Bidirectional associations between insomnia symptoms and unhealthy behaviours

It has been suggested that there are associations among insomnia symptoms and unhealthy behaviours. However, previous studies are sparse and mainly cross-sectional, and have not been focused on several key unhealthy behaviours. The aim of this study was to examine whether the associations are bidirectional, i.e. whether insomnia symptoms are associated with subsequent unhealthy behaviours, and whether unhealthy behaviours are associated with subsequent insomnia symptoms. The data were derived from the Helsinki Health Study prospective cohort study. The baseline data were collected in 2000-02 (n = 8960, response rate 67%) among 40-60-year-old employees of the City Helsinki, Finland. The follow-up data were collected in 2007 (n = 7332, response rate 83%). Logistic regression analysis was used to examine the associations among insomnia symptoms and unhealthy behaviours, including smoking, heavy and binge drinking, physical inactivity and unhealthy food habits. Frequent insomnia symptoms at baseline were associated with subsequent heavy drinking [odds ratio (OR): 1.34; 95% confidence interval (CI): 1.07-1.68] and physical inactivity (OR: 1.27; 95% CI: 1.08-1.48) after full adjustment for gender, age, corresponding unhealthy behaviour at baseline, marital status, occupational class, sleep duration and common mental disorders. Additionally, heavy drinking (OR: 1.48; 95% CI: 1.22-1.80) and binge drinking (OR: 1.26; 95% CI: 1.08-1.46) at baseline were associated with subsequent insomnia symptoms at follow-up after full adjustment. In conclusion, insomnia symptoms were associated with subsequent heavy drinking and physical inactivity, and heavy and binge drinking were also associated with subsequent insomnia symptoms.

Associations of relative weight with subsequent changes over time in insomnia symptoms: a follow-up study among middle-aged women and men

BACKGROUND

Obese people tend to report more insomnia symptoms than their normal-weight counterparts. However, longitudinal studies are sparse. We aimed to examine whether relative weight is associated with changes over time in insomnia symptoms.

METHODS

The data were derived from the prospective Helsinki Health Study cohort among 40-60-year-old employees of the City of Helsinki. Baseline survey data were collected in 2000-2002 (n=8960, response rate 67%) and follow-up data in 2007 (n=7332, response rate 83%). Body mass index (BMI) was calculated from self-reported height and weight. Insomnia symptoms were measured at baseline and follow-up. Multinomial logistic regression analysis was used.

RESULTS

45% of women and 59% of men were overweight or obese at baseline. Most participants reported at least occasional or transient insomnia symptoms, with 29% of women and 34% of men reporting no or rare symptoms at both time points. Adjusting for age, baseline BMI was strongly associated with persistent and increasing insomnia symptoms. The associations mainly remained after adjustments for marital status, occupational class, alcohol consumption, physical inactivity, common mental disorders, physical health, and employment status.

CONCLUSION

BMI is a strong determinant of persistent and increasing insomnia symptoms. Successful maintenance of a healthy body weight probably helps prevent insomnia symptoms, and their increase and persistence, among both women and men.

Household economic resources, labour-market advantage and health problems - a study on causal relationships using prospective register data

Our aim was to find out whether the associations between health and both individual and household economic position reflected a causal effect on health of household affluence and consumption potential. We attempted to separate this effect from health-selection effects, in other words the potential effect of health on economic position, and from various effects related to occupational position and prestige that might correlate with the economic indicators. We made a distinction between individual labour-market advantage and household economic resources in order to reflect these theoretical definitions. Our aim was to test and compare two hypotheses: 1) low household economic resources lead to an increase in health problems later on, and 2) health problems are disadvantageous on the labour market, and consequently decrease the level of economic resources. We used prospective register data obtained from the databases of Statistics Finland and constituting an 11-per-cent random sample of the Finnish population in 1993-2006. Health problems were measured in terms of sickness allowance paid by the Finnish Social Insurance Institution, household economic resources in terms of household-equivalent disposable income and taxable wealth, and labour-market advantage in terms of individual taxable income and months of unemployment. We used structural equation models (n = 211,639) to examine the hypothesised causal pathways. Low household economic resources predicted future health problems, and health problems predicted future deterioration in labour-market advantage. The effect of economic resources on health problems was somewhat stronger. These results suggest that accumulated exposure to low economic resources leads to increasing health problems, and that this causal mechanism is a more significant source of persistent health inequalities than health problems that bring about a permanent decrease in economic resources.

Working conditions as risk factors for disability retirement: a longitudinal register linkage study

BACKGROUND

Early retirement due to disability is a public health and work environment problem that shortens working careers. Transition to disability retirement is based on ill-health, but working conditions are also of relevance. We examined the contributions of work arrangements, physical working conditions and psychosocial working conditions to subsequent disability retirement.

METHODS

The data were derived from the Helsinki Health Study cohort on employees of the City of Helsinki, Finland. Information on working conditions was obtained from the baseline surveys conducted in 2000, 2001 and 2002. These data were linked with register data on disability retirement and their main diagnoses obtained from the Finnish Centre for Pensions. Follow up by the end of 2008 yielded 525 disability retirement events. The analysed data included 6525 participants and 525 disability retirement events. Hazard ratios (HR) and 95% confidence intervals (95% CI) were calculated from Cox regression analysis.

RESULTS

Several working conditions showed own associations with disability retirement before adjustment. After adjustment for all working conditions, the primary risk factors for all-cause disability retirement were physical workload among women (HR 2.02, 95% CI 1.57-2.59) and men (HR 2.00, 95% CI 1.18-3.38), and low job control among women (HR 1.60, 95% CI 1.29-1.99). In addition, for disability retirement due to musculoskeletal causes, the risk factors were physical workload and low job control. For disability retirement due to mental causes the risk factors were computer work and low job control. Furthermore, occupational class was a risk factor for disability retirement due to all causes and musculoskeletal diseases.

CONCLUSIONS

Among various working conditions, those that are physically demanding and those that imply low job control are potential risk factors for disability retirement. Improving the physical working environment and enhancing control over one's job is likely to help prevent early retirement due to disability.

