UICC World Cancer Congress 2006

Objective: Since there are differences in smoking pattern in urban and rural areas in India , the objective of this study was to assess mortality from smoking among men in urban and rural India.

Methods:A case-control study was conducted, in collaboration with the University of Oxford (UK), with 27,000 adult men in urban and 16,000 men in rural, who had died in the state of Tamil Nadu, southern India from medical causes and 20, 000 urban and 15,000 male controls. The main analyses are of mortality at ages 25-69 years.

Results:In urban area, the smoker:non-smoker risk ratio at ages 25-69, adjusted for age, educational level and tobacco chewing, was 2.1 for mortality from cancer or the aggregate of all medical causes,1.8 for mortality from vascular disease and 4.5 for respiratory tuberculosis. At ages 25-69, most of the smoking-associated cancer deaths involved cancers of respiratory or upper digestive tract, with relative risks of 3.6 for cancer of the lung, 3.6 for cancer of the mouth and throat, 2.3 for cancer of the oesophagus, and 2.6 for cancer of the stomach (each p<0.001). The standardized risk ratio for mortality from cancer associated with smoking at older ages (70+) was 1.4-fold. The risk was substantial both for cigarette smoking (the main urban habit) and for bidi smoking (the main rural habit). The proportional excess of cancer mortality at ages 25-69 years among ever smokers in urban area was replicated with similarly narrow confidence intervals for risk ratios in the rural study area.