Background While physical health has improved considerably over recent decades in Finland, the disease burden of mental health, especially that of depression, has become increasingly demanding. However, we lack long-term data on the natural course of subjective well-being in the general population. The aim of this study was to investigate the long-term course of self-reported life satisfaction.
Background
While physical health has improved considerably over recent decades in Finland, the disease burden of mental health, especially that of depression, has become increasingly demanding. However, we lack long-term data on the natural course of subjective well-being in the general population. The aim of this study was to investigate the long-term course of self-reported life satisfaction.Methods This was a 15-year prospective cohort study on a nationwide sample of adult Finnish twins (N = 9679), aged 18–45 and healthy at baseline, who responded to postal questionnaires in 1975, 1981 and 1990 including a 4-item life satisfaction scale (happiness/easiness/interest in life and feelings of loneliness). Life satisfaction score (range: 4–20) was classified into three categories: satisfied (4–6), intermediate (7–11) and dissatisfied group (12–20). The associations between life satisfaction scores during the follow-up were studied with linear/logistic regression.
Methods
This was a 15-year prospective cohort study on a nationwide sample of adult Finnish twins (N = 9679), aged 18–45 and healthy at baseline, who responded to postal questionnaires in 1975, 1981 and 1990 including a 4-item life satisfaction scale (happiness/easiness/interest in life and feelings of loneliness). Life satisfaction score (range: 4–20) was classified into three categories: satisfied (4–6), intermediate (7–11) and dissatisfied group (12–20). The associations between life satisfaction scores during the follow-up were studied with linear/logistic regression.Results Moderate stability and only a slight effect of age or birth-cohort on mean life satisfaction score (LS) were detected. In 1990, 56% of all and 31% of the dissatisfied remained in the same LS category as at baseline. Only 5.9% of the study subjects changed from being satisfied to dissatisfied or vice versa. Correlations between continuous scores (1975, 1981 and 1990) were 0.3–0.4. Baseline dissatisfaction (compared to satisfaction) predicted dissatisfaction in 1981 (OR = 10.4; 95%CI 8.3–13.1) and 1990 (5.6; 4.6–6.8). Multiple adjustments decreased the risk only slightly.
Results
Moderate stability and only a slight effect of age or birth-cohort on mean life satisfaction score (LS) were detected. In 1990, 56% of all and 31% of the dissatisfied remained in the same LS category as at baseline. Only 5.9% of the study subjects changed from being satisfied to dissatisfied or vice versa. Correlations between continuous scores (1975, 1981 and 1990) were 0.3–0.4. Baseline dissatisfaction (compared to satisfaction) predicted dissatisfaction in 1981 (OR = 10.4; 95%CI 8.3–13.1) and 1990 (5.6; 4.6–6.8). Multiple adjustments decreased the risk only slightly.Conclusions Life satisfaction in adult Finns was moderately stable during 15 years. Among an identifiable group (i.e. the dissatisfied) life dissatisfaction may become persistent, which places them at a greater risk of adverse health outcomes.
Conclusions
Life satisfaction in adult Finns was moderately stable during 15 years. Among an identifiable group (i.e. the dissatisfied) life dissatisfaction may become persistent, which places them at a greater risk of adverse health outcomes.

Background While physical health has improved considerably during recent decades in Finland, the disease burden of mental health – especially that of depression – has become increasingly demanding for the health care services and society. When the global disease burden – including both fatal and non-fatal outcomes – has been assessed, major depression has been shown to be one of its leading causes [ 1 ]. However, not only diagnosed depression but also incomplete recovery from depression and subthreshold depressive symptoms have adverse consequences and chronic courses [ 2 - 6 ]. In general, poor mental health affects somatic health and subjective well-being, but poor subjective well-being might also develop into mental disorder and create a loss of functional capacity, if not a sign of an undiagnosed mental disorder already at baseline. Life satisfaction and happiness are some of the concepts that have previously been viewed as indicators of subjective well-being [ 7 , 8 ]. Life dissatisfaction, even reported by seemingly healthy subjects, is associated with several indicators of poor health or health risk factors, but especially with depressive symptoms [ 9 - 11 ]. Longitudinally, it predicts poor health outcomes such as morbidity, mortality and premature work disability – due to both somatic as well as psychiatric causes – among the healthy but dissatisfied subjects [ 9 , 11 - 15 ]. When dissatisfaction is repeatedly reported over years the risk of a poor health outcome increases even more [ 13 - 15 ]. Due to these adverse health outcomes and shortened life expectancy among the identifiable group from the healthy general population (i.e. the dissatisfied), more attention should be paid to the natural course of life dissatisfaction in the general population. However, good mental health is also an area that should be studied in psychiatry. It is something more than the absence of symptoms. It is a mental state that is objectively desirable, indicating for example maturity, emotional and social intelligence, resilience and subjective well-being according to Vaillant [ 16 ]. While the possibilities to directly assess mental health at the level of the general population are limited, subjective well-being at the population level can be measured. Subjective well-being has mainly been investigated in cross-sectional settings and among the elderly, while follow-ups may have been brief and data from the general population have been sparse. Even if subjective well-being in general population has been suggested to be quite stable [ 9 , 17 - 23 ], it has also been pointed out that the apparent stability should not be due to the insensitivity of measurements to change or due to fact that most people report satisfaction with life [ 17 , 20 ]. However, this is not the case with psychiatric patients and life satisfaction, among whom life satisfaction has been shown to be lower than in any other patient group [ 9 ] and to improve markedly concurrently with their recovery from depression [ 10 ]. Mental health policy plays an increasingly recognized role in society, but it needs both epidemiological data as well as experts on the field of mental health to monitor the populations and trends [ 24 ]. Thus, in psychiatry, we need information on the natural long-term course of subjective well-being in the general population. This study aimed to examine the long-term course of life satisfaction in healthy adults and to determine how strongly self-reported life dissatisfaction predicts future life dissatisfaction.
