Household air pollution linked to cardiovascular disease risk

April 5, 2018, University of Oxford
Household air pollution linked to cardiovascular disease. Credit: Shutterstock

Exposure to household air pollution from using wood or coal for cooking and heating is associated with higher risk of death from heart attack and stroke, according to new research published in the Journal of the American Medical Association (JAMA).

Around three billion people worldwide use solid fuels (e.g. coal, wood, charcoal and crop wastes) to cook and to heat their homes. When burnt, these fuels produce smoke that contains a very high concentration of fine particles (known as PM2.5) and other harmful substances, especially in houses without adequate ventilation.

It is estimated that worldwide about 2.5 million deaths in 2016 were related to the resulting household air pollution. In China, despite rapid urbanisation in recent decades, about one in three people still rely heavily on solid fuels, mostly coal and wood, for domestic purposes. The health impact of household air pollution on the Chinese population is therefore believed to be substantial, but previous research has not provided concrete evidence.

Researchers from the University of Oxford, Huazhong University of Science and Technology, the Chinese Academy of Medical Sciences, and Peking University in China have studied the association of the long-term use of solid fuels for cooking and heating with the risk of death from in a large study of 271,000 residents in five in China.

This study is based on the China Kadoorie Biobank prospective study of 0.5 million adults from five urban and five rural areas, which was established jointly by the University of Oxford and Chinese Academy of Medical Sciences during 2004-08. The present report only included participants from 5 rural areas, where use of solid fuels for domestic purposes is still common. The health status of study participants was monitored through linkages to death registries for an average of seven years. During this time over 5,500 participants died of cardiovascular disease (e.g. stroke, ) among those who had no history of cardiovascular disease at the initial recruitment.

The researchers found that, compared with people who mainly used gas or electricity ('clean fuels'), those who regularly cooked using coal or wood ('solid fuels') had a 20% higher mortality risk from cardiovascular disease, and people who heated their homes using solid fuels had a 29% increase in risk, after taking account of the effects of age, sex, socio-economic status, smoking, alcohol drinking, diet, physical activity, and adiposity. The study also showed clearly that the longer people used solid fuels, the higher the risk of death. Moreover, there were synergistic effects of household air pollution and tobacco smoking, with the risk of death from cardiovascular disease being 76% higher among smokers who used solid fuel than non-smokers who used clean fuels.

Study author, Professor Zhengming Chen, from the University of Oxford, UK, the co-lead Principal Investigator of the China Kadoorie Biobank, said: "Air pollution has caused a lot of concern in China, but people have been focusing mainly on the outdoor air quality and overlooking the health consequences of pollution arising from domestic burning of coal and wood for cooking and heating, which may have a more profound impact on health."

While it is known that burning solid fuels gives rise to harmful PM2.5, the direct evidence linking household air pollution to long-term risk of death, especially from cardiovascular causes, has been very limited. The analysis of data in this very large study provides new evidence of the hazards of long-term exposure and ways to mitigate excess risk of death. The study showed that switching from solid to clean fuels for cooking reduced the risk of cardiovascular death by 17% and switching from solid to clean fuels for heating reduced the risk by 43%. An equally important finding was that individuals who cooked on stoves using solid fuels but had proper ventilation had an 11% lower risk, compared with those whose cookstoves were not properly ventilated.

Study author, Professor Tangchun Wu, from Huazhong University of Science and Technology, China, said: "These findings are important because even though people might have been using solid fuels for a long time, there are still clear health benefits in switching to cleaner fuels. Installing ventilation facilities will be a cheaper and effective alternative for those who cannot switch to clean fuels."

In recent decades, Chinese government has launched a massive campaign to replace traditional cooking stoves and to encourage more widespread use of clean fuels. Findings from this study confirm the health benefits of switching to clean fuels and having proper ventilation. Despite this, use of solid to cook and heat and poor ventilation are still prevalent in many rural areas of China, which will continue to cause many premature deaths from vascular (and many other) diseases.

Study author, Professor Liming Li, Peking University, China, the co-lead Principal Investigator of the China Kadoorie Biobank, said: "We can't conclude from these observational findings that burning coal and wood on its own is causing , but, irrespective of this, China and other low and middle-income countries should encourage their people to change to cleaner domestic fuels, and to prioritise policies and practices to allow a swift, widespread and sustainable switch."

Explore further: Household air pollution linked to higher risk of heart attacks, death

More information: Kuai Yu et al. Association of Solid Fuel Use With Risk of Cardiovascular and All-Cause Mortality in Rural China, JAMA (2018). DOI: 10.1001/jama.2018.2151

Related Stories

Household air pollution linked to higher risk of heart attacks, death

June 13, 2016
Long-term exposure to household air pollution from lighting, cooking or heating with fuels, such as kerosene or diesel, may increase the risk of heart attacks and death, according to new research in the American Heart Association's ...

Nigeria: Clean-burning stoves improve health for new mothers

January 13, 2017
In a small clinical trial that replaced widely used biomass and kerosene cookstoves with clean-burning ethanol stoves, a team of researchers from the University of Chicago and the University of Ibadan (Nigeria) was able to ...

Domestic coal use linked to substantial lifetime risk of lung cancer in Xuanwei, China

August 30, 2012
The use of "smoky coal" for household cooking and heating is associated with a substantial increase in the lifetime risk of developing lung cancer, finds a study from China published in the British Medical Journal today.

Household air pollution puts more than one in three people worldwide at risk of ill health and early death

September 3, 2014
Household air pollution, caused by the use of plant-based or coal fuel for cooking, heating, and lighting, is putting nearly three billion people worldwide at risk of ill health and early death, according to a new Commission, ...

Cooking fuels contribute to childhood pneumonia in developing countries

September 19, 2016
Solid fuels used for cooking are the prevailing source of indoor pollution in developing countries. Now a worldwide ecological assessment has found that rates of pneumonia among young children in different countries are linked ...

Women cooking with biomass fuels more likely to have cataracts

May 25, 2016
Women in India who cook using fuels such as wood, crop residues and dried dung instead of cleaner fuels are more likely to have visually impairing nuclear cataracts¹, according to a new study published in the journal Environmental ...

Recommended for you

New cellular pathway helps explain how inflammation leads to artery disease

June 21, 2018
Investigators have identified a new cellular pathway that may help explain how arterial inflammation develops into atherosclerosis—deposits of cholesterol, fats and other substances that create plaque, clog arteries and ...

'Smart stent' detects narrowing of arteries

June 19, 2018
For every three individuals who have had a stent implanted to keep clogged arteries open and prevent a heart attack, at least one will experience restenosis—the renewed narrowing of the artery due to plaque buildup or scarring—which ...

Marriage may protect against heart disease / stroke and associated risk of death

June 18, 2018
Marriage may protect against the development of heart disease/stroke as well as influencing who is more likely to die of it, suggests a pooled analysis of the available data, published online in the journal Heart.

Deaths from cardiac arrest are misclassified, overestimated

June 18, 2018
Forty percent of deaths attributed to cardiac arrest are not sudden or unexpected, and nearly half of the remainder are not arrhythmic—the only situation in which CPR and defibrillators are effective—according to an analysis ...

Tick-borne meat sensitivity linked to heart disease

June 15, 2018
University of Virginia School of Medicine researchers have linked sensitivity to an allergen in red meat—a sensitivity spread by tick bites—with a buildup of fatty plaque in the arteries of the heart. This buildup may ...

The molecules that energize babies' hearts

June 14, 2018
A metabolic process that provides heart muscle with energy fails to mature in newborns with thickened heart walls, according to a Japan–Canada research team.


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.