Blood pressure is associated with same day PNC from a central site monitor for a population most of whom live near a major highway

摘要

Background: Studies have shown various degrees of acute effects of air pollution on systolic and diastolic blood pressure (SBP; DBP) as well as pulse pressure (PP). Aim: To examine the associations between SBP, DBP, and PP and the same day particle number concentration (PNC), and potential modifiers such as obesity and preexisting hypertension. Methods: Multivariate linear regression analyses (using SAS~? Mixed model) were performed in 213 out of 270 participants over 40 years of age, were analyzed most of whom lived near a major highway in two study areas in the Boston, MA area. Participants had automated SBP and DBP measurements at clinic visits in the Community Assessment of Freeway Exposure and Health (CAFEH) study. PNC was measured at a central site about 7 km away from the study areas. Daily averages of PNC (number/cm3) were created using means of the hourly data. Results: The mean (range) of daily PNC was 16,391 (6,908 to 29,530) across the days when blood pressure measures were obtained in the analytic sample. The mean (range) of SBP, DBP, and PP were 135 (91 to 191), 78 (46 to 107), and 57 (29 to 114) mmHg, respectively. Same day PNC was positively associated with SBP (P=.006) and PP (P=.018) but not DBP (P=0.20), after controlling for age, gender, race, education, income, smoking, statin medication, hypertension, and obesity. A 5,000 unit increase in PNC was associated with increases in mean SBP (SE) 2.21 (0.81) and PP 1.56 (0.65) mmHg. On average, obese participants had higher blood pressure than non-obese participants. There was a significant interaction between obesity and hypertension (P=0.003) for the association between PNC and DBP, but not for the other two models. Conclusions: Our findings suggest a possible link between particle number concentration and systolic blood pressure, diastolic blood pressure and pulse pressure, but many factors may modify the associations.