Abstract
This study investigates the relationship between homocysteine (Hcy) levels and decreased intrinsic capacity (DIC) in older adults over 60 years of age, against the backdrop of rising cognitive decline in aging populations. Elevated Hcy, linked to various diseases, may serve as a biomarker for DIC. A cross-sectional study was conducted on 1311 community-dwelling older adults aged 60-91 years in Hangzhou, China, from March 2023 to June 2023. The primary exposure was Hcy level, with DIC as the outcome, assessed via the World Health Organization Intrinsic Capacity Composite Assessment scale. Covariates included gender, age, education, blood pressure, body mass index, and C-reactive protein. Data were analyzed using logistic regression models. Higher Hcy levels were significantly associated with increased DIC risk (OR = 1.03, 95% CI: 1.00-1.07, P = .0439). A non-linear relationship was observed, with a threshold effect at 14.6 μmol/L. Below this, each 1 μmol/L increase in Hcy corresponded to an 8% rise in DIC risk (95% CI: 1.02-1.15, P = .0137). In the very elderly, a stronger association was noted below 11.8 μmol/L (OR = 1.35, 95% CI: 1.143-1.61, P = .0005). Elevated Hcy levels are positively associated with the risk of DIC, especially among middle-aged and older adults, and exhibit a non-linear threshold effect. These findings suggest the potential of Hcy as a biomarker for DIC, advocating for age-specific management strategies. Further research should explore underlying mechanisms and validate these results across diverse populations.