Factors associated with weight loss by age among community-dwelling older people

Background Factors associated with weight loss in community-dwelling older people have been reported in several studies, but few studies have examined factors associated with weight loss by age groups. The purpose of this study was to clarify factors associated with weight loss by age in community-dwelling older people through a longitudinal study. Methods Participants in the SONIC study (Longitudinal Epidemiological Study of the Elderly) were community-dwelling people aged 70 or older. The participants were divided into two groups: 5% weight loss and maintenance groups, and compared. In addition, we examined factors affecting weight loss by age. The analysis method used was the χ 2 test, and the t-test was used for comparison of the two groups. Factors associated with 5% weight loss at 3 years were examined using logistic regression analysis with sex, age, married couple, cognitive function, grip strength, and the serum albumin level as explanatory variables. Results Of the 1157 subjects, the proportions showing 5% weight loss after 3 years among all subjects, those aged 70 years, 80 years, and 90 years, were 20.5, 13.8, 26.8, and 30.5%, respectively. In logistic regression analysis, factors associated with 5% weight loss at 3 years by age were influenced by BMI of 25 or higher (OR = 1.90, 95%CI = 1.08–3.34, p = 0.026), a married couple (OR = 0.49, 95% = 0.28–0.86, p = 0.013), serum albumin level below 3.8 g/dL (OR = 10.75, 95% = 1.90–60.73, p = 0.007) at age 70, and the grip strength at age 90 (OR = 1.24, 95%CI = 1.02–1.51, p = 0.034), respectively. Conclusions The results suggest that factors associated with weight loss by age in community-dwelling older people through a longitudinal study differ by age. In the future, this study will be useful to propose effective interventions to prevent factors associated with weight loss by age in community-dwelling older people.