Economic difficulties and subsequent sleep problems: evidence from British and Finnish occupational cohorts

Background

Social determinants of sleep may prove to be as important as health status. In this study we examined the extent to which persistent and changing economic difficulties are associated with sleep problems in two prospective occupational cohorts.

Methods

We used data from Finnish (baseline 2000–2002; follow-up 2007; n = 6328) and British (baseline 1997–1999; follow-up 2003–2004; n = 5002) public sector employees. Economic difficulties, sleep problems, and a variety of covariates were assessed at baseline and follow-up.

Results

Prevalence of frequent sleep problems at follow-up was 27% and 20% among women and men in the Finnish cohort, and 34% and 27% in the British cohort, respectively. Odds for sleep problems were higher among those with persistent economic difficulties (frequent economic difficulties at baseline and follow-up) compared to those with no difficulties. This association remained after multiple adjustments, including parental and current socioeconomic position, in the Finnish (OR 1.72, 95% CI 1.35–2.18) cohort. Increases in economic difficulties were similarly associated with sleep problems in the Finnish and the British cohort.

Conclusion

Evidence from two occupational cohorts suggests strong associations between economic difficulty and poor sleep. Awareness of this association will help health care professionals identify and prevent sleep problems.

Trajectories of mental health before and after old-age and disability retirement: a register-based study on purchases of psychotropic drugs

OBJECTIVES

Retirement from paid work is a major life event facing increasingly large numbers of people in the coming years. We examined trajectories of mental health five years before and five years after old-age and disability retirement using data on purchases of psychotropic drugs.

METHODS

The study included all employees from the City of Helsinki, Finland, retiring between 2000-2008 due to old age (N=4456) or disability (N=2549). Purchases of psychotropic drugs were analyzed in 20 3-month intervals before and after retirement using graphical methods and growth curve models.

RESULTS

Old-age retirement was unrelated to purchases of psychotropic drugs. Among disability retirees, psychotropic medication tripled before retirement. The average increase was 0.95 [95% confidence interval (95% CI) 0.73-1.16] daily defined doses (DDD) 5-1.5 years before retirement; from 1.5 years until retirement it was 5.68 DDD (95% CI 5.33-6.03) for each 3-month interval. After disability retirement, purchases of antidepressants decreased on average by 0.40 DDD (95% CI 0.57-0.23) for each 3-month interval, those of hypnotics and sedatives increased by 0.30 DDD (95% CI 0.12-0.47), and no changes were seen for other psychotropic drugs. The changes before and after retirement were largest among those who retired due to mental disorders and those whose retirement had been granted as temporary.

CONCLUSIONS

While no overall decrease in psychotropic medication after retirement was observed, purchases of antidepressants decreased after disability retirement. Long-term trajectories suggest that disability retirement might be prevented if mental health problems were tackled more efficiently earlier in the pre-retirement period.

Sex Differences in Genetic and Environmental Factors Contributing to Body-Height

Sex differences in the heritability of self-reported body-height in two Finnish twin cohorts were studied by using sex-limitation models. The first cohort was born in 1938–1949 (N = 4873 twin pairs) and the second in 1975–1979 (N = 2374 twin pairs). Body-height was greater in the younger cohort (difference of 3.1 cm for men and 2.9 cm for women). The heritability estimates were higher among men (h2 = 0.87 in the older cohort and h2 = 0.82 in the younger cohort) than women (h2 = 0.78 and h2 = 0.67, respectively). Sex-specific genetic factors were not statistically significant in either cohort, suggesting that the same genes contribute to variation in body height for both men and women. The stronger contribution of environmental factors to body-height among women questions the hypothesis that women are better buffered against environmental stress, at least for this phenotype.

Interrelationships between education, occupational social class, and income as determinants of disability retirement

AIMS

The association between a low socioeconomic position and disability retirement is established in the literature, but the interrelationships between various subdomains of socioeconomic position are poorly understood. We examined the independent and interdependent effects of education, social class, and income on disability retirement.

METHODS

Using nationally representative register data we followed up over 260,000 Finns aged 30-63 at the end of 1995 for disability retirement from 1996 to 2004. Cox regression analysis was used to calculate hazard ratios (HR) and relative indices of inequality (RII).

RESULTS

Each socioeconomic indicator had a linear negative association with disability retirement. The socioeconomic gradients were stronger in the younger age groups. The effect of education was largely mediated through succeeding social class. Social class was largely explained by preceding education, but was only moderately mediated through income. Income was largely explained by education, and even further by social class. The independent effects of education, social class, and income on disability retirement as measured by the RII were 1.74 (95% CI 1.60-1.90), 1.95 (1.78-2.15), and 1.35 (1.25-1.47) for men and 1.76 (1.61-1.92), 2.14 (1.95-2.34), and 1.14 (1.05-1.24) for women.

CONCLUSIONS

The effects of socioeconomic position on disability retirement may not be fully captured if the pathways between the various subdomains are disregarded. Our results suggest that efforts to delay and prevent disability retirement should focus on lifestyle and cognitive factors associated with education, as well as on factors associated with social class such as working conditions and power resources.

Low back pain and neck pain as predictors of sickness absence among municipal employees

Objective: To study whether having ever had local low back pain (LBP), sciatica, neck pain (NP), or some combination of LBP and NP, predicts sickness absence among municipal employees. Methods: The study sample ( n=6911, 80% women, response rate 67%) included employees of the City of Helsinki who reached the age of 40, 45, 50, 55, or 60 years between 2000–02. Survey data on pain, working conditions, and health behaviours were linked to register data on sickness absence for three subsequent years. Sickness absence was categorised as self-certified (lasting for 1–3 days) and medically certified (lasting for 4 days or more) and the number of spells during the follow up was analysed using Poisson regression analysis. Results: In women, medically certified sickness absence was predicted by sciatica (rate ratio, RR, 1.3, 95% CI 1.1–1.6), NP (RR 1.3, 95% CI 1.2–1.5) and the combination of sciatica and NP (RR 1.8, 95% CI 1.6–2.1), allowing for working conditions, body mass index, and smoking. In men, the corresponding RRs were 1.5 (95% CI 1.0–2.1), 1.7 (95% CI 1.2–2.4), and 2.2 (95% CI 1.6–2.9). Local LBP did not predict medically certified sickness absence. Self-certified sickness absence was modestly predicted by all pain categories in women (RRs between 1.2 and 1.5) and by NP alone and with local LBP or sciatica in men (RRs between 1.4 and 1.6). Conclusions: Medically certified sickness absence was predicted by sciatica and NP, but not by local LBP. The association was accentuated in those with both sciatica and NP. Pain combinations may have a stronger effect on work ability than pain in one location.

