of occupational injuries. The OHS questions that were included in the 2009 LFS questionnaire were based on questions from European and Scandinavian surveys on OHS, modified at a WAHSA workshop by OHS professionals from 8 SADC member states, and then further modified in consultation with CSO. Questionnaires were administered in the homes of the survey participants by trained research assistants in a language chosen by the interviewee.Data on 61871 employed persons out of a total of 129,765 respondents were available for analysis. Frequencies were used to estimate the magnitudes of occupational injuries. Logistic regression analysis was conducted in order to determine the degree of association between demographic, social and economic factors on one hand and injury and compensation on the other. Unadjusted odds ratios and adjusted odds ratios together with their 95% Confidence Intervals are reported.Of the 61,871 study participants, 30,478 (49.2%) were males. The social, demographic and economic distributions of participants by gender are shown in Table The distribution of injuries reported to have been sustained at work, by gender, is shown in Table In multivariate analysis Table , all theOverall, only 5.5% of the participants were compensated, with 8.0% among males and 1.7% among females Table . Table 4Data on occupational injuries is scarce and unreliable in Zambia, and it is therefore difficult for stakeholders  to estimate their health and socio-economic impacts and target or assess the efficacy of interventions. While data is routinely collected in Zambia through accident notifications to the Ministry of Labour and Social Security, and Worker's Compensation Fund, there is widespread underreporting of cases, and until now there has not been regular system of supplementary or corroborative data such as the annual surveys carried out in Scandinavia or elsewhere . Only 14The labour force survey is one of the largest regular household surveys conducted in Zambia. The results from the 2009 LFS indicate that 8.1% of workers reported having been injured in the past 12 months, and 60.5% reported having been absent from work because of workplace injuries. The injury rate is less than what was reported in the 2005 LFS of 20.6% among persons of age 15 years or older : this maThere are gender differences in the distribution of reported injury. Men were 27% more likely to report having suffered serious injuries than women, and this difference has been reported elsewhere. In the National Health Interview Survey (NHIS) in the United States, Forrest and Cali  reportedWe found that workers who were paid employees were more likely to be injured than unpaid family workers. There are several possible reasons why this may be the case. Firstly, it is possible that unpaid family workers may have some control over their environments if working in their own homes. Secondly, it is possible the unpaid family workers may be more liberal in excusing themselves from work due to injury while it may be harder for those who are paid employees. Finally, it is also possible that the nature of the jobs in unpaid family workers may have been different from those in paid employment such that the nature and severity of injuries may have been different.Finally, our findings indicate that workers in specific geographic areas of Zambia, and employed by private companies or households, are particularly at risk of occupational injury. This information is valuable for the introduction of targeted interventions to reduce injury rates where they are highest, and is information that the Zambian Ministry of Labour has not previously had at its disposal.The present study has a number of limitations. Firstly, data were collected via self-reports. To the extent that study participants misreported either intentionally or unintentionally, our findings may have suffered from misclassification. If for instance there was a difference in the extent of misreporting between males and females, or between old or younger workers, our results may have been biased. We however do not have information to suggest that such may have been the case. Secondly, the questionnaire was not translated into local languages. Although interviewers were trained in how to administer the questionnaire in local languages, the questions may not have been standardized. The correct procedure is to have one expert translate it into a local language and another expert independently translates it back to English. However, we believe that the bias that might have been introduced into our findings was minimal because CSO uses experienced interviewers. Thirdly, since the design of the data collection was cross sectional, it is not possible to assign causation to any of the explanatory variables. We also did not explore what other factors, e.g., underlying medical conditions , stress Data generated through the addition of OHS related questions to a routine household survey in Zambia provide useful information on the distribution and determinants of occupational injury, as has been reported from the addition of OHS related questions to national household surveys in South Africa . The preThe authors declare that they have no competing interests.SS analysed the data, interpreted the results and participated in the drafting of the manuscript. ASM participated in the interpretation of the results and led the drafting of the manuscript. AR participated in the designing of the questionnaire, interpretation of results and drafting of the manuscript. ER participated in the interpretation of the results and drafting of the manuscript. All authors read and approved the final manuscript.