Background
While physical health has improved considerably during recent decades in Finland, the disease burden of mental health – especially that of depression – has become increasingly demanding for the health care services and society. When the global disease burden – including both fatal and non-fatal outcomes – has been assessed, major depression has been shown to be one of its leading causes [ 1 ]. However, not only diagnosed depression but also incomplete recovery from depression and subthreshold depressive symptoms have adverse consequences and chronic courses [ 2 - 6 ]. In general, poor mental health affects somatic health and subjective well-being, but poor subjective well-being might also develop into mental disorder and create a loss of functional capacity, if not a sign of an undiagnosed mental disorder already at baseline.Life satisfaction and happiness are some of the concepts that have previously been viewed as indicators of subjective well-being [ 7 , 8 ]. Life dissatisfaction, even reported by seemingly healthy subjects, is associated with several indicators of poor health or health risk factors, but especially with depressive symptoms [ 9 - 11 ]. Longitudinally, it predicts poor health outcomes such as morbidity, mortality and premature work disability – due to both somatic as well as psychiatric causes – among the healthy but dissatisfied subjects [ 9 , 11 - 15 ]. When dissatisfaction is repeatedly reported over years the risk of a poor health outcome increases even more [ 13 - 15 ]. Due to these adverse health outcomes and shortened life expectancy among the identifiable group from the healthy general population (i.e. the dissatisfied), more attention should be paid to the natural course of life dissatisfaction in the general population.However, good mental health is also an area that should be studied in psychiatry. It is something more than the absence of symptoms. It is a mental state that is objectively desirable, indicating for example maturity, emotional and social intelligence, resilience and subjective well-being according to Vaillant [ 16 ]. While the possibilities to directly assess mental health at the level of the general population are limited, subjective well-being at the population level can be measured.Subjective well-being has mainly been investigated in cross-sectional settings and among the elderly, while follow-ups may have been brief and data from the general population have been sparse. Even if subjective well-being in general population has been suggested to be quite stable [ 9 , 17 - 23 ], it has also been pointed out that the apparent stability should not be due to the insensitivity of measurements to change or due to fact that most people report satisfaction with life [ 17 , 20 ]. However, this is not the case with psychiatric patients and life satisfaction, among whom life satisfaction has been shown to be lower than in any other patient group [ 9 ] and to improve markedly concurrently with their recovery from depression [ 10 ].Mental health policy plays an increasingly recognized role in society, but it needs both epidemiological data as well as experts on the field of mental health to monitor the populations and trends [ 24 ]. Thus, in psychiatry, we need information on the natural long-term course of subjective well-being in the general population. This study aimed to examine the long-term course of life satisfaction in healthy adults and to determine how strongly self-reported life dissatisfaction predicts future life dissatisfaction.Methods This prospective cohort study with a follow-up from 1975 to 1990 was based on the Finnish Twin Cohort, a nationwide sample of all Finnish same-sex twin pairs born before 1958 with both members alive in 1975. A baseline health questionnaire was sent in 1975 to twin candidates [ 25 ]. The follow-up questionnaires in 1981 and 1990 were sent only to verified twins. Furthermore, the 1990 questionnaire was sent only to twins from pairs born in 1930–1957 with both co-twins alive and residing in Finland. The overall response rates to the questionnaires were 89% in 1975, 84% in 1981 and 77% in 1990. The study procedure has been presented in detail elsewhere [ 12 , 25 ]. The questionnaires included a four-question scale for life satisfaction, which was modified from a questionnaire developed for measuring the quality of life for research purposes in Nordic countries [ 26 ]. It has been used among all adult age-groups [ 9 , 12 ] as well as among psychiatric patients [ 9 , 10 , 27 ]. The study subjects were asked to rate aspects of life satisfaction: interest in life, happiness, ease of living and loneliness (very interesting/happy/easy/not at all lonely = 1, fairly interesting/happy/easy = 2, fairly boring/unhappy/hard/lonely = 4, very boring/unhappy/hard/lonely = 5). Missing data and the response 'cannot say' were scored as 3. If three or four items were missing, the sum score was recorded as 'missing'. Thus, the total score (LS) ranged from 4–20, with  increasing scores indicating a decrease in life satisfaction . On the basis of the distribution of the sum score (LS), subjects were categorized into the satisfied (LS:4–6), the intermediate group (LS:7–11) and the dissatisfied (LS:12–20) [ 12 ]. The intermediate group consisted of those with an LS score within one standard deviation from the mean [ 9 ]. At baseline, responses to all four items were provided by 95.8% (N = 22,416) and at least two items, enabling LS to be calculated, by 99.2% (N = 23,212) of all respondents aged 18–45 years. Thus, one or two missing values were recoded as '3' values for 3.4% of subjects. The criteria for inclusion in the present study were the availability of baseline life satisfaction data, an age of 18–45 years on 1 January 1976 and being a twin (N = 19,973), since only twins were eligible to receive follow-up questionnaires, as well as being healthy at baseline (N = 16,496, see below for criteria). Moreover, the questionnaire was sent in 1990 only to those whose twin partner was alive. Thus, from these eligible subjects, study subjects were those with all three life satisfaction scores available (N = 9679). They consisted of 4466 (46.1%) male and 5213 (53.9%) female twins (Table  1 ). The mean age (SD) at baseline was 28.8 years (7.5) for men and 28.1 years (7.6) for women. Those subjects who had incomplete follow-up data (N = 6817) were compared with study subjects. Their life satisfaction data was available as follows: 1) LS 1975 and 1981 (n = 4930); 2) LS 1975 and 1990 (n = 385); 3) LS 1975 only (n = 1502). Table 1 Baseline characteristics of the study subjects and those with incomplete follow-up data on life satisfaction*. Study subjects Subjects with incomplete follow-up p-value Baseline characteristics N (9679) column % N (6817) column % Sex <0.001 1)  Men 4466 46.1 3932 57.7  Women 5213 53.9 2885 42.3 Age-group <0.001 2)  18 – 25 4121 42.6 3100 45.5  16 – 35 3513 36.3 2431 35.6  36 – 45 2045 21.1 1286 18.9 Social class <0.001 3)  Upper 565 5.8 361 5.3  Intermediate 2695 27.8 2121 31.1  Lower 6419 66.4 4335 63.6 Marital status <0.001 4)  Cohabiting 5386 55.7 3443 50.6  Living alone 4291 44.3 3366 49.4 Smoking cigarettes daily <0.001 5)  Non-smoker 6698 69.3 3991 58.7  1 – 19 2344 24.2 2976 30.5  > 19 627 6.5 737 10.8 Pure alcohol g/month <0.001 6)  None 1361 14.1 807 11.9  1 – 99 4077 42.2 2334 34.3  100 – 399 2626 27.1 2076 30.5  400 – 799 1083 11.2 939 13.8  ≥ 800 524 5.4 648 9.3 Physical activity/month <0.01 7)  < 1 1138 12.2 888 13.7  1 – 5 4585 49.3 3045 46.9  ≥ 6 3577 38.5 2563 39.4 Life satisfaction in 1975 <0.001 8)  4 – 6 2214 22.9 1370 20.1  7 – 11 6239 64.4 4303 63.1  12 – 20 1226 12.7 1144 16.8 * Life satisfaction data not available from 1981 and/or 1990. 1)  F(1, 10007) = 165;  2)  F(2, 10006) = 7.02;  3)  F(2, 10006) = 9.17;  4)  F(1, 10002) = 36.1;  5)  F(2, 9995) = 94.0;  6)  F(4, 9995) = 45.0;  7)  F(2, 9786) = 5.50;  8)  F(2, 10006) = 29.0 The criteria for baseline health were based on a health questionnaire (Q) and three nationwide registries: the Hospital Discharge Registry (H), the Registry of Specially Refunded Medication (M) and the Cancer Registry (C). Thus, those with symptoms or diseases covering cardiovascular disease, diabetes, chronic obstructive pulmonary disease or malignant cancer, those who used medications for 37 selected chronic somatic or psychiatric diseases, as well as those who were on a work disability pension due to any cause or had an inpatient admission between 1972 and April 1976, were excluded [ 12 ]. The specific exclusion criteria for psychiatric disorders covered work disability (Q), inpatient treatment due to psychiatric causes (ICD-8: 290–309) (H), the right to free medication for psychosis before 1977 (M) and use of hypnotics/tranquilizers for more than 10 days in the preceding year (Q). It has previously been reported that 4-item life satisfaction is associated with a lower age, female sex, cohabiting, an upper social class, non-smoking, lower alcohol consumption and physical activity [ 9 , 12 , 13 ]. Thus, the multivariate model included baseline variables such as age (18–24/25–34/35–45), sex, marital status (married or cohabiting/single, divorced or widowed), social class (lower/intermediate/upper group), physical activity (at least 30 minutes of exercise < 1/1–5/ ≥ 6 times a month), current smoking status (non-smoker/1–19/ > 19 cigarettes daily) and alcohol consumption (none/1–99/100–399/400–799/ ≥ 800 g pure alcohol/month) [ 12 ]. The upper social class consisted of those with at least 13 years of education and sedentary work, while the lower social class consisted of those with less than 10 years of education and work involving at least standing and walking. Data analysis was carried out using STATA (version 7.0). Since a study subject could be an age- and sex-matched twin sibling of another study subject, not all the observations were necessarily independent. Therefore, correct standard errors were computed by treating each pair of twins as a single unit (i.e. cluster sampling). The statistical significance of differences was tested by estimates of means (SVYMEAN and SVYLC procedure) for continuous variables and by the chi-squared test for categorical variables (SVYTAB procedure), corrected for clustered data and converted into F-statistics. The stability of life satisfaction over time was examined by computing Pearsonian correlation coefficients between continuous variables. To study how former life dissatisfaction predicts later life dissatisfaction, linear and logistic regression for clustered data was used.
