ArticlesSmoking and mortality from tuberculosis and other diseases in India: retrospective study of 43 000 adult male deaths and 35 000 controls
Introduction
Smoking has been widespread for many decades among men in India,1, 2, 3, 4 where most adult deaths involve vascular disease, tuberculosis, or other respiratory disease. However, we know of no substantial completed studies of the extent to which smoking is causing death from these or other diseases, or of how the hazards vary between urban and rural India. In rural areas most smoking involves not cigarettes but bidis, which are smaller and consist of 0·2–0·3 g tobacco rolled in the leaf of another plant, temburni. Large prospective studies are in progress,5, 6, 7, 8, 9, 10 but will take many years to accumulate sufficient numbers of deaths from particular causes. We report two large case-control studies of smoking and cause-specific mortality in southern India, one urban and one rural. In both study areas large population surveys of tobacco use were also carried out (chiefly for other purposes7). Although many women in these particular parts of India chew tobacco, fewer than 0·1% smoke it. Hence, the present analyses of the effects of smoking involve only men.
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Case-control studies in urban and in rural areas among men aged 25 years and older
The urban study area is the whole of the city of Chennai, formerly Madras (population 4 million), the capital of the state of Tamil Nadu. Elsewhere in that state the rural study area is (the whole of the district of Vilippuram, population 2·5 million, in 2000 villages) in the former district of South Arcot. The cases are all the men (27 000 urban, 16 000 rural) who died of disease in those areas in particular years (1995–97 urban, 1997–98 rural) and whose household could be visited by
Results
Since chronic illness may make some smokers stop, the term smoker is consistently used to mean ever smoker. Assignment of causes by verbal autopsy is likely to have been more reliable in urban than in rural areas, and more reliable at ages 25–69 years than at older ages; moreover, deaths before age 70 years involve a substantially greater loss of life expectancy than deaths at older ages. Hence, detailed analyses of urban mortality are presented first, with particular emphasis on the age range
Smoking as a cause of tuberculosis
In this study the two most important associations with smoking, in terms of the absolute numbers of deaths involved, were the excess respiratory mortality, particularly that from tuberculosis, and the excess vascular mortality, particularly that from cardiac disease. Respiratory disease was the second most important cause of death in middle age, and was about four times as common among those who had smoked as among those who had not. Hence, even in the urban study area, the absolute excess of
Conclusions
About a quarter of all persistent smokers of cigarettes or of bidis are killed by tobacco before age 70 years, losing about 20 years of life expectancy. A third of the deaths caused by smoking are from vascular disease and half are from tuberculosis or other respiratory disease. Mortality from tuberculosis is four times as great among smokers as among non-smokers.
Among Indian male smokers and non-smokers together, smoking causes half of all deaths from tuberculosis and a quarter of all deaths
References (37)
- et al.
Risk factors for acute myocardial infarction in Indians: a case-control study
Lancet
(1996) Tobacco or health: a global status report
(1997)IARC monographs on the evaluation of the carcinogenic risk of chemicals to humans, volume 38: tobacco smoking
(1986)IARC monographs on the evaluation of the carcinogenic risk of chemicals to humans, volume 83: tobacco smoking
(2003)Survey of sociodemographic characteristics of tobacco use among 99,598 individuals in Bombay, India using handheld computers
Tob Control
(1996)- et al.
Cohort study of all-cause mortality among tobacco users in Mumbai, India
Bull World Health Organ
(2000) - et al.
Tobacco epidemiology in the state of Tamil Nadu, India
Asian Pac J Cancer Prev
(2000) - et al.
Prospective studies of tobacco use and health in Kerala, India
- et al.
Sample registration system bulletin, Office of the Registrar-General of India
(2002)