Power plants and vehicle release nitrogen dioxide.
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In the long term, people living in areas with high levels of air pollution can develop chronic high blood pressure issues.
The study results were published May 31 in the journal Hypertension. Also, while it appeared that ozone and carbon monoxide were tied to higher blood pressure, these two links did not reach “statistical significance”, the researchers said. Short-term occurred over a number of days, while long-term exposure continued for a number of years.
Pooled odds ratio for hypertension in association with each 10 µg/m increase in air pollution was calculated using a random-effects model for studies with significant heterogeneity, or a fixed-effect model for studies without significant heterogeneity. “Our findings are of public health importance because both air pollution and hypertension are important worldwide public health problems”.
The study team added that further research will be required on the subject to check the impact of pollution on overall health.
In places with poor air quality, people should avoid outdoor activities or wear filtered masks.
More than three million people in the United States suffer from hypertension. Hypertension can lead to health disease and raises the risk of stroke.
“The short-term and long-term effects of air pollution may have non-mutually exclusive biological mechanisms, that is, direct and indirect effects on the sympathetic nervous system, oxidative stress, endothelial and other hemodynamic function, and vascular tone”, the researchers wrote.
More specifically, Liu and his colleagues focused on the following air pollutants: nitrogen oxide from burned fossil fuels and vehicle exhaust, sulfur dioxide from burned fossil fuels, and particulate matter (PM) such as dirt, dust, liquid droplets and smoke.
Researchers combed through 17 studies that assessed the health effects of different types of air pollution and hypertension risk on more than 108,000 hypertension patients and 22,000 non-hypertensive controls.
High blood pressure was defined as systolic blood pressure more than 140 mm Hg and/or diastolic blood pressure over 90 mm Hg or by antihypertensive drug use, researchers said. Air pollution exposure was assessed by averaging data from nearest air pollution monitoring stations, or using complex dispersion models or land use regression models.
And the pooled study findings are in agreement with many published studies suggesting a link between exposure to air pollution and cardiovascular disease, said American Heart Association spokesperson Martha Daviglus, MD, PhD, of the University of Illinois College of Medicine in Chicago, who was not involved with the research.
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Previous studies have indicated that air pollution might be a risk factor for hypertension but the results were controversial, Liu said.