Italian Society for Paediatric Gastroenterology, Hepatology and Nutrition (SIGENP). They are principally addressed to medical professionals involved in casualty. Because there is paucity of good quality clinical trials in children on this topic, many of the recommendations are currently extrapolated from adult experiences or based on experts opinions. The document represents a level 2 to 5 degree of evidence (according to the Oxford Centre for Evidence-based Medicine Levels of Evidence), gathered from clinical experience, recent studies, and expert reports discussed during a consensus conference of the Endoscopic Section of the Italian Society of Paediatric Gastroenterology Hepatology and Nutrition. This working group comprises paediatricians, endoscopists, paediatric surgeons, toxicologists, and ENT surgeons, who are all actively involved in the management of these children. Recommendations are intended to serve as an aid to clinical judgement, not to replace it and therefore do not provide answers to every clinical question; nor does adherence to them ensure a successful outcome in every case. The ultimate decision on the clinical management of an individual patient will always depend on the specific clinical circumstances of the patient, and on the clinical judgement of the health care team.The following recommendations for management of caustic and foreign body ingestion in children have been developed following a multicentre study performed by the  The first step of clinical approach, in case of CI, is to establish whether the substance is a real caustic or not.Strong acids have a pH of less than 2 and strong alkalis a pH of greater than 12 .The time, modality of exposure, duration of contact, and any action taken at the scene of the incident are important in determining the management. The product container should be always collected to identify the substance. Frequently parents can only provide the brand name of the substance and if they do not bring the container to casualty, the composition may be difficult to be obtained; in this case such composition can be identified contacting the Poison Control Centre provided by most National Health Services.The oesophageal and gastric damage depends on the volume of the ingested caustic; most children do not present any symptoms and do not have any lesion because the caustic has not really been ingested but only tasted. We would like to introduce the new concept of “accidental-deliberate” ingestion. The child drinks a consistent amount of caustic substance which is contained in a bottle of drinkable fluid . This is most commonly the case of a rather older child who eagerly drinks a large amount of an apparently drinkable but in fact caustic substance by mistake .Patients who present for medical care following caustic ingestion may be asymptomatic, but may also have varied signs and symptoms. Physical examination may reveal the presence of burns on the lips, chin, and hands due to manipulation of the substance.It is discouraged to induce vomiting because this determines a further step back into the oesophagus of caustic with increased risk of injury or ab-ingestiis  and the At the moment there are no certain biochemical markers of injury, although some parameters such as neutrophilic leukocytosis and metabolic acidosis can give an indication on the severity of the patient's clinical condition. Hemogasanalysis is useful for defining the severity of lesions . A stateThe panel's opinion, according with the literature, is that endoscopy can be performed even earlier not later than 24 hours , 6. In cThe results of a recent observational Italian study  demonstrThe risk of severe damage to the esophagus increases proportionally with the number of the patient's signs and symptoms. Endoscopy is warranted in all symptomatic children.Endoscopy is also of great importance for monitoring the injuries and their possible stenotic evolution . There aThe involvement of the larynx during CI is usually considered rare. The commitment of respiratory function presents different values between the adult (1%) and the child (2.5%) –18. The The medical treatment has a supportive role, and there is no evidence of any direct effect on injuries and the prevention of stenosis . De JongThe Nasogastric tube can be useful in the most serious cases to avoid the formation of adhesions between the oesophageal wall preventing the oesophageal stenosis . ControvMedical therapy based on endoscopic grading of lesions is in Two attitudes regarding the treatment of oesophageal strictures are described in the literature. The first is conservative and involves a quick execution of oesophageal endoscopic dilatation. The second, less common, provides the consolidation of stenosis, possibly around an NG-tube, and the execution of surgical oesophageal replacement. According to the majority of the literature –31, the Early (from fourth to sixth weeks after the ingestion) start of expansion in order to avoid stenosis tortuous and slim. Various authors , 30, 31 The panel suggests the pneumatic dilatation in the treatment of stenosis of the recent appearance and semirigid (Savary) in stenosis with scarring consolidated results.On this point there is no correlation. The panel, based on its experience and the literature , suggestIt has been proposed to use topical Mitomycin C, applied after dilatation, in order to slow the fibroblastic proliferation and relapse of stenosis. It is suggested at a concentration of 0.1 mg/mL and 5 minutes of application .The panel believes, according to the literature  that a sFB ingestion is a quite common event in childhood, with the highest peak incidence between 1 and 2 years