Methods
This prospective cohort study with a follow-up from 1975 to 1990 was based on the Finnish Twin Cohort, a nationwide sample of all Finnish same-sex twin pairs born before 1958 with both members alive in 1975. A baseline health questionnaire was sent in 1975 to twin candidates [ 25 ]. The follow-up questionnaires in 1981 and 1990 were sent only to verified twins. Furthermore, the 1990 questionnaire was sent only to twins from pairs born in 1930–1957 with both co-twins alive and residing in Finland. The overall response rates to the questionnaires were 89% in 1975, 84% in 1981 and 77% in 1990. The study procedure has been presented in detail elsewhere [ 12 , 25 ].The questionnaires included a four-question scale for life satisfaction, which was modified from a questionnaire developed for measuring the quality of life for research purposes in Nordic countries [ 26 ]. It has been used among all adult age-groups [ 9 , 12 ] as well as among psychiatric patients [ 9 , 10 , 27 ]. The study subjects were asked to rate aspects of life satisfaction: interest in life, happiness, ease of living and loneliness (very interesting/happy/easy/not at all lonely = 1, fairly interesting/happy/easy = 2, fairly boring/unhappy/hard/lonely = 4, very boring/unhappy/hard/lonely = 5).Missing data and the response 'cannot say' were scored as 3. If three or four items were missing, the sum score was recorded as 'missing'. Thus, the total score (LS) ranged from 4–20, with  increasing scores indicating a decrease in life satisfaction . On the basis of the distribution of the sum score (LS), subjects were categorized into the satisfied (LS:4–6), the intermediate group (LS:7–11) and the dissatisfied (LS:12–20) [ 12 ]. The intermediate group consisted of those with an LS score within one standard deviation from the mean [ 9 ]. At baseline, responses to all four items were provided by 95.8% (N = 22,416) and at least two items, enabling LS to be calculated, by 99.2% (N = 23,212) of all respondents aged 18–45 years. Thus, one or two missing values were recoded as '3' values for 3.4% of subjects.increasing scores indicating a decrease in life satisfactionThe criteria for inclusion in the present study were the availability of baseline life satisfaction data, an age of 18–45 years on 1 January 1976 and being a twin (N = 19,973), since only twins were eligible to receive follow-up questionnaires, as well as being healthy at baseline (N = 16,496, see below for criteria). Moreover, the questionnaire was sent in 1990 only to those whose twin partner was alive. Thus, from these eligible subjects, study subjects were those with all three life satisfaction scores available (N = 9679). They consisted of 4466 (46.1%) male and 5213 (53.9%) female twins (Table  1 ). The mean age (SD) at baseline was 28.8 years (7.5) for men and 28.1 years (7.6) for women. Those subjects who had incomplete follow-up data (N = 6817) were compared with study subjects. Their life satisfaction data was available as follows: 1) LS 1975 and 1981 (n = 4930); 2) LS 1975 and 1990 (n = 385); 3) LS 1975 only (n = 1502).Baseline characteristics of the study subjects and those with incomplete follow-up data on life satisfaction*.* Life satisfaction data not available from 1981 and/or 1990.1)  F(1, 10007) = 165;  2)  F(2, 10006) = 7.02;  3)  F(2, 10006) = 9.17;  4)  F(1, 10002) = 36.1;  5)  F(2, 9995) = 94.0;  6)  F(4, 9995) = 45.0;  7)  F(2, 9786) = 5.50;  8)  F(2, 10006) = 29.0The criteria for baseline health were based on a health questionnaire (Q) and three nationwide registries: the Hospital Discharge Registry (H), the Registry of Specially Refunded Medication (M) and the Cancer Registry (C). Thus, those with symptoms or diseases covering cardiovascular disease, diabetes, chronic obstructive pulmonary disease or malignant cancer, those who used medications for 37 selected chronic somatic or psychiatric diseases, as well as those who were on a work disability pension due to any cause or had an inpatient admission between 1972 and April 1976, were excluded [ 12 ]. The specific exclusion criteria for psychiatric disorders covered work disability (Q), inpatient treatment due to psychiatric causes (ICD-8: 290–309) (H), the right to free medication for psychosis before 1977 (M) and use of hypnotics/tranquilizers for more than 10 days in the preceding year (Q).It has previously been reported that 4-item life satisfaction is associated with a lower age, female sex, cohabiting, an upper social class, non-smoking, lower alcohol consumption and physical activity [ 9 , 12 , 13 ]. Thus, the multivariate model included baseline variables such as age (18–24/25–34/35–45), sex, marital status (married or cohabiting/single, divorced or widowed), social class (lower/intermediate/upper group), physical activity (at least 30 minutes of exercise < 1/1–5/ ≥ 6 times a month), current smoking status (non-smoker/1–19/ > 19 cigarettes daily) and alcohol consumption (none/1–99/100–399/400–799/ ≥ 800 g pure alcohol/month) [ 12 ]. The upper social class consisted of those with at least 13 years of education and sedentary work, while the lower social class consisted of those with less than 10 years of education and work involving at least standing and walking.Data analysis was carried out using STATA (version 7.0). Since a study subject could be an age- and sex-matched twin sibling of another study subject, not all the observations were necessarily independent. Therefore, correct standard errors were computed by treating each pair of twins as a single unit (i.e. cluster sampling). The statistical significance of differences was tested by estimates of means (SVYMEAN and SVYLC procedure) for continuous variables and by the chi-squared test for categorical variables (SVYTAB procedure), corrected for clustered data and converted into F-statistics. The stability of life satisfaction over time was examined by computing Pearsonian correlation coefficients between continuous variables. To study how former life dissatisfaction predicts later life dissatisfaction, linear and logistic regression for clustered data was used.Results The baseline characteristics of the study population and those whose follow-up data on life satisfaction was not available at all three data collection times is presented in Table  1 . Study subjects were more often women, cohabiting, non-smokers and used less alcohol than those whose follow-up data on life satisfaction was incomplete. There were also slight differences in social class and physical activity. Furthermore, study subjects were somewhat more satisfied (mean LS 8.23; 95%CI 8.18–8.29 vs. LS 8.61; 8.54–8.68) and slightly older (mean age 28.4; 28.2–28.6 vs. 27.9; 27.7–28.1) than those with incomplete follow-up data (Table  1 ). In the study population with complete follow-up data on life satisfaction, no marked differences were observed in mean LS scores between age or gender groups or measurement times (Table  2 ). There was only a slight decrease in mean life satisfaction during the follow-up of 15 years. The main decrease took place in women during 1981–1990. When birth cohorts were studied, only those born during 1940–49 showed a trend of decreasing satisfaction throughout the follow-up, regardless of gender, but they were also the most satisfied group at baseline, being then 26–35 years of age. Young men aged 18–25 at baseline were and remained the most dissatisfied group throughout the follow-up. Table 2 Mean (95% CI) life satisfaction (LS) according to sex, birth cohort and current age among 9679 Finnish adults in 1975, 1981 and 1990. Subjects (n) LS 1975 (n) LS 1981 (n) LS 1990 All (9679) 8.23 (8.18 – 8.29) (9679) 8.26 (8.20 – 8.31) (9679) 8.35 (8.29 – 8.41) Men (4466) 8.30 (8.22 – 8.38) (4466) 8.33 (8.25 – 8.41) (4466) 8.38 (8.30 – 8.46) Women (5213) 8.18 (8.10 – 8.25) (5213) 8.19 (8.12 – 8.27) (5213) 8.32 (8.24 – 8.40) Birth cohorts, all 1950 – 57 (4121) 8.46 (8.36 – 8.55) (4121) 8.31 (8.23 – 8.40) (4121) 8.45 (8.36 – 8.54) 1940 – 49 (3513) 7.98 (7.90 – 8.07) (3513) 8.13 (8.05 – 8.22) (3513) 8.32 (8.22 – 8.41) 1930 – 39 (2045) 8.22 (8.11 – 8.32) (2045) 8.35 (8.23 – 8.46) (2045) 8.19 (8.08 – 8.31) Current age, all 18 – 23 (3254) 8.50 (8.40 – 8.61) - - - - 24 – 32 (3608) 8.04 (7.96 – 8.13) (4520) 8.28 (8.20 – 8.36) - - 33 – 45 (2817) 8.17 (8.08 – 8.26) (4101) 8.19 (8.11 – 8.27) (6236) 8.39 (8.31 – 8.46) 46 – 51 (1058) 8.39 (8.23 – 8.55) (1679) 8.37 (8.23 – 8.50) 52 – 60 - - (1764) 8.18 -(8.06 – 8.30) In terms of 3-category LS scores (Table  3 ), more than half (56%) of the study subjects in 1990 scored in the same category as they did in 1975, but the relationship was less stable for the satisfied (36%) and the dissatisfied (31%) than the intermediate group (69%). However, only 5.9% of the study subjects were satisfied (LS 4–6) at one of the three data collection times but dissatisfied (LS12-20) at one of the other time points. Table 3 The distribution of study subjects according to their self-reported life satisfaction (LS*) in 1975 and 1990. LS 1990 Satisfied Intermediate Dissatisfied TOTAL N row % N row % N row % N row % LS 1975 Satisfied 785 35.5 1266 57.2 163 7.4 2214 100 Intermediate 1088 17.4 4293 68.8 858 13.8 6239 100 Dissatisfied 122 10.0 728 59.4 376 30.7 1226 100 TOTAL 1995 20.6 6287 65.0 1397 14.4 9679 100 * Life satisfaction score: satisfied (LS 4–6); intermediate (LS 7–11); dissatisfied (LS 12–20). The correlation was 0.30 between continuous life satisfaction scores in 1975 and 1990, 0.38 between 1975 and 1981 scores and 0.40 between 1981 and 1990 scores. These coefficients were similar for men and women, but lowest among those aged 18–25 (0.26, 0.34 and 0.39, respectively) and highest among those aged 36–45 (0.36, 0.47 and 0.42, respectively). For the total study population the annual auto-correlation was estimated as 0.92 during 1975–90. Baseline life dissatisfaction predicted future life dissatisfaction (Table  4 ). This was also true after adjusting for all the covariates as well as when the categories of each covariate were separately investigated. The same pattern was shown both with categorical and continuous life satisfaction scores. The predictive ability was expectedly stronger for the shorter follow-up (1975–1981) than for the total follow-up (1975–1990). When the odds ratios were compared with those which could be calculated for the subjects with incomplete life satisfaction follow-up data, no significant differences were found. Table 4 Prediction of future dissatisfaction (LS 12–20*) according to baseline dissatisfaction. Risk (OR with 95%CI) for the dissatisfied (LS 12–20) compared to the satisfied (LS 4–6) at baseline. COMPARISON OF LS SCORES BETWEEN 1975 & 1981 1975 & 1990 Subjects (n) OR (95 % CI) OR (95 % CI) All † 9679 10.42 (8.28 – 13.10) 5.56 (4.55 – 6.80)  Adjusted ‡ 9283 9.79 (7.68 – 12.47) 5.23 (4.24 – 6.46) Men † 4466 14.81 (10.19 – 21.51) 6.11 (4.47 – 8.35)  Adjusted ‡ 4298 12.86 (8.74 – 18.91) 5.62 (4.05 – 7.80) Women † 5213 7.93 (5.89 – 10.68) 5.29 (4.06 – 6.90)  Adjusted ‡ 4985 7.94 (5.78 – 10.92) 4.98 (3.78 – 6.56) * Risk of future dissatisfaction : LS 12–20 vs. LS 4–12 † Adjusted for age ‡ Adjusted simultaneously for age, sex, marital status, social class, alcohol consumption, current smoking and physical activity (cf. method section).
