The Relationship between Body Mass Index and Poor Self-rated Health in the Korean Population

Objective Several previous studies have evaluated associations between body mass index (BMI) and self-rated health (SRH); however, the results were inconsistent. This study aimed to examine the association between BMI and SRH in Korean adults. Methods The study was conducted in 214,997 adults who participated in the 2016 Korean Community Health Survey. Participants were categorized into four groups based on BMI: underweight (<18.5 kg/m 2 ), normal weight (18.5–24.9 kg/m 2 ), overweight (25.0–29.9 kg/m 2 ), or obese (≥30.0 kg/m 2 ). Multivariate Poisson regression analysis with sampling weights and robust variance estimators was performed to evaluate the relationship between BMI categories and poor SRH. Results There was a J-shaped association between BMI and poor SRH in both sexes, with the lowest risk observed in the normal weight group in both sexes. Compared with normal weight subjects, the age and lifestyle adjusted prevalence rate ratios for poor SRH were 1.61 (95% CI, 1.50–1.74) for underweight, 1.16 (95% CI, 1.11–1.21) for overweight, and 2.35 (95% CI, 2.13–2.58) for obese men; and 1.24 (95% CI, 1.17–1.32) for underweight, 1.26 (95% CI, 1.22–1.31) for overweight, and 1.77 (95% CI, 1.64–1.91) for obese women. Conclusions In a cross-sectional study using a nationally representative survey, there was a nonlinear relationship between BMI and poor SRH. This relationship was more prominent in men than in women. Prospective studies are needed to further clarify the relationship between BMI and SRH.