Exposure to fine particles increases blood pressure of hypertensive outdoor workers: A panel study.

BACKGROUND: Hypertension and air pollution are two important risk factors for cardiovascular morbidity and mortality. Although several studies suggest that air pollution has a significant impact on blood pressure, studies on long-term effects are sparse and still controversial. OBJECTIVE: To evaluate the effects of exposure of outdoor workers to different levels of traffic-generated PM2.5 on blood pressure. DESIGN: This is an observational panel study. PARTICIPANTS: 88 non-smoking workers exposed to different concentrations of air pollution were evaluated weekly along four successive weeks. MEASUREMENTS: In each week, personal monitoring of 24-h PM2.5 concentration and 24-h ambulatory blood pressure were measured. The association between blood pressure variables and PM2.5, adjusted for age, body mass index, time in job, daily work hours, diabetes, hypertension and cholesterol was assessed by means of multiple linear regression models fitted by least squares. RESULTS: Exposure to PM2.5 (ranging from 8.5 to 89.7 µg/m3) is significantly and consistently associated with an increase in average blood pressure. An elevation of 10 µg/m3 in the concentration of PM2.5 is associated with increments of 3.9 mm Hg (CI 95% = [1.5; 6.3]) in average systolic 24-h blood pressure for hypertensive and/or diabetic workers. CONCLUSION: Exposure to fine particles, predominantly from vehicular traffic, is associated with elevated blood pressure in hypertensive and/or diabetic workers.