Association Between Insulin-Like Growth Factor-1 and Frailty Among Older Adults

OBJECTIVES: Frailty is a course experienced in advanced aging. Identification of a biological factor associated with frailty is required. Although serum insulin-like growth factor-1 (IGF-1) is a potential factor related with frailty, consensus has not been reached regarding this relationship. This study aimed to investigate the association between IGF-1 and frailty in older adults. DESIGN: Cross-sectional study. SETTING: Cohort study that was part of the "National Center for Geriatrics and Gerontology - Study of Geriatric Syndromes." PARTICIPANTS: The study participants were 4133 older adults (mean age, 71.8 ± 5.4 years). MEASUREMENTS: We assessed serum IGF-1 levels and frailty status and collected demographic variables, including cognitive function, as covariates. RESULTS: Frailty and pre-frailty were present in 274 subjects (7%) and 1930 subjects (47%), respectively. Subjects were divided into four groups based on quartiles of IGF-1 levels. Multinomial logistic analysis showed that the lowest group had significant odds of pre-frailty (crude model: odds ratio [OR] 1.58, 95% confidence interval [CI] 1.30-1.90, p < .001; adjusted model: OR 1.38, 95% CI 1.13-1.68, p = .002) and frailty (crude model: OR 3.42, 95% CI 2.38-4.92, p < .001; adjusted model: OR 1.54, 95% CI 1.02-2.32, p = .039), compared with the highest group. CONCLUSION: Lower serum IGF-1 levels were independently related with frailty in older adults.