Hypertension was associated with exposure to some air pollutants commonly associated with the burning/combustion of fossil fuels, dust and dirt, a new study shows. Researchers suggest people – especially those with high blood pressure – limit their time outdoors when pollution levels are high. “In our analysis of 17 previously-published studies we discovered a significant risk of developing high blood pressure due to exposure to air pollution,” said Tao Liu, Ph.D. “People should limit their exposure on days with higher air pollution levels, especially for those with high blood pressure, even very short-term exposure can aggravate their conditions.”
They performed a meta-analysis of available published studies in the world assessing health effects of all air pollution on HT risk. In the first study to simultaneously estimate the effects of short-term and long-term exposure to air pollutants on hypertension by meta-analysis, researchers focused on these air pollutants:
~sulfur dioxide (SO2), from the burning of fossil fuel;
~nitrogen oxide (NOx), which comes from fossil fuels burned at power plants and vehicle exhaust;
~Particulate matter (PM) are particles found in the air, including dust, dirt, smoke and liquid droplets. (PM 2.5 is smaller than a speck of dust, and the most common and hazardous type of air pollution. PM10 includes both PM2.5 and PM2.5-10).
Results: HT was significantly associated with: ~short-term exposure to SO2, PM2.5 and PM10; and
~long-term exposure to nitrogen dioxide (NO2), which is produced from combustion, and PM10.
For the portion of the study that assessed short-term effects of ~ozone and CO exposure, no significant associations were found. Researchers said ozone and carbon monoxide’s links to high blood pressure requires further study.
Of the 5,687 air pollution studies initially identified, 17 were the focus of this – which involves >108,000 hypertension patients and 220,000 non-hypertensive controls. High blood pressure was defined systolic BP >140 mm Hg and/or diastolic BP >90 mm Hg or by antihypertensive drug use. Air pollution exposure was assessed by averaging data from nearest air pollution monitoring stations, or using complex dispersion models or land use regression models.
High blood pressure is a major risk factor for cardiovascular disease and stroke. Previous studies have indicated that air pollution might be a risk factor for hypertension but the results were controversial, Liu said. The mechanism by which air pollution could contribute to the development of high blood pressure includes inflammation and oxidative stress, which may lead to changes in the arteries. “Next we plan to further delve into the effects of particulate matter and their sources on hypertension risk, which we hope will inform air-pollution control policy-makers,” Liu said. http://newsroom.heart.org/news/high-blood-pressure-linked-to-short-long-term-exposure-to-some-air-pollutants?preview=99a3f3d0bf908245d471354272229ed9
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