Moderating effect of age on the relationships between pre-frailty and body measures

This study aims to investigate the relationship between body measures and the presence of two frailty-related phenotypes, and the moderating effect of age on this relationship. This is a secondary data analysis of the baseline data of an interventional study. The participants were residents of seven districts in Hong Kong, aged 55 or older, able to ambulate independently and to function well cognitively. Pre-frailty refers to the presence of two frailty-related phenotypes: low physical activity or poor handgrip strength or both. Included in the study were 199 individuals with a mean age of 73.43 (SD 7.54). Regression models showed that body weight (OR = 0.95, 95% CI 0.92-0.99, p < .05) was significantly associated with pre-frailty, as was body height (OR = 0.88, 95% CI 0.83-0.94, p < .001). Age is a significant moderator of the relationship between pre-frailty and body weight and body height. The effect of body weight (beta = -0.044, p < .05) and height (beta = -0.16, p < .001) on pre-frailty was significant and negative in the younger age groups. The findings indicate that raw body measures (i.e. body weight, body height) are more predictive of pre-frailty than BMI in older Chinese people. However, in the old-old group, these measures are not significant predictors of pre-frailty in Chinese community-dwelling adults. Practitioners should consider adopting body measures as predictors of pre-frailty in the younger-old population.