Self-rated health as a predictor of disability retirement--the contribution of ill-health and working conditions

Objective

Self-rated health is a generic health indicator predicting mortality, many diseases, and need for care. We examined self-rated health as a predictor of subsequent disability retirement, and ill-health and working conditions as potential explanations for the association.

Methods

Self-rated health and the covariates were obtained from the Helsinki Health Study baseline mail surveys in 2000–2002 conducted among municipal employees aged 40–60 years (n = 6525). Data for disability retirement events (n = 625) along with diagnoses were linked from the Finnish Centre for Pensions, with a follow-up by the end of 2010. Hazard ratios (HR) and their 95% confidence intervals (CI) were calculated using competing risks models.

Results

Less than good self-rated health predicted disability retirement due to all causes among both women (HR = 4.60, 95% CI = 3.84–5.51) and men (HR = 3.83, 95% CI = 2.64–5.56), as well as due to musculoskeletal diseases (HR = 5.17, 95% CI = 4.02–6.66) and mental disorders (HR = 4.80, 95% CI = 3.50–6.59) among women and men pooled. Ill-health and physical working conditions partly explained the found associations, which nevertheless remained after the adjustments. Among the measures of ill-health limiting long-standing illness explained the association most in all-cause disability retirement and disability retirements due to musculoskeletal diseases, whereas common mental disorders explained the association most in disability retirements due to mental health disorders. Among working conditions physical work load and hazardous exposures at work explained the association most, although much less than ill-health.

Conclusions

Self-rated health is a strong predictor of disability retirement. This can be partly explained by ill-health and working conditions. Poor self-rated health provides a useful marker for increased risk of work disability and subsequent disability retirement.

Sex inequalities in physical and mental functioning of British, Finnish, and Japanese civil servants: role of job demand, control and work hours

In general, women report more physical and mental symptoms than men. International comparisons of countries with different welfare state regimes may provide further understanding of the social determinants of sex inequalities in health. This study aims to evaluate (1) whether there are sex inequalities in health functioning as measured by the Short Form 36 (SF-36), and (2) whether work characteristics contribute to the sex inequalities in health among employees from Britain, Finland, and Japan, representing liberal, social democratic, and conservative welfare state regimes, respectively. The participants were 7340 (5122 men and 2218 women) British employees, 2297 (1638 men and 659 women) Japanese employees, and 8164 (1649 men and 6515 women) Finnish employees. All the participants were civil servants aged 40-60 years. We found that more women than men tended to have disadvantaged work characteristics (i.e. low employment grade, low job control, high job demands, and long work hours) but such sex differences were relatively smaller among employees from Finland, where more gender equal policies exist than Britain and Japan. The age-adjusted odds ratio (OR) of women for poor physical functioning was the largest for British women (OR = 2.08), followed by for Japanese women (OR = 1.72), and then for Finnish women (OR = 1.51). The age-adjusted OR of women for poor mental functioning was the largest for Japanese women (OR = 1.91), followed by for British women (OR = 1.45), and then for Finnish women (OR = 1.07). Thus, sex differences in physical and mental health was the smallest in the Finnish population. The larger the sex differences in work characteristics, the larger the sex differences in health and the reduction in the sex differences in health after adjustment for work characteristics. These results suggest that egalitarian and gender equal policies may contribute to smaller sex differences in health, through smaller differences in disadvantaged work characteristics between men and women.

Occupational social class and disability retirement among municipal employees--the contribution of health behaviors and working conditions

OBJECTIVES

The mechanisms through which a low socioeconomic position leads to disability retirement are not yet established. We examined, on the one hand, the associations between occupational social class and disability retirement due to all causes, musculoskeletal diseases, and mental disorders and, on the other hand, the contribution of health behaviors and working conditions to these associations.

METHODS

Middle-aged municipal employees from the Helsinki Health Study cohort baseline surveys in 2000-2002 (N=6516) were followed up until the end of 2010 for disability retirement. Retirement data were obtained from the registers of the Finnish Centre for Pensions and social class and covariates from the baseline surveys. Social class was categorized into managers and professionals, semi-professionals, routine non-manual employees, and manual workers. Cox regression analysis was used to calculate hazard ratios and their 95% confidence intervals.

RESULTS

The risk of disability retirement was generally higher among those in lower social classes with a strong gradient for all causes, an even stronger gradient for musculoskeletal diseases, and a weaker non-linear association for mental disorders. These associations were largely mediated through physical workload among both women and men and hazardous exposures particularly among men. In mental disorders, job control also mediated the association. Strenuous desktop work and job demands widened the social class differences particularly among men and in mental disorders. The contribution of health behaviors was modest.

CONCLUSIONS

Improvements particularly in the physical working conditions but also the job control of those in lower social classes are likely to reduce socioeconomic differences in disability retirement.

Changes in leisure-time physical activity after transition to retirement: a follow-up study

Background

Retirement is a major life change that is likely to affect lifestyles. The aim of this study was to examine changes in leisure-time physical activity of moderate and vigorous intensity among ageing employees facing transition to retirement over a follow-up of 5-7 years.

Methods

The baseline data were collected by questionnaire surveys in 2000-2002 among 40-60-year-old employees of the City of Helsinki. A follow-up survey was conducted among the baseline respondents in 2007 (n = 7332, response rate 83%). Those who were on disability retirement at the follow-up were distinguished from old-age retirees. Leisure-time physical activity was measured using similar questions in both surveys.