of life. FB ingestion is always an accidental event (93% of cases) except for patients with neurological defects or psychiatric diseases. An FB usually passes through the digestive tract without damage; among paediatric patients, approximately 80% eliminate the FB naturally over a week ; 20% reqThe different types of ingested FB can be schematically listed, both on the basis of morphological categories, both in relation to their potential hazard:Foods: meat boli, large pips, bones, cartilage, bones of fish).Objects: harmless  or dangerous Toxiccontainers .Children may be asymptomatic but may also present scialorrhea, food refusal and odynophagia, hematemesis, vomiting, dysphagia, drooling, cough, wheezing, and dyspnoea. The symptoms depend on the location of the FB and its characteristics.If the FB has exceeded the lower oesophageal sphincter, the patient is usually asymptomatic, as occurs in approximately 50% of children .In case of ingested substance containing lead, symptoms of acute intoxication may occur, involving the digestive tract as well as the renal function and the nervous system .The main goal of the physical examination of the patient should be to highlight signs of damage or oesophageal perforation, as the subcutaneous emphysema of the neck (crackles and/or hyperaemia of the neck region). If the patient presents with inspiratory stridor, we are certainly facing an obstruction of the upper airway. Unilateral wheezing or a localized reduction of murmur vesicular can suggest lower airway obstruction. The abdomen should always be examined to detect the presence of any evidence of peritonitis and in these situations the opinion of the surgeon is crucial .The radiological examination is a very important and often decisive step in the assessment of a patient with an ingested FB. A chest X-ray without contrast is generally sufficient to verify the presence and localization of radiopaque FB.If radiopacity of the FB is questionable, it can be very useful to assess a twin object, when present. Radiolucent objects can escape the first detection; the use of an adequate contrast can be useful. The X-ray examination should be performed, if possible, at the erected station, including the neck, the chest , and the abdomen . The radThe indication and timing of endoscopic removal in the management of paediatric patients who accidentally swallowed an FB depend on many factors: (1) the type of FB; (2) the site in which the FB is trapped in; (3) the general conditions of the patient and the clinical picture; (4) the availability of logistic supports and adequate equipment for the endoscopic procedures.Indications and timing of FB endoscopic removal are in Coins represent the most frequently ingested FB among children; in 2003, 92 166 cases in US were documented , 42.As stated before, risk factors conditioning the FB impact are, stenosis or malformations, previous surgical oesophageal interventions or contemporary ingestion of more than one coin. In case of proximal trapping patients can present with serious symptoms . Children can be unable to control their secretions and present higher risk of aspiration (ab-ingestis). Coins localized in the middle and lower oesophagus give usually less important symptoms . Endoscopic removal is to be considered mandatory and urgent for all coins trapped at the upper oesophagus but also for symptomatic coins anywhere localized in oesophagus.There is no agreement in the literature concerning the management of asymptomatic patients , 44. In Stylus-shaped batteries (SSBs) generally do not release toxic compounds and therefore should be considered as simple FB. Their endoscopic removal will depend on their size and localization. Nevertheless, particular warning must be given to the quality certification of the batteries themselves. Disk batteries (DBs) commonly used for watches or cameras are of different types, according to their different electrolyte system . In any case the leakage of their contents can produce mucosal damage or systemic toxicity.The dangerous power of DB is determined by two main factors: local activation of electric current and possible DB splitting, followed by release of caustic compounds with consequent local or systemic toxicity.DB splitting, apart from traumatic causes such as a bite, is related to the corrosive power of the acid gastric juice which may destroy the plastic seal connecting the two poles of the battery, with subsequent leakage of toxic compounds and caustic substances. Therefore the “critical time” is represented by the DB staying in the gastric cavity; while as the battery passes the pylorus and it is still remaining intact the risk of splitting decreases. Nevertheless the risk of systemic toxicity, concerning above all DB containing mercury, is theoretical. In fact no deaths were registered by the National Button Battery Ingestion Hotline among 2320 cases collected in 7 years , 46.The following recommendations are suggested by the panel.DB in the oesophagus: endoscopic retrieval as soon as possible.DB in the stomach: endoscopic retrieval if symptoms are present, if X-ray shows lack of integrity or splitting, if the battery has failed to pass the pylorus at 48 hours.DB in the duodenum: no indication for retrieval: 85% of DB disappear spontaneously within 24 hours .Washing bowel solutions can be used to facilitate the DB's progression through the bowel itself .Singly ingested magnets do not cause specific problems and have to be considered as not dangerous foreign bodies. Two or more magnetic objects lying into different intestinal loops may produce a considerable attraction force with consequent crushing of intestinal walls. Severe damages