Childhood Loneliness and Risk of Incident Cardiovascular Disease in Middle-Aged and Older Chinese Adults: A Nationwide Cohort Study.

BACKGROUND: Although adult loneliness is an established risk factor for cardiovascular disease (CVD), the long-term effects of loneliness experienced during childhood remain insufficiently understood. This study aims to examine the association between childhood loneliness and the risk of developing CVD in a substantial nationwide cohort of middle-aged and older Chinese adults.

METHODS: The study cohort comprised 12 431 participants from the China Health and Retirement Longitudinal Study (CHARLS) who were free from CVD at the baseline in 2011 and took part in the 2014 Life History Survey. Childhood loneliness was classified into three categories ("no," "possible," or "childhood loneliness") based on self-reported data. Participants were monitored until 2020. We used discrete-time survival models with a complementary log-log link to calculate hazard ratios (HRs) for the incidence of CVD. Findings were validated through sensitivity analyses using Cox proportional hazards models. Additionally, subgroup and mediation analyses were performed to identify potential effect modifiers and elucidate underlying pathways.

RESULTS: Over a median follow-up period of 9.0 years, 2872 cases of incident CVD were documented. In the fully adjusted model, both possible childhood loneliness (HR: 1.11; 95% CI: 1.03-1.20) and definite childhood loneliness (HR: 1.19; 95% CI: 1.07-1.36) were associated with a modestly increased risk of incident CVD. This association appeared more pronounced for incident stroke. The association was strongest among individuals with lower educational attainment. Mediation analysis suggested that the relationship between childhood loneliness and incident CVD may be partially explained by the persistence of loneliness into adulthood.

CONCLUSIONS: In this nationwide cohort, retrospectively reported childhood loneliness is associated with a higher long-term risk of CVD, particularly stroke. The persistence of loneliness into adulthood appears to be an important factor in this relationship. These findings suggest that early-life psychosocial well-being may be a relevant target for long-term cardiovascular health promotion.