Association between air pollutants with calcaneus ultrasound T-score change in a large Taiwanese population follow-up study.

Exposure to ambient air pollution has been associated with increased rates of mortality and morbidity and a shorter life expectancy. Few studies have evaluated the associations between air pollution and change in calcaneus ultrasound T-score (∆T-score). Therefore, in this longitudinal study, we explored these associations in a large group of Taiwanese participants. We used data from the Taiwan Biobank database and Taiwan Air Quality Monitoring Database, which contains detailed daily data on air pollution. We identified 27,033 participants in the Taiwan Biobank database who had both baseline and follow-up data. The median follow-up period was 4 years. The studied ambient air pollutants included particulates of 2.5 µm or less (PM2.5), particulates of 10 µm or less (PM10), ozone (O3), carbon monoxide (CO), sulfur dioxide (SO2), nitric oxide (NO), nitrogen dioxide (NO2), and nitrogen oxide (NOx). Multivariable analysis showed that PM2.5 (ß, -0.003; 95% confidence interval (CI), -0.004 to -0.001; p < 0.001), PM10 (ß, -0.005; 95% CI, -0.006 to -0.004, p < 0.001), O3 (ß, -0.008; 95% CI, -0.011 to -0.004; p < 0.001), and SO2 (ß, -0.036; 95% CI, -0.052 to -0.020; p < 0.001) were negatively associated with ∆T-score, and that CO (ß, 0.344; 95% CI, 0.254, 0.433; p < 0.001), NO (ß, 0.011; 95% CI, 0.008 to 0.015; p < 0.001), NO2 (ß, 0.011; 95% CI, 0.008 to 0.014; p < 0.001), and NOx (ß, 0.007; 95% CI, 0.005 to 0.009; p < 0.001) were positively significantly associated with ∆T-score. Furthermore, PM2.5 and SO2 (ß, -0.014; 95% CI, -0.016 to -0.013; p < 0.001) and PM10 and SO2 (ß, -0.008; 95% CI, -0.009 to -0.007; p < 0.001) had synergistic negative effects on ∆T-score. In conclusion, we found that high PM2.5, PM10, O3, and SO2 were associated with a rapid decline in T-score, whereas high CO, NO, NO2, and NOx were associated with a slow decline in T-score. Furthermore, PM2.5 and SO2 and PM10 and SO2 had synergistic negative effects on ∆T-score, causing an acceleration in T-score decline. These findings may be helpful when developing policies on air pollution regulation.