Akseli Aittomäki

Register-based study among employees showed small nonparticipation bias in health surveys and check-ups

OBJECTIVES To examine nonparticipation to a questionnaire survey and occupational health check-ups by sociodemographic variables and health status, measured by medically confirmed sickness absence, and whether the associations between other study variables and participation were affected by health status. STUDY DESIGN AND SETTING Questionnaire surveys and health check-ups were conducted among the City of Helsinki employees. Sample information was derived from the employers personnel register and analyzed by participation and giving consent to link the data to external administrative registers. RESULTS Participation to the questionnaire survey was more common among the older, higher occupational classes, those with higher income, permanent employment, and those with no absence due to medically confirmed sickness. Among women in particular, the differences were small. Consent giving followed generally similar patterns than survey response. Nonparticipation to health check-ups was related to low income and temporary employment contract. In both questionnaire survey and health check-ups, associations between other study variables and participation were not affected by health status. CONCLUSIONS Questionnaire surveys and health check-ups were broadly representative of the target population. Associations between other study variables and participation did not differ by health status. This suggests that even when the data are not fully representative associations between the study variables need not to be biased.

Cohort Profile: The Helsinki Health Study

The Helsinki Health Study cohort was set up to enable longitudinal studies on the social and work related determinants of health and well-being, making use of self-reported as well as objective register data. The target population is the staff of the City of Helsinki, Finland. Baseline data for the cohort were derived from questionnaire surveys conducted in 2000, 2001 and 2002 among employees reaching 40, 45, 50, 55 or 60 years of age in each year. The number of responders at baseline was 8960 (80% women, response rate 67%). Additional age-based health examination data were available. A follow up survey was conducted in 2007 yielding 7332 responders (response rate 83%). Measures of health include health behaviours, self-rated health, common mental disorders, functioning, pain, sleep problems, angina symptoms and major diseases. Social determinants include socio-demographics, socio-economic circumstances, working conditions, social support, and work-family interface. Further register linkages include sickness absence, hospital discharge, prescribed drugs, and retirement updated at the end of 2010. The cohort allows comparisons with the Whitehall II study, London, UK, and the Japanese Civil Servants Study from western Japan. The cohort data are available for collaborative research at Hjelt Institute, Department of Public Health, University of Helsinki, Finland.

Gender differences in the association of age with physical workload and functioning

Aims: To test whether (1) physically demanding work is less frequent for older than younger employees, and whether (2) the association of physically demanding work with decline of physical functioning is stronger for older employees than their younger counterparts. The gender differences in these associations were examined. Methods: Subjects of the study were 40–60 year old employees of the City of Helsinki. Data (n = 5802) were collected with mail questionnaires in 2000 and 2001. Functioning was measured with the Role Limitations due to Physical Health Problems scale of the SF36 health questionnaire. Logistic regression models were used to analyse the data. Results: There was a linear trend of less physically demanding work in older than in younger age groups. This trend was more marked for men than women. Age and physically demanding work were associated with poor functioning. In women the association of physically demanding work with poor functioning tended to be stronger for older than for younger age groups, while the opposite was observed in men. Conclusions: Results suggest that physically demanding work causes more ailments in women of high age than men. It is possible that less men than women are still employed in physically demanding occupations at high age, even though direct evidence of exit from physically demanding work cannot be obtained from cross-sectional data. In these data the physically demanding occupations for men and women were largely different. High physical workload among women working in social and health care is likely to contribute to the gender differences.

The associations of household wealth and income with self-rated health - A study on economic advantage in middle-aged Finnish men and women

The economic resources available to an individual or a household have been hypothesised to affect health through the direct material effects of living conditions as well as through social comparison and experiences of deprivation. The focus so far has been mainly on current individual or household income, and there is a lack of studies on wealth, a potentially relevant part of household resources. We studied the associations of household wealth and household income with self-rated health, and addressed some theoretical issues related to economic advantage and health. The data were from questionnaire survey of Finnish men and women aged from 45 to 67 years, who were employed by the City of Helsinki from five to seven years before the collection of the data in 2007. We found household wealth to have a strong and consistent association with self-rated health, poor health decreasing with increasing wealth. The relationship was only partly attributable to the association of wealth with employment status, household income, work conditions and health-related behaviour. In contrast, the association of household income with self-rated health was greatly attenuated by taking into account employment status and wealth, and even further attenuated by work conditions. The results suggested a significant contribution of wealth differentials to differences in health status. The insufficiency of current income as the only measure of material welfare was demonstrated. Conditions associated with long-term accumulation of material welfare may be a significant aspect of the causal processes that lead to socioeconomic inequalities in ill health.

