Couple BMI trajectory patterns during mid-later years: Socioeconomic stratification and later-life physical health outcomes

Although previous studies have documented spousal resemblance in health attributes, questions remain regarding the longitudinal resemblance of spouses' body mass index (BMI) and the possible formation of couple-level BMI trajectory patterns. Consequentially, we know little about how the longitudinal resemblance of spouses' BMI may link couples' varying socioeconomic experiences to their physical health outcomes in later years. Thus, the present study using prospective data from a sample of 255 couples in enduring marriages over a period of 26 years (from 1991 to 2017) examined (a) the existence of couple-level BMI trajectory patterns in mid-later years, (b) their social stratification into heterogeneous groups of couples associated with family economic hardship (FEH), and (c) differential later-life health outcomes of these groups. The results provided evidence for groups of couples with distinct BMI trajectory patterns. These groups were associated with latent groups of FEH trajectories, suggesting a persistent association between couple BMI and FEH. Couple BMI trajectory patterns were consequential for physical health consequences in later years. Two features of couple BMI trajectory patterns, severity and synchrony, were utilized to explain these associations. Taken together, the results provided evidence for a couple-level FEH-BMI-health process over the life course and emphasize the impact of severity and synchrony in couples' BMI for their health problems in later adulthood. Findings are discussed as they relate to health policies and interventions focusing on the well-being of married couples in later life, particularly the need for couple-focused obesity-related interventions and policies that mitigate economic hardship given its long-lasting health impacts.