A major US study involving 50,000 women has found that using an indoor wood stove or fireplace increases the risk of developing lung cancer by 43% compared with those who do not use wood heating. The research, published in the journal Environmental Health Perspectives, suggests that even occasional wood burning can contribute to lung cancer.
The study, part of the Sister Study tracking women who had sisters with breast cancer, followed participants for an average of 11 years. During that period, 347 women were diagnosed with lung cancer. The risk was found to be higher among those who used wood heating more frequently: using a wood burner on more than 30 days a year was associated with a 68% increased risk.
Lead author Dr Suril Mehta from the US National Institute of Environmental Health Sciences said: 'Our study provides evidence that even occasional indoor wood burning from stoves and fireplaces can contribute to lung cancer in populations where indoor wood burning is not the predominant fuel source.' The increased risk was observed in both smokers and non-smokers.
Wood smoke contains hazardous pollutants such as benzene and polycyclic aromatic hydrocarbons, which are known or suspected to cause lung cancer. In the UK, only 4% of homes using solid fuel rely on it as their sole heating source, with wood often used as a secondary heat source.
Professor Fay Johnston from the Menzies Institute for Medical Research in Tasmania, who was not involved in the study, said: 'The message for policymakers and the public is clear. Wood heater smoke is not safe. Interventions to reduce exposure in homes and neighbourhoods should be a priority.'
The findings add to growing evidence of cancer risks from wood smoke. The International Agency for Research on Cancer classified wood smoke as probably carcinogenic to humans in 2006. An earlier Sister Study report also linked indoor wood burning to an increased risk of breast cancer.
