This research has aimed to identify the perceptions of women apprentice welders about physical, chemical, biological, and physiological risk factors to which they are exposed and evaluate the identification of health disorders self-reported for women apprentice welders before and after implementation of a nursing socioenvironmental intervention. A quantitative study was performed with 27 women apprentice welders (first phase) and before and after an intervention with 18 women (second phase) in Southern Brazil in 2011. The data were analysed using SPSS 19.0. The participants identified the following risk types: physical (96.2%), chemical (96.2%), physiological (88.8%), and biological (62.9%). The results show a significant difference of the pre- and posttest averages for the musculoskeletal system and a posttest average increase for the integumentary, respiratory, and auditory system. A correlation of the women apprentices' ages and the identification of health disorders were made. It was understood that the perception of women apprentices regarding a particular set of occupational risks is essential for public health nursing to develop an effective risk communication as a positive tool for teaching and learning. This paper discusses the perceptions of women apprentices about the risks they are exposed to during welding activity. It also presents the development of a nursing socioenvironmental intervention as a tool for risk communication for health education of women apprentice welders. In different countries, for example, Nigeria , Sri LanThe motivation for the proposed research came from a literature review about the theoretical approach of risk perception –9. On thThe literature regarding apprentice welders shows concern about the achievement of improving welding techniques –17. SpecA search of the literature showed that there are texts that present apprentice welders as subjects, covering the welding technique and health of the subjects. The improvement of welding techniques contributes to the reduction of accidents during this activity, as it also does regarding possible injuries and accidents as a result of welding activity. However, there were no texts that show risk perception related to the activity of apprentice welders and the concern with the apprenticeship process about health and safety at work, from theories of risk perception and risk communication because of the approaches necessary for system management of risk to human health at work. There were also no texts observed which identify women as subjects of this occupational activity. According to the theoretical orientation, this research assumed that the notion of risk perception involves two factors: the magnitude of potential loss and the probability of its occurrence . In otheRisk perception encompasses both personal and work-environment-related ideas and constructions because, to perceive it, you have to believe it . TherefoRisk communication is here understood as an interactive process of exchange of information and opinion among individuals, groups, and institutions . Risk coAnother theoretical orientation is a classification of different risk factors that the apprentice welders are exposed to. Therefore, the Act of 16 June 1999  was usedThese factors can create or worsen occupational health disorders. Among some of the health disorders that may be triggered due to welding activity are cited burns on the skin, which can cause skin cancer –27, lungThe physical risk factors that welders are exposed to include noise from welding machines and nonionizing radiation from open welding arcs. Such factors may trigger disturbances related to the auditory system , 33 and Chemical risk factors still include contact with different metals in a gaseous state. Risk factors from exposure to welding fumes include chemical contact with different metals. Exposure to welding fumes from the burning of these metals can cause respiratory disorders. An example of a harmful compound is stainless steel, the smoke of which can cause acute lung injury and the size of the inhaled particles and exposure time are significant factors in welding, which must be considered in the development of protective strategies . AnotherBesides the respiratory system, exposure to chemicals also exposes welding workers to disturbances in their cardiovascular systems. Research conducted with construction workers, and this included welders, indicated heart rate variability during occupational exposure and also at night, showing that inhaled metal particles during work have an organic influence, specifically causing arrhythmias . AnotherPhysiological risk factors include poor posture during welding because workers perform the activity with a flat piece of metal and they must move around the piece to make the weld. This feature demands that the employees remain in an ergonomically incorrect posture in order to obtain a better result of the weld. Furthermore, excessive vibration from the welding machine is associated with back pain . For these reasons, the present study has aimed to identify the perceptions of women apprentice welders about physical, chemical, biological, and physiological risk factors to which they are exposed and evaluate the identification of health disorders self-reported for women apprentice welders before and after implementation of a nursing socioenvironmental intervention. This study consists of two phases. The first phase is a quantitative, exploratory, and descriptive study involving women apprentice welders, conducted in 2011 in Rio Grande . The second phase consists of a quasi-experimental, nonrandomized study, which was made before and after nursing socioenvironmental intervention as a tool for risk communication for women apprentice welders enrolled in this study, using the results obtained in the exploratory study (first phase), conducted in 2011 in the same region.Health, Risks and Occupational Diseases: An Integrated Study in Different Work Environments” [This study is part of a larger research project entitled “onments” . It was  The sample of subjects, intentional nonprobabilistic, was composed of 27 women apprentice welders (first phase) enrolled in the technical programme for training as welders in Rio Grande, Rio Grande do Sul, Brazil. Women apprentice welders were divided into eleven classes. The total number of apprentice welders was 162. Women apprentices represented 16.6% of the total number of apprentice welders. For the second phase, consisting of a nursing socioenvironmental intervention as a tool for risk communication, six classes  were invited, all of which participated in the first phase. In addition to the apprentice welders, six members of the research group LAMSA also participated, as mediators of the nursing socioenvironmental intervention. The welding course which the apprentices were doing includes theoretical and practical lessons. The classes in which nursing socioenvironmental intervention activities were applied had already started practical lessons. The first phase of the study was conducted, based on the following question: how do women apprentice welders perceive the risks to which they are exposed? From the theoretical basis assumed in the study, the existence of a relationship between risk perception and identification of health disorders self-reported by women apprentice welders was identified. Data collection was performed in 2011, through a structured interview from a questionnaire, composed of mixed questions—multiple-choice and single-choice. The structured questionnaire had multiple-choice and single-choice questions corresponding to the following variables: participant characteristics ; time of experience in welding; risk perception among apprentice welders .Upon the completion of the first phase of the research, the authors organized a nursing socioenvironmental intervention in the study group (second phase). The results of the first phase were used to develop risk communication concerning the risk factors of the work environment as an apprenticeship tool to help apprentice welders for the promotion of individual and collective health in the workplace. Only data from nursing socioenvironmental intervention with women apprentice welders will be presented in this study. After analysing data from the first phase, the issues to be developed during the nursing socioenvironmental intervention with apprentice welders were organized. Six apprenticeship workshops were conducted, each with a group of apprentice welders. The time used for planning was 40 hours. Four hours were allocated for holding each apprenticeship workshop, making a total of 24 hours. The apprenticeship workshops took place in the theoretical room of the institution. This practice also included the Health Promotion in Different Work Environments Programme (HPDWEP) , 38 of LThe nursing socioenvironmental intervention was developed, based on the risk communication concept , 23, 39.Physiological systems were approached in the nursing socioenvironmental intervention in the following order: integumentary, respiratory, cardiovascular, auditory, musculoskeletal, and gastric. Anatomic-physiological systems, risk factors present in welding activity, and health recommendations for apprentice welders were presented to the apprentice welders. The nursing socioenvironmental intervention used the following steps: (1) presentation of the study and research group and the signing of an informed consent agreement; (2) completion of a pretest questionnaire; (3) implementation of the nursing socioenvironmental intervention; (4) completion of a posttest questionnaire . The lasTo trigger the development of communication (first step) with the apprentices who were participating in the intervention, the following question was used: what personal protective device is used during welding activity? The responses were expressed on a whiteboard for all the apprentices to see. The answers were welding cap, welding apron, welding coat, welding boots, earplugs, welding trousers, welding goggles, welding mask, breathing mask with filter, and welding gloves. This promoted the apprentices to make comparisons, considerations, and suggestions on the subject. There were comparisons about the personal protective device used by the apprentices because some only use the welding coat and trousers  and others use items not included in the personal protective device supplied by the technical programme for training, for example, the welding apron , in order to increase protection. Moreover, some apprentices do not use the breathing mask with filter because it is uncomfortable, which generated discussion among the participants of the apprenticeship workshops. To continue the process of risk communication, visualization of personal protective devices used to perform welding activity made it possible to show the different body systems  which are protected by personal protective devices. Besides these, the gastric, cardiovascular, and musculoskeletal systems were included, which, despite not being protected by personal protective devices, require attention during welding activity. During the presentation of the integumentary system, concerns about the physical risk factor, nonionizing radiation, and chemical risk factors, due to frequent skin contact with metals, were focused upon. Apprentices were asked about the composition of the wire used to perform the welding. They use a wire called E71T-1, which is composed of carbon, manganese, silicon, phosphorus, and sulphur. It was emphasized that every time the apprentices have skin contact, either by touching the metal or through weld splash, they are in contact with heavy metals and minerals present in the wire, especially when the skin is hit by a weld splash because, due to its elevated temperature, the splash causes chemical burns. It was recommended to use sunscreen, especially during welding activity and when exposed to solar radiation, and also to use welding gloves during activity followed by proper hand washing in order to minimize contact with metals. To explain the proper hand washing method, a poster was devised by LAMSA. During the explanation the gastric system was discussed because the apprentice welders can ingest metals when they eat if proper sanitation of their hands is not performed after working with the solder.Concerning the respiratory system, chemical risk factors were dealt with which apprentices are exposed to because they breathe the fumes resulting from the burning of metals during welding activity. The composition of the wire E71T-1 was again referred to explore the importance of a breathing mask with filter, a respiratory mask with filter being provided by the technical programme for training, which protects against dust and fumes from welding. It is important to use a breathing mask with filter under the welding mask because without it the welders will be inhaling dust and fumes from the welding process. Besides the chemical compounds present in fume welding, apprentices are also in contact with gases (acetylene and carbon dioxide) that are released during the opening of the flame. Unfortunately, the mask provided does not protect against inhalation of gases. For these reasons, it was recommended that apprentices do not remain in the environment of the welding practice rooms unnecessarily and/or without the protection of the respiratory mask with filter. Physical activities were recommended that promote breathing, such as running races, in order to encourage gas exchange, which also promotes the health of the cardiovascular system. For the auditory system approach the physical risk factor was noise. The apprentices were informed about exposure to 89-90 dB from the welding machine during practical activities. During the practical classes of each class about 14 welding machines are used. The noise is caused by exhaust fans, which exceed the limit of 115 dB, which is the imposed limit for occupational exposure without proper protection, according to Regulatory Standard 15 from Brazil , which pFor the musculoskeletal system, the following physiological risk factors were approached: performing repetitive movements, staying in the same posture for long periods and sometimes incorrect posture, and risk factors which apprentice welders are exposed to. To minimize exposure to these risk factors, the apprentices were asked to perform stretching exercises. During the exercises, apprentices were instructed to carry out the activity of stretching before and after welding practice and at intervals of 10 minutes after 50 minutes of welding activity. Physiological systems, risk factors, and health effects during welding activity are presented in In addition to these recommendations, after exposure of the systems, the following general recommendations were made: prioritize foods rich in iron and calcium to promote the excretion of manganese, prioritize foods rich in vitamin C to facilitate iron absorption, and prioritize food rich in fiber to facilitate removal of manganese and other metals by feces, since only some of the manganese is eliminated in the urine. To continue risk communication, the results of this research were presented. This approach focused on reestablishing the perception of risk factors  to which apprentices are exposed and health disorders related to welding activity. The presentation was concluded with the delivery of explanatory posters, which were placed in the welding practice rooms, so that by looking at the poster the implementation of protective measures during welding activity and the minimization of exposure to risk factors would be stimulated. The pre- and posttest questionnaire consisted of 41 variables related to identification of health disorders: musculoskeletal (15 items), integumentary (12 items), auditory (4 items), gastric (4 items), respiratory (3 items), and cardiovascular (3 items). The answers were given on a Likert Scale of five points, with the lowest being 0 (never feel/felt it) and the highest 4 . Thus, the maximum average of each block of questions was four. t test (P < 0.05). The Spearman correlation was used to analyse the intensity of the relation between the variable age, time of experience in welding, and self-reported health disorders by women apprentice welders before and after nursing socioenvironmental intervention. The Statistical Package for Social Sciences (SPSS) software Version 19.0 was used to organize and describe analysis of the data (first phase). Data from nursing socioenvironmental intervention (second phase) was presented using percentage, mean, and standard deviation (±SD). For paired samples analysis, were used student The sample included 27 women apprentices enrolled on the technical programme for training as welders in Rio Grande, Rio Grande do Sul, Brazil. Their ages ranged from 18 to 56 years, with an average of 30.26 years (±8.39); 11 (40.7%) were ethnically white and 11 (40.7%) ethnically black; 19 (70.4%) were single; 14 (51.9%) had finished secondary school and 12 (44.4%) had no children . RegardiThe results of the questionnaire on risk perception in the welding apprenticeship environment showed that 26 (96.2%) women apprentice welders identified physical risks, 26 (92.2%) identified chemical risks, 24 (88.8%) physiological risks and 17 (62.9%) biological risks. Among the risk factors identified, the most frequent was the heat during welding activity and the presence of gases, cited by 21 (77.8%) women apprentice welders . Comparing the means before and after nursing socioenvironmental intervention, it can be seen that there was an increase of the auditory, musculoskeletal, respiratory, and integumentary means. This increase of averages indicates that there was identification of disorders in these systems after nursing socioenvironmental intervention. The evaluation after the nursing socioenvironmental intervention shows a decrease in the mean cardiovascular and gastric systems, which points to a lower reference of women apprentice welders to disorders related to these systems. t-test detected a higher difference between means before and after nursing socioenvironmental intervention in the musculoskeletal system (P < 0.05). For the other systems there were no significant differences. The P < 0.01); that is, the lower the age, the higher the average during the valuations of such systems. The pattern changes when the correlation between organ systems is analysed, indicating among most of them positive and significant correlation. Time of experience was not correlated with any variable. Spearman correlation between age, time of experience, and self-reported health disorders by women apprentice welders revealed a negative correlation between age of women apprentices welders and the average after intervention for the gastric system .t-test the musculoskeletal system showed significant difference. These findings are similar to those found in the literature on welding-work-related disorders, which present the welders as a group at risk for musculoskeletal and integumentary disorders [It should be emphasized that with the isorders –27, 34.The physiological risk was reported by 88.8% of women apprentice welders, showing mainly poor posture and repetitive