Association of routine blood and biochemical indicators with frailty among people aged 80 years and older in China

Objective to explore the association of routine blood and biochemical indicators with frailty among the elderly population in China.Methods A cross-sectional study design was employed using data from the Chinese Longitudinal Healthy Longevity Survey (CLHLS) in 2009, 2012, and 2014, A total of 2,434 individuals aged 80 and above were included, accounting for 3,222 observation records. Information on the demographic characteristics and health status of the participants was collected through questionnaires. Routine blood and biochemical indicators were measured using automatic biochemical analyzer. A multifactorial generalized mixed-effects model was performed to analyze the association between routine blood, biochemical indicators, and frailty.Results Among the 3,222 observation records, 2,103 cases (65.3%) were classified as frail, while 1,119 cases (34.7%) were non-frail. The results of the multifactorial generalized mixed-effects analysis, after adjusting for covariates, showed that an increase in plasma total cholesterol (OR = 1.13, 95%CI = 1.01~1.26), blood glucose (OR = 1.13, 95%CI = 1.03~1.22), blood urea nitrogen (OR = 1.11, 95%CI = 1.01~1.22), high-sensitivity C-reactive protein (OR = 1.16, 95%CI = 1.05~1.27), and malondialdehyde (OR = 1.17, 95%CI = 1.07~1.28) levels were positively associated with an increased risk of frailty in the elderly population. Conversely, a decrease in red blood cell count (OR = 0.84, 95%CI = 0.76~0.95) and blood creatinine levels (OR = 0.79, 95%CI = 0.70~0.88) was associated with an increased risk of frailty in the elderly.Conclusion Plasma total cholesterol, blood glucose, blood urea nitrogen, high-sensitivity C-reactive protein, and malondialdehyde levels were positively correlated with frailty in the elderly Chinese population, while red blood cell count and blood creatinine levels were negatively correlated with frailty.