Association between light BioAge and cognitive impairment risk in middle-aged and elderly people: a retrospective cohort study

Aging is the most significant factor affecting an individual’s cognitive function. This study aimed to explore the association between light BioAge, a novel indicator to assess aging, and the risk of cognitive impairment in middle-aged and elderly people. This retrospective cohort study included individuals aged 45 and above without cognitive impairment at baseline from the China Health and Retirement Longitudinal Study (CHARLS) database 2011–2020. Light BioAge was calculated as: Age + 8.3313 × Creatinine (mmol/L) + 0.8270 × Glucose (mg/dL) + 5.7305 × Log (CRP) − 13.5298. The relationships of light BioAge with the risks of cognitive impairment, mental intactness decline, and episodic memory decline were explored by the Cox regression models, and this relationship was further analyzed in different characteristic subgroups. A total of 4,818 individuals were included in this study. Cognitive impairment occurred in 1,143 (23.72%) individuals, mental intactness declined in 1,961 (40.70%) individuals, and episodic memory declined in 1,693 (35.14%) individuals during the follow-up period. Older BioAge was associated with increased risks of cognitive impairment [HR = 1.24 (95%CI: 1.13–1.36)], episodic memory decline [HR = 1.14 (95%CI: 1.05–1.23)], and mental intactness decline [HR = 1.10 (95%CI: 1.02–1.18)]. Compared with light BioAge < 42.45 years, light BioAge ≥ 56.82 years remained related to higher risks of cognitive impairment [HR = 1.37 (95%CI: 1.05–1.80)] and episodic memory decline [HR = 1.45 (95%CI: 1.16–1.81)]. Higher BioAge was correlated with an increased risk of cognitive impairment in middle-aged and elderly people. Light BioAge may serve as a potential indicator for identifying the risk of cognitive impairment in individuals.