Two-thirds of the young men in China start to smoke, mostly before age 20, and the study, led by researchers from Oxford University, UK, the Chinese Academy of Medical Sciences and the Chinese Centre for Disease Control, shows that around half of those who start smoking cigarettes as young men will eventually be killed by tobacco, unless they stop permanently.
The researchers conducted two large, nationally representative studies 15 years apart, tracking the health consequences of smoking in a large group of people in China. The first study took place in the 1990s, and involved a quarter of a million men. The second study is ongoing, and involved half a million men and women.
The results show that in China the annual number of tobacco deaths, mostly among men, had reached 1 million by 2010, and if current trends continue, it will be 2 million by 2030. Among Chinese women, however, smoking rates have plummeted and the risk of premature death from tobacco is low and falling.
In recent decades there has been a large increase in cigarette smoking by young men, and the research shows the consequences that are now emerging. The proportion of all male deaths at ages 40-79 that are attributed to smoking has doubled, from about 10% in the early 1990s, to about 20% now. In urban areas this proportion is higher, at 25%, and is still rising. In rural areas it is currently lower, but is set to rise even more steeply than in cities, due to the high prevalence of smoking and low rate of cessation in rural China.
Conversely, the women of working age in China now smoke much less than the older generation. About 10% of the women born in the 1930s smoked, but only about 1% of those born in the 1960s did so. Hence, overall female deaths caused by tobacco are decreasing, and less than 1% of deaths in women born since 1960 are due to tobacco. Other studies, however, have shown a recent increase in smoking uptake by young women that could eventually reverse this downward trend.
Professor Zhengming Chen from the University of Oxford, UK, a study co-author, says: ‘About two-thirds of young Chinese men become cigarette smokers, and most start before they are 20. Unless they stop, about half of them will eventually be killed by their habit.’
However, an increasing proportion of smokers are choosing to stop, and the study results show that between 1991 and 2006, the proportion of smokers who had quit rose from 3% to 9%. For smokers who stopped before developing any serious disease, after ten years of not smoking their risk was similar to that of people who had never smoked.
According to study co-author Professor Liming Li, from the Academy of Medical Sciences, Beijing, China, ‘Without rapid, committed, and widespread action to reduce smoking levels China will face enormous numbers of premature deaths.’
Co-author Professor Sir Richard Peto, from the University of Oxford, UK, said ‘Over the past 20 years tobacco deaths have been decreasing in Western countries, partly because of price increases. For China, a substantial increase in cigarette prices could save tens of millions of lives.’
In a linked Comment, Jeffrey Koplan from Emory University, Atlanta, USA, and Michael Eriksen from Georgia State University, Atlanta, USA, write: ‘Several myths about tobacco and its use have limited the effectiveness of health education messages in China. These include the belief that protective biological mechanisms specific to Asian populations make smoking less hazardous, that it is easy to quit smoking, and that tobacco use is an intrinsic and ancient part of Chinese culture. The new study clearly shows the severe health consequences of tobacco use for premature mortality among Chinese men.’
This study was funded by Wellcome Trust, MRC, BHF, CR-UK, Kadoorie Charitable Foundation, Chinese MoST and NSFC.
The paper, Contrasting male and female trends in tobacco-attributed mortality in China: evidence from successive nationwide prospective cohort studies, is published in the Lancet.
University of Oxford