stress. The postures, repetitive movements, and constant vibration of the welding machines are examples of wear suffered by the musculoskeletal system. Most activities in welding require a variety of movements, such as bending, stretching, and long periods of standing, and, to perform these activities, specific muscle groups are used, such as the lumbar and scapular muscles, resulting in overload and increase of the risk of disorders . In addiStudies , 44 wereIt is important to highlight that musculoskeletal disorders associated with welding activity may occur due to the need for constant physical effort of women apprentices and future workers. To be specific, a significant difference to the musculoskeletal system can be explained by the fact that the pains arising from disturbances in this system presented multifactorial origins, related to work, the individual worker characteristics, personality traits, and life history . Thus, tConcerning physical risks, they were identified by 96.2% of the study participants. This is due to the constant exposure of women apprentice welders to weld spatter and hot metal objects, according to the activity they perform. This frequent exposure can cause a greater number of disorders related to the integumentary system. The main risk identified was physical heat for 77.8% of the participants. The heat self-reported by women welding apprentices arises from the nonionizing radiation produced by welding activity. More specifically, heat is produced during the opening of the electric arc , which cStudy findings show that the intensity and wavelength of nonionizing radiation produced would depend on many factors, such as the type of welding process, welding parameters, and the composition of metals, fluxes, and any coatings that may be on the base material. Moreover, the radiation exposure time was considered compatible with each 8 hour exposure within a 24-hour period. Therefore, two exposures of 5 minutes during a workday can be considered as a single 10-minute exposure. The research results show that the minimum safe distance for 1 minute is 32 cm .Another study  conducteThe integumentary system is mainly exposed to ultraviolet (UV) radiation coming from the open arc welding activity. Occupational exposure to UV increases the risk of skin cancer –26. An eExamples of integumentary disorders that may be caused by physical and chemical risks present in welder's activity are occupational burns. Occupational burns are divided into three categories. Thermal burns include events that result from high levels of heat caused by explosions, flame, radiant heat, and direct contact with hot surfaces. Electric injuries result from electrical explosions, flashes, or direct contact with an electrical current. Chemical burns result from the reaction of biological tissue with chemical materials . Specifically with apprentice welders, burns that can occur include thermal burns and chemical burns. There is a study which describes the occurrence of work-related injuries from thermal, electrical, and chemical burns among electric utility workers, among these the welders. Welders (not a common occupation in the electric utility workforce) had the highest age-adjusted injury rates for all burn-related injuries  and for thermal/heat burns  . It is uAnother important issue is related to exposure to radiation from welding machines. The effects of exposure to such radiation were tested on male and female welders who are parents and who are exposed to magnetic fields. The investigation was performed in order to detect an increased risk of cancer in the children of these workers. The association between these factors has not been proven . LikewisThe findings also suggest that the perception of chemical risk identified by 96.2% of the participants and the identification of health disorders involving this risk, for example, respiratory and integumentary disorders, increased after nursing socioenvironmental intervention. This risk perception, related to the chemical risk and identification of health disorders related to the chemical risk, is related to the raw material that the apprentices handle during welding activity, for example, the hot metal . The metAmong the chemical risks, 77.8% of women apprentice welders recognized the gases with which they deal during welding activity as risk factors, 59.3% identified the dust present in the apprenticeship environment, and 29.6% the fumes from welding. Research indicates that the welding fumes from the chemical compound, stainless steel, can cause acute lung injury and the size of the inhaled particles and exposure time are significant factors in the welding, which must be considered in the development of protective strategies . Lung fuAnother important pathology in welders is lung cancer. A cohort  conducteA longitudinal study of apprentice welders showed a significant association between welding-related metal fume and respiratory symptom fever as well as a decrease in lung function values after 15 months in welding school .Analysing the average of the remaining systems obtained in the pre- and posttest, it was noted that there was an increase in the average posttest for the auditory and respiratory systems and a decrease in the average for the cardiovascular and gastric systems. It can therefore be considered that the provision of a nursing socioenvironmental intervention for women apprentice assists in the dissemination of knowledge to identify health disorders related to welding work. By identifying these results, the conclusion will be the idea that risk communication strategies, as is the case with nursing socioenvironmental intervention, enable different groups to identify sources of information and knowledge, which are specific instruments in the role of health protectors of apprentices and future workers, as well as their colleagues. It should also be noted that by relating characteristics of the work and the conditions of exposure to different risks related to possible disorder, the apprentice can become proactive in the protection of her health.A study with different groups of community residents in the United States but with similar exposure problems examined the presence of manganese in the air and identified the community perception of the local air quality and the effects of manganese exposure on health. Through this identification, the authors used the risk communication strategy for teaching/learning self-care for this group. The results of risk communication showed a strong link with the academic community responsible for this area. However, such a result was possible due to the type of risk communication established, which visualized the needs and experiences of the community, integrating this knowledge with research protocols . SimilarThe correlation between age and the results of the posttest for the gastric system indicates that the youngest women apprentice welders identified more disorders related to the systems than apprentices who were older. It is understood that the opportunity to relate the health disorders with welding activity during the nursing socioenvironmental intervention provided by nurses was seized by the younger welders. This result was also evidenced in research that sought to explore the impact of an online learning theoretical course of welding and electrics, where younger learners had higher levels of compliance . The conIn conclusion, women apprentice welders realize that they are exposed to risk factors, especially chemical and physical risk factors related to the fact that their workplace is particularly dangerous. Results showed that the nursing socioenvironmental intervention provided information about health disorders related to welding activity for the auditory, cardiac, gastric, musculoskeletal, respiratory, and integumentary systems. Such information enabled the women apprentice welders to evaluate information and through this self-report health disorders. Analysis of the mean pre- and posttest of the musculoskeletal system allowed for observation of the influence of nursing socioenvironmental intervention on the apprehension of women apprentices of health disorders knowledge related to welding activity. In order to minimize musculoskeletal health disorders related to welding activity, the recommendation is made that women apprentices should perform stretching activities before and after work and must perform ten-minute breaks every 50 minutes of work. Besides musculoskeletal disorders, other disorders, for example, integumentary disorders, such as skin cancer, can be prevented through simple measures, as through the use of sunscreen during welding activity; respiratory, gastric, and cardiac disorders, such as lung and stomach cancer and cardiac arrhythmias, can be prevented by the use of a respirator, doing physical activities in order to facilitate gas exchange, and washing hands after working with weld to prevent ingestion of metals; and auditory disorders, such as noise-induced hearing loss, can be avoided through the use of hearing protection during the whole period of working with weld.It is believed that risk communication, through a process of health education, can modify individual behaviour because it is a process in which apprentices perceive and multiply knowledge in their work/apprenticeship environment and thus interfere with collective work conditions. It is understood that the perception of women apprentices regarding a particular set of occupational risks is essential for public health nursing to develop an effective risk communication as a positive tool for health education.