Results
The baseline characteristics of the study population and those whose follow-up data on life satisfaction was not available at all three data collection times is presented in Table  1 . Study subjects were more often women, cohabiting, non-smokers and used less alcohol than those whose follow-up data on life satisfaction was incomplete. There were also slight differences in social class and physical activity. Furthermore, study subjects were somewhat more satisfied (mean LS 8.23; 95%CI 8.18–8.29 vs. LS 8.61; 8.54–8.68) and slightly older (mean age 28.4; 28.2–28.6 vs. 27.9; 27.7–28.1) than those with incomplete follow-up data (Table  1 ).In the study population with complete follow-up data on life satisfaction, no marked differences were observed in mean LS scores between age or gender groups or measurement times (Table  2 ). There was only a slight decrease in mean life satisfaction during the follow-up of 15 years. The main decrease took place in women during 1981–1990. When birth cohorts were studied, only those born during 1940–49 showed a trend of decreasing satisfaction throughout the follow-up, regardless of gender, but they were also the most satisfied group at baseline, being then 26–35 years of age. Young men aged 18–25 at baseline were and remained the most dissatisfied group throughout the follow-up.Mean (95% CI) life satisfaction (LS) according to sex, birth cohort and current age among 9679 Finnish adults in 1975, 1981 and 1990.In terms of 3-category LS scores (Table  3 ), more than half (56%) of the study subjects in 1990 scored in the same category as they did in 1975, but the relationship was less stable for the satisfied (36%) and the dissatisfied (31%) than the intermediate group (69%). However, only 5.9% of the study subjects were satisfied (LS 4–6) at one of the three data collection times but dissatisfied (LS12-20) at one of the other time points.The distribution of study subjects according to their self-reported life satisfaction (LS*) in 1975 and 1990.* Life satisfaction score: satisfied (LS 4–6); intermediate (LS 7–11); dissatisfied (LS 12–20).The correlation was 0.30 between continuous life satisfaction scores in 1975 and 1990, 0.38 between 1975 and 1981 scores and 0.40 between 1981 and 1990 scores. These coefficients were similar for men and women, but lowest among those aged 18–25 (0.26, 0.34 and 0.39, respectively) and highest among those aged 36–45 (0.36, 0.47 and 0.42, respectively). For the total study population the annual auto-correlation was estimated as 0.92 during 1975–90.Baseline life dissatisfaction predicted future life dissatisfaction (Table  4 ). This was also true after adjusting for all the covariates as well as when the categories of each covariate were separately investigated. The same pattern was shown both with categorical and continuous life satisfaction scores. The predictive ability was expectedly stronger for the shorter follow-up (1975–1981) than for the total follow-up (1975–1990). When the odds ratios were compared with those which could be calculated for the subjects with incomplete life satisfaction follow-up data, no significant differences were found.Prediction of future dissatisfaction (LS 12–20*) according to baseline dissatisfaction. Risk (OR with 95%CI) for the dissatisfied (LS 12–20) compared to the satisfied (LS 4–6) at baseline.* Risk of future dissatisfaction : LS 12–20 vs. LS 4–12† Adjusted for age‡ Adjusted simultaneously for age, sex, marital status, social class, alcohol consumption, current smoking and physical activity (cf. method section).Discussion Life satisfaction was moderately stable in healthy adult Finns during a 15 year period. Age or the birth-cohort had only a slight effect on mean life satisfaction. One third of those dissatisfied at baseline remained the same after the 15-year follow-up. The ability of baseline life satisfaction to predict future life satisfaction was strong, but decreased during the follow-up period, which is a trend that has also been suggested previously [ 23 ]. Previous studies have indicated that depression and depressive symptoms may have a chronic course [ 2 - 6 ]. On the other hand, in non-patient samples subjective well-being has also been suggested to be stable [ 17 - 22 ]. Concomitant anxiety or personality traits might play a role in this [ 28 - 32 ]. However, our results concerning the possible chronic course of life dissatisfaction are now based on a very long follow-up and a large sample of adults who reported or were found to have no indication of sickness at baseline. Although regression towards the mean in life satisfaction score was shown in the follow-up and greater instability among the dissatisfied and the satisfied than in the intermediate group, a complete shift from one extreme to another was rare. In Finland the number of new work disability pensions due to depression has strongly increased [ 33 ]. However, at the population level, subjective well-being seems not to have decreased correspondingly according to a comparison of two separate cross-sectional national surveys in 1980 and 2000 using the 12-item General Health Questionnaire [ 34 ]. Our cohort study with the 4-item life satisfaction scale measured three times during a 15-year follow-up on the same population strengthens these findings. On the other hand, during these years the physical health of the Finnish population has improved in many objectively assessed ways [ 34 ], but an improvement has not been seen in mental health indicators or in life satisfaction at population level. Thus, objectively assessed better somatic health or strong national economic growth (an increase of 48% in inflation-adjusted gross national income per capita from 1975 to 1990), which has also taken place during these years, seems not to guarantee better subjective well-being in a population that is globally speaking already quite well-off. This kind of trend has also been suggested previously [ 16 , 32 , 35 ]. On the contrary, the mean level of subjective well-being, which was previously sufficient to maintain work ability, seems not to meet the requirements of today's working life. Our results with respect to predictions seemed not to be overestimations. Those subjects whose dissatisfaction might have led to the most adverse result, i.e. death, were excluded from our study. The response to follow-up surveys was somewhat lower among the dissatisfied, but the observed risks among the study subjects did not differ statistically significantly from those obtained from the subjects with incomplete follow-up data. Similarly, when adjusting for follow-up health behavior instead of baseline health behavior variables, these predictions strengthened slightly, but not significantly. The 4-item life satisfaction scale is easily administered and well accepted. Its sum score was available for 96% (with imputed scores for 99%) of all respondents at baseline [ 12 , 13 ]. This might be due to the low number of items and its ability to tap the positive pole of subjective well-being [ 7 ], even if its sum score is also strongly associated with scores obtained by the 21-item Beck Depression Inventory [ 10 , 11 , 13 , 36 ]. In the general population, life dissatisfaction predicts both fatal and non-fatal poor long-term health outcomes [ 11 - 15 ]. Thus, it is worthwhile to assess subjective well-being. In general, if only poor subjective well-being is detected, our long follow-up suggests that there seems to be time to intervene. To prevent a process from leading to more adverse outcomes, subjects should acknowledge their situation and use their own personal resources, if available. According to a panel of experts, the concept of mental health can be regarded as a developmental process providing an individual or a group with the necessary resources to cope with the demands of life without the simultaneous appearance of negatively experienced moods of longer duration [ 37 ]. Society and health care services should support the growth of personal resources and start to intervene when these resources are inadequate and poor subjective well-being persists. In psychiatry, however, according to Vaillant, "since primary prevention is clearly superior to treating disease once it has occurred, we need to study also individuals with positive mental health the way that agronomists study wheat that is resistant to drought and blight" [ 16 ]. Our large nationwide sample with a high response rate and a long follow-up period enabled an examination of the long-term course of life satisfaction. The exclusion criteria for baseline health disorders were comprehensive and based on both self-reports and several national registries with high coverage and validity [ 38 - 41 ]. Although these analyses were performed on individuals drawn from a twin cohort, the results should be applicable to the general population. Being a twin does not affect the predictive ability of life satisfaction for mortality or suicide [ 12 , 13 ], and there is at most only a modest contribution of genetics to inter-individual differences in life satisfaction [ 42 ]. However, the potential influence of twinship was taken into account in the statistical analysis. The arbitrary exclusion of those twins who did not have a living twin partner in 1990, required in the composition of the Twin Finnish Cohort data, enabled us to control for the loss of a twin sibling.
