Giridhara R Babu, Associate Professor, PHFI; member on the NCD surveillance leadership workgroup of the International Society for Disease Surveillance (ISDS), and Wellcome Trust-DBT fellow debunks the claims of some Loksabha MPs that there is no clear link between tobacco consumption and cancer
Galileo Galilei said, “We cannot teach people anything; we can only help them discover it themselves”. He was reprimanded and troubled by the Church till his death. His fault was that, he said that the earth revolved around the sun, not a mere hypothesis but he backed it with telescopic evidence. The Pope apologised several eras after Galileo’s death. India has lost several such lives due to using tobacco. This time, it is some members of parliament who doubt the otherwise obvious evidence. They might have been guided by instinct and less by science, but each of their utterance has to be denounced. Otherwise, it might have dreadful longstanding upshots on the health of Indians. But, thank you MPs. I say this with deep gratitude, as it is parliamentarians who created attention regarding misconceptions about tobacco. This provides a perfect opportunity to explain that MPs are absolutely mistaken like most folks on tobacco use.
In epidemiology, bias is a systematic deviation of results from truth. Let us examine some statements of the MPs and understand whether these are based on truth.
“I can produce a lot of people in front of you who are chain smokers of beedi and till date they have had no disease, no cancer,” said Shyam Charan Gupta, Lok Sabha MP from Allahabad.
“Whether or not smoking causes cancer is debatable. I know two elderly people who drank a bottle of alcohol and smoked 60 cigarettes every day. One is still alive, the other died at 86,” said Ram Prasad Sarmah, BJP MP from Assam.
No doubts here, MPs indeed might have observed few chain smokers who have not yet got cancer. However, for every surviving smoking male in 100 people, 19 other smoking men would have died. Those who have got cancer and/ or have died earlier, won’t be noticed by the observer. Instead, if the MP examines elderly population in each age group, it would not be a surprise that most of this group would be composed of non-smokers (as smokers would have died of cancer or other diseases). This is survivor bias. There is another problem termed observer bias, wherein the observer (MP)s biased of consequences of tobacco, arising from financial stakes or conflicts of interest. In the finite sample the observer (MP) has seen, he has observed chain smokers,who have not yet got cancer. However, he is not following people temporally to see whether they get cancer or not. Cancers take at least a decade to develop and mere observation wouldn’t diagnose the condition. We cannot be sure of the diagnostic ability of the MPs as the cancers and other non-communicable diseases (NCDs) are asymptomatic for a long time till they get complications such as heart attack or stroke.
“There is no Indian study to show the link between tobacco usage and cancer,” said Dilip Gandhi, who