Results

Old-age retirees increased significantly their time spent in moderate-intensity physical activity: women 31 minutes per week and men 42 minutes per week on average. Such changes were not found among disability retirees or those remaining employed. There were no changes in vigorous activity. Leisure-time physical inactivity at follow-up was lower among old-age retirees compared with employees of nearly the same age. Adjustments made for potential baseline covariates had no effects on these findings.

Conclusions

Transition to old-age retirement was associated with an increase in moderate-intensity leisure-time physical activity and a decrease in the proportion of inactive. Encouraging people to leisure-time physical activity after retirement is worthwhile as the increase in free time brings new possibilities for it.

Sleep problems and disability retirement: a register-based follow-up study

Among aging employees, sleep problems are prevalent, but they may have serious consequences that are poorly understood. This study examined whether sleep problems are associated with subsequent disability retirement. Baseline questionnaire survey data collected in 2000-2002 among employees of the city of Helsinki, Finland, were linked with register data on disability retirement diagnoses by the end of 2008 (n = 457) for those with written consent for such linkages (74%; N = 5,986). Sleep problems were measured by the Jenkins Sleep Questionnaire. Cox regression analysis was used to calculate hazard ratios and 95% confidence intervals for disability retirement. Gender- and age-adjusted frequent sleep problems predicted disability retirement due to all causes (hazard ratio (HR) = 3.22, 95% confidence interval (CI): 2.26, 4.60), mental disorders (HR = 9.06, 95% CI: 3.27, 25.10), and musculoskeletal disorders (HR = 3.27, 95% CI: 1.91, 5.61). Adjustments for confounders, that is, baseline sociodemographic factors, work arrangements, psychosocial working conditions, and sleep duration, had negligible effects on these associations, whereas baseline physical working conditions and health attenuated the associations. Health behaviors and obesity did not mediate the examined associations. In conclusion, sleep problems are associated with subsequent disability retirement. To prevent early exit from work, sleep problems among aging employees need to be addressed.

Psychosocial work environment and emotional exhaustion among middle-aged employees

Background

This study examined the associations of job control, organizational justice and bullying at the workplace with emotional exhaustion. This was done by adjusting firstly for age and occupational class, secondly physical work factors, thirdly mutually adjusting for the three psychosocial factors and fourthly adjusting for all studied variables simultaneously.

Data were derived from the Helsinki Health Study baseline surveys conducted in 2001 and 2002, including 40-60-year-old employees of the City of Helsinki (n = 5819, response rate 66%). Exhaustion was measured with a six-item subscale from Maslach Burnout Inventory (MBI). Psychosocial factors included Karasek's job control, organizational justice and bullying at the workplace. Logistic regression analysis was used.

Results

Among women 23% and among men 20% reported symptoms of emotional exhaustion. Among women all psychosocial factors were associated with exhaustion when adjusted for age and occupational class as confounders. When physical work factors were additionally adjusted for, the associations slightly attenuated but remained. When psychosocial work factors were simultaneously adjusted for each other, their associations with exhaustion attenuated but remained. Among men all psychosocial factors were associated with exhaustion when adjusted for confounders only. When adjusted for physical work factors the associations slightly attenuated. When psychosocial factors were simultaneously adjusted for each other, associations of organizational justice and bullying with exhaustion attenuated but remained whereas job control lost its association.

Conclusions

Identifying risk factors for emotional exhaustion is vital for preventing subsequent processes leading to burnout. Psychosocial factors are likely to contribute to exhaustion among female as well as male employees. Thus management and occupational health care should devote more attention to the psychosocial work environment in order to be able to prevent exhaustion and burnout at the workplaces.

Changes in occupational class differences in leisure-time physical activity: a follow-up study

Background

Physical activity is known to have health benefits across population groups. However, less is known about changes over time in socioeconomic differences in leisure-time physical activity and the reasons for the changes. We hypothesised that class differences in leisure-time physical activity would widen over time due to declining physical activity among the lower occupational classes. We examined whether occupational class differences in leisure-time physical activity change over time in a cohort of Finnish middle-aged women and men. We also examined whether a set of selected covariates could account for the observed changes.

Methods

The data were derived from the Helsinki Health Study cohort mail surveys; the respondents were 40-60-year-old employees of the City of Helsinki at baseline in 2000-2002 (n = 8960, response rate 67%). Follow-up questionnaires were sent to the baseline respondents in 2007 (n = 7332, response rate 83%). The outcome measure was leisure-time physical activity, including commuting, converted to metabolic equivalent tasks (MET). Socioeconomic position was measured by occupational class (professionals, semi-professionals, routine non-manual employees and manual workers). The covariates included baseline age, marital status, limiting long-lasting illness, common mental disorders, job strain, physical and mental health functioning, smoking, body mass index, and employment status at follow-up. Firstly the analyses focused on changes over time in age adjusted prevalence of leisure-time physical activity. Secondly, logistic regression analysis was used to adjust for covariates of changes in occupational class differences in leisure-time physical activity.

Results

At baseline there were no occupational class differences in leisure-time physical activity. Over the follow-up leisure-time physical activity increased among those in the higher classes and decreased among manual workers, suggesting the emergence of occupational class differences at follow-up. Women in routine non-manual and manual classes and men in the manual class tended to be more often physically inactive in their leisure-time (<14 MET hours/week) and to be less often active (>30 MET hours/week) than those in the top two classes. Adjustment for the covariates did not substantially affect the observed occupational class differences in leisure-time physical activity at follow-up.

Conclusions

Occupational class differences in leisure-time physical activity emerged over the follow-up period among both women and men. Leisure-time physical activity needs to be promoted among ageing employees, especially among manual workers.

Workplace bullying and common mental disorders: a follow-up study

BACKGROUND

Workplace bullying has been associated with mental health, but longitudinal studies confirming the association are lacking. This study examined the associations of workplace bullying with subsequent common mental disorders 5-7 years later, taking account of baseline common mental disorders and several covariates.

