THIRUVANANTHAPURAM: Tobacco is being used in a wide variety of ways in India, either as smokeless tobacco as chewing pan, pan masala or gutka, and ‘mishri’ (a powdered tobacco rubbed on the gums as toothpaste) or as tobacco smoke such as cigarettes, beedi, cigars etc. Tobacco consumption accounts for half of the all the cancers in men and a quarter of all cancers in women in India, in addition to being a risk factor for cardiovascular diseases and chronic obstructive pulmonary diseases.
India also has one of the highest rates of oral cancer in the world, partly attributed to high prevalence of tobacco chewing.
Richard Doll and Bradford Hill showed that smoking was a cause, and an important cause, of the rapidly increasing epidemic of lung cancer in the UK. In 1951, they started the prospective study of smoking and mortality in British doctors that Doll continued for over 50 years, showing that half of all smokers are eventually killed by their habit and that stopping smoking is remarkably effective.
Between 1950 and 2005, overall UK death rates decreased by half in middle age; more than half of this decrease was due to the decrease in mortality from smoking.
The centenary of Richard Doll is being celebrated in October this year and it is relevant to remember the contribution of Doll and Richard Peto, who initiated large prospective studies across continents of Asia, Africa and Latin America to ascertain the mortality related to tobacco epidemic.
There is a lack of large population-based studies on the on the socio-demographic characteristics and health profile of the tobacco users and follow-up prospectively for the mortality and morbidity.
We have carried out a large follow-up of cohort in Thiruvananthapuram district mentored by Prof Richard Peto from Oxford University, UK and supported partly by Medical Research Council, UK, Imperial Cancer Research Fund and NIH, United States.
This study was initiated in 2000 in the district, both in the urban and rural population. The main objective was to assess the pattern of morbidity and cause-specific morbidity and mortality attributable to tobacco use in the form of smoked and smokeless tobacco.
The house-to-house survey was confined to 74 wards of Thiruvananthapuram Corporation and using electoral rolls, we collected data from 1,18,772 permanent resident adult males aged 25 and above.
Habits: 48.8 per cent were ever (current plus past) smokers and 35.1 per cent were current smokers. Smoking was more in the age group 40-69 years (54 per cent) and in the young (25-29 years), it was 32 per cent.
Current use of smokeless tobacco was 12.8 per cent and ever use was 16.7 per cent. 42.2 per cent consumed alcohol in any form.
Tobacco habits were associated with low levels of schooling and the prevalence rate of smoking was 65 per cent in the illiterate; 68.8 per cent in the primary (1-5 years of schooling); 63 per cent in the secondary (6-9 years of schooling); 47 per cent in the matriculate and 35 per cent in the educated group (11 years or more of schooling).
37 per cent did not have any habits; 25 per cent had at least one habit and 28 per cent had two habits and 8.4 per cent had all the three. There was inverse relation with income, type of housing and possessions.
Quit rates of tobacco among the various age groups were: 25 to 29 years: 3.7 per cent; 30 to 44 years: 7.8 per cent; 45-59 years 16.4 per cent; 60 and above 26.9 per cent. Obesity was observed in 26 per cent in the young (25-43 years), 28 per cent in the middle age (44 to 59) and 20 per cent in the elderly (60 and above)
Burden of Disease
Coronary artery diseases were two-fold among the smokers compared to non-smokers. The most striking feature was that tuberculosis was three-fold among the smokers and a similar risk was noted with chronic bronchitis. Stroke and peptic ulcer risk was two-fold with smokers than the non-smokers. Stroke has a five-fold risk in those with coronary artery disease.
Studies were conducted on adult males aged 25 and above from 58 panchayats and 2,79,118 males were evaluated. Current smoking rate was 18.8 per cent in the age group of 25-29 years and showed a progressive increase and it was 43 per cent in the 50-59 age group. Ever smoking rates were 34 per cent, 53.6 per cent and 58 per cent in the young (25-43), middle age (44-59) and 60 + groups respectively.
This study was initiated in 2000 and two follow-up rounds have been conducted till 2012 and 87 per cent of these subjects were available for second and third interviews.
The pattern of death among the smoking men was much higher than the non-smokers and most important causes of death were coronary artery disease and stroke, followed by respiratory diseases, cancer and gastrointestinal ailments.
This study was conducted by a team lead by Dr K T Shenoy, Dr Sheela Shenoy and Dr K B Leena of the Population Health and Research Institute, Thiruvananthapuram, an NGO working in the area of tobacco-related diseases and smoking cessation and quit smoking campaign and other gastrointestinal and non-communicable diseases.
Dr K T Shenoy
(The author is Executive Director, Population Health and Research Institute, Thiruvananthapuram-11)