Use of Bidi increases cancer risk in Kerala : study
Thiruvananthapuram, Mar 21 : India's first cohort studies have conclusively proven that bidi smoking presents a many fold increase in the incidence of Kerala's most prevalent cancers among men.
Separate studies on the impact of bidi smoking on lung and oral cancers and cancers of larynx and hypo pharynx in men between the age group of 30-84 in Karunagappally of Kollam District shows that bidi - unfiltered tobacco flakes rolled in tendu leaf and tied with thread - is indeed among the most harmful smoking products.
The cohort study on bidi and lung cancer, covering a total of 65,829 men, found that bidi smokers had a 3.9-fold increase in lung cancer incidence when compared to those who never smoked them, the report said.
The study also found that lung cancer risk among former 'bidi' smokers was higher than those who never smoked bidis. Increasing
number of bidis smoked and younger ages of starting 'bidi' smoking contribute to elevating lung cancer risk.
The study provides succour to quitters as it has shown that the risk of lung cancer was lower in former smokers than current smokers.
The lung cancer risk was found to have shown a statistically significant decrease among those who had stopped bidi smoking for 10 years or longer, when compared to current bidi smokers. The risk of cancers affecting the cheek (buccal) and lips (labial) showed a nearly four-fold increase in the cohort study covering 66,277 men. Larger daily consumption of bidis significantly increased the risk associated with cancers of the gum and the mouth, the study showed.
Also tongue cancer risk significantly increased among men who smoked bidis for 30 years or longer, and among men who started bidi smoking at 18 years or while younger.
Yet another painful group of cancers are those affecting the lower part of the throat including voice box, known as laryngeal and hypo pharyngeal cancers.
Another cohort study conducted on 69,943 men, again in the 30-84 age group in Karunagappally, shows a significant relationship relation between bidi smoking and cancers affecting the larynx and hypo pharynx. The results show that those with a history of bidi smoking for more than 30 years have a higher risk of laryngeal cancers. Smokers who puff more than 15 bidis a day are at increased risk of hypo pharyngeal cancers.
Dr P Jayalekshmi of Regional Cancer Centre and the principal author of the studies on bidi-induced lung, oral, laryngeal and hypo pharyngeal cancers said, 'The mainstream smoke of bidi contains a much higher concentration of carcinogenic hydrocarbons.
Bidi smokers also are found to be taking five puffs per minute compared to two puffs by cigarettes in the same time. All these contribute to increasing the carcinogenic nature of bidi smoke.'
On the reason for choosing Karunagappally as the study location, Dr Jayalekshmi added, 'Karunagappally is known for its thorium-containing monazite sand, which causes high background radiation. Figures with Regional Cancer Centre here show that 821 and 863 males registered as lung and oral cancer patients respectively during 2011-12 alone.
Another 392 patients registered for care of hypo pharyngeal & laryngeal cancers during the same period. As many as 1.6 million males in Kerala smoke bidis, which have been proven to contain higher levels of hazardous chemicals when compared to cigarettes.
The Karunagappally studies have also reiterated the common knowledge that bidi smoking is more widespread among those with lowers levels of education and lower family income. The Global Adult Tobacco Survey (GATS 2009-10) has it that 31.1 per cent of male bidi smokers in the country have no formal schooling while 19.7 per cent are self-employed. Bidi smokers in Kerala spend nearly Rs 140 monthly.