METHODS

Baseline questionnaire survey data were collected in 2000-2002 among municipal employees, aged 40-60 years (n=8960; 80% women; response rate 67%). Follow-up data were collected in 2007 (response rate 83%). The final data amounted to 6830 respondents. Workplace bullying was measured at baseline using an instructed question about being bullied currently, previously or never. Common mental disorders were measured at baseline and at follow-up using the 12-item version of the General Health Questionnaire. Those scoring 3-12 were classified as having common mental disorders. Covariates included bullying in childhood, occupational and employment position, work stress, obesity and limiting longstanding illness. Logistic regression analysis was used.

RESULTS

After adjusting for age, being currently bullied at baseline was associated with common mental disorders at follow-up among women (OR 2.34, CI 1.81 to 3.02) and men (OR 3.64, CI 2.13 to 6.24). The association for the previously bullied was weaker. Adjusting for baseline common mental disorders, the association attenuated but remained. Adjusting for further covariates did not substantially alter the studied association. CONCLUSION The study confirms that workplace bullying is likely to contribute to subsequent common mental disorders. Measures against bullying are needed at workplaces to prevent mental disorders.

Association of sleep duration with weight and weight gain: a prospective follow-up study

The objective of this study was to examine the associations of sleep duration with subsequent weight and major weight gain in women and men during a follow-up period of 5-7years. The data were derived from the Helsinki Health Study cohort mail questionnaire surveys among 40-60-year-old employees of the City of Helsinki, Finland. At baseline in 2000-2002, 8960 people responded to the survey (80% women, response rate 67%). The follow-up survey was conducted in 2007 among all respondents to the baseline survey (n=7332, response rate 83%). Sleep duration (5h or less up to 10h or more) and weight and weight gain of at least 5kg were based on self-reports. Analyses of variance and logistic regression analyses were used to examine the associations between sleep duration and weight, as well as major weight gain. Short sleep duration was associated with major weight gain [odds ratio (OR) 1.52; 95% confidence interval (CI) 1.08, 2.14] during the follow-up. Adjusting for several covariates had only minor effects on that association. Long sleep duration was associated with major weight gain after adjusting for age (OR 1.35; 95% CI 1.00-1.81). No associations were found among men. Sleep duration was associated with major weight gain among middle-aged employed women. Short sleep may be a risk factor for subsequent weight gain.

Risk factors of sciatic pain: a prospective study among middle-aged employees

OBJECTIVE

To study the effects of occupational class, physical and psychosocial working conditions, health behaviours, and pain in the low back and the neck on sciatic pain among middle-aged employees.

METHODS

The participants were municipal employees without previous sciatica, aged 40, 45, 50, 55, and 60 years at baseline (n=5261, 80% women). Sciatica was defined as low back pain radiating to the calf or the foot. Data on occupational class, physical and psychosocial working conditions, body mass index, smoking, leisure-time physical activity, neck pain, local low back pain, and sciatica were obtained from baseline questionnaire surveys in 2000-2002. The question on sciatica was repeated in a follow-up survey in 2007. Logistic regression analysis was used.

RESULTS

In women, manual occupational class (OR 1.3; 95% CI 1.0-1.6 compared with managers/professionals), overweight (1.3; 1.1-1.5), obesity (1.4; 1.1-1.7), smoking (1.5; 1.2-1.7), low leisure-time physical activity (1.3; 1.0-1.7), previous acute (1.5; 1.3-1.7) and chronic (1.5; 1.1-2.0) local low back pain, and acute (1.20; 1.0-1.4) and chronic (1.5;1.2-1.9) neck pain predicted the onset of sciatica in a multivariable model. In men, semi-professionals (1.5; 1.1-2.1) and manual workers (2.0; 1.4-2.8) had an increased risk compared with managers/professionals; also acute (1.5; 1.2-2.0) and chronic (2.1; 1.2-3.9) local low back pain predicted sciatica.

CONCLUSIONS

Manual occupational class in both genders and semi-professional occupations in men, unhealthy behaviours and previous pain both in the neck and the lower back predicted sciatica, while physical and psychosocial working conditions had no independent effect.

Workplace bullying and subsequent sleep problems--the Helsinki Health Study

OBJECTIVE

The associations between workplace bullying and subsequent sleep problems are poorly understood. This study aims to address this evidence gap.

METHODS

We used the Helsinki Health Study questionnaire survey data at baseline in 2000-2002 and follow-up in 2007 (N=7332). The 4-item Jenkins sleep questionnaire was used in both surveys. Two measures of workplace bullying asked whether the respondent had (i) reported being bullied and (ii) observed bullying. Logistic regression models were fitted, adjusting for age, childhood bullying, education, working conditions, obesity, common mental disorders, limiting long-standing illness, and baseline sleep problems.

RESULTS

At baseline, 5% of women and men reported being currently bullied. Additionally, 9% of women and 7% of men had frequently observed bullying at their workplace. Adjusted for age, reporting bullying was associated with sleep problems at follow-up among women [odds ratio (OR) 1.69, 95% confidence interval (95% CI) 1.30-2.20) and men (OR 3.17, 95% CI 1.85-5.43). Also, reporting earlier bullying was associated with sleep problems among both women (OR 1.47, 95% CI 1.26-1.72) and men (OR 1.58, 95% CI 1.06-2.36). Separate adjustments for covariates had some effects on the associations. After full adjustment for childhood bullying and baseline sociodemographic factors, working conditions, health, and sleep problems, the associations reduced. Similarly, adjusted for age, observing bullying was associated with sleep problems among women (OR 2.00, 95% CI 1.61-2.48) and men (OR 2.04, 95% CI 1.23-3.39).

CONCLUSIONS

Workplace bullying is associated with sleep problems, but associations attenuate after factors related to the social environment, work, and health are simultaneously taken into account.

Different domains of health functioning as predictors of sickness absence--a prospective cohort study

OBJECTIVES

The aim of this study was to examine different domains of health functioning as predictors of sickness absence.

METHODS

The Short Form 36 (SF-36) is one of the best known instruments measuring various domains of physical and mental health functioning. A questionnaire including the SF-36 was mailed to 40-60-year-old employees of the City of Helsinki in 2000-2002. For the subsequent three years, sickness absence episodes >2 weeks were derived from the employer's register. The predictive ability of the eight subscales and two component summaries of the SF-36 were compared using regression methods and receiver operating characteristic (ROC) curve analysis.

