Frontiers in Public Health · Oct 31, 2026
Long-Term Air Quality Index and Osteoporosis Prevalence: A Cross-Sectional Study in Nanjing, China
By Xuening Dai, Xiangyang Dai, Liang Zhou et al.
Objective: To examine the association between long-term air quality index (AQI) and osteoporosis prevalence and assess potential sex differences among adults undergoing health examinations in Nanjing, China. Methods: This single-center cross-sectional study used routine health-examination records from 1,033 participants comprising men aged ≥50 years and postmenopausal women in Nanjing (2020–2023). Records were linked by residential address to five-year AQI and pollutant exposures estimated using inverse distance weighting (IDW) from nine monitoring stations. Osteoporosis was defined as a femoral neck or lumbar spine T-score ≤−2.5, assessed by dual-energy X-ray absorptiometry (DXA). Modified Poisson regression was used to estimate adjusted prevalence ratios (PRs) and 95% confidence intervals (CIs). Restricted cubic splines and interaction terms were used to assess nonlinearity and sex differences, respectively. Results: Osteoporosis prevalence was 25.8%. The AQI association was nonlinear: the adjusted PR for Q4 versus Q1 was 5.46 (95% CI, 3.33–8.97), and the overall log-linear summary PR per interquartile range increase was 1.86 (95% CI, 1.63–2.14). The relative association was stronger in men on the multiplicative scale (PRs, 2.39 and 1.52 in men and women, respectively; P for interaction <0.001). Fine particulate matter (PM₂.₅), inhalable particulate matter (PM₁₀) and sulfur dioxide were associated with higher osteoporosis prevalence and lower T-scores. Carbon monoxide and nitrogen dioxide were associated with osteoporosis prevalence but not continuous T-scores; ozone showed no consistent association. Conclusion: Higher long-term AQI was associated with higher osteoporosis prevalence, with a stronger relative association in men on the multiplicative scale. Prospective studies are needed to confirm these associations.