Cancer higher in gas leak zone but tobacco likely cause: report

However,according to the ICMR,this appeared less significant when the tobacco habits in the populations of the two areas were taken into account

More than two decades after the gas leak in Bhopal,the Indian Council of Medical Research (ICMR) has reported a higher incidence of cancer in affected areas those where the residents suffered the effects of the methyl isocyanate from the Union Carbide plant than in other areas of the neighbourhood.

However,according to the ICMR,this appeared less significant when the tobacco habits in the populations of the two areas were taken into account. The data suggest the higher AAR (age-adjusted incidence rates) in the affected areas was due to a higher proportion of the population consuming tobacco products rather than due to the effect of the exposure to the gas,said the report.

The ICMR report,which recorded cases from 1988 to 2007,found higher incidence of tobacco-related cancers in areas affected by the leak as compared to those not affected. As per the ICMR estimates,over 60 per cent of the population suffered due to inhalation of the toxic fumes and nearly 2,000 persons died within 72 hours of being exposed to the gas.

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A large number of survivors suffered acute multisystem morbiditie,eyes and lungs being the main target organs, says the ICMR report. For all anatomical sites of cancer in both males and females,the overall AAR was found to be higher in the affected area.

On the tobacco association,the report says,In males cancers of certain anatomical sites associated with the use of tobacco showed a higher incidence rate in the affected area compared to the unaffected area. Thus cancers of the tongue,mouth,hypopharynx,oesophagus and lungs showed a higher incidence in the affected area compared to the unaffected area.

All anatomical sites,both sexes and both areas considered,the AAR showed a statistically significant increasing trend in over the period 1988 to 2007,the report said. Cancer of the lungs in males showed a significant increase during the first 11 years (1988-1999) and thereafter a decline in the affected area. There was no significant change in the AAR of lung cancer (in males) in the unaffected area.

Among females,the AAR of cancer of the breast showed a significant increase in both areas. In addition,among females in the affected area,a higher incidence of cancer of the cervix,too,was found.

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The report reveals that the number of cancer cases rose from 167 in 1988 to 359 in 2007 in the affected areas. On the other hand,the number of cases recorded from the unaffected areas,as low as 85 in 1988,gradually rose to 317 in 2007.

Following the disaster,the ICMR initiated a population-based cancer registry to evaluate the ill effects of the toxic gas. Some of the information on cases was collected by interviewing those affected and their relatives at the source,while some details were noted from medical records and case files.