RESULTS

All eight SF-36 subscales and the two component summaries predicted the occurrence of sickness absence over the follow-up period. Among women, bodily pain was the strongest predictor, with 1 standard deviation increase in bodily pain increasing the occurrence of sickness absence by 77% [95% confidence interval (95% CI) 68-86%]. Role limitations due to emotional problems were the weakest predictor of sickness absence (29%, 95% CI 23-36%). Among men, the results were similar to those of women. In both genders, the area under the ROC curve was largest for bodily pain, general health, and physical functioning and lowest for mental health and role limitation due to emotional problems.

CONCLUSIONS

The subscales measuring physical domains of functioning were more strongly associated with sickness absence than the mental subscales. In particular, ability to perform daily activities, pain, and general health were important predictors of sickness absence >2 weeks.

Changes of occupational class differences in physical functioning: a panel study among employees (2000-2007)

BACKGROUND

Panel studies on changes of occupational class differences in health have given varying results. The aim of this study was to examine changes of occupational class differences in physical functioning and the factors that explain these changes.

METHODS

A cohort of middle-aged employees of the City of Helsinki was followed up for an average of 6 years in two surveys from 2000-2002 and 2007. Hierarchical linear random effects models were fitted to analyse the changes of occupational class differences in SF-36 physical functioning, as well as the contribution of physical and psychosocial working conditions, material conditions, health behaviours and employment status to these changes.

RESULTS

Lower occupational classes had worse physical functioning at baseline: among women, the SF-36 scores ranged from 50.5 in the highest class to 47.1 in the lowest one, and among men from 52.2 to 48.9, with higher scores indicating better health. Occupational class differences widened during the follow-up due to stronger decline of physical functioning in the lower occupational classes than in the higher occupational classes. The largest difference in the decline of functioning between classes was 1.2 scores among women and 1.5 scores among men. Among women the widening of the class differences could be explained partly by health behaviours and employment status and among men by material conditions.

CONCLUSION

Occupational class differences in physical functioning widened due to a faster decline of physical functioning in the lower occupational classes. Health behaviours, employment status and material conditions explained the widening class differences in physical functioning.

Work arrangements, physical working conditions, and psychosocial working conditions as risk factors for sickness absence: Bayesian analysis of prospective data

PURPOSE

To determine which work arrangements, physical working conditions, and psychosocial working conditions are important risk factors for sickness absence.

METHODS

Survey data on working conditions collected among the employees of the City of Helsinki during 2000 to 2002 (N = 6503, response rate 67%) were linked to the employer's sickness absence records for the subsequent 3 years. First occurrences of short-term (1-3 days), intermediate (4-14 days), and long-term (15 days or more) sickness absence episodes were examined by the use of proportional hazards models with Bayesian model averaging.

RESULTS

Working overtime decreased the risk of short-term sickness absence by 19%. Heavy physical work load and hazardous exposures were consistently associated with increased sickness absence episodes of all lengths. The risk of intermediate and long-term absence episodes was increased by 24% to 28% per one standard deviation increase in physical work load. Low job control in women and job dissatisfaction in men increased the risk of sickness absence episodes of all lengths.

CONCLUSIONS

Heavy physical work load and hazardous exposures had the strongest associations with sickness absence. Furthermore, low job control in women and job dissatisfaction in men were consistently associated with increased risk of sickness absence. Systematic differences in risk factors for absence episodes of different lengths were not found.

Economic difficulties and physical functioning in Finnish and British employees: contribution of social and behavioural factors

BACKGROUND

Childhood and current economic difficulties are associated with physical health. However, evidence concerning the factors underlying these associations is sparse. This study examines the contribution of a range of social and behavioural factors to associations between economic difficulties and physical functioning.

METHODS

We used comparable data on middle-aged white-collar employees from the Finnish Helsinki Health Study cohort (n = 3843) and the British Whitehall II Study cohort (n = 3052). Our health outcome was physical functioning measured by the SF-36 Physical Component Summary. Relative indices of inequality (RII), calculated using logistic regression analysis, were used to examine associations between economic difficulties and physical functioning, and the contribution of further socio-economic circumstances, health behaviours, living arrangements and work-family conflicts to these associations.

RESULTS

In age-adjusted models, childhood (RII = 1.76-3.06) and current (RII = 1.79-3.03) economic difficulties were associated with poor physical functioning in both cohorts. Further adjusting for work-family conflicts attenuated the associations of current economic difficulties with physical functioning in both cohorts, and also those of childhood economic difficulties in the Helsinki cohort. Adjustments for other socio-economic circumstances also caused some attenuation, while health behaviours and living arrangements had small or negligible effects.

CONCLUSIONS

Conflicts between work and family contribute to the associations of economic difficulties with physical functioning among employees from Finland and Britain. This suggests that supporting people to cope with economic difficulties, and efforts to improve the balance between paid work and family may help employees maintain good physical functioning.

The impact of physical activity on physical health functioning--a prospective study among middle-aged employees

OBJECTIVE

To examine whether physical activity contributes to physical health functioning five to seven years later among middle-aged employees.

METHODS

Baseline data were collected in 2000-2002 by questionnaire surveys among 40-60-year-old employees of Helsinki City. A follow-up survey was conducted among baseline respondents in 2007 (n=7330, response rate 83%). Physical activity during leisure time or commuting within the previous 12 months was asked at baseline. Physical health functioning was measured by physical component summary (PCS) of the Short-Form 36 questionnaire. PCS mean scores were examined, as were poor and good PCS scores.

RESULTS

Vigorously active and conditioning exercisers had better subsequent physical health functioning than did the inactive and moderately active. Baseline health and functioning explained a major part of the differences found. Smoking, alcohol use and BMI further explained some of the differences. No clear differences in physical health functioning mean scores emerged during follow-up. In good physical health functioning, however some differences between conditioning and inactive women remained after adjustments.

CONCLUSIONS

Prospective associations between physical activity and physical health functioning were relatively weak, but high physical activity may help in maintaining good physical health functioning. Vigorous activity may be more beneficial than moderate activity.

