Exploring sex differences regarding the mediation of the relationship between depression and quality of life via moderate and vigorous physical activity in old age: A longitudinal study

Depression (DEP) is common in old age and is associated with poor quality of life (QoL) as well as a poor level of physical activity (PA). The objective of this study was to investigate the association between DEP, moderate physical activity (MPA), and vigorous physical activity (VPA) with QoL, as well as longitudinally examine in depth whether MPA and VPA mediate the relationship between DEP and QoL in men and women aged ≥50 years residing in 12 European countries. Longitudinal mediation analysis, that included 20,647 individuals (8042 men) aged >50 years, who responded to the fourth (in 2011), fifth (in 2013), and sixth (in 2015) wave of the Survey of Health, Ageing and Retirement in Europe (SHARE). The analyzed variables were DEP (EURO-D scale), QoL (CASP-12), and self-reported MPA and VPA in daily life. Comparatively, women indicated a higher DEP score, lower perception of QoL, and levels of MPA and VPA. In both sexes, DEP and QoL indicated a negative association (p < 0.001), and MPA and VPA were positively associated with QoL (p < 0.001). Mediation analysis showed that DEP directly affected MPA and VPA 2 years later and QoL 4 years later. MPA and VPA partially mediated the longitudinal relationship between DEP and QoL over 4 years. Regarding sex, there were no differences between the longitudinal measurement paths. Policies should be created to encourage the older European population to reach adequate physical activity levels to improve QoL and combat depressive symptoms.