Association Between Dietary Quality and Pulmonary Function Among Older Adults: Results from the Korea National Health and Nutrition Examination Survey, 2024

Background: Dietary quality is important for preventing and managing chronic diseases in older adults; however, its association with respiratory health remains insufficiently understood. This cross-sectional study examined the association between dietary quality and lung function among older adults in South Korea. Methods: This cross-sectional study included 1021 adults aged ≥65 years from the 2024 Korea National Health and Nutrition Examination Survey. Dietary quality was measured using the Korean Healthy Eating Index (KHEI; range, 0–100). The forced expiratory volume in 1s (FEV1), forced vital capacity (FVC), FEV1/FVC ratio, forced mid-expiratory flow between 25% and 75% of FVC (FEF25–75%), and peak expiratory flow (PEF) were measured using spirometry. Linear regression models were used with beta coefficients and 95% confidence intervals (CIs). Results: The mean (standard deviation [SD]) KHEI score was 67.41 (10.97). The mean (SD) values for the lung function parameters were 2.95 (0.72) L for FVC, 2.21 (0.54) L for FEV1, 75.22 (7.68)% for the FEV1/FVC ratio, 1.93 (0.79) L/s for FEF25–75%, and 6.03 (1.73) L/s for PEF. The β (95% CI) for the relationship between the KHEI (unit = 1-SD increment) and lung function outcomes was 0.013 (−0.016–0.041) L for FVC, 0.028 (0.003–0.053) L for FEV1, 0.539 (0.129–0.950) % for the FEV1/FVC ratio, 0.057 (0.010–0.104) L/s for FEF25–75%, and 0.066 (−0.018–0.149) L/s for PEF. Conclusions: KHEI was positively associated with FEV1, FEV1/FVC, and FEF25–75%, whereas no clear associations were observed with FVC or PEF.