Sleep complaints in middle-aged women and men: the contribution of working conditions and work-family conflicts

This study aimed to examine how physical working conditions, psychosocial working conditions and work-family conflicts are associated with sleep complaints, and whether health behaviours explain these associations. We used pooled postal questionnaire surveys collected in 2001-2002 among 40-60-year-old employees of the City of Helsinki (n = 5819, response rate 66%). Participants were classified as having sleep complaints if they reported sleep complaints at least once a week on average (24% of women and 20% of men). Independent variables included environmental work exposures, physical workload, computer work, Karasek's job strain and work-family conflicts. Age, marital status, occupational class, work arrangements, health behaviours and obesity were adjusted for. Most working conditions were associated strongly with sleep complaints after adjustment for age only. After adjustment for work-family conflicts, the associations somewhat attenuated. Work-family conflicts were also associated strongly with women's [odds ratio (OR) 5.90; confidence interval (CI) 4.16-8.38] and men's sleep (OR 2.56; CI 1.34-4.87). The associations remained robust even after controlling for unhealthy behaviours, obesity, health status, depression and medications. Physically strenuous working conditions, psychosocial job strain and work-family conflicts may increase sleep complaints. Efforts to support employees to cope with psychosocial stress and reach a better balance between paid work and family life might reduce sleep complaints. Sleep complaints need to be taken into account in worksite health promotion and occupational health care in order to reduce the burden of poor sleep.

Sense of coherence and intentions to retire early among Finnish women and men

Background

Previous studies have shown that age, physical and mental health status and working circumstances, along with different socio-economic and psychosocial factors affect the retirement process. However, the role of psychological resources, such as sense of coherence (SOC), on the retirement process is still poorly understood. This study investigated the associations between SOC and intentions to retire early and whether these associations were explained by socio-economic, psychosocial and work and health related factors.

Methods

The data were derived from the Finnish Health and Social Support (HeSSup) Study. The information was gathered from postal surveys in 1998 (baseline) and in 2003 (follow-up). The analyzed data consisted of 7409 women and 4866 men aged 30-54 at baseline. SOC and background factors including childhood circumstances, language, education, working circumstances, social support, health behaviour and somatic and mental health status were assessed at baseline. The intentions to retire early were assessed at follow-up using logistic regression analysis.

Results

SOC was associated with intentions to retire early among both genders. Socio-economic, psychosocial and work and health behaviour related factors did not influence the association between SOC and intentions to retire early among women and men reporting somatic or mental illness. Further, the association between SOC and intentions to retire early remained among (somatically and mentally) healthy men. Among healthy women the association was weaker and statistically non-significant. Among unhealthy women, the odds ratios of SOC was 0.97 (CI 95% 0.96-0.98) and 0.97 among ill men (CI 95% 0.96-0.98), i.e., each additional SOC score reduced the risk of intentions by 3% among both genders.

Conclusion

Unhealthy employees with low SOC and low education were in the greatest risk to have reported intentions to retire early. SOC had an independent effect on intentions to retire early, and a strong SOC may have a potential to prevent early retirement in groups otherwise at risk. An important challenge would be to target the resources of SOC to the most vulnerable and design appropriate interventions in order to strengthen the level of SOC and hence prolong working years of the aging employees.

Health-related behaviours and sickness absence from work

OBJECTIVES

To compare associations of health-related behaviours with self-certified and medically confirmed sickness absence, and to examine whether these associations can be explained by psychosocial and physical working conditions and occupational social class.

METHODS

The study included 5470 female and 1464 male employees of the City of Helsinki surveyed in 2000-2002. These data were linked to sickness absence records until the end of 2005, providing a mean follow-up time of 3.9 years. Poisson regression analysis was used to examine associations of smoking, alcohol use, physical activity, dietary habits and relative weight (body mass index) with self-certified (1-3 days) and medically confirmed (> or =4 days) absence spells. Population attributable fractions (PAFs) were calculated to quantify the sickness absence burden related to the behaviours.

RESULTS

Smoking and high relative weight were most strongly associated with sickness absence, while the associations of other studied health-related behaviours were weaker. The associations were stronger for medically confirmed sickness absence spells for which heavy smoking and obesity more than doubled the risk of sickness absence in men and nearly doubled it in women. Adjusting for psychosocial working conditions had little or no effect on the associations. Physical working conditions and social class somewhat attenuated the associations, especially for smoking and relative weight. In self-certified sickness absence the PAF for smoking (16.4 in men, 10.3 in women) was largest, while in medically confirmed absence relative weight had the largest PAF (23.5 in men, 15.0 in women).

CONCLUSIONS

Health-related behaviours, smoking and high relative weight in particular, were associated with subsequent sickness absence independently of psychosocial and physical working conditions and social class. Decreasing smoking and relative weight is likely to provide important gains in work ability and reduce sickness absence.

Interrelationships between education, occupational class, income and sickness absence

BACKGROUND

Socio-economic position measures, such as education, occupational class and income, are well-known determinants of health. However, previous studies have not paid attention to mutual interrelationships between these socio-economic position measures and medically confirmed sickness absence.

METHODS

The study is a register-based study. The participants were municipal employees of the City of Helsinki aged 25-59 years in 2003. There were 21,599 women and 5841 men participants. Three socio-economic position measures were used, namely three-level education, four-level occupational class and gross individual income quartiles. Main outcome measure was medically confirmed sickness absence spells of 4 days or longer. Inequality indices were calculated using Poisson regression analysis.

RESULTS

High education, occupational class and individual income were all consistently associated with lower sickness absence rates among both women and men. After mutual adjustment, education and occupational class remained independent determinants of sickness absence. The association of individual income with sickness absence was practically explained by temporally preceding education and occupational class.

CONCLUSIONS

Our results indicate that education and occupational class-rather than income-are strong determinants of sickness absence. Education, occupational class and income are complementary socio-economic position measures. To better inform sickness absence policy, future studies should aim to establish whether the observed socio-economic differences reflect broader differences in ill-health, lifestyle and working conditions.