End-stage lung disease (ESLD) is a frequent cause of death. What are the differences in the supports needed by caregivers of individuals with ESLD at end of life versus other life-limiting diagnoses?The South Australian Health Omnibus is an annual, random, face-to-face, cross-sectional survey. In 2002, 2003 and 2005-2007, respondents were asked a range of questions about end-of-life care; there were approximately 3000 survey participants annually (participation rate 77.9%). Responses were standardised for the whole population. The families and friends who cared for someone with ESLD were the focus of this analysis. In addition to describing caring, respondents reported additional support that would have been helpful.physical care, information provision, and emotional and spiritual support.Of 1504 deaths reported, 145 (9.6%) were due to ESLD. The ESLD cohort were older than those with other 'expected' causes of death  and were less likely to access specialised palliative care services . For those with ESLD, the mean caring period was significantly longer at 25 months (standard deviation (SD) 24) than for 'other diagnoses' . Domains where additional support would have been useful included Caregiver needs were similar regardless of the underlying diagnosis although access to palliative care specialist services occurred less often for ESLD patients. This was despite significantly longer periods of time for which care was provided. Caregivers of people at the end-of-life face emotional, social and financial sequelae. At a population level, there is the potential for poorer health outcomes including morbidity and mortality. Understanding the pressures on caregivers may help to develop interventions that improve these outcomes ,2.Quantitative -5 and quA basic description of the caring experience for ESLD patients is needed, especially as it pertains to the most intense and uncertain period in the illness - end-of-life. It is imperative to understand what additional support would be of benefit and, subsequently, how this might improve caregiver outcomes. The aim of this population-based study was to describe differences in caring and the support needed by caregivers of people with advanced ESLD compared to caregivers of people with other life-limiting diagnoses. The null hypothesis was that there were no demonstrated differences between caregivers for people with ESLD and caregivers for people at the end of life with other diagnoses.South Australia has a population of 1.56 million people , the majority of whom live in Adelaide (population 1.1 million) with the balance residing in small non-metropolitan centres  .One interview (60-90 minutes in duration) is conducted per household with the person over age 15 who most recently had a birthday. If this person declines to participate, the person cannot be replaced by another member of the household.The South Australian Health Omnibus is an annual, face-to-face, cross-sectional survey. A multi-stage, systematic area sampling method is used; annual survey results are standardised against weighted population-based norms to accommodate random imbalances in sampling. Omnibus is run by a commercial research organisation using trained interviewers who survey between September and December annually . The surThe survey draws 75% of its sample from greater Adelaide. Annually, more than 5, 000 properties are approached seeking a resident to participate Figure . Not allIn Australia, the smallest census administrative data area is a collector district (CD), which has approximately 200 dwellings. There are 2, 041 CDs in Adelaide . There are another 1, 010 non-metropolitan CDs of which 100 are included. All eight towns in the state with a population of more than 10, 000 are included and towns with populations 1, 000 to 10, 000 are randomly selected with probability of selection proportional to the size of the town. This gives a statewide total of 440 starting points. A map in each selected CD is numbered for all corners, and a random number generator is used to choose the starting point in each CD. Each surveyor uses a standard algorithm to move from the starting point through the CD.Data are double entered. Missing responses are followed up by telephone by a research supervisor. For quality assurance, 10% of each interviewer's respondents are selected randomly and also re-contacted, asked to reconfirm their eligibility and re-answer a sub-set of questions. Aggregated data are then anonymised before release to researchers.Researchers pay to submit their own questions and in return are provided with de-identified demographic data for all respondents and the responses to the researchers' own submitted questions.Approximately 200 questions about health beliefs and behaviors from a wide range of disciplines are included. Annually, prior to the main survey, a pilot of 50 interviews with members of the general public is conducted to test questions, validate the survey instruments, and reconfirm survey procedures.For the purposes of this study, a 'gateway' question was asked - 'In the past five years, has anyone close to you died of a terminal illness..?' Figure  If the aInitially, data were weighted by the inverse of the respondent's probability of selection for the survey, adjusted for participation rates in metropolitan and rural areas, and then re-weighted and directly standardised against the South Australian population 2006) for gender, 10 year age group, country of birth and region of residence 006 for g. Before Demographic information collected in the survey included the respondent, limited information about the deceased care recipient, their relationship and the nature of care provided (if any) and perceptions about additional support that would have been of benefitFigure . This stAll available demographic data were used in the analysis. Bivariate Chi-square analyses were used to explore demographic characteristics for caregivers, the deceased and palliative care service use. Bonferroni correction was applied given multiple comparisons. Using the demographic, clinical and service variables that were unlikely to change as a result of the death of someone close, an exploratory logistic regression model was created in PWAS . This model included seven key factors .Strategies to minimise bias included random starting points (choosing CDs and choosing the starting point in CDs), minimising response bias in question design and piloting, and excellent geographic coverage to minimise under-coverage. Non-response is difficult to assess, but weighted and unweighted data were compared to confirm that the sample was representative and, in a sensitivity analysis, unweighted data confirmed the direction and magnitude of findings.The survey received annual South Australian Department of Health Research Ethics Committee approval. Given that this was a community survey in people's homes, verbal consent was acceptable and continued participation accepted as continuing consent. The reporting of this study complies with the STROBE consensus statement on reporting observational studies .A total of 14, 624 surveys were completed during the period. One in three respondents had someone close to them die an expected death in the five years before the interview . In bivariate analyses, there was no difference in the age of caregivers but people dying of ESLD were more likely to be > 65 , highest educational achievement, country of birth, the relationship to the deceased , specialist palliative care service utilisation, and diagnosis. Identifying that additional emotional or spiritual support would have been of value was more likely for younger caregivers  0.965 to 0.988; p < 0.0001), people dying of diseases other than ESLD  and females . The Hosmer and Lemeshow goodness-of-fit (p = 0.477) suggested that the model adequately fitted the data, and was confirmed by the Omnibus Tests of Model coefficients (p = 0.000).Given that there was a trend suggesting that people providing care for people with ESLD were This study identifies caregivers for people at the end-of-life at a whole-of-population level, regardless of health service access or utilisation. The study reiterates that caregivers for people at the end of life have perception of significant unmet needs regardless of diagnosis. It follows previous work that explored the characteristics of caregivers for people with ESLD  and now Chronic obstructive pulmonary disease (COPD) is the major cause of ESLD in our community. People with advanced COPD have been shown to have significant physical and psychosocial care needs at least as intense as people with lung cancer -23. Theyet al concluded there is a dearth of information on the needs of caregivers of people with COPD and interventions that may best support them [This current study has a younger cohort of (mostly) non-spousal caregivers. In qualitative studies, spousal caregivers of people with advanced COPD have discussed the burden of caring ,10 and hort them . This cuBereaved caregivers of people who died from COPD have indicated that access to support services is limited by a lack of knowledge about, and signposting to available services, a perception among caregivers and, at times, patients that it is embarrassing to ask for help, and a lack of agreement between the patient and the caregiver as to what services should be accessed .et al have postulated that low access to specialist palliative care services may be due to the nature of breathlessness itself with its surreptitious onset and slow progression; patients' assigning stigma to breathlessness; and the way health professionals often discredit the patients' experiences of breathlessness and merely ascribe the finding to being an expected clinical sign [Poor rates of service utilisation might relate to the perception that specialist palliative care services are historically for people with cancer or the intensity of the perceived needs are not appreciated by the clinicians as caring is provided over much longer periods of time . Patientcal sign .The length of time for which people experience symptomatic COPD has been noted to be longer than many other end-stage diseases . The proLong periods of caregiving with inadequate support may result from a combination of:appears to be adequate;(a) recalibration (response shift) such that the need for service support (b) upskilling of caregivers in their roles; and/oris actually less.