Life-Course Transitions, Socioeconomic Status and Health Behaviours
Life Transitions & Health Behaviours
It has been widely reported that major life transitions, such as going to college, finding a stable job, or becoming unemployed, are associated with poor health outcomes, such as …. (1-3). Moreover, there is solid evidence that life transitions are also associated with health behaviours: some studies have reported poorer dietary intake during college (4), or higher rates of smoking (5, 6) and heavy drinking (7, 8) among those facing unemployment. In fact, health behaviours have been reported to account for about one-quarter of socioeconomic disparities in health (9).
Traditionally, two alternative explanations are offered for the association between specific life events and health (behaviours) that differ in the directionality of the causality: the social causation hypothesis and the health selection hypothesis (10, 11).
The social causation hypothesis argues that life events, e.g. job loss, lead to unhealthy behaviours through different mechanisms: first, high stress levels associated with unemployment may lead to unhealthy behaviours like smoking or alcohol use as coping mechanisms (3). Alternatively, a decrease in material resources may lead to unhealthy behaviours like poor diet due to a higher availability and affordability of industrially-processed products (9).
Alternatively, the selection hypothesis claims that pre-existing health behaviours make individuals more or less prone to experiencing certain events, like finding a partner (12) or becoming unemployed (13). In the specific case of young adults, there is evidence that health selection mainly operates through mental (e.g.. ..) and behavioural disorders (e.g. ..) rather than physical conditions (e.g. ..) (14). For instance, substance use may lead to difficulties to cope with duties of daily life (15), and thus to being less eligible for a job and more prone to unemployment (16, 17).
In fact, there is evidence that both social causation and health selection processes are involved in the social gradient of health behaviours (10, 18, 19, 20). Furthermore, there is evidence that both operate simultaneously, in a bidirectional association (13, 21, 22).
Traditionally, studies have mostly focused on testing either causation or selection (3, 16, 17, 19, 20, 23). The few studies that test both simultaneously, tended to consider the general association between life events -e.g. unemployment- and health behaviours –e.g. alcohol use- (13, 21), without specifically looking at potential subgroup effects.
However, the relative contribution of social causation or health selection to inequalities in health -and health behaviours- may be modified by external factors, i.e. moderators. For instance, a meta-analysis investigating the association between unemployment and health was moderated by occupational status and social support (i.e. stronger effect for manual workers and weaker effect among those with strong social networks) (19). Similarly, studies on health selection (i.e. poor health) into unemployment have shown that gender moderates the association, with selection being stronger among women than among men (24).
To the best of our knowledge, no studies have focused on testing both causation and selection, and at the same time addressing the role of moderators. Thus, important questions like ‘for whom is one or the other effect stronger?’ and ‘in which socioeconomic contexts is health selection stronger than causation, and vice versa?’ remain unresolved.
In order to tackle these questions, we simultaneously analyse social causation and health selection processes in the association between life transitions and health behaviours, and which factors moderate the strength of these associations.
Life transitions include events like entry into a partner relationship, parenthood, and completing an education. A special focus is placed on unemployment, since it has been reported to “represent the greatest threat to worker’s well-being” (25).
Health behaviours include smoking, alcohol and illicit drug use, dietary patterns and physical activity. Finally, key moderators are SES –i.e. educational level, income, and occupation-, (perceived) family and social support, and gender. Age, as well as stressful life events will be taken into account as covariates.