Longitudinal dyadic associations between body mass index and depressive symptoms among Chinese older couples

Obesity and depression are becoming widespread conditions among older adults. Existing studies have examined the relationship between individuals’ body mass index (BMI) and depressive symptoms, yet the findings remain quite controversial. This study aimed to examine the dyadic associations between BMI and depressive symptoms among Chinese older couples. The analytic sample consisted of 1,710 older married couples aged 60 and older from three waves (2011, 2013, and 2015) of the China Health and Retirement Longitudinal Study. BMI was defined as weight in kilograms divided by height in meters squared, and depressive symptoms were measured using the Center for Epidemiologic Studies Depression Scale. Data were analyzed using the Longitudinal Actor–Partner Interdependence Model with autoregressive and cross-lagged paths in Mplus. The results showed that individuals’ earlier BMI and depressive symptoms were positively associated with their subsequent BMI and depressive symptoms across the three waves. For actor effects, husbands’ earlier BMI was negatively associated with their later depressive symptoms, whereas the reverse association was not significant. Partner effects were also found, with one’s earlier BMI being negatively associated with his/her spouse’s subsequent depressive symptoms, one’s earlier depressive symptoms being positively associated with his/her spouse’s subsequent depressive symptoms, and wives’ earlier BMI being positively associated with their husbands’ subsequent BMI. Our findings suggest a unidirectional association from BMI to depressive symptoms and highlight the complexity of dyadic associations between BMI and depressive symptoms in Chinese older couples. Couple-based interventions and programs should be taken to improve older adults’ physical and mental health conditions.