Women in developing countries who cook over a wood stove for years and inhale the smoke can develop chronic obstructive pulmonary disease (COPD) and experience the same clinical characteristics, diminished quality of life and increased mortality rates as tobacco smokers.
These findings from a Mexican study appear in the second issue for February 2006 of the American Journal of Respiratory and Critical Care Medicine, published by the American Thoracic Society.
Over a seven-year period, Alejandra Rammrez-Venegas, M.D., and six associates from the COPD Clinic at the National Institutes of Respiratory Diseases in Mexico City, followed up on clinical, functional, health-related quality of life and survival characteristics of 481 COPD patients. Of this group, 345 persons (76 percent of whom were male) had COPD associated with tobacco smoke and 186 individuals (86 percent female) developed the disease as a result of inhaling wood smoke.
Although cigarette smoking is a greater risk factor for COPD in developed countries, indoor air pollution from solid fuel use is responsible for more than 1.6 million annual deaths and 2.7 percent of the global burden of COPD in developing countries, according to the World Health Organization.
COPD results from persistent obstruction of the airways associated with either severe emphysema or chronic bronchitis. In emphysema, the tiny air sacs of the lung (alveoli) become enlarged and their walls are destroyed. In chronic bronchitis, the bronchial glands enlarge, causing a chronic cough and excess mucus. Ten to 15 percent of all smokers develop COPD as a result of irritants in tobacco that cause inflammation of the alveoli.
"Biomass (wood) smoke is composed of a relatively equal mixture of coarse and ultrafine particles and can penetrate deeply into the lung, producing a variety of morphologic and biochemical changes," said Dr. Rammrez-Venegas.
According to the authors, the patients in the wood smoke group were older, shorter and had a greater body mass than those in the tobacco smoke group.
The cumulative exposure for the wood smoke COPD patients was expressed in hour-years, the number of hours of cooking with wood stoves multiplied by the average number of hours spent daily in the kitchen. The average cumulative exposure was 214 hour-years for the wood smoke group and 56 pack years for the tobacco smokers.