[Biological Aging Affects the Rate of Cognitive Decline in Middle-aged and Elderly Populations: A Cohort Study Based on CHARLS].

OBJECTIVE

To investigate the relationship between biological aging and the rate of cognitive decline in middle-aged and elderly populations.

METHODS

Longitudinal tracking data of cognitive function were obtained from the China Health and Retirement Longitudinal Study (CHARLS). We employed the Klemera and Doubal method (KDM) to estimate biological age (BA), and calculate the biological aging index (BAI) and biological aging type (BAT). A multivariate linear regression model was employed to analyze the relationships between baseline BAI, BAT, and cognitive function scores. Based on the baseline analysis, a mixed-effects model was used to examine the longitudinal associations between baseline BAI, BAT, and cognitive function during follow-up.

RESULTS

A total of 5897 participants were included in the study. BAI was found to be negatively associated with baseline cognitive function scores, with the partial regression coefficient (β) (95% CI) being －0.185 (－0.231, －0.139) (P < 0.001). Compared with the lagged aging group, the premature aging group had lower cognitive function scores (β [95% CI]: －0.741 [－0.966, －0.516]). For age and sex, for each additional year of baseline BAI, cognitive function scores declined by an average of 0.012 (95% CI: －0.019, －0.005) points per year after adjusting for age and sex, and declined by 0.011 (95% CI: －0.018, －0.004) points per year after adjusting for other covariates. Compared with participants with lagged aging, those with premature aging experienced, on average, an additional decline of 0.042 (95% CI: －0.075, 0.009) points per year in cognitive function scores after adjusting for age and sex alone, and by 0.039 (95% CI: －0.072, －0.007) points per year after adjusting for other covariates.

CONCLUSION

Biological aging affects the rate of cognitive decline in middle-aged and elderly populations. A higher BAI is associated with a faster decline in cognitive function. Compared with those with lagged aging, individuals with premature aging exhibit a more rapid rate of cognitive decline.