Korea is expected to become a super-aged society in 2026, and improving nutritional status, which is directly related to health problems, is therefore important for increasing healthy life expectancy. Frailty is the most complex phenotype of aging, and leads to adverse health outcomes, disability, poor quality of life, hospitalization, and mortality. Malnutrition is a major risk factor for frailty syndrome. This study aimed to investigate the incidence of pre-frailty or frailty in the second wave (T2, 2018–2019) according to general characteristics and nutritional status in the first wave (T1, 2016–2017); and examine the longitudinal association of nutritional status in T1 and the incidence of pre-frailty or frailty in T2 among older adults living in a community.

A secondary data analysis was performed using the Korean Frailty and Aging Cohort Study (KFACS). Participants comprised 1125 community-dwelling older Korean adults aged 70–84 years (mean age: 75.03 ± 3.56 years; 53.8% males). Frailty was assessed using the Fried frailty index, and nutritional status was assessed using the Korean version of the Mini Nutritional Assessment Short-Form and blood nutritional biomarkers. Binary logistic regression was used to identify longitudinal associations between the nutritional status at T1 and pre-frailty or frailty at T2.

Over the two-year follow-up period, 32.9% and 1.7% of the participants became pre-frail and frail, respectively. After the potential confounders were adjusted (sociodemographic, health behaviors, and health status characteristics), pre-frailty or frailty had a significant longitudinal association with severe anorexia (adjusted odds ratio [AOR], 4.17; 95% confidence interval [CI], 1.05–16.54), moderate anorexia (AOR, 2.31; 95% CI, 1.46–3.64), psychological stress or acute disease (AOR, 2.61; 95% CI, 1.26–5.39), and body mass index (BMI) less than 19 (AOR, 4.11; 95% CI, 1.20–14.04).

Anorexia, psychological stress, acute disease, and low BMI are the most significant longitudinal risk factors for pre-frailty or frailty in older adults. As nutritional risk factors may be preventable or modifiable, it is important to develop interventions targeting the same. Community-based health professionals in health-related fields should recognize and manage these indicators appropriately to prevent frailty among older adults living in the community.