A multinational research team, led by scientists at Tulane University School of Public Health and Tropical Medicine, has lent more force to the suggestion that smoking is a significant risk factor for mortality and disease.
The study has provided an estimate of the number of premature deaths in China in 2005 that were caused by smoking.
"With a population of 1.3 billion, China is the worldıs largest producer and consumer of tobacco and bears a large proportion of deaths attributable to smoking worldwide," The New England Journal of Medicine quoted the researchers as saying.
The researchers have revealed that they carried out a cohort study in a nationally representative sample of Chinese adults, with a view to estimating the number of deaths attributable to smoking in the country.
They examined survey data on smoking and other risk factors collected on 167,871 Chinese adults (83,533 men and 86,338 women) who were 40 years or older.
Initial data on the study group was collected by investigators for the China National Hypertension Survey in 1991. Smokers were defined as those who had smoked at least one cigarette a day for one year or more, and trained staff collected data on their demographic characteristics, medical histories, and life-style risk factors using a standard questionnaire.
Follow-up evaluations were conducted with this group in 1999 and 2000.
The Tulane researchers revealed that there was a significant dose-response association between "pack-years" smoked, the total number of cigarettes smoked, and deaths attributable to smoking in both men and women.
According to the researchers' estimates, smoking caused a total of 673,000 deaths in 2005 in China.
The leading causes of smoking-related deaths were in the group were: cancer, 268,200; cardiovascular disease, 146,200; and respiratory disease, 66,800.
"These findings have important public health implications. Data from our study and others provide strong evidence that tobacco smoking causes an increased risk of cancer, vascular disease and respiratory disease in China and elsewhere," says Jiang He, principal investigator of the study and the Joseph S. Copes MD Chair in Epidemiology, professor of epidemiology and medicine, and chair of the Department of Epidemiology at Tulane University's of Public Health and Tropical Medicine.
The researchers said that their study provided an urgent reminder that there was continued need for strengthening of smoking prevention and cessation programs in China.