Numbers of people in China who are now classified as overweight and obese have risen sharply in a relatively short time, says Professor Yangfeng Wu from the Chinese Academy of Medical Sciences in Beijing.

They account for one fifth of the world's population in this condition, despite China once being seen as country with a lean population.

Figures from the 2002 national nutrition and health survey in China showed 14.7% of Chinese were overweight and another 2.6% were obese “ meaning that there were an estimated 184 million overweight people and a further 31 million obese people there.

Data from the China national surveys on the constitution and health in school children also showed that the prevalence of overweight and obesity in children aged 7-18 increased 28 times and obesity increased four times between 1985 and 2000.

The reasons for this can be attributed to a combination of factors including changes to traditional diet, reduced levels of physical activity, and a more sedentary lifestyle, says Professor Wu, for example, with a large rise in the number of cars being bought. Production of cars in China rose from 5,400 in 1980 to over 2 million in 2003.

"As in other countries, China's epidemic of overweight and obesity poses a considerable public health problem, and it is becoming increasingly clear that we need to act now to prevent any further increase," he writes.

Ways of doing this are uncertain, he suggests, but lifestyle education could help as well as listing the prevention and control of obesity as a goal in China's framework and policy on health.

Contact: Yangfeng Wu, Director of Clinical Research Program, Peking University Health Science Center, ChinaTel (office): +86 10 8280 1898; mobile: +86 1350 125 3457; home: +86 10 8481 5382Email: yangfengwu263; ywugeorge.cn

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They found that tobacco use in any form, including sheesha smoking popular in the Middle East and beedie smoking common in South Asia, was harmful. Compared to people who had never smoked, smokers had a three-fold increased risk of a heart attack. Even those with relatively low levels of exposure (8 “10 cigarettes a day) doubled their risk of heart attack. However, the researchers did find that the risk of heart attack decreased with time after stopping smoking; among light smokers (<10 cigarettes a day) there was no excess risk 3 “5 years after quitting. By contrast, moderate and heavy (20> cigarettes a day) smokers still had an excess risk of around 22%, 20 years after quitting. The team also found that exposure to second hand smoke increased the risk of heart attack in both former and non-smokers. The findings suggest that individuals with the highest levels of exposure to SHS (22 hours or more per week) may increase their risk of heart attack by around 45%.

Chewing tobacco also increased the risk of a heart attack two fold, indicating that all forms of tobacco use or exposure are harmful, added Dr Koon Teo.

Professor Yusuf concludes: Since the risks of heart attack associated with smoking dissipate substantially after smoking cessation, public-health efforts to prevent people from starting the habit, and promote quitting in current smokers, will have a large impact in prevention of heart attack worldwide.

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