Smoke from biofuels bad for lungs
People who burn wood or other biofuels for heat or cooking may have a heightened risk of emphysema and related lung conditions.
Biomass refers to biological materials that can be burned for energy, including wood, crops and animal dung. They are major sources of energy in the developing world, and are thought to be used for cooking and heating in half of homes worldwide. Cigarette smoking is the primary risk factor for chronic obstructive pulmonary disease (COPD), a group of serious lung diseases that includes emphysema and chronic bronchitis. But the role, if any, for smoke from wood and other forms of biomass has been unclear.
To ascertain the relationship between biomass smoke and COPD, researchers combined and analysed the results of 15 studies from Asia, South America, Mexico and Spain involving a total of 3,719 adults with COPD and nearly 39,000 healthy men and women. The studies compared COPD patients with healthy individuals, surveying them about, among other things, their past exposure to biomass smoke at home. Such studies cannot prove cause-and-effect, but can only show whether there is a relationship between the variables being measured – in this case, biomass smoke exposure and COPD risk.
Across the studies, it was found that participants who reported exposure to biomass smoke at home were more than twice as likely to have COPD as those with no such exposure. The risks were similar in men and women and across geographical regions. Biomass smoke also seemed to affect COPD risk independent of cigarette smoking, possibly exacerbating the ill effects of cigarettes. Among non-smokers, exposure to biomass smoke was linked to a 2.5-fold increase in the risk of COPD. Smokers exposed to biomass smoke, meanwhile, had a more than four-fold greater risk of COPD than non-smokers who did not burn biomass fuels at home.
These above findings strengthen the evidence that exposure to biomass smoke is a risk factor for COPD. The findings also call for efforts to reduce people’s exposure to such smoke to prevent some cases of lung diseases.