(c) better garnering of resources over time such that the need for service support Recalibration can occur where an individual's understanding or perception changes over time through any number of mechanisms and internal processes. This change in perception, or internal standards, is known as 'response shift' which has been rarely documented for caregivers. Studies of caregivers of people with dementia have identified stable caregiver burden and improved psychological and physical well-being despite increased dementia severity suggesting that there may be a caregiver response shift .Another possible parallel explanation is that of upskilling. Given the long period of time for which care is likely to be provided, the upskilling of caregivers  could result. Thus caregivers' ability to care might be enhanced through experiential learning.Prolonged caring may also enable the garnering of resources such as access to: community resources; increasing support from family and friends; primary care services; or respiratory services. This current dataset cannot delineate between these mechanisms, but does point to the need to define prospectively the contribution that each makes in reducing perceived caregiver burden.This study identifies caregivers from right across the population without gate keeping by clinical staff . This alValid and reliable recall of information is crucial in a retrospective survey. Retrospective assessments may be altered by grief or by the difficulties of recall . InterviPeople who had provided informal care were asked to identify the cause of death of the care recipient during the interview. Objective measures of the accuracy of responses are not available.Any differential needs for caregivers living in rural or remote communities will not be reflected in these data. Although the data for analysis are weighted to the demographic composition of the whole population, given under-representation of some groups  in the initial interviews, it is possible that the responses do not encompass every single issue of note. Needs of people in residential aged care facilities will not be reflected. Given that the weighting is based on ten year age groups, gender and rurality, it is likely that on balance weighting adds rather than detracts from the findings.The current study reports exploratory whole-of-population data that can help to shape a future research agenda. Ideally, a prospective longitudinal study that directly explores actual unmet needs of caregivers while in the role and after they have relinquished the role is the next step. This will minimise recall bias and may allow for the control of any response shift. It would also be the opportunity to explore the reason for the seemingly low rates of perceived unmet needs expressed by former caregivers in this study. Given the paucity of longitudinal studies of caregivers in general and especially of people with ESLD, there is an urgent need for such studies to be undertaken. Given the reliance of health and social systems on the care provided by family and friends at the end-of-life, it is imperative to know how best to support them. Ultimately unmet needs of caregivers is best reflected in differential outcomes for patients, or in the wellbeing of caregivers while in the role and subsequently.The strength of these findings suggests that such prospective work could be in the form of a randomised intervention that explores whether the identification and follow up of needs generates better outcomes than identification alone or retrospectively.Quantitative data need to be complemented with qualitative approaches with caregivers over the time course of caring. This research should identify needs, whether and how they are being met, how they could be better met and how skills and confidence in the role change over time. It should arguably also include how clinicians are assessing caregivers' needs, and whether or how they offer support.This study builds on earlier work outlining the demographic profile of people providing care at the end-of-life for those with ESLD . These aCaregiver needs were similar when comparing people providing this care for patients with end-stage lung disease and other diagnoses. The context for this was that there was a much longer period of care in a more elderly population of care recipients. Further work needs to be done to understand why needs do not demonstrate such differentials when this is not the case with other specific diagnoses. This may relate to the length of time for which care is offered given that potentially it would allow sufficient time to mobilise support networks or allow other mechanisms to adjust to the role.The authors declare that they have no competing interests.Conception and design DC, AA, Obtaining funding DC, AA, Acquisition of data DC, AA, Analysis DC, Interpretation of data DC, AA, GC, AW, MF, Drafting of report DC, Critical revision DC, AA, GC, AW, MF. All authors read and approved the final manuscript.The costs for the survey were generously supported by Daw House Hospice Foundation, and salary for Dr Farquhar is provided my Macmillan Cancer Support.The pre-publication history for this paper can be accessed here:http://www.biomedcentral.com/1471-2466/11/55/prepub


Continuity of care is a key component of care in complex and chronic conditions. Despite its importance, it is often absent in chronic-disease management. One challenge has been identifying tools to measure care continuity. In one context important to families, namely pediatric palliative care, we undertook a project to identify continuity and to pilot the use of network analysis as a tool.Network analysis studies patterns of relationships or interactions between members, providing qualitative and quantitative description of network structure.In this report we applied network analysis to paper records of clinical consultations and reports for 6 patients with complex conditions. A high degree of discontinuity was identified, and care was fragmented amongst specialist and generalist providers. Information was shared selectively and often moved in only one direction.Families have anecdotally reported frustration with poor continuity of care. Network analysis can be a useful tool in describing the discontinuity of care experienced by families dealing with complex and chronic conditions. This tool could be expanded to other systems such as electronic health records and many other health care situations. The term "continuity of care" in healthcare first appeared in the literature almost 80 years ago, and has been the subject of published research inquiry for at least 40 years ,2. ContiContinuity of care is valued by patients and, by extension, parents caring for children with chronic health conditions ,5. ContiFrom a methodological standpoint, continuity of care is a complex construct that can be evaluated in a number of different ways. In a recent study, Miller, Condin and colleagues successfully used qualitative methodology to obtain rich and powerful narratives of parents' perspectives of continuity of care for their children with chronic health conditions . ParentsThese findings also agree with the clinical experience of one of the present authors (HS), which more generally provided the impetus for the present work. Specifically, the families of children diagnosed with life-limiting conditions often voice frustration at not having a "map" to guide them as they navigate the array of required services. The clinical context for care of children with severe chronic illnesses typically involves a wide variety of providers and agencies from an array of disciplines and sectors. As such, the salience of inter-provider and inter-disciplinary communication and coordination may be especially heightened. To the aim of furthering our understanding of continuity of care in this setting, we conducted a pilot study to evaluate the utility of a specific methodology, namely network analysis, in mapping out the process of information sharing/continuity. We applied the network analysis method to study how clinical reports are shared as one aspect of informational continuity.Network analysis involves the study of patterns of relationships or interactions between members, providing both qualitative and quantitative description of network structure and supporting further study of network functioning . AnalysiThe research protocol was approved by the institutional review boards at the University of British Columbia, Children's and Women's Health Centre of British Columbia (BC), and Canuck Place Children's Hospice, all in Vancouver, Canada. Data were collected through retrospective chart review of paediatric patients who had been diagnosed with life-limiting conditions (n = 18). The subjects, chosen at random from a larger study sample, were referred for or receiving care through BC Children's Hospital and Canuck Place Children's Hospice between January and March of 2008. Each child's hospice and hospital chart was reviewed for the 3-month period following their most recent hospice visit.Clinicians and patients were assigned unique identifying codes to preserve anonymity, and de-identified data were obtained via chart review. Relevant data collected from patient files included basic demographic information, diagnostics, lab/test history, and involvement with health care professionals. Data were entered into an electronic spreadsheet to facilitate analysis.This pilot phase focused specifically on the written communications that occurred between care providers during the 3-month study period. The patient chart serves as a record of this communication and can be used to determine the presence and frequency of interaction between the providers and agencies that comprise a patient's care network. The care network was first defined for each patient, including the individual clinicians, clinical teams, and agencies who sent, received, or were copied on letters or reports found in the patient chart, or who were identified as being involved in the patient's care during the hospice intake process. Each of the network members was assumed to have the potential of receiving, recording, and relaying information; however, it was also expected that one or more family physicians or pediatricians would play a central role in network communications. Residents, medical students, and auxiliary staff were not included in the analysis due to a high rotation rate and the expectation that a senior physician was managing the care centrally. Of the 18 original subjects, 6 had a sufficient number of reports or letters recorded in their charts over the 3 months to be suitable for analysis.Matrices were constructed to denote the flow of written information  between network members. A tie between network members represents the presence of a written communication documented in the patient chart, indicating that the provider sent, received, or was copied on a letter or report from another network member. The majority of reports or letters were actually sent to the patients' charts ; however, they were typically copied to one or more other providers. The analysis preserved both the direction and frequency of communications. The relationships were treated as asymmetrical .The matrices were diagrammed to provide a visual representation of communications between network members. These diagrams can be visually examined to describe the structure of the network, including the density of relationships between network members and the presence of holes or disconnects, which indicate potential breaks in the flow of information. The direction of communication is indicated by arrowheads, while the frequency of communication is denoted by line thickness . Each network member was also characterized in terms of its centrality within each patient's care network. Degree centrality quantitatively describes each network member's position or importance within the network, by summarizing the number of ties sent out and received from other members of the network. The analysis