Effects of particulate air pollution on blood pressure in a highly exposed population in Beijing, China: a repeated-measure study

• Main Authors: Baccarelli Andrea, Barretta Francesco, Dou Chang, Zhang Xiao, McCracken John P, Díaz Anaité, Bertazzi Pier, Schwartz Joel, Wang Sheng, Hou Lifang
• Format: Article
• Language: English
• Published: BMC 2011-12-01
• Series: Environmental Health
• Subjects: Particulate Matter; Personal Monitoring; Blood Pressure; Traffic Pollution; China
• Online Access: http://www.ehjournal.net/content/10/1/108

<p>Abstract</p> <p>Background</p> <p>Particulate Matter (PM) exposure is critical in Beijing due to high population density and rapid increase in vehicular traffic. PM effects on blood pressure (BP) have been investigated as a mechanism mediating cardiovascular risks, but results are still inconsistent. The purpose of our study is to determine the effects of ambient and personal PM exposure on BP.</p> <p>Methods</p> <p>Before the 2008 Olympic Games (June 15-July 27), we examined 60 truck drivers and 60 office workers on two days, 1-2 weeks apart (n = 240). We obtained standardized measures of post-work BP. Exposure assessment included personal PM_2.5and Elemental Carbon (EC, a tracer of traffic particles) measured using portable monitors during work hours; and ambient PM₁₀averaged over 1-8 days pre-examination. We examined associations of exposures (exposure group, personal PM_2.5/EC, ambient PM₁₀) with BP controlling for multiple covariates.</p> <p>Results</p> <p>Mean personal PM_2.5was 94.6 μg/m³(SD = 64.9) in office workers and 126.8 (SD = 68.8) in truck drivers (p-value < 0.001). In all participants combined, a 10 μg/m³increase in 8-day ambient PM₁₀was associated with BP increments of 0.98 (95%CI 0.34; 1.61; p-value = 0.003), 0.71 (95%CI 0.18; 1.24; p-value = 0.01), and 0.81 (95%CI 0.31; 1.30; p-value = 0.002) mmHg for systolic, diastolic, and mean BP, respectively. BP was not significantly different between the two groups (p-value > 0.14). Personal PM_2.5and EC during work hours were not associated with increased BP.</p> <p>Conclusions</p> <p>Our results indicate delayed effects of ambient PM₁₀on BP. Lack of associations with exposure groups and personal PM_2.5/EC indicates that PM effects are related to background levels of pollution in Beijing, and not specifically to work-related exposure.</p>