Set for life? Socioeconomic conditions, occupational complexity, and later life health

Life expectancy has increased in the western parts of the world and more people reach old age. Some groups of people have benefitted more of the increase in life expectancy and have better health than others. Because of biological, psychological, behavioral, and social factors over the life course, adverse health accumulates in later life. Most societies are socially structured and people higher in the social structure tend to have better health. People’s position in the social hierarchy is commonly assessed by socioeconomic position (indicated by education, social class [occupation based], and income). Labor market stratification plays a central role in stratifying people in to socioeconomic positions. An important factor in the labor market stratification is the level of complexity of work. All these stratification principles could play a role in shaping the risk of adverse later life health. Identifying factors associated with later life health has become more important because of the growing number of people that reach old age.

The overall aim of this thesis was to investigate the relationships between socioeconomic conditions, the complexity level of peoples’ work (measured as occupational complexity), and health in late life by studying 1) the association between complexity of work during midlife and later life health and 2) health inequalities in late life attributable to differences in socioeconomic position. All studies used individually linked data from the Swedish Level of Living Survey (LNU) and the Swedish Panel Study of Living Conditions of the Oldest Old (SWEOLD).

Results from study I showed that higher occupational complexity in midlife decreased the odds of psychological distress 20 years later. Socioeconomic position partly accounted for the association between occupational complexity and psychological distress. Still, occupational complexity may play a role in shaping the risk of psychological distress in old age.

Results from study II showed that the magnitude and direction of the effect sizes, for education, social class, and occupational complexity were similar in relation to later life health (psychological distress and physical functioning). Income was more strongly associated with late life health than the other indicators of socioeconomic position. The income-health association was also the only one that remained significant in the mutually adjusted models. Thus, if the primary objective to include socioeconomic position is to statistically adjust for socioeconomic position, income may be the preferable single indicator. However, if the primary objective of a study is to analyze socioeconomic health inequalities, and the underlying mechanisms that drive these inequalities, then the choice of how to measure socioeconomic position should be carefully considered.

Results from study III initially showed that occupational complexity scores aggregated from across the working life and different trajectories of occupational complexity were associated with physical function (as indicated by mobility and ADL limitations) in late life. Adjusting for socioeconomic position diminished the association. This suggest that the association was confounded (or possibly mediated in the case of income) through socioeconomic position.

Results from study IV showed that financial hardship in childhood increased the risk of psychological distress in late life (at mean age of 81 years). This was partly explained by a direct association from financial hardship in childhood to psychological distress in later life. In addition, chains of risks were found between financial hardship in childhood and psychological distress in later life. This means that financial hardship in childhood increased the risk of a) psychological distress in midlife, b) lower levels of education, c) unemployment in midlife, and d) financial hardship in midlife, which, in turn, increased the risk of psychological distress in later life.

In summary, the results from this thesis showed that there are socioeconomic health inequalities in later life. Lower socioeconomic position in midlife and financial hardship in childhood increase the risk of adverse later life health. Moreover, higher occupational complexity in midlife was investigated, and showed, to play a role in shaping the risk of psychological distress in late life. In contrast, the results showed that occupational complexity is not associated with physical functioning. Occupational complexity play a role in determining socioeconomic position, however, it does not capture an aspect of general life chances that comes with higher socioeconomic position and is relevant for health, beyond that of education, social class, and income.

List of scientific papers

I. Darin-Mattsson A, Andel R, Fors S, Kåreholt I. Are occupational complexity and socioeconomic position related to psychological distress 20 years later? Journal of Aging and Health. 2015:7:1266-1285.
https://doi.org/10.1177/0898264315580120

II. Darin-Mattsson A, Fors S, Kåreholt I. Different indicators of socioeconomic status and their relative importance as determinants of health in old age. International Journal for Equity in Health. 2017:16:1:173.
https://doi.org/10.1186/s12939-017-0670-3

III. Darin-Mattsson A, Andel R, Fors S, Nilsen C, Fritzell J, Kåreholt I. Occupational complexity and late life physical functioning in Sweden. [Manuscript]

IV. Darin-Mattson A, Andel R, Keller Celeste R, Kåreholt I. Linking financial hardship throughout the life-course with psychological distress in old age: sensitive period, accumulation of risks, and chains of risk hypotheses. [Manuscript]