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UC Berkeley Press Release

Researchers find that passive smoking kills as many women as active smoking in China

– Exposure to secondhand smoke kills as many women in China as does smoking, according to new study findings by researchers at the University of California, Berkeley.

The study estimated that in 2002, 48,400 women in China died from lung cancer and ischemic heart disease attributed to passive smoking compared with 47,300 lung cancer and heart disease deaths from "active" smoking.

The UC Berkeley researchers worked with Yuan Jiang, M.D., deputy director of the tobacco control research office in China's Center for Disease Control and Prevention. They will present their findings at the 10th International Conference on Indoor Air Quality and Climate in Beijing, China, on Monday, Sept. 5 (Beijing local time).

"The magnitude of the deaths from smoking was not surprising considering the number of smokers in China, but the finding that mortality rates among women for passive smoking were comparable to active smoking was a bit unexpected," said Quan Gan, UC Berkeley Ph.D. student in environmental health sciences and lead author of the study.

The new study is part of a grant to UC Berkeley researchers from the Fogarty International Center of the National Institutes of Health (NIH), and is part of the Tobacco Control Policy in China. The Fogarty grant supports research on the economic impact of smoking prevention efforts in China, the largest producer and consumer of cigarettes in the world.

The most recent national smoking survey in China found that 36 percent of people above age 15 were smokers, with the total number exceeding 350 million. "This makes tobacco smoking in China one of the largest epidemics in human history in terms of expected future health impacts," said Kirk Smith, UC Berkeley professor of environmental health sciences and study co-author.

The researchers say their new findings reflect the fact that far fewer women than men smoke in China. Among active smokers, only 4 percent of the smokers were women, compared with 63 percent for men. In addition, about 52 percent of non-smokers are regularly exposed to secondhand tobacco smoke in the country.

"This is an involuntary risk these women are experiencing," said S. Katharine Hammond, UC Berkeley professor of environmental health sciences and co-author of the study. "And while children were not included in this analysis, other studies have established that passive smoking is known to cause diseases such as pneumonia and asthma among children and low birth weight among newborns."

Exposure to secondhand smoke has been linked to a host of diseases around the world, such as lung cancer, ischemic heart disease, cervical cancer, breast cancer and various respiratory diseases. The study examined the impact on lung cancer and ischemic heart disease, the two diseases that make up the bulk of adult mortality and morbidity caused by passive smoking.

The researchers combined data for smoking prevalence in China with projected mortality rates attributed to smoking. According to the study results, in 2002 active smoking caused 137,000 lung cancer deaths and 191,000 ischemic heart disease deaths in China. About 86 percent of these premature deaths were among men.

The study also found that of the 12,000 lung cancer deaths in 2002 attributed to passive smoking, 73 percent, or 8,800, were among women. Similarly, women accounted for 84 percent, or 39,600, of the 47,000 ischemic heart disease deaths from passive smoking.

"These findings are important because experience has shown that promotion of public awareness of the health effects of passive smoking is one of the best ways to change public perceptions and government policies about smoking in general," said Smith.

The researchers note that the Chinese government is taking encouraging steps towards curbing the country's reputation for lighting up, even as the number of young female smokers appears to be on the rise. At the end of August, the National People's Congress of China ratified the World Health Organization Framework Convention on Tobacco Control (FCTC), an international treaty aimed at curbing tobacco-related death and disease.

The treaty provisions include a ban on tobacco advertising, promotion and sponsorship on radio, television, print media and the Internet within the next five years. Tobacco-company sponsorship of international events and activities, including athletic competitions, is also banned.

"This is a very important step forward for China," said Teh-wei Hu, UC Berkeley professor of health economics and principal investigator of the study. "The Chinese government should also consider raising taxes on cigarettes, which has helped reduce smoking rates in the United States. The hope is that studies such as ours on the health impacts of smoking in China – particularly passive smoking – will help provide ammunition for the Ministry of Health to implement tougher tobacco control policies."