The role of financial scarcity in the relationship between income and health behaviors: a causal mediation analysis

Abstract

Background: Financial scarcity is an increasing problem and health behaviors may be impaired by subjective experience of stress due to financial scarcity. Financial scarcity is a stress-response to having insufficient financial means and may affect cognitive functioning. This study aimed to assess whether financial scarcity mediates the association between income and health behaviors. Methods: We used self-reported cross-sectional data of 2379 adults from the 2021 wave of the Dutch population-based GLOBE study. The exposure was equivalent household income, divided in quartiles. The mediator was financial scarcity, measured with the validated Psychological Inventory of Financial Scarcity (range 5–25). Outcomes were body mass index (BMI), fruit consumption, vegetable consumption, leisure time physical activity, and attempts to change health behavior in the past year, respectively: to (1) eat healthier, (2) increase physical activity and (3) lose body weight. Causal mediation analysis adjusted for eight covariables was used to decompose the total effect of income on the outcomes into a direct and indirect effect via financial scarcity as the mediator. Results: Contrasting the lowest and highest income group showed the largest effects of income on health behaviors. We found a total effect of income on BMI (-1.13, 95% CI: -1.68;-0.56) and fruit consumption (155 g per week, 95% CI: 19.61;281.40), but not for leisure time physical activity, vegetable consumption, and attempts to lose weight, eat healthier and increase physical activity. Financial scarcity mediated the effect of income on BMI (natural indirect effect: − 0.42, 95% CI: − 0.64;-0.24), and fruit consumption (natural indirect effect: 41.78, 95% CI: 3.46;79.88), and also mediated the non-significant effects of income on leisure time physical activity, and whether a respondent reported an attempt to eat healthier, lose weight, and increase physical activity. Contrasting adjacent income groups showed smaller effects. Conclusions: Financial scarcity mediated the effect of income on BMI and all health behaviors studied except vegetable consumption. Financial scarcity may trigger mechanisms that affect health behaviors, which are currently not addressed in health behavior interventions. Reducing financial scarcity may contribute to closing income inequalities in health behavior.