Discussion
Life satisfaction was moderately stable in healthy adult Finns during a 15 year period. Age or the birth-cohort had only a slight effect on mean life satisfaction. One third of those dissatisfied at baseline remained the same after the 15-year follow-up. The ability of baseline life satisfaction to predict future life satisfaction was strong, but decreased during the follow-up period, which is a trend that has also been suggested previously [ 23 ].Previous studies have indicated that depression and depressive symptoms may have a chronic course [ 2 - 6 ]. On the other hand, in non-patient samples subjective well-being has also been suggested to be stable [ 17 - 22 ]. Concomitant anxiety or personality traits might play a role in this [ 28 - 32 ]. However, our results concerning the possible chronic course of life dissatisfaction are now based on a very long follow-up and a large sample of adults who reported or were found to have no indication of sickness at baseline. Although regression towards the mean in life satisfaction score was shown in the follow-up and greater instability among the dissatisfied and the satisfied than in the intermediate group, a complete shift from one extreme to another was rare.In Finland the number of new work disability pensions due to depression has strongly increased [ 33 ]. However, at the population level, subjective well-being seems not to have decreased correspondingly according to a comparison of two separate cross-sectional national surveys in 1980 and 2000 using the 12-item General Health Questionnaire [ 34 ]. Our cohort study with the 4-item life satisfaction scale measured three times during a 15-year follow-up on the same population strengthens these findings. On the other hand, during these years the physical health of the Finnish population has improved in many objectively assessed ways [ 34 ], but an improvement has not been seen in mental health indicators or in life satisfaction at population level. Thus, objectively assessed better somatic health or strong national economic growth (an increase of 48% in inflation-adjusted gross national income per capita from 1975 to 1990), which has also taken place during these years, seems not to guarantee better subjective well-being in a population that is globally speaking already quite well-off. This kind of trend has also been suggested previously [ 16 , 32 , 35 ]. On the contrary, the mean level of subjective well-being, which was previously sufficient to maintain work ability, seems not to meet the requirements of today's working life.Our results with respect to predictions seemed not to be overestimations. Those subjects whose dissatisfaction might have led to the most adverse result, i.e. death, were excluded from our study. The response to follow-up surveys was somewhat lower among the dissatisfied, but the observed risks among the study subjects did not differ statistically significantly from those obtained from the subjects with incomplete follow-up data. Similarly, when adjusting for follow-up health behavior instead of baseline health behavior variables, these predictions strengthened slightly, but not significantly.The 4-item life satisfaction scale is easily administered and well accepted. Its sum score was available for 96% (with imputed scores for 99%) of all respondents at baseline [ 12 , 13 ]. This might be due to the low number of items and its ability to tap the positive pole of subjective well-being [ 7 ], even if its sum score is also strongly associated with scores obtained by the 21-item Beck Depression Inventory [ 10 , 11 , 13 , 36 ]. In the general population, life dissatisfaction predicts both fatal and non-fatal poor long-term health outcomes [ 11 - 15 ]. Thus, it is worthwhile to assess subjective well-being. In general, if only poor subjective well-being is detected, our long follow-up suggests that there seems to be time to intervene.To prevent a process from leading to more adverse outcomes, subjects should acknowledge their situation and use their own personal resources, if available. According to a panel of experts, the concept of mental health can be regarded as a developmental process providing an individual or a group with the necessary resources to cope with the demands of life without the simultaneous appearance of negatively experienced moods of longer duration [ 37 ]. Society and health care services should support the growth of personal resources and start to intervene when these resources are inadequate and poor subjective well-being persists. In psychiatry, however, according to Vaillant, "since primary prevention is clearly superior to treating disease once it has occurred, we need to study also individuals with positive mental health the way that agronomists study wheat that is resistant to drought and blight" [ 16 ].Our large nationwide sample with a high response rate and a long follow-up period enabled an examination of the long-term course of life satisfaction. The exclusion criteria for baseline health disorders were comprehensive and based on both self-reports and several national registries with high coverage and validity [ 38 - 41 ]. Although these analyses were performed on individuals drawn from a twin cohort, the results should be applicable to the general population. Being a twin does not affect the predictive ability of life satisfaction for mortality or suicide [ 12 , 13 ], and there is at most only a modest contribution of genetics to inter-individual differences in life satisfaction [ 42 ]. However, the potential influence of twinship was taken into account in the statistical analysis. The arbitrary exclusion of those twins who did not have a living twin partner in 1990, required in the composition of the Twin Finnish Cohort data, enabled us to control for the loss of a twin sibling.Conclusions Life satisfaction among healthy adult Finns was moderately stable in a 15-year follow-up. Since the dissatisfied, one third of whom consistently rated themselves as dissatisfied, can be identified from the general population, and since dissatisfaction places them at a risk, and repeatedly reported dissatisfaction at even greater risk, of adverse health outcomes, assessing subjective well-being should be encouraged both in surveys and in clinical practice in order to identify those in need of further evaluation of their mental health.
Conclusions
Life satisfaction among healthy adult Finns was moderately stable in a 15-year follow-up. Since the dissatisfied, one third of whom consistently rated themselves as dissatisfied, can be identified from the general population, and since dissatisfaction places them at a risk, and repeatedly reported dissatisfaction at even greater risk, of adverse health outcomes, assessing subjective well-being should be encouraged both in surveys and in clinical practice in order to identify those in need of further evaluation of their mental health.Competing interest The author(s) declare that they have no competing interest.
Competing interest
The author(s) declare that they have no competing interest.Authors' contributions KJ participated in composing the Finnish Twin Cohort data, in planning, commenting on, revising and approving the final manuscript. KM participated in composing the Finnish Twin Cohort data, in planning, commenting on, revising and approving the final manuscript. HR participated in planning, commenting on, revising and approving the final manuscript. HV participated in planning, commenting on, revising and approving the final manuscript. KHH planned the study, performed the statistical analyses and was the main author.
Authors' contributions
KJ participated in composing the Finnish Twin Cohort data, in planning, commenting on, revising and approving the final manuscript.KM participated in composing the Finnish Twin Cohort data, in planning, commenting on, revising and approving the final manuscript.HR participated in planning, commenting on, revising and approving the final manuscript.HV participated in planning, commenting on, revising and approving the final manuscript.KHH planned the study, performed the statistical analyses and was the main author.Pre-publication history The pre-publication history for this paper can be accessed here:
Pre-publication history
The pre-publication history for this paper can be accessed here:


Welcome to  CytoJournal ! We would like to introduce you to your journal, one that is run by and for the scientific cytopathology community with incontestable benefits of Open Access, and support from Cytopathology Foundation, Inc.  CytoJournal  is a peer-reviewed, PubMed indexed, online journal, publishing research in the field of cytopathology and related areas, with world wide free access. Authors submitting to CytoJournal retain the copyright to their hard earned work.CytoJournalCytoJournal

Welcome to CytoJournal  ! We would like to introduce you to your journal, one that is run by and for the scientific cytopathology community with incontestable benefits of Open Access  .  CytoJournal  is a peer-reviewed cytopathology journal is owned and supported by Cytopathology Fondation, Inc.   It is a PubMed indexed, online journal, publishing research in the field of cytopathology and related areas with world wide free access. Authors submitting to CytoJournal retain the copyright to their hard earned work.