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.

Job decision latitude as a potential modifier of the contribution of physical workload to poor functioning in middle-aged employees.

ObjectivesIt was hypothesised that job decision latitude may alleviate the detrimental health effect of physical workload. The objective was to test whether job decision latitude modifies the effect of physically demanding work on poor physical functioning, and whether the effects of physically demanding work and job decision latitude are dependent on occupational social class.MethodsData were derived from the Helsinki Health Study baseline questionnaire survey. The participants were employees of the City of Helsinki, Finland, aged 40–60 years. Functioning was measured by Short Form 36 physical component summary. Logistic regression models were used to analyse the data.ResultsThe hypothesised modification of the effect of physical demands at work on physical functioning by job decision latitude could not be demonstrated. The expected interaction effect was observed only for the semi-professional class, and interaction of physical demands, decision latitude and occupational social class was not statistically significant. Furthermore, the effects of physically demanding work as well as low decision latitude were of similar magnitude in all the occupational social classes.ConclusionsThe results suggest that for the majority of employees the effect of physical workload on physical functioning is independent of job decision latitude or occupational social class in general. Control over work conditions is unlikely to reduce difficulties to cope with physical demands, when the actual physical tasks are not changed.

Sickness absence, employment history, and high-risk employees: a 10-year longitudinal study.

Objective: To investigate the impact of employment characteristics on the occurrence of long-term sickness absence taking socioeconomic covariates into account. Methods: A longitudinal analysis was conducted for 62,745 employees aged 18 to 64 during 1990–1999. A nonlinear random-effects model was used. In particular, the missing data patterns and their relationship with sickness absence were studied. Results: Strong relationship of socioeconomic background with occurrence of long-term sickness absence (≥3 days) was found. The missing data patterns significantly predicted sickness absence for female employees. In subsequent analysis, the discontinuous employment history with high occurrence of short-term sickness absence (<3 days) appeared to be strongly linked to long-term sickness absence in young women. Conclusions: An investigation of missing values and short-term sickness absence as predictors for long-term sickness absence uncovered that young women with irregular employment history constituted high-risk employees.

Household income and health problems during a period of labour-market change and widening income inequalities – A study among the Finnish population between 1987 and 2007

Income inequalities widened considerably from 1987 to 2007 in Finland. We compared the association between household income and health problems across three periods and in several different ways of modelling the dependence. Our aim was to find out whether the change in the distribution of income might have led to wider income-related inequalities in health problems. The data represent an 11-per-cent random sample of the Finnish population, and we restricted the analysed sample to those between 18 and 67 years of age and not in receipt of any pension in each of the three six-year periods examined (n between 280,106 and 291,198). The health outcome was sickness-allowance days compensated. Household-equivalent taxable income was applied with two different scale transformations: firstly, as real income adjusted for price level and secondly, as rank position on the income distribution. We used negative binomial regression models, with and without zero inflation, as well as decomposition analysis. We found that sickness-allowance days decreased with increasing income, while differences in the shape and magnitude of the association were found between the scales and the periods. During the study period the association strengthened considerably at both the lowest fifth and the top fifth of the rank scale, while the observed per-unit effect of real income changed less. Decomposition analysis suggested that slightly less than half of the observed increase in concentration of health problems at lower end of the rank scale could be accounted for by the change in real income distribution. The results indicate that widening differences in household consumption potential may have contributed to an intensified impact of household income on inequalities in health problems. Explaining the change only in terms of consumption potential, however, was problematic, and changes in the interdependence of labour-market advantage and health problems are likely to contribute as well.