Blood Biomarkers and Functional Disability Among Extremely Longevous Individuals: A Population-Based Study Zuyun Liu,1,* Yong Wang,2,* Jiapin Huang,1 Xuefeng Chu,2 Degui Qian,3 Zhengdong Wang,2 Xunming Sun,1 Fei Chen,3 Jun Xu,3 Shilin Li,1 Li Jin,1 and Xiaofeng Wang1

Background. Several blood biomarkers have been linked to functional disability, a health problem in general populations. However, there are limited data for evaluating the potential association of biomarkers with functional disability in an extremely longevous (95+) population. Methods. We used data from 420 extremely longevous individuals from the Rugao longevity cohort, a population-based association study conducted in Rugao, a longevity town in China. Functional disability was assessed by the Katz Index of Independence in activities of daily living. Blood biomarkers, including serum lipid, lipoprotein cholesterol, serum albumin, and lymphocyte count, were correlated with activities of daily living. Results. Among extremely longevous women, following the degree of functional disability, serum albumin and lymphocyte count decreased significantly (all p for trend < .001). In a univariate model, serum albumin (β = −0.279, p < .001), lymphocyte count (β = −0.187, p < .001), and neutrophil count (β = 0.140, p = .012) were found to be significantly associated with activities of daily living in women. After adjustment for other covariates, the significance remained. Notably, multivariate regression analysis revealed independent effects of all the three biomarkers on activities of daily living (β = −0.242, ‒0.185, and 0.143, all p < .05). We did not observe any association in men. Conclusions. We found significant associations between serum albumin, lymphocyte count, and neutrophil count and physical disability even after adjustment for potential confounders in extremely longevous women, which call for further study. The findings provide preliminary but crucial clues for future studies specifically aimed at exploring the longitudinal relationships of interest before proceeding with interventions.