When support turns into risk: how excessive financial dependence on adult children accelerates cognitive decline in aging China

Although the traditional view holds that financial support from adult children is beneficial for older adults, it remains unknown whether potential risks, such as the loss of economic independence, might impair their cognitive function. Using four waves of the China Health and Retirement Longitudinal Study, 36,187 observations were analyzed. Intergenerational financial dependence was defined as the proportion of total income derived from children among aging people. Cognitive function was assessed through a validated composite score covering memory, orientation, calculation, and visuospatial ability. Analytical approaches included linear mixed-effects models, restricted cubic spline (RCS) analyses, Cox survival models, cross-lagged mixed-effects models, and mediation analyses incorporating multiple imputation. Higher financial dependence was consistently associated with poorer cognitive performance of aging population. Compared with the low-dependence group (Q1), cognitive scores were significantly lower in Q3 and Q4, with the greatest decline observed in Q4 (> 75% dependence; β = − 0.248, 95% CI: − 0.314 to − 0.181, P < 0.001). RCS analyses revealed a pronounced nonlinear pattern, with cognitive decline accelerating rapidly once dependence exceeded ~ 50% ( P < 0.001). Individual cognitive trajectory modelling showed that, compared with the cognitive decline group, older adults in the cognitive maintenance/improvement group exhibited a 50% lower all-cause mortality risk (HR = 0.50, 95% CI: 0.34–0.73). Cross-lagged models demonstrated bidirectional causation. Social isolation exerted a modest partial mediating effect, accounting for 4.74% of the total association. Excessive financial dependence on adult children is an overlooked social determinant of cognitive deterioration in older adults. Dependence beyond 50% constitutes a critical threshold for accelerated decline. Interventions aimed at enhancing economic autonomy, reducing social isolation, and improving chronic disease management may be crucial for disrupting the dependence–decline cycle and protecting cognitive health in aging societies.