Welcome to CytoJournal  ! We would like to introduce you to your journal, one that is run by and for the scientific cytopathology community with incontestable benefits of Open Access  .  CytoJournal  is a peer-reviewed cytopathology journal is owned and supported by Cytopathology Fondation, Inc.   It is a PubMed indexed, online journal, publishing research in the field of cytopathology and related areas with world wide free access. Authors submitting to CytoJournal retain the copyright to their hard earned work.CytoJournalWhy CytoJournal is needed One could argue whether we need more journals in cytopathology, but without a shadow of doubt there is a global need for greater access to scientific information in this field. As an Open Access journal CytoJournal will meet this need, by removing subscription barriers. Communication in general has been revolutionized in the last decade. With the emergence of the internet, entire libraries of scientific information are potentially just a mouse click away. Open Access to quality controlled, scientific information to the general public and scientific community alike is extremely valuable for harvesting the fruits of hard work by academicians. However, to date little has been done to realize the potential of this technological revolution. It is now affordable to make our hard earned scientific information available to a much wider audience. Millions of students, teachers, physicians, scientists, general public, and other potential readers can have free access to the gold mine of this scientific information. The traditional model for journal publication has performed an admirable job of disseminating research and advancing science. Unfortunately, it neither can fully utilize recent technology nor extend its benefits to the scientific community and the general public. Principally, why should scientific information generated by academicians and published without charge, not be freely available? Giving away the copyrights to the original research reports and then paying for access of the same material is paradoxically anachronistic. With the advent of the internet and image digitization, the time has come for the development and implementation of a new model – a model beneficial to the scientific community and general public, alike. The recent adoption of an Open Access model by the Public Library of Science (PLoS) [ 1 ] and its recognition by other scientific organizations, including the National Institute of Health (NIH), has generated significant community interest. This has provided impetus for the creation of new journals such as  CytoJournal  with increasing support to open access philosophy by some of the existing leading journals. The benefits of an online journal can include rapid turnaround time, real time publication, significant cost savings, and a reduction in the environmental burden engendered in the production and disposal of a print publication. Presumably in the future, the majority of research publications will be of this type [ 2 ]. Free flow of scientific information is crucial for advancements in diagnosis and management of diseases in both the developed and developing world. Simply providing a conduit of information is not enough. There is one matter involving the human element that must be dealt with – peer review. We do not see a future where authors post their manuscripts on the web without peer-review. Science requires that publications be properly vetted (peer-reviewed) and experimental findings logically presented. In brief, standards must be maintained! This critical role is played by peer review. Acting on behalf of the scientific community, it is peer review that helps the scientific community distinguish between legitimate scientific work and quackery [ 3 - 7 ]. Thus, to maintain the quality and confidence, peer review will continue to be the keystone of scientific publishing. The peer-review process at CytoJournal combines the expertise of both professional editors, who are available to survey the broad landscape of cytopathology, and academic editors, who understand deeply the strengths and limitations of their specific area of research. Every article that is published in CytoJournal will be reviewed carefully by selected reviewers, in addition to evaluation by a managing/academic editor and professional editor, who work together throughout the editorial process. A summary of your peer review process is illustrated in Figure  1 . Figure 1 CytoJournal's online peer review process.
Why CytoJournal is needed
One could argue whether we need more journals in cytopathology, but without a shadow of doubt there is a global need for greater access to scientific information in this field. As an Open Access journal CytoJournal will meet this need, by removing subscription barriers.Communication in general has been revolutionized in the last decade. With the emergence of the internet, entire libraries of scientific information are potentially just a mouse click away. Open Access to quality controlled, scientific information to the general public and scientific community alike is extremely valuable for harvesting the fruits of hard work by academicians.However, to date little has been done to realize the potential of this technological revolution. It is now affordable to make our hard earned scientific information available to a much wider audience. Millions of students, teachers, physicians, scientists, general public, and other potential readers can have free access to the gold mine of this scientific information.The traditional model for journal publication has performed an admirable job of disseminating research and advancing science. Unfortunately, it neither can fully utilize recent technology nor extend its benefits to the scientific community and the general public. Principally, why should scientific information generated by academicians and published without charge, not be freely available? Giving away the copyrights to the original research reports and then paying for access of the same material is paradoxically anachronistic.With the advent of the internet and image digitization, the time has come for the development and implementation of a new model – a model beneficial to the scientific community and general public, alike. The recent adoption of an Open Access model by the Public Library of Science (PLoS) [ 1 ] and its recognition by other scientific organizations, including the National Institute of Health (NIH), has generated significant community interest. This has provided impetus for the creation of new journals such as  CytoJournal  with increasing support to open access philosophy by some of the existing leading journals.CytoJournalThe benefits of an online journal can include rapid turnaround time, real time publication, significant cost savings, and a reduction in the environmental burden engendered in the production and disposal of a print publication. Presumably in the future, the majority of research publications will be of this type [ 2 ].Free flow of scientific information is crucial for advancements in diagnosis and management of diseases in both the developed and developing world. Simply providing a conduit of information is not enough. There is one matter involving the human element that must be dealt with – peer review. We do not see a future where authors post their manuscripts on the web without peer-review. Science requires that publications be properly vetted (peer-reviewed) and experimental findings logically presented.In brief, standards must be maintained! This critical role is played by peer review. Acting on behalf of the scientific community, it is peer review that helps the scientific community distinguish between legitimate scientific work and quackery [ 3 - 7 ]. Thus, to maintain the quality and confidence, peer review will continue to be the keystone of scientific publishing.The peer-review process at CytoJournal combines the expertise of both professional editors, who are available to survey the broad landscape of cytopathology, and academic editors, who understand deeply the strengths and limitations of their specific area of research. Every article that is published in CytoJournal will be reviewed carefully by selected reviewers, in addition to evaluation by a managing/academic editor and professional editor, who work together throughout the editorial process. A summary of your peer review process is illustrated in Figure  1 .Definition of Open Access CytoJournal's Open Access  policy changes the way in which articles are published. First, all articles become freely and universally accessible online, and so an author's work can be read by anyone, free of charge. Second, the authors hold copyright for their work and grant anyone the right to reproduce and disseminate the article, provided that it is correctly cited and no errors are introduced [ 8 ]. Third, a copy of the full text of each Open Access article is permanently archived in an online repository separate from the journal.  CytoJournal's  articles are archived in PubMed Central [ 9 ], the US National Library of Medicine's full-text repository of life science literature, and also in repositories at the University of Potsdam [ 10 ] in Germany, at INIST [ 11 ] in France and in e-Depot, the National Library of the Netherlands' digital archive of all electronic publications [ 12 ].
Definition of Open Access
CytoJournal's Open Access  policy changes the way in which articles are published. First, all articles become freely and universally accessible online, and so an author's work can be read by anyone, free of charge. Second, the authors hold copyright for their work and grant anyone the right to reproduce and disseminate the article, provided that it is correctly cited and no errors are introduced [ 8 ]. Third, a copy of the full text of each Open Access article is permanently archived in an online repository separate from the journal.  CytoJournal's  articles are archived in PubMed Central [ 9 ], the US National Library of Medicine's full-text repository of life science literature, and also in repositories at the University of Potsdam [ 10 ] in Germany, at INIST [ 11 ] in France and in e-Depot, the National Library of the Netherlands' digital archive of all electronic publications [ 12 ].CytoJournal's Open AccessCytoJournal'sBenefits of Open Access Open Access has four broad benefits for science and the general public. First, authors are assured that their work is disseminated to the widest possible audience, given that there are no barriers to their work. This is accentuated by the authors being free to reproduce and distribute their work, for example by placing it on their institution's website. It has been suggested that free online articles are more highly cited because of their easier availability [ 13 ]. Second, the information available to researchers will not be limited by their library's budget, and the widespread availability of articles will enhance literature searching [ 14 ]. Third, the results of publicly funded research will be accessible to all taxpayers and not just those with access to a library with a subscription. As such, Open Access could help to increase public interest in, and support of, research. Note that this public accessibility may become a legal requirement in the USA if the proposed Public Access to Science Act is made law [ 15 ]. Fourth, a country's economy will not influence its scientists' ability to access articles because resource-poor countries (and institutions) will be able to read the same material as wealthier ones (although creating access to the internet is another matter) [ 16 ].
