Indoor air pollution and not smoking is the most important cause of chronic obstructive pulmonary disease (COPD) in India, says a prevalence study conducted by Pune-based Chest Research Foundation (CRF) in collaboration with the KEM Hospital, Pune, and the Imperial College, London. In the West and other wealthier countries, smoking is the single most important causative factor of COPD.

The CRF study found that the prevalence of the respiratory disease was 6.9 per cent in the Indian population. Among those identified with COPD, only 7 per cent were smokers while the remaining 93 per cent were non-smokers.

Over 700 million people in India suffer from high levels of indoor air pollution affecting women and young children as 75 per cent homes use biomass fuel like wood, crop residue and dung cakes.

Other research says that exposure to wood smoke through home heating and cooking or through ambient neighborhood pollution may further increase the risk of COPD and related pulmonary problems in smokers.

The age factor was particularly disturbing. "Nearly 23 per cent of COPDs occurred in people less than 40 years of age. It was believed that COPD starts after 40 in people who have been smoking for over 15-20 years. In India, where the exposure to indoor air pollution begins from childhood, it occurs in younger people," said chest physician Sundeep Salvi, director of the CRF.

According to a report published by the Maharashtra State Health Resource Centre in March 2010 that examined the top 10 causes of deaths in Maharashtra, COPD was the number one cause.

What can help at this moment is a national COPD control programme. "We have such programmes for malaria, filariasis, tuberculosis and AIDS. The mortality is far too high in COPD than any of these diseases. Policy makers should take up the issue and act fast, " said Salvi.

"Even though there is no similar report from other states in India, it seems likely that COPD may be one of the leading causes of death in other states too. The WHO had compiled a nationwide analysis in 2002, and reported that deaths due to chronic respiratory diseases accounted for the second largest cause of death, with COPD as the main cause of respiratory deaths," said Salvi.

He spearheaded the study along with social scientist Sanjay Juvekar from KEM Hospital and Peter Barnes, an eminent progessor of respiratory medicine at Imperial College, London (UK).

The study was conducted in 22 rural villages in Pune district with a population of over 1 lakh. As many as 3,000 adults over the age of 25 years were randomly selected for the study which used a standardised respiratory health questionnaire and spirometry (lung function test for determining COPD).

In the western, tobacco smoking is believed to be the most important risk factor for COPD. However, recent evidence refutes this. "Exposure to biomass fuel smoke is the biggest risk factor, not only for India, but even globally. Compared to 1.1 billion smokers, more than 3 billion people (50% of the global population) use biomass fuel for cooking and heating purposes worldwide," Salvi said.

"A woman living in a rural home in India spends on an average 60,000 hours cooking during her lifetime, during which she inhales a total volume of 25 million litres of polluted air. This causes extensive damage to the lungs leading to the development of COPD," he said.

Tobacco smoking is the second biggest cause of COPD in India. As the numbers of smokers increase in India, the burden of COPD is estimated to rise further. The other causes of COPD include poorly treated chronic asthma, certain occupations such as building and construction, mining, sand blasting, leather industry and farming, recurrent lung infections during childhood and poor nourishment especially during childhood.