Vision impairment and cognitive function in Chinese older adults with diabetes: multiple mediating effects of social...

Vision impairment and cognitive decline are common concerns among older adults with diabetes. Although visual difficulties have been associated with poorer cognitive function, the social and psychological pathways underlying this association remain insufficiently understood. This study aimed to examine the independent and serial indirect roles of social participation and perceived control in the association between vision impairment and cognitive function among Chinese older adults with diabetes.

Data were obtained from the 2018 wave of the Chinese Longitudinal Healthy Longevity Survey. A total of 1,072 Chinese adults aged 65 years or older with diabetes were included. Descriptive statistics were used to summarize participants' sociodemographic and health-related characteristics. Spearman's rank correlation analysis was conducted to examine the associations among vision impairment, social participation, perceived control, and cognitive function. A serial multiple mediation analysis was performed using Model 6 of the SPSS PROCESS macro version 4.0. Age, years of education, sex, place of residence, self-reported quality of life, and self-rated health were included as covariates. Indirect effects were estimated using 5,000 bootstrap samples and bias-corrected 95% confidence intervals. To assess the robustness of the mediation results to different covariate-adjustment strategies, sensitivity analyses were additionally performed using an unadjusted model without covariates and a fully adjusted model including all candidate covariates.

Vision impairment was significantly associated with poorer social participation, poorer perceived control, and lower cognitive function, and all study variables were significantly correlated with one another (p < 0.01). After adjustment for the mediators and covariates, greater vision impairment remained significantly associated with lower cognitive function (direct effect = -0.8085, SE = 0.1971, 95% CI: -1.1952 to -0.4218). The total indirect effect through social participation and perceived control was statistically significant (effect = -0.0783, SE = 0.0317, 95% CI: -0.1466 to -0.0215). The indirect pathway through social participation alone was significant (effect = -0.0484, SE = 0.0226, 95% CI: -0.0965 to -0.0089), whereas the indirect pathway through perceived control alone was not statistically significant (effect = -0.0260, SE = 0.0235, 95% CI: -0.0830 to 0.0090). The serial indirect pathway through social participation followed by perceived control was statistically significant (effect = -0.0038, SE = 0.0026, 95% CI: -0.0102 to -0.0002).

Greater vision impairment was associated with poorer cognitive function among Chinese older adults with diabetes. Social participation showed a significant independent indirect association, while perceived control alone did not. However, social participation and perceived control jointly formed a significant serial indirect pathway. These findings suggest that social participation and perceived control may be relevant to understanding the association between vision impairment and cognitive function. Given the cross-sectional design, the temporal sequence and causal direction of these relationships require confirmation in longitudinal studies.