This research project aims to derive a strategy for reducing socioeconomic inequalities in health (SEIH). This strategy is based on an examination of differences in socioeconomic, psychosocial, lifestyle, and health characteristics between three cohorts of middle-aged Dutch adults born in three distinct decades. The project answers the following research questions: 1) how has the composition of educational groups in terms of socioeconomic resources changed across cohorts; 2) which psychological, social, and behavioural factors have become more important for explaining SEIH over time?; and 3) to what extent have changes in socioeconomic groups and explanatory factors contributed to the persistence of SEIH over time? This project will provide major contributions to the evidence-base that informs policy makers and intervention specialists in their efforts to reduce and prevent excessive SEIH. Particularly, it addresses the following gaps in knowledge:
First, a leading theoretical explanation for the persistence of SEIH states that due to wider societal developments, the mechanisms generating SEIH are changing over time (1). These developments include fundamental changes in the distribution of socioeconomic resources (e.g. education, prestige, income, and wealth), and in the psychological, social, and behavioural factors that link socioeconomic position (SEP) to health. Interventions based on the factors that once were dominant in explaining SEIH may thus become outdated, and be rendered ineffective. To date, despite its fundamental implications for public health policy if this theory were true, few studies have been able to test it with large scale observational data. This project employs a unique birth cohort-comparative design that provides crucial information needed to keep prevention and intervention programs up-to-date, and to anticipate future developments.
Second, the mechanisms known to produce SEIH cross disciplinary boundaries, and include psychological, behavioural, and social pathways (2–4). Few studies have been able to single out from this multitude of factors the specific key mechanisms responsible for generating SEIH. Even less studies examined changes in the importance of these factors over time, which may be crucial to understand the persistence of SEIH. Therefore, this multidisciplinary project includes a wide range of explanatory factors: 1) intergenerational social mobility; 2) lifestyle, including smoking, alcohol use, physical activity and obesity; 3) personality characteristics, including mastery, self-efficacy, and neuroticism; 4) cognitive ability; and 5) social network size, composition, and support. Based on statistical analyses, this project shall identify which of these factors primarily account for observed health disparities and changes therein over time. These should receive priority in policies aimed at SEIH.
Third, reviews suggest that previous life style interventions in the lower educated have largely failed to produce health improvement, and that generic health intervention programs have often benefited the high educated more than the low educated, thereby increasing rather than diminishing SEIH (5,6). This points to a lack of studies showing which factors could particularly benefit those with the lowest SEP. Therefore, this project analyses whether some explanatory factors are particularly important for the health of persons with a low SEP compared to an intermediate SEP. By examining the role of explanatory factors of SEIH across the socioeconomic gradient, this project can accurately indicate targets for prevention or intervention aimed at specific socioeconomic groups.
Analyses for this project shall be conducted on available data from two Dutch prospective cohort studies: the Longitudinal Aging Study Amsterdam (LASA) and the Doetinchem Cohort Study (DCS) (7–9). These data sets provide the multidimensional and multi-cohort structure needed to examine explanations of the persistence of SEIH. The health outcomes included in this study are self-rated health, morbidity, depressive s