was conducted with specialized network software, UCINET v.6  and NetDOf the 6 patients included in this report, 2 had brain tumours, 1 had a solid tumour, 1 had a neuromuscular disease, 1 had a congenital heart defect and 1 had a neuro-metabolic condition. Figures The care networks ranged in size from 6 members for patients #4, #5 and #6, up to 19 members for patient #3. All were multidisciplinary in nature and all contained either a family physician or primary pediatrician. However, great variation in network composition was evident. For instance, while the network for patient #1 included 3 oncologists and an oncology nurse, 3 neurosurgeons, 2 palliative care pediatricians, a psychologist, the Canuck Place hospice team, and 1 family physician . However, 2 reports (for patients #2 and #3) were simply placed in the patient's chart without being addressed to any other providers. Without their being explicitly copied, it is not possible to confirm whether the other providers involved in the patient's care would have had reliable access to the report and would have been aware of its findings.Overall, the number of ties between network members was quite low, in most cases averaging less than 1 per provider. Exceptions were the care networks for patients #3 and #4, where the number of ties averaged 1.26 and 1.17 per provider . Across networks, the most active and central members were specialists in neurosurgery (patient #1), pediatrics (patients #2 and #3), oncology (patients #2 and #4), dermatology (patient #5), or cardiology (patient #6). Of particular note, in the care network for patient #3, one pediatrician  and provider characteristics . Findings may support efforts to develop and test models of optimal communication patterns, which can in turn inform ongoing work on continuity of care and the link to patient outcomes.et al qualitatively describing parents' experience of continuity of care (or lack thereof) [et al explore a very broad range of serious, chronic, childhood conditions, ranging from mental health conditions (Attention Deficit Hyperactivity Disorder), to diseases with long-term health needs (spina bifida), and then to conditions ending in early death (neurodegenerative diseases). It is across this broad spectrum that continuity of care needs to be improved. Whether there are differences in the experience of continuity of care across broad diagnostic categories with varying co-occurring conditions is an interesting avenue for future study.At this preliminary stage, the substantive conclusions emanating from this research are limited. From the perspective of formal clinical reporting, these care networks were typically fragmented and characterized by a low degree of document-sharing and reciprocity. In addition, there was also variability evident in the density and reciprocity of the formal clinical reporting process across the care networks for individual patients. These findings await replication in larger samples, but provide initial support for the use of network analysis to explore patterns of communication and link them to patient outcomes. Notably, this work complements that by Miller thereof) . TogetheIn this pilot study, we examined the capabilities of network analysis with respect to a single aspect of informational continuity: written communications. The importance of written documentation as a necessary component of informational continuity has been noted, particularly in clinical environments characterized by low relational continuity  . WrittenOver and above the written documentation that ends up in patient charts, broader assessment of informational continuity through primary collection of network data  would be highly valuable. Use of chart review precluded consideration information flow via email, telephone, and in-person conversations. The extent to which these forms of communication play a role in the care of chronically-ill children, and their relative effectiveness in relaying important information, is unknown. The degree to which providers mix and match communication modalities and technologies is a worthwhile inquiry for future investigations.This pilot study shows the potential of using the framework of a network to better understand health care provision. The next step will be to expand primary data collection in order to undertake an evaluation of a broader set of indicators of network structure, such as provider perceptions of the helpfulness or value of collaboration with other network members, or provider awareness of the service mandates and details of care provided by other network members. This would provide valuable contextual information for mapping the formal clinical reporting process, and interpreting network diagrams and meaning of centrality indicators. Classes of providers grouped according to their centrality across a number of measures of network structure can be generated statistically , and linked with traditional attributional data  to examine questions of network functioning. In addition, the qualitative and quantitative indicators of network structure could be used to inform and supplement additional qualitative investigation of parent or other caregiver perceptions of continuity; for instance, by asking parents to comment on the meaning of identified patterns of communication between providers and interpreting the placement of different providers within the care network. They could equally be used in longitudinal evaluations to determine change in structure following the introduction of specific interventions designed to improve continuity of care.The network approach can successfully capture elements of direction, frequency and reciprocity in the flow of information. It lacks, however, the capability to address the time-sequence inherent in provider interactions. It could, therefore, be helpfully supplemented by methods such as process mapping, which are able to capture the sequence and time-dependency of interactions in documenting continuity ,16. A teIn summary, we believe our findings in this pilot study highlight the promise of network approaches to the study of continuity of care among chronically-ill children, and likely to chronic disease management in general. As part of a mixed-method approach to the study of continuity of care, and supplemented by attributional data and indicators of time-sequence, the analysis of relational data with network methods offers a valuable depiction of interactions and ties in complex clinical contexts. It provides a straight-forward way of identifying the occurrence and placement of gaps in informational continuity, and to identify particular providers who occupy central and influential roles within specific care networks. The mix of quantitative and qualitative information on network structure can be easily integrated with additional contextual data, as described above.We hope that this pilot study will be the starting point for a fuller, richer analysis with mixed methods design to describe the nature of care as experienced by children with chronic disease. Ultimately, a comprehensive understanding of this care process may provide the basis for new program initiatives to make care more efficient, effective, safe and satisfying overall.The authors declare that they have no competing interests.The authors contributed equally to this work. HS developed the research question and gathered the case examples. KU undertook the network analysis. Both authors contributed equally to writing the manuscript. Both authors read and approved the final manuscript.The pre-publication history for this paper can be accessed here:http://www.biomedcentral.com/1472-6963/11/343/prepub


Epidemiological evidence showing a consistent association between the risk of childhood leukaemia and exposure to power frequency magnetic fields has been accumulating. This debate considers the additional precautionary intervention needed to manage this risk, when it exceeds the protection afforded by the exposure guidelines as recommended by the International Commission on Non-Ionizing Radiation Protection.The Bradford-Hill Criteria are guidelines for evaluating the scientific evidence that low frequency magnetic fields cause childhood leukaemia. The criteria are used for assessing the strength of scientific evidence and here have been applied to considering the strength of evidence that exposures to extremely low frequency magnetic fields may increase the risk of childhood leukaemia. The applicability of precaution is considered using the risk management framework outlined in a European Commission (EC) communication on the Precautionary Principle. That communication advises that measures should be proportionate, non-discriminatory, consistent with similar measures already taken, based on an examination of the benefits and costs of action and inaction, and subject to review in the light of new scientific findings.The main evidence for a risk is an epidemiological association observed in several studies and meta-analyses; however, the number of highly exposed children is small and the association could be due to a combination of selection bias, confounding and chance. Corroborating experimental evidence is limited insofar as there is no clear indication of harm at the field levels implicated; however, the aetiology of childhood leukaemia is poorly understood. Taking a precautionary approach suggests that low-cost intervention to reduce exposure is appropriate. This assumes that if the risk is real, its impact is likely to be small. It also recognises the consequential cost of any major intervention. The recommendation is controversial in that other interpretations of the data are possible, and low-cost intervention may not fully alleviate the risk.The debate shows how the EC risk management framework can be used to apply the Precautionary Principle to small and uncertain public health risks. However, despite the need for evidence-based policy making, many of the decisions remain value driven and therefore subjective. Leukaemia is the most common type of childhood cancer, accounting for 30% of all cancers diagnosed in children younger than 15 years . Within Exposure guidelines such as those published by the International Commission on Non-Ionizing Radiation Protection (ICNIRP)  are usedThe Precautionary Principle is an increasingly influential aspect of modern policy making, challenging regulators to take steps to protect against potential harms, even if causal chains are uncertain -12. TherThis paper considers the application of precaution to address the possible risk of childhood leukaemia from exposure to power frequency magnetic fields. The Bradford-Hill Criteria are used to evaluate the scientific evidence and precaution is considered within the risk management framework of the EC communication on the Precautionary Principle.The first part of the evaluation uses the Bradford-Hill Criteria  to examiThe second part of the evaluation considers the applicability of precaution within the risk management framework outlined in the EC communication on the Precautionary Principle . The fraTable The conclusion is in accord with the findings of a number of authoritative bodies that have reviewed the scientific evidence