Work and health : epidemiological studies of sickness absence and mortality with special reference to work environment, factors outside work and unemployment

Abstract

The level and costs of sickness absence in Sweden have fluctuated over time and there are also important regional variations within the country with a higher rate of sickness absence in the northern part. Sickness absence tend to be more common in women than in men and several factors, besides ill health, at a societal, organisational, social and individual level have been discussed as possible causes of sickness absence. Sweden has had a long tradition of low unemployment. During the last decade there have been substantial changes in the Swedish labour market that have resulted in an increased unemployment rate. Large studies have shown an increased mortality associated with unemployment but it is still controversial to what extent this represents a causal association.

The general aim of this thesis was twofold: Firstly, to study factors at work and outside work in relation to sickness absence in an integrated fashion and keeping a gender perspective. Secondly, to analyse unemployment in relation to subsequent mortality taking into account sociodemographic, lifestyle, personality and early childhood factors.

In the analyses of sickness absence the study population consisted of all employees in three of Sweden Post's regional organisations (n=3 470). Incidence of sickness absence in the study population was recorded during the period 1992-1994. An extensive questionnaire was sent out in 1994 including questions about factors at work and outside work of possible importance for sickness absence.

The association between unemployment and mortality was analysed using the younger cohort of the Swedish twin registry including all same sexed twin pairs born 1926-1958. The study population encompassed those responding to a comprehensive mailed questionnaire in 1973 reporting a job title (n=20 632 individuals). All causes of death as well as specific causes of death were followed between 1973 and 1996.

A decrease in the incidence of sickness absence was observed after the introduction of a qualifying day in 1993. The proportion of long-term sick-leave events (15-365 days) increased and among men, long-term events of sickness absence increased also in absolute terms. Long-lasting or serious illness and frequent colds showed strong associations with sickness absence. Subjects with high sickness absence frequently reported physical exhaustion after work and tiredness prohibiting leisure time activities. Among women, m particular complaints due to work in a forward-bent position, complaints due to heavy lifting, occurrence of bullying at the workplace and working while ill (sickness presenteeism) was associated with a high sickness absence. Among men, a high sickness absence was related to anxiety about reorganisation of the workplace, working while ill, no supervisor position and complaints due to heavy lifting. Concerning factors outside work, use of tranquillizers, and a need to recover from staying at home with sick children was associated with high sickness absence among women. In addition, for married/cohabitant women with children a high domestic workload increased the occurrence of sickness absence. Among men, experience of a relative's serious sickness, accident or death, use of alcohol as sedative, and divorce were suggested to be important determinants.

Unemployment was found to increase the risk of early death even after adjustment for several social, behavioural, health, personality and early childhood factors among both women and men. Use of tranquillisers or sleeping pills, certain personality characteristics, low education, and serious or long lasting illness was found to further strengthen the association between unemployment and mortality The increased mortality among unemployed subjects was in part attributable to an increased mortality from suicides and accidents or injuries with uncertainty if caused by accident or by intention.

In conclusion the results of this thesis suggest that changes in the sickness benefit system as well as several factors at work and outside work, besides Ill health, influence the incidence of sickness absence. In addition, the results indicate that unemployment increases the risk of early death, in part due to an increased risk of suicides, in both men and women taking several sociodemographic, lifestyle, personality and early childhood factors into account.