Cigarette smoking and PM2.5 might jointly exacerbate the risk of metabolic syndrome
Hao‐Hung Tsai, Disline Manli Tantoh, Wen Yu Lu, Chih-Yi Chen, Yung‐Po Liaw
Abstract
Background Cigarette smoking and particulate matter (PM) with aerodynamic diameter < 2.5 μm (PM 2.5 ) are major preventable cardiovascular mortality and morbidity promoters. Their joint role in metabolic syndrome (MS) pathogenesis is unknown. We determined the risk of MS based on PM 2.5 and cigarette smoking in Taiwanese adults. Methods The study included 126,366 Taiwanese between 30 and 70 years old with no personal history of cancer. The Taiwan Biobank (TWB) contained information on MS, cigarette smoking, and covariates, while the Environmental Protection Administration (EPA), Taiwan, contained the PM 2.5 information. Individuals were categorized as current, former, and nonsmokers. PM 2.5 levels were categorized into quartiles: PM 2.5 ≤ Q1, Q1 < PM 2.5 ≤ Q2, Q2 < PM 2.5 ≤ Q3, and PM 2.5 > Q3, corresponding to PM 2.5 ≤ 27.137, 27.137 < PM 2.5 ≤ 32.589, 32.589 < PM 2.5 ≤ 38.205, and PM 2.5 > 38.205 μg/m 3 . Results The prevalence of MS was significantly different according to PM 2.5 exposure ( p -value = 0.0280) and cigarette smoking ( p -value < 0.0001). Higher PM 2.5 levels were significantly associated with a higher risk of MS: odds ratio (OR); 95% confidence interval (CI) = 1.058; 1.014–1.104, 1.185; 1.134–1.238, and 1.149; 1.101–1.200 for 27.137 < PM 2.5 ≤ 32.589, 32.589 < PM 2.5 ≤ 38.205, and PM 2.5 > 38.205 μg/m 3 , respectively. The risk of MS was significantly higher among former and current smokers with OR; 95% CI = 1.062; 1.008–1.118 and 1.531; 1.450–1.616, respectively, and a dose-dependent p -value < 0.0001. The interaction between both exposures regarding MS was significant ( p -value = 0.0157). Stratification by cigarette smoking revealed a significant risk of MS due to PM 2.5 exposure among nonsmokers: OR (95% CI) = 1.074 (1.022–1.128), 1.226 (1.166–1.290), and 1.187 (1.129–1.247) for 27.137 < PM 2.5 ≤ 32.589, 32.589 < PM 2.5 ≤ 38.205, and PM 2.5 > 38.205 μg/m 3 , respectively. According to PM 2.5 quartiles, current smokers had a higher risk of MS, regardless of PM 2.5 levels (OR); 95% CI = 1.605; 1.444–1.785, 1.561; 1.409–1.728, 1.359; 1.211–1.524, and 1.585; 1.418–1.772 for PM 2.5 ≤ 27.137, 27.137 < PM 2.5 ≤ 32.589, 32.589 < PM 2.5 ≤ 38.205, and PM 2.5 > 38.205 μg/m 3 , respectively. After combining both exposures, the group, current smokers; PM 2.5 > 38.205 μg/m 3 had the highest odds (1.801; 95% CI =1.625–1.995). Conclusion PM 2.5 and cigarette smoking were independently and jointly associated with a higher risk of MS. Stratified analyses revealed that cigarette smoking might have a much higher effect on MS than PM 2.5 . Nonetheless, exposure to both PM 2.5 and cigarette smoking could compound the risk of MS.