Causes of COPD
The primary cause of chronic obstructive pulmonary disease (COPD) is tobacco smoke (including second-hand or passive exposure).
WHO estimates that in 2005 5.4 million people died due to tobacco use. Tobacco-related deaths are projected to increase to 8.3 million deaths per year by 2030.
Other risk factors
The causes for COPD have opposite patterns according to the geographic areas. In high- and middle-income countries tobacco smoke is the biggest risk factor, meanwhile in low-income countries exposure to indoor air pollution, such as the use of biomass fuels for cooking and heating, causes the COPD burden.
Almost 3 billion people worldwide use biomass and coal as their main source of energy for cooking, heating, and other household needs. In these communities, indoor air pollution is responsible for a greater fraction of COPD risk than smoking or outdoor air pollution. Biomass fuels used by women for cooking account for the high prevalence of COPD among nonsmoking women in parts of the Middle East, Africa and Asia. Indoor air pollution resulting from the burning of wood and other biomass fuels is estimated to kill two million women and children each year.
Other risk factors for COPD include occupational dusts and chemicals (such as vapours, irritants, and fumes) and frequent lower respiratory infections during childhood.