Older Adults' Social Profiles and Links to Functional and Biological Aging in the United States and Mexico.

Objective: Social stress-loneliness, isolation, and low relationship quality-increase risks of aging-related diseases. However, the ways in which they intersect to undermine healthy aging remain poorly understood. We used latent class analysis to identify groups of older adults based on their social stress in both the United States and Mexico. Thereafter, we examined their cross-sectional associations with markers of functional and biological aging.

Method: Participants in the Health and Retirement Study (HRS; N = 8316) and Mexican Health and Aging Study (MHAS; N = 15,001) reported their loneliness, isolation (i.e., living alone), and relationship quality with spouse, children, and friends. Outcomes included C-reactive protein, functional limitations, self-rated health, comorbidities, gait speed, and grip strength. Models controlled for demographics, health behaviors, and body mass index.

Results: In both countries, five classes emerged, a supported group and four with elevated social stress: a) strained, b) isolated, c) spousal ambivalence, and d) unhappily married. Compared with the others, strained participants in both samples had greater functional limitations, poorer self-rated health, and more comorbidities, as well as slower gait in HRS and weaker grip in MHAS. Generally, supported participants fared better than the other groups. In HRS, C-reactive protein levels differed between the strained group and others, but these associations were explained by health behaviors and body mass index.

Conclusions: Older adults in both countries with strained relationships fared worst in their aging-related outcomes, revealing new insights about the links between toxic social stress and unhealthy aging.