Benefits of Open Access
Open Access has four broad benefits for science and the general public. First, authors are assured that their work is disseminated to the widest possible audience, given that there are no barriers to their work. This is accentuated by the authors being free to reproduce and distribute their work, for example by placing it on their institution's website. It has been suggested that free online articles are more highly cited because of their easier availability [ 13 ]. Second, the information available to researchers will not be limited by their library's budget, and the widespread availability of articles will enhance literature searching [ 14 ]. Third, the results of publicly funded research will be accessible to all taxpayers and not just those with access to a library with a subscription. As such, Open Access could help to increase public interest in, and support of, research. Note that this public accessibility may become a legal requirement in the USA if the proposed Public Access to Science Act is made law [ 15 ]. Fourth, a country's economy will not influence its scientists' ability to access articles because resource-poor countries (and institutions) will be able to read the same material as wealthier ones (although creating access to the internet is another matter) [ 16 ].Open Access Publishing Model and Finance Open Access facilitates the transformation of scientific literature from rows of printed journals on library shelves to an instantly searchable archive of data. Liberating scientific literature from the vestiges of paper publication introduces the potential of various opportunities such as navigating, integrating, mining, annotating, and mapping connections in the high-dimensional space of scientific knowledge. To provide Open Access,  CytoJournal  will use a new business model. Our editorial expenses (managing peer review, providing editorial insight, and ensuring the highest production standards) will be supported by corporate sponsors through Cytopathology Foundation, Inc.   and honorary  pro bono  services by the academicians (Figure  2 ). The publication cost for our publishers, BioMed Central, will be recovered by imposing a modest charge (currently US$ 525) to authors for each article accepted for publication after peer review. There is no charge for the submission of a manuscript and therefore, if the manuscript is submitted but not accepted for publication, the authors will not be charged. Figure 2 Core Principles of 'CytoJournal' and 'Cytopathology-Foundation' Our sponsors do not influence in any way the content of  CytoJournal  and it's editorial and publication decisions. However, they will be acknowledged and their links will be displayed on the home page of CytoJournal as a  thank you  note.
Open Access Publishing Model and Finance
Open Access facilitates the transformation of scientific literature from rows of printed journals on library shelves to an instantly searchable archive of data. Liberating scientific literature from the vestiges of paper publication introduces the potential of various opportunities such as navigating, integrating, mining, annotating, and mapping connections in the high-dimensional space of scientific knowledge.To provide Open Access,  CytoJournal  will use a new business model. Our editorial expenses (managing peer review, providing editorial insight, and ensuring the highest production standards) will be supported by corporate sponsors through Cytopathology Foundation, Inc.   and honorary  pro bono  services by the academicians (Figure  2 ). The publication cost for our publishers, BioMed Central, will be recovered by imposing a modest charge (currently US$ 525) to authors for each article accepted for publication after peer review. There is no charge for the submission of a manuscript and therefore, if the manuscript is submitted but not accepted for publication, the authors will not be charged.CytoJournalpro bonoOur sponsors do not influence in any way the content of  CytoJournal  and it's editorial and publication decisions. However, they will be acknowledged and their links will be displayed on the home page of CytoJournal as a  thank you  note.CytoJournalthank youFee Waivers We understand that there are many scientists who might wish to publish in our journal but do not have access to grant funds or institutional support. For such authors, a decision can be made by the Editors-in-Chief to waive publication fees. Furthermore, the fee will automatically be waived for authors from institutes that are members of BioMed Central  . We never want our publication charges to be a barrier to publication and are committed to publishing any manuscript that our editors and reviewers deem to be appropriate for the journal; we will treat the costs of handling these papers as a fundamental expense of running a high-quality journal through support from Cytopathology Foundation Inc.
Fee Waivers
We understand that there are many scientists who might wish to publish in our journal but do not have access to grant funds or institutional support. For such authors, a decision can be made by the Editors-in-Chief to waive publication fees. Furthermore, the fee will automatically be waived for authors from institutes that are members of BioMed Central  . We never want our publication charges to be a barrier to publication and are committed to publishing any manuscript that our editors and reviewers deem to be appropriate for the journal; we will treat the costs of handling these papers as a fundamental expense of running a high-quality journal through support from Cytopathology Foundation Inc.Joining Forces CytoJournal  is your journal and you can lead the way. However, we have to face and overcome a few traditional obstacles. First, an unfamiliarity to the Open Access model. Second, lack of the benefits of an established "brand name" aura. Because of this, despite stringent standards and an extraordinary editorial team,  CytoJournal  may have an uphill task. Private foundations with a commitment to science and education have contributed generously to the cause. Like any new business, Cytopathology Foundation Inc. needed to raise funds to cover our startup costs. Initial support from Cytopathology Foundation Inc. and the publisher, BioMed Central, has enabled us to launch  CytoJournal . Other individuals and organizations   have also provided generous and welcome support. The start-up support made it possible to assemble an outstanding editorial board and staff, who have accomplished an extraordinary feat of launching this new premiere journal in cytopathology. We wish to thank and applaud the efforts and spirit of the pioneering authors who chose to send their articles to  CytoJournal . In the end, it is the contributions by authors like you that will make  CytoJournal  a collective success. We encourage you to participate in the future of  CytoJournal  by reading, citing, submitting manuscript, sending any suggestions, and joining the panel of core reviewers. Bookmark the home page of  Cytojournal   for your quick reference! You may also link  CytoJournal  web site or recommend its linking through various other web sites.
Joining Forces
CytoJournal  is your journal and you can lead the way. However, we have to face and overcome a few traditional obstacles. First, an unfamiliarity to the Open Access model. Second, lack of the benefits of an established "brand name" aura. Because of this, despite stringent standards and an extraordinary editorial team,  CytoJournal  may have an uphill task.CytoJournalCytoJournalPrivate foundations with a commitment to science and education have contributed generously to the cause. Like any new business, Cytopathology Foundation Inc. needed to raise funds to cover our startup costs. Initial support from Cytopathology Foundation Inc. and the publisher, BioMed Central, has enabled us to launch  CytoJournal . Other individuals and organizations   have also provided generous and welcome support. The start-up support made it possible to assemble an outstanding editorial board and staff, who have accomplished an extraordinary feat of launching this new premiere journal in cytopathology.CytoJournalWe wish to thank and applaud the efforts and spirit of the pioneering authors who chose to send their articles to  CytoJournal . In the end, it is the contributions by authors like you that will make  CytoJournal  a collective success. We encourage you to participate in the future of  CytoJournal  by reading, citing, submitting manuscript, sending any suggestions, and joining the panel of core reviewers.CytoJournalCytoJournalCytoJournalBookmark the home page of  Cytojournal   for your quick reference! You may also link  CytoJournal  web site or recommend its linking through various other web sites.CytojournalCytoJournal