Burning wood or coal to cook food a practice prevalent in low income countries like India — may increase risk of hospitalisation or dying from respiratory diseases, a study has found.
About three billion people around the world live in households that regularly burn wood, coal or other solid fuels to cook their food, researchers said. Solid fuels emit very high levels of pollutants, especially very small particles that can penetrate deep into the lungs.
Typically, these households are found in the rural areas of low- and middle-income countries.
Although China is rapidly urbanising, one third of its population still relies on solid fuels.
Researchers from the Oxford University in the UK and the Chinese Academy of Medical Sciences found that chronic and acute respiratory disease hospitalisations or deaths were 36 per cent higher among those who used wood or coal for cooking compared to those who used electricity or gas.
According to the study published in the American Journal of Respiratory and Critical Care Medicine, the longer people used solid fuels, the higher the risk of hospitalisation or death from a respiratory disease than those who cooked with gas or electricity.
People who used wood or coal for 40 years or longer had a 54 per cent higher risk of hospitalisation or death from respiratory disease.
Those who switched from solid fuels to clean-burning fuels reduced their risk to only 14 per cent higher than those who never cooked with wood or coal.
The researchers adjusted their findings to account for age, sex, socio-economic status, passive smoking, alcohol drinking, diet, physical activity and obesity.
The study reviewed the health records of 280,000 adults, age 30 to 79, in China. The participants were from 10 areas of the country, had never smoked and were free of respiratory and other major chronic diseases when they enrolled in the study. They were followed for nine years.
During that time, 19,823 were either hospitalised or died from a major respiratory disease. Of these events, 10,553 were due to asthma or chronic obstructive pulmonary disease (COPD), and 7,324 were due to acute lower respiratory infections, most often pneumonia.
“While many previous studies have suggested a link between solid fuel use and COPD, most of them focused on changes in lung function, rather than hospital admissions or deaths,” said Ka Hung Chan, a doctoral student at the University of Oxford.
Compared to other studies that have found a two- to three-fold increase in COPDamong those burning wood or coal in their cookstoves, the study found a weaker association between burning wood or coal in a cookstove and COPD.