Drinking habits and sickness absence: The contribution of working conditions

Aims: The main aim was to examine whether drinking habits including average, binge and problem drinking are associated with self-certified and medically confirmed sickness absence among middle-aged municipal employees. Another aim was to examine whether psychosocial and physical working conditions and work arrangements explain these associations. Methods: The data on drinking habits and working conditions of 5,119 female and 1,390 male middle-aged employees of the City of Helsinki was obtained from postal questionnaires collected in 2000—2002. The data on sickness absence (2000—2005) were derived from the employer’s registers. Poisson regression analysis with self-certified (1—3 days) and medically confirmed (over 3 days) sickness absence spells as outcomes was used in performing the analyses. Results: Heavy average, binge and problem drinking were all associated with an increase in self-certified sickness absence. Both non-drinkers and heavy drinkers had excess medically confirmed sickness absence compared to moderate drinkers. Problem drinking and among women also binge drinking were associated with medically confirmed sickness absence. Psychosocial working conditions slightly attenuated the association of drinking habits and sickness absence mainly among men. Physical working conditions and work arrangements slightly explained medically confirmed sickness absence among male problem drinkers. Conclusions: All studied drinking habits were associated with both self-certified and medically confirmed sickness absence. Thus, a decrease in unhealthy drinking habits among employees is likely to prevent sickness absence. The effects of working conditions were small but psychosocial working conditions slightly explained the associations between drinking habits and sickness absence mainly among men.

Social class differences in health behaviours among employees from Britain, Finland and Japan: the influence of psychosocial factors

This study aims to examine social class differences in smoking, heavy drinking, unhealthy food habits, physical inactivity and obesity, and work-related psychosocial factors as explanations for these differences. This is done by comparing employee cohorts from Britain, Finland and Japan. Social class differences in health behaviours are found in the two western European countries, but not in Japan. The studied psychosocial factors related to work, work-family interface and social relationships did not explain the found class differences in health behaviours.

Physical and psychosocial working conditions as explanations for occupational class inequalities in self-rated health

BACKGROUND

Socio-economic health inequalities are well documented, but efforts to explain health inequalities are less. However, previous studies suggest that working conditions provide potential explanations for inequalities in health.

METHODS

Cross-sectional questionnaire survey data, collected from municipal employees of the City of Helsinki, aged 40-60 years (n = 8960, response rate 67%) in 2000-02, were examined using binomial regression analysis. Socio-economic position was measured by six occupational social classes ranging from top managers to manual workers, and the outcome was self-rated health (SRH). Key physical and psychosocial working conditions and work arrangements were included as explanatory factors for inequalities in health.

RESULTS

Occupational class inequalities in SRH were clear among women [prevalence ratio (PR) 1.89, 95% confidence interval (CI) 1.54-2.32] and men (PR 1.78, 95% CI 1.40-2.25). Heavy physical workload explained a half of the health inequalities among women and almost one-third among men. Physical and chemical exposures at work explained one-fifth of the health inequalities among women and a half among men. Job control explained 24% of the men's and 40% of women's inequalities, whereas job demands widened the inequalities by 13-14%. The effects of shift work and working hours were negligible. In the fully adjusted model, 60% of the women's and 32% of the men's inequalities in SRH were explained.

CONCLUSION

Physical working conditions explained a large part and job control, a somewhat smaller part of socio-economic inequalities in SRH. Improving physical working conditions and increasing job control provide potential routes to reduced inequalities in health among employees.

Job strain and symptoms of angina pectoris among British and Finnish middle-aged employees

BACKGROUND

High job strain has been linked with cardiovascular outcomes. This study aimed to examine whether job strain is associated with angina pectoris symptoms among British and Finnish non-manual employees.

METHODS

Postal questionnaire survey data among 40-60-year-old employees of the British Whitehall II Study (n = 4551, 27% women) and the Finnish Helsinki Health Study (n = 7605, 83% women) cohort were analysed. Angina pectoris symptoms were the outcome in logistic regression analysis. Karasek's job strain was examined. Models were adjusted first for age, second for occupational class and finally for smoking, heavy drinking, physical inactivity, unhealthy food habits and obesity.

RESULTS

Angina pectoris symptoms were reported by 5% of women and 3% of men in Britain, and by 6% of women and 4% of men in Finland. High job strain was associated with angina pectoris symptoms among men in Britain (OR 2.08; CI 95% 1.07 to 4.02) and women in Finland (OR 1.90; CI 95% 1.36 to 2.63) independent of age, occupational class, and behavioural risk factors. However, similar associations between job strain and angina pectoris symptoms were not observed among men in Finland or women in Britain.

CONCLUSION

The results yielded partial support for the association between job strain and angina pectoris symptoms across national contexts.

Economic difficulties and common mental disorders among Finnish and British white-collar employees: the contribution of social and behavioural factors

BACKGROUND

In addition to conventional indicators of socioeconomic position, material conditions such as economic difficulties are associated with mental health. However, there has been little investigation of these associations. This study aims to examine the association of current economic difficulties with common mental disorders (CMD) and the contribution of social and behavioural factors to this association in two cohorts of Finnish and British white-collar employees.

METHODS

Comparable survey data from the Finnish Helsinki Health Study and the British Whitehall II Study were used. CMD were measured with the GHQ-12. Inequality indices from logistic regression analysis were used to examine the association between current economic difficulties and CMD, and the contribution of other past and present socioeconomic circumstances, health behaviours, living arrangements and work-family conflicts to this association. Inequality indices show the average change in ill health for each step up in the level of economic difficulties. Analyses were conducted separately for men and women.

RESULTS

Clear associations between current economic difficulties and CMD were found. Adjusting for work-family conflicts attenuated the associations. Adjusting for indicators of past and present socioeconomic circumstances, health behaviours and living arrangements had generally negligible effects. The results were very similar among both sexes in the two cohorts.

CONCLUSIONS

Conflicts between work and family contribute to the association between economic difficulties and CMD in both Finland and Britain. Supporting people to cope not only with everyday economic difficulties but also with work-family conflicts may be important for reducing inequalities in mental health.