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Both short, long-term exposure to air pollutants linked to hypertension risk
Short- and long-term exposure to particulate matter and other ambient air pollutants was significantly associated with increased risk for hypertension, according to results of a systematic review and meta-analysis.
“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,” Tao Liu, PhD, deputy director and epidemiologist of the environmental health division at Guangdong Provincial Institute of Public Health in China, and colleagues wrote in Hypertension. “Explicating the differences between the short-term and long-term effects of air pollution could provide further information for policy makers and clinical prevention for hypertension.”
A number of studies have been conducted since the 1990s on the link between air pollution and hypertension but, according to Liu and colleagues, the results were controversial. The researchers conducted a review of all studies on this association and identified 17 relevant studies that examined the effects of short-term (n = 6) and long-term (n = 11) exposure to air pollutants including carbon monoxide (CO), nitrogen oxide (NO2 and NOx), ozone (O3), particulate matter (PM2.5 and PM10) and sulfur dioxide (SO2). Included in these studies were more than 108,000 patients with hypertension and 220,000 control participants without hypertension.
According to the results, short-term exposure to SO2, PM2.5 and PM10 was significantly associated with development of hypertension (OR = 1.046; 95% CI, 1.012-1.081; OR = 1.069; 95% CI, 1.003-1.141; OR = 1.024; 95% CI, 1.016-1.032, respectively). Two of the studies on short-term air pollutant exposure and hypertension risk were conducted in China, two in Canada, and two in Brazil and Iran. Long-term exposure to NO2, and PM10 were significantly associated with hypertension risk (OR = 1.034; 95% CI, 1.005-1.063; OR = 1.054; 95% CI, 1.036-1.072, respectively). Three of the studies on long-term air pollutant exposure and hypertension risk were conducted in China, two in the United States, two in Sweden, and four in Canada, Denmark, Germany or Spain.
Although this meta-analysis yielded associations between air pollution exposure and hypertension, the researchers said further data are needed.
“Our findings are of public health importance because both air pollution and hypertension are important worldwide public health problems,” Liu and colleagues wrote. “Even though a small risk of hypertension is induced by the air pollution exposure, it may bring a large population-attributable disease burden of hypertension because of the ubiquitous nature of air pollution. Therefore, if these exposures are avoided, they theoretically could reduce the incidence of hypertension.” – by Dave Quaile
Disclosure: The researchers report no relevant financial disclosures.