Chronic obstructive pulmonary disease (COPD) patients who are exposed frequently to biomass smoke emitted by burning wood and coal have a similar risk of exacerbation — acute pulmonary symptoms worsening — as patients who smoke tobacco, a study suggests.
As a result of this finding, biomass smoke should be considered a significant risk factor for COPD, researchers advise.
The study, “Risk of acute exacerbations in chronic obstructive pulmonary disease associated with biomass smoke compared with tobacco smoke,” was published in the journal BMC Pulmonary Medicine.
Long-term exposure to lung irritants such as tobacco smoke and fumes from cooking oils are known risk factors for COPD. In fact, most COPD cases (85-90%) occur among tobacco smokers, according to the American Lung Association. However, other risk factors should be considered in the management of the disease.
Biomass smoke has gained recognition as a risk factor for COPD because it has a composition similar to that of tobacco smoke, and because, according to the World Health Organization, 40% of the world’s population still depends on wood or coal for cooking and heating.
People with COPD associated with biomass smoke are predominantly women, and have more severe symptoms and poorer quality of life than tobacco smokers with COPD.
Studies have shown that COPD associated with biomass smoke is linked to a slower lung function decline than in tobacco smokers, but the relationship between these factors and the risk of exacerbations has been inadequately studied.
Korean researchers investigated whether the risk of exacerbation associated with biomass or tobacco smoke differed among COPD patients. To do so, they recruited 1,033 patients, age 40 or older, who were registered in the Korean Obstructive Lung Disease (KOLD) group, or the Korean COPD Subgroup Study (KOCOSS; NCT02800499). Patients were followed for a mean period of three years.
The occurrence of moderate and severe exacerbations was registered. Moderate exacerbations were those that required treatment with medication, such as corticosteroids; severe exacerbations were those that required hospitalization.
Four groups of patients were created based on their biomass and tobacco smoke exposure. More biomass was defined as more than 25 years exposure, and more tobacco was described as smoking for 10 or more pack years. (One pack year equals one pack of 20 cigarettes a day for one year.)
The four groups formed were: less tobacco-less biomass (107 patients, mean age 67 years); less tobacco-more biomass (40 patients, mean age 70 years); more tobacco-less biomass (631 patients, mean age 68 years); and more tobacco-more biomass (255 patients, mean age 69 years).
Results showed that the incidence of exacerbations between the groups less tobacco-more biomass and more tobacco-less biomass was similar, suggesting that the association between biomass smoke and COPD exacerbations is similar to that of tobacco smoke.
Other factors, such as the time to the first exacerbation, and the characteristics of the exacerbations, were similar among the four groups.
“We found that clinical and radiological differences between COPD associated with biomass and tobacco smoke may not lead to significant differences in clinical outcomes,” the researchers concluded.
“Clinicians should suspect a diagnosis of COPD in any patient with a history of exposure to biomass fuel smoke who has dyspnea [difficulty breathing], chronic cough, or sputum production, and any patient with COPD associated with biomass smoke should be treated actively,” they added.
The team also recommended the implementation of non-pharmacological strategies, such as improvement of kitchen ventilation and the use of clean fuels, to reduce biomass smoke exposure.