The study, which was published early online on 13th February in the New England Journal of Medicine, is the work of researchers from India, Canada and the UK, and is the first nationally representative investigation of smoking in India as a whole.
There are about 120 million (12 crore in Indian counting system) smokers in India. About 5 per cent of women and more than one third of men aged between 30 and 69 smoke either conventional cigarettes or bidis, a type of Asian cigarette made from one quarter of the tobacco content of a conventional cigarette and wrapped in the leaf of a temburni plant.
The researchers calculated that on average in India, compared with non smokers, men who smoke bidis die about six years earlier, women who smoke them die about eight years earlier, and men who smoke cigarettes die about 10 years earlier (about the same as in the West).
Even low levels of smoking were not found to be safe, wrote the researchers. Smoking a few bidis a day brought substantial risks, and smoking a few cigarettes a day brought even more, to the point of doubling the risk of death in middle age, they wrote.
India's Health Minister, Dr Abumani Ramadoss, said he was alarmed at the results of the study, and that:
"The government of India is trying to take all steps to control tobacco use; in particular by informing the many poor and illiterate of smoke risks."
Professor Prabhat Jha of the Centre for Global Health Research (CGHR), St. Michael's Hospital at the University of Toronto in Canada, who led the study said:
"The extreme risks from smoking that we found surprised us, as smokers in India start at a later age than those in Europe or America and smoke less. And, smoking kills not only from diseases like cancer and lung diseases but also from tuberculosis and heart attacks."
The large study employed some 900 field workers to carry out a nationally representative survey of 1.1 million (11 lakh) homes throughout India. From this the researchers were able to compare the smoking histories of 74,000 adults who had died (33,000 women and 41,000 men) with 78,000 living unmatched controls (35,000 women and 43,000 men). They then worked out the risk ratios for death comparing smokers and non smokers and adjusted them for age, educational level, and alcohol consumption.
The results showed that among men who died at ages 30 to 69, smoking was responsible for:
- 38 per cent of all deaths from tuberculosis (1,174 deaths out of 3,119).
- 31 per cent of all deaths from respiratory disease (1,078 of 3,487).
- 20 per cent of all deaths from vascular disease (1,102 of 5,409).
- 32 per cent of all deaths from cancer (709 of 2,248).
- 23 per cent of all deaths from any disease (5,651 of 25,290)
The study also found that:
- Smoking 1 to 7 bidis a day raised risk of death by one-third, and smoking 1 to 7 cigarettes a day nearly doubled it.
- Smoking is responsible for most of the gap between male and female rates of death in middle age.
- The risks were significant among both educated and illiterate adults, in both urban and in rural areas.
- Quitting smoking works, but only 2 per cent of adults in India have quit, mostly after falling ill.
"It is truly remarkable that one single factor, namely smoking, which is entirely preventable, accounts for nearly one in ten of all deaths in India."
He said that the study "brings out forcefully the need for immediate public action in this much neglected field".
Study co-author Professor Sir Richard Peto of Oxford University said:
"Smoking kills, but stopping works."
"About a quarter of all smokers will be killed by tobacco in middle age, unless they stop," he added, saying that "British studies show that stopping smoking is remarkably effective".
"A Nationally Representative Case-Control Study of Smoking and Death in India."
Jha, Prabhat, Jacob, Binu, Gajalakshmi, Vendhan, Gupta, Prakash C., Dhingra, Neeraj, Kumar, Rajesh, Sinha, Dhirendra N., Dikshit, Rajesh P., Parida, Dillip K., Kamadod, Rajeev, Boreham, Jillian, Peto, Richard, the RGI-CGHR Investigators.
N Engl J Med 2008 0: NEJMsa0707719
Published online ahead of print February 13, 2008
DOI: 10.1056/NEJMsa0707719, in print March 13, 2008.
Click here for Article.
Sources: NEJM article and press release.