Abstracts: ISEE 22nd Annual Conference, Seoul, Korea, 28 August–1 September 2010: Air Pollution - Exposure Characterization and Health Effects
Despite evidence of a cross-sectional association between ambient fine particulate matter (PM2.5) and high blood pressure, no population-based study has explored the association of fine particle exposure with incident hypertension. This study examined whether ambient PM2.5 is associated with hypertension incidence.
The study included 3006 participants, aged 45–84 years and without hypertension (systolic blood pressure ≥140 mm Hg, diastolic blood pressure ≥90 mm Hg, or on antihypertensive medications) at the baseline examination (2000–2002) of the Multiethnic Study of Atherosclerosis. Annual average PM2.5 concentrations at participant residences were calculated for 2001 using a spatio-temporal model and used as a proxy for exposure over the 5-year follow-up period. Incident hypertension was defined by participant's SBP ≥ 140 mm Hg, DBP ≥ 90 mm Hg, or on antihypertensive medications at follow-up visits. Hazard ratios of incident hypertension per 10 μg/m3 increment in PM2.5 were estimated using interval censored survival analysis, adjusting for age, sex, race/ethnicity, systolic blood pressure, diastolic blood pressure, body mass index, diabetes, smoking, passive smoking, alcohol use, healthy diet index, and physical activity at baseline.
A total of 825 new cases of hypertension occurred over the 5-year follow-up. The mean estimated PM2.5 exposure was 17.3 μg/m3 (standard deviation, 3.2 μg/m3). For each 10 μg/m3 increment of PM2.5, the adjusted hazard ratio for incident hypertension was 1.22 (95% confidence interval, 0.93–1.59). The point estimate of association remained positive and not statistically significant after further adjustment for study site and socioeconomic status (income and education) at baseline.
Results from our study sample provide only weak support to the hypothesis that exposure to ambient fine particulate air pollution may contribute to onset of hypertension.