Association between long-term air pollution and increased blood pressure and hypertension in China

Several studies have investigated the short-term effects of ambient air pollutants in the development of high blood pressure and hypertension. However, little information exists regarding the health effects of long-term exposure. To investigate the association between residential long-term exposure to air pollution and blood pressure and hypertension, we studied 24 845 Chinese adults in 11 districts of 3 northeastern cities from 2009 to 2010. Three-year average concentration of particles with an aerodynamic diameter ≤10 μm (PM ₁₀), sulfur dioxide (SO₂), nitrogen dioxides (NO ₂), and ozone (O₃) were calculated from monitoring stations in the 11 districts. We used generalized additive models and 2-level logistic regressions models to examine the health effects. The results showed that the odds ratio for hypertension increased by 1.12 (95% confidence interval [CI], 1.08-1.16) per 19 μg/m³ increase in PM₁₀, 1.11 (95% CI, 1.04-1.18) per 20 μg/m³ increase in SO₂, and 1.13 (95% CI, 1.06-1.20) per 22 μg/m³ increase in O₃. The estimated increases in mean systolic and diastolic blood pressure were 0.87 mm Hg (95% CI, 0.48-1.27) and 0.32 mm Hg (95% CI, 0.08-0.56) per 19 μg/m ³ interquartile increase in PM₁₀, 0.80 mm Hg (95% CI, 0.46-1.14) and 0.31 mm Hg (95% CI, 0.10-0.51) per 20 μg/m³ interquartile increase in SO₂, and 0.73 mm Hg (95% CI, 0.35-1.11) and 0.37 mm Hg (95% CI, 0.14-0.61) per 22 μg/m³ interquartile increase in O₃. These associations were only statistically significant in men. In conclusion, long-term exposure to PM₁₀, SO₂, and O₃ was associated with increased arterial blood pressure and hypertension in the study population.