Social connections are differentially related to subjective age and physiological age acceleration amongst older adults.

Human social connections are complex ecosystems formed of structural, functional and quality components. Weak social connections are associated with adverse age-related health outcomes, but we know little about the ageing-related processes underlying this. Using data from 7047 adults aged 50+ in the English Longitudinal Study of Ageing, we explore associations between diverse aspects of social connections and both older subjective age and accelerated physiological age using a validated physiological ageing combining cardiovascular, respiratory, haematologic and metabolic indicators. Doubly robust estimations using inverse-probability-weighted regression adjustment estimators show that living alone, low social integration and low social support are risk factors for physiological age acceleration. However, weak social connections did not have a statistically significant association with older subjective age. Analyses are robust to multiple sensitivity analyses and maintained four years later. We propose the hypothesis that accelerated physiological ageing may be a mechanism underpinning the relationship between weak social connections and age-related morbitidy and mortality.