and acknowledged the possibility of a risk, including the independent Advisory Group on Non-ionising Radiation -17, ICNIOn the basis of the epidemiological evidence, IARC classified power frequency magnetic fields as a possible human carcinogen (Group 2B) ,29. The et al [et al study was based on the geometric mean magnetic field level in nine studies and suggested that exposure to power frequency magnetic fields in the home above an average of 0.4 μT was associated with a doubling of the risk of leukaemia in children less than 15 years of age. In a separate, but similar, pooled analysis [et al [The epidemiological evidence for the association is illustrated in Figure et al . The Ahlanalysis . Lookings [et al , providiet al [et al [More recent studies continue to confirm an association . A largeet al  and Greel [et al  combinedl [et al . Interesl [et al .As yet, there is no clear explanation for the observed association; it could arise if power frequency magnetic fields have a causal role in the development of the disease or, alternatively, it could arise as a result of a statistical artefact reflecting selection bias, confounding or chance . The proThe evidence for a causal relationship would be strengthened considerably if experimental studies were to demonstrate that magnetic fields affect biological systems at the exposure levels implicated in the epidemiological studies. The various mechanisms by which magnetic fields might interact with the body have been considered by a WHO Task Group . HoweverIn addition to investigating the possible direct acting carcinogenic properties of magnetic fields, indirect roles in leukemogenesis have also been suggested, including mechanistic links related to corona ions from power lines -42, suppIt cannot be excluded nevertheless that the lack of effect seen overall in the experimental laboratory studies could in part be due to lack of appropriate models for the complex processes that lead to the development of childhood leukaemia. There is, therefore, perhaps the need for new and/or refined models to be developed and tested in order to conclusively demonstrate that exposure to magnetic fields at the relevant environmental levels neither induces molecular and genetic changes associated with leukaemia initiation, nor drives disease progression.The absence of supporting experimental evidence also needs to be considered in the context of how little is known about the development of the disease. The causes of most types of leukaemia are largely unknown ,2,25. IoThe potential of power frequency magnetic fields to cause diseases other than childhood leukaemia has received less attention ,25. SCENAccording to the EC communication, the measures based on the Precautionary Principle must not be disproportionate to the desired level of protection and must not aim at zero risk. This reflects the Principle of Proportionality used in EU law, which dictates that measures implemented through Community provisions must be appropriate for attaining the objective pursued and must not go beyond what is necessary to achieve it, thus preventing the unreasonable use of precaution .Here, in the context of childhood leukaemia and magnetic fields, the scientific uncertainty may be sufficient to trigger the application of precaution, but the likely magnitude of the risk would argue against high-cost intervention to reduce exposure. For example, cancer in children is rare, and the cumulative risk of developing leukaemia before the age of 15 in the UK equates to approximately 1:1,500 . At the vice versa. However, recent evidence in the UK suggests that restricting precaution to high voltage power lines may be discriminatory, in that many low-voltage sources are also associated with high exposure [Much of the discussion has focused on reducing the exposure from high voltage power lines, either by restricting building of homes in the vicinity of lines or exposure ,64. In texposure . Most ofexposure ,64. ThusThe consistency criterion requires that the measures should be of comparable scope and nature to those already taken in equivalent areas in which all the scientific data are available. The criterion is difficult to evaluate because there are no obvious parallels in adjacent parts of the electromagnetic spectrum and the causes of the disease remain largely unknown. In relation to ionising radiation, where carcinogenic effects are relatively well established, the as low as reasonably achievable (ALARA) approach is taken which assumes a linear no-threshold exposure-response model. In relation to chemical pollutants, the converse is often true i.e. there may be good experimental evidence suggesting the possibility of harm but the evidence from human health studies is more difficult to establish. Thus the consistency criterion is difficult to apply and does not add much to clarify the issue.The consideration of cost-benefit is an important criterion to adhere to in evaluating a particular intervention. Its scope in the EC communication is much broader than a purely economic cost-benefit assessment, stating it includes non-economic considerations such as efficacy of possible options and their acceptability to the public. Figure Implicit in the application of the Precautionary Principle is a commitment to review the arrangements and to carry out research aimed at understanding the underlying issue ,66. AnalThe strengths and weaknesses of the Precautionary Principle as a risk management strategy have been reviewed elsewhere -12,66-69Issues surrounding the application of precautionary intervention to public health risks have been elaborated by various authors ,66,67. FEarly preventative action has been recommended by Gee  to limitThe evaluation presented in this debate is consistent with other studies which suggest that precautionary action is warranted ,25. In 2The main conclusion of this evaluation, namely only low-cost interventions should be pursued at this time, is critically dependent on the assumption that if the risk is real, its impact is likely be small. The Bradford-Hill Criteria have been used as the basis for the evaluation; however, it is also acknowledged that very few causal agents meet all these criteria, and whilst support of the criteria can be robust evidence for a causal association, the complex and multi-causal nature of biological interactions means that the converse is not necessarily true . The evaThe small impact assumption is based on applying a threshold model to the data; however, the precise relationship of the exposure-response model is unknown, and although the risk becomes detectable at around 0.3-0.4 μT, the observed data are consistent with trend models that are nearly flat, or curves that rise and then fall, or even curves that rise exponentially ,6,71. IfThe interpretation of 'low-cost' is inherently subjective. It is normally taken to include various measures such as the provision of public information and improvements to engineering practices; however it might also include, depending on circumstances, the sensitive siting of new power lines and substations, and new homes and other buildings occupied by the public. In the UK, the Stakeholder Advisory Group on ELF EMF (SAGE) was set up to identify and explore the implications for a precautionary approach in response to concerns about possible health effects at field levels below the ICNIRP guidelines . In its The California EMF project , on the The value of informing the public about precautionary measures has been called into question by studies which show that such advice may in fact heighten public concern -77. PrecThe low-cost recommendation is controversial to the extent that it involves societal acceptance of the possibility of a risk that may not necessarily be fully alleviated by the proposed level of intervention. This creates an ethical dilemma for policy makers of what value should be put on a child's life. There is also a prioritisation principle, not mentioned in the EC communication, which argues against excessive expenditure on precautionary measures. Public spending on established health risks which have a large impact on society is more easily justifiable than public spending on less certain risks which have a small impact. Opportunity cost consideration also dictates that the cost of precautionary measures should be weighed alongside other possible uses of the same resources. In the case of childhood leukaemia, improving outcomes for those children who don't respond well to the current treatment regimes and research into its causes might be preferable. Alternative preventative options include the screening of newborns, and appropriate follow-up, for TEL-AML1 and other pre-disposing genetic abnormalities ,80, althThis paper considers the application of precaution to address the possible risk of childhood leukaemia from exposure to power frequency magnetic fields. The main evidence for a risk is an epidemiological association observed in several studies and meta-analyses; however, the number of highly exposed children is small and the association could be due to a combination of selection bias, confounding and chance. Corroborating experimental evidence is limited insofar as there is no clear indication of harm at the field levels implicated; however, the aetiology of childhood leukaemia is poorly understood. Taking a precautionary approach suggests that low-cost intervention to reduce exposure is appropriate. This assumes that if the risk is real, its impact is likely to be small. It also recognises the consequential cost of any major intervention. The recommendation is controversial in that other interpretations of the data are possible, and low-cost intervention may not fully alleviate the risk. The debate shows how the EC risk management framework can be used to apply the Precautionary Principle to small and uncertain public health risks. However, despite the need for evidence-based policy making, many of the decisions remain value driven and therefore subjective.The authors declare that they have no competing interests.MM conceived of the evaluation. TL assessed the causes of childhood leukaemia and JS considered the epidemiological evidence. ZS and AMcK contributed to the overall discussion. All authors read and approved the revised manuscript.The pre-publication history for this paper can be accessed here:http://www.biomedcentral.com/1471-2458/10/673/prepub


