Wood Smoke Risky in COPD
By Kristina Fiore, Staff Writer, MedPage Today
Published: July 19, 2010
Reviewed by Adam J. Carinci, MD; Instructor, Harvard Medical School.
Exposure to wood smoke may increase the risk of chronic obstructive pulmonary disease (COPD) -- particularly among current smokers, researchers have found.
Breathing in wood smoke, either through home heating, cooking, or ambient outdoor pollution, was associated with a twofold increased risk of airflow obstruction, according to Yohannes Tesfaigzi, PhD, of Lovelace Respiratory Research Institute in Albuquerque, N.M., and colleagues.
They reported their findings in the American Journal of Respiratory and Critical Care Medicine.
"Because exposure to wood smoke appears to increase the risk of reducing lung function, cigarette smokers should try to avoid heating their homes or cooking with wood stoves and try to avoid environments where wood smoke is likely, for example, neighborhoods where wood smoke is common," Tesfaigzi said in a statement.
Wood smoke-associated chronic obstructive pulmonary disease (COPD) is common among women in developing countries, but hasn't been adequately described in developed countries, the researchers said.
So to determine whether wood smoke exposure was a risk factor for COPD among smokers in the U.S., the researchers conducted a cross-sectional study of 1,827 patients from the Lovelace Smokers' Cohort, which is predominantly female and maintains records of wood smoke exposure.
About 28% of the cohort reported such exposure.
The researchers found that breathing wood smoke was independently associated with greater odds of respiratory disease, particularly among current smokers, non-Hispanic whites, and men.
Self-reported exposure was independently associated with a significant risk of low percent predicted forced expiratory volume (FEV1) (P<0.001).
It was also associated with a higher prevalence of airflow obstruction and chronic bronchitis (OR 1.96, 95% CI 1.52 to 2.52 and OR 1.64, 95% CI 1.31 to 2.06, respectively, both significant at P<0.001).
The associations were significantly stronger among current cigarette smokers, non-Hispanic whites, and men, the researchers said.
And in genetic association analyses, wood smoke exposure also interacted in a dose-dependent manner with aberrant promoter methylation of the p16 or GATA4 genes on lower percent predicted FEV1.
Among those exposed, methylation of the p16 gene and of GATA 4 was significantly associated with lower percent predicted FEV1. GATA4 methylation was also associated with higher odds of airflow obstruction.
"Because the same gene changes were associated with increased risk for lung cancer, one would assume that wood smoke exposure also increases the risk of developing lung cancer," Tesfaigzi said in a statement. "Future studies may show that it would be appropriate to screen patients for lung cancer if these exposures were present for prolonged periods."
The study was limited because it may not be generalizable, the authors wrote.
Still, the researchers called for additional studies on associations between wood smoke and COPD in cigarette smokers "with particular emphasis on understanding the characteristics and dose-response relationship of wood smoke exposure."
sourcehttp://www.medpagetoday.com/Pulmonology ... COPD/21236