Long-term exposure to high particulate matter pollution and incident hypertension: a 12-year cohort study in northern China.

Numerous cohort studies have reported the association of long-term exposure to particulate matter <10 μm in diameter (PM10) and hypertension in American and European countries. However, these results have been inconsistent and subject to various confounding factors. The study aimed to explore the effect of long-term exposure to high-level concentrations of PM10 on incident hypertension in a large-scale cohort from northern China. A retrospective cohort study of 39,054 participants aged between 23 and 98 years old from four cities in northern China was followed from 1998 to 2009. Excluding those with hypertension, 37,386 non-hypertensive participants (overall population) were followed for self-reported hypertension. The individuals' exposure to PM10 was the mean concentration during the follow-up period, according to the data of local environmental monitoring centers. Hazard ratios (HRs) were calculated by Cox proportional hazards models. The adjusted potential confounding factors included sociodemographic information, lifestyle, and diet. There were 2619 (7.0%) incident cases of hypertension among the overall population. In multivariable models, the HR (95% CI) of incident hypertension was 1.537 (1.515, 1.560) for each 10 μg/m3 increase in PM10. Stratified analyses showed individuals (age <65) were prone to developing hypertension. Moreover, the effects of PM10 increased and produced an HR (95% CI) of 1.555 (1.527, 1.584) for the healthy population in the sensitivity analysis. We found that the association between long-term exposure to PM10 air pollution and incident hypertension was significantly positive.