Based on evolutionary theory, Trivers & Willard (TW) predicted the existence of mechanisms that lead parents with high levels of resources to bias offspring sex composition to favor sons and parents with low levels of resources to favor daughters. This hypothesis has been tested in samples of wealthy individuals but with mixed results. Here, I argue that both sample selection due to a high number of missing cases and a lacking specification of the timing of wealth accumulation contribute to this equivocal pattern. This study improves on both issues: First, analyses are based on a data set of U.S. billionaires with near-complete information on the sex of offspring. Second, subgroups of billionaires are distinguished according to the timing when they acquired their wealth. Informed by recent insights on the timing of a potential TW effect in animal studies, I state two hypotheses. First, billionaires have a higher share of male offspring than the general population. Second, this effect is larger for heirs and heiresses who are wealthy at the time of conception of all of their children than for self-made billionaires who acquired their wealth during their adult lives, that is, after some or all of their children have already been conceived. Results do not support the first hypothesis for all subgroups of billionaires. But for males, results are weakly consistent with the second hypothesis: Heirs but not self-made billionaires have a higher share of male offspring than the U.S. population. Heiresses, on the other hand, have a much lower share of male offspring than the U.S. average. This hints to a possible interplay of at least two mechanisms affecting sex composition. Implications for future research that would allow disentangling the distinct mechanisms are discussed. Trivers and Willard predicted an association between maternal conditions and sex ratios at birth In human populations, a sex ratio of about 105–106 boys for every 100 girls is considered ‘natural’ The mixed empirical pattern may be the result of data limitations in previous studies. Therefore, this study improves two central issues: First, I use an improved data set with a much lower rate of missing information than previous studies and minimize sample selection bias in the estimate of the TW effect. For two reasons male offspring is more likely to appear in newspaper or Web searches than female offspring: Females more often than males change their last names upon marriage and, given a persisting ‘glass ceiling’ effect Following-up on recent advances in research on the TW effect among animals, the second issue to be improved is to provide a better specification of the timing of wealth accumulation relative to the timing of conception of a child. This allows me to derive important differences in the TW effect between subgroups of the wealthy. Similar to studies on human samples, studies examining the TW effect among animals often rely on correlational evidence and report mixed findings. Potential small-sample and publication biases have prompted researchers to ask whether the TW effect may, in fact, be an artifact In studies on the TW effect in human populations, maternal condition, operationalized as socioeconomic status The sample is based on a list of the 400 richest US Americans published by Forbes Magazine in 2009 Of the initial 400 cases, 39 women and 87 men were listed as heirs, and 3 women and 271 men as self-made billionaires. A total of 374 cases remained in the sample after 20 childless billionaires, three cases for which parental status could not be identified, and the only three self-made female billionaires were removed from the data. The latter group was removed because the group size is too small for reasonable subgroup analyses. The remaining sample consists of 37 heiresses, 82 heirs, and 255 self-made, male billionaires. Of the 37 heiresses, 26 inherited their wealth from their parents and 11 from their deceased partner. Of the 82 heirs, 51 inherited their wealth from parents who were themselves self-made billionaires, 30 from parents who were themselves heirs, and one inherited in first generation from a non-family member.Heiresses who inherited their wealth from their partners should be distinguished from those who inherited from their parents. This distinction is necessary for two reasons: First, it should matter if the male or female partner in a dyad is responsible for achieving wealth, given a strong association between social status and mating preferences Information on offspring sex is complete for 93.32% of all listees. For an additional 4.28% of listees information on the sex of at least some children is available. This leaves only 2.41% of listees for which the sex of none of their children is known. If we count the number of missing cases as the percentage of children whose sex is unknown we have the sex missing for 4.39% of all recorded children, leaving a total of 1165 valid cases of biological children. Except for the three individuals, for whom parental status could not be identified, the total number of children is known for all cases. This turnout means a considerable improvement in coverage as compared to previous studies in which, using Forbes data from 1982 and 2008, information on offspring sex was missing for more than half of the respective samples of wealthy parents m) for the complete sample of billionaires and for specific billionaire subgroups to the corresponding proportion in the general U.S. population. Second, I examined differences in the proportion of male offspring between billionaire subgroups. Third, I conducted a robustness test by repeating the group comparison using a multilevel logistic regression model. In the following, I report the percentages of male offspring for the complete sample of billionaires and for specific subgroups. Sex ratios (SR), defined here as number of males per female, are reported in brackets. The following formula (F1) is used to transform values for the proportion of male offspring into sex ratios:To examine whether a TW effect can be found in the sample of billionaires, I used a combination of different methods. First, I conducted a series of binomial tests to compare the proportion of male offspring (pWith about 52.4% (SR: 1.10), the percentage of male offspring for the sample of billionaires is just slightly higher than the corresponding percentage in the general US population for the last half century  −12), there are no dependencies within parents. In other words, the sex of one child is not connected to the sex of another child from the same billionaire. In the following, I thus use regular binomial tests. The first hypothesis suggests a specific direction of the deviation from the population percentage of male offspring m≈.427 vs. pm≈.571; p≈.035). However, after correcting for multiple comparisons all three tests are insignificant . The ICC depicts possible within-parent dependencies that can affect the binomial test cant see .β) which correspond to the respective sex ratios (SR) (see F2). The predicted sex ratios from the logistic regression in As a robustness check, the influence of billionaire status  on offspring sex was also tested using a multilevel logistic regression. Whereas in the pooled model, clustering of multiple births among the same billionaire parents is not accounted for, in the random effects model this is achieved by including parent-level random intercepts. Both models yield the same results see , confirmThe results clearly speak against the first hypothesis and thus against the existence of a TW effect in all subgroups of U.S. billionaires. This finding deviates in part from earlier studies analyzing similar data sets. On the one hand it confirms the result from at least one other study based on Forbes data from 1982 which also reports a null-effect In the second hypothesis I predicted a higher proportion of male offspring among billionaires who inherited their wealth than among self-made billionaires. This hypothesis is weakly supported, but only for men: Heirs have a much higher share of male offspring than both self-made billionaires and the general population. They have their complete fertility history as wealthy individuals: Every time a new child is conceived by the spouse or partner of an heir, sex composition may be affected by the putative TW mechanism. Self-made billionaires, on the other hand, only have a slightly higher percentage of male offspring than the general population, a difference that is not statistically significant. This is plausible, given that self-made billionaires have at least some of their children at a time when they have not yet achieved high wealth status. In emphasizing the importance of timing of socioeconomic condition in measuring the TW effect, this finding is consistent with research based on animal studies that finds a higher share of TW-consistent results in studies that measure parental condition close or around the time of conception A limitation of the current study is that the timing of wealth accumulation, self-made wealth vs. inheritance, is rather coarse. In fact, among self-made billionaires there is considerable variation in the type of occupations parents hold, including both sons of poor immigrants and sons of parents with high-status jobs like lawyers, doctors, or scientists. There is also considerable variation with regard to the timing of status achievement and childbearing. In fact, the group of self-made billionaires should consist of individuals who achieved high wealth status before they started their fertility history, during their fertility history, and after they completed their fertility history. If future data collection efforts could yield more fine-tuned measurements on these dimensions, more detailed hypotheses on the timing and strength of the TW effect would become possible.A striking result of the current study, one implied by neither of the two initially stated variants of the TW hypothesis, is that heiresses have a considerably lower percentage of male offspring than heirs, self-made billionaires, and the general population. That is, for women, the observed effect is actually diametrical to the prediction made on the basis of the TW hypothesis. The difference in the proportion of male offspring between heiresses and heirs is, in fact, the highest difference observed in this study. Despite the large size of the effect and due to the low group size of 26 heiresses, however, it is only statistically significant when not controlling for multiple comparisons. Once this correction is applied, the difference remains only slightly above statistical significance in the logistic regression model. Future research should test whether this finding can be replicated with larger samples of elite women. Also, future samples should be extended to include a higher share of women who are self-made billionaires. In the current analysis, the difference between heiresses and self-made women could not be tested.These objections notwithstanding: What could drive this distinct finding for men and for women? A clue to an answer may be provided by the literature on the effect of various stressors on reducing the percentage of male offspring In sum, the current study contributes importantly to research on the upper limits of the TW effect in humans. First, it shows that no TW effect could be discerned in the full sample of U.S. billionaires. Second, it provides estimates that are sensitive to the timing of maternal condition and conception of a child. Third, it illustrates that distinctive mechanisms may be at play and produce diametrical effects, depending on whether the focal elite individual is male or female. More detailed data on the occupational and fertility histories of wealthy individuals and their partners are necessary to shed more light on how the TW mechanism operates. Promising sources of data are population registers: these include in-depth information on occupational and fertility histories for a very large number of individuals and their partners