such as ulcerations, perforation, haemorrhage, and fistulas can occur , 50. Accurgent retrieval for multiple magnets when localized into the stomach,close clinical followup if they have passed the pylorus,immediate surgical approach if patient becomes symptomatic .Given the wide diffusion of improperly controlled objects, the possibility of ingestion of FB containing toxic amount of lead has been reported , 48, 52.In 1991 the Centre for Disease Control and Prevention stated that lead blood level greater than 10 mcg/dl must be considered toxic for paediatric age .Clinical syndromes usually appear when lead level raise over 45 mcg/dl: abdominal pain, haemolytic anaemia, renal and hepatic failure, acute encephalopathy, chronic and irreversible neurotoxicity.In case of ingestion of lead containing objects the following management is suggested:X-ray evaluation of the localization,urgent endoscopic retrieval, even in asymptomatic patient,blood test for lead level, if > 45 mcg/dl start with 2-3 mesodimercaptosuccinic acid Succimer 10 mg/Kg 3 times a day for 5 days, than 10 mg/Kg bid for 2 weeks (protocol approved by FDA for paediatric population),PPI's administration in order to decrease the lead leakage from the object if it is still gastric-located.If endoscopic retrieval cannot be performed, the FB must be closely monitored by X-ray and serial tests for blood lead concentration must be done. We finally underline that in case of ingestion of an unknown metallic FB, lead blood levels must be checked.General anaesthesia with airway intubation is the best approach for the removal of foreign bodies since it guarantees the following:airway protection,complete muscular relaxation,Total unconsciousness in order to prevent patient's reactivity,easy switch into open surgery when endoscopy is unsuccessful or in case of complications.Almost 20% of foreign body ingestion require endoscopic removal .The procedure is performed using a flexible video endoscope which should have the highest possible diameter in order to be able to use all the available devices. If an object identical to the ingested one is available, it is very useful to test on it the grip strength as well as the easy release mechanism of different devices . Never use a device that could stick to the ingested object since in case the removal becomes too difficult or risky, it might be impossible to extract the endoscope.Patient should possibly lay on the left side with the head not too flexed on the neck in order to reduce the sharpness of the angle of the upper oesophageal sphincter level and facilitate the foreign body retrieval.Changing patient's position should always be possible in case it gives a better endoscopic access to the ingested object.Endoscopic intubation must be done under visual control especially if the foreign body is located in the oesophagus to prevent lesions of the oesophageal wall.If it is not stuck, and there is no previously known oesophageal pathology, the foreign body can be gently pushed along the oesophagus into the gastric lumen where all the endoscopic manoeuvres are easier and safer. Mild insufflation is useful to detach the object from the oesophageal wall. An adequate mucosal protection device is recommended in case of wounding objects.In case of voluminous bodies a disinflation of the tracheal tube balloon could make the retrieval easier.In case of elongated foreign bodies the major diameter of the object should be parallel to the endoscope's positioning the wounding extremity.Cardias can be a difficult point to pull the object through. The advice is to not immediately force the pulling but to maintain a gentle traction and wait until the sphincter pressure diminishes and allows the object to be pulled backwards smoothly.Food boli impaction in the paediatric age is usually due to a pre-existent oesophageal pathology  , 54. WheMultiple magnet ingestion represents a serious emergency. Sticking together in the bowel lumen, magnets can cause an obstruction. Even if they are in different bowel loops they can still attract and stick together causing ischaemia and possible perforation of the pinched enteric wall area –57.An urgent endoscopy, such as a foreign body retrieval, cannot be set up without a very trained organization. Most urgent paediatric endoscopies are performed in the operative surgical room, whose quality levels and operative standards are usually well defined.The staff must be trained by an expert endoscopist, at least one endoscopy-dedicated nurse who has adequate training in the management of instruments and accessories, the anaesthetists with a nurse for anaesthesia assistance.There are no clinical trials or reports with strong recommendations on this topic, thus the conditions for the surgeon's involvement in the present paper are stated on the basis of panel opinion.Emergency surgical procedure must be considered if complications occur during endoscopic removal .Delayed surgical treatment should be considered in cases of FB being too bulky or potentially harmful to predict a complete and safe endoscopic removal. This is the case, for example, of bezoars, whose evacuation requires gastrostomy even in cases not complicated by pica , 60, or Patients presenting with multiple magnet ingestion should be timely managed by surgical approach if the magnets have already passed the duodenum , 62–65.Laparotomy must be also considered in cases in which FB progression through the gut has failed and X-ray examination shows that it is blocked .Finally, the literature emphasizes the need for surgical evaluation in children whose malformative pathologies are known  as well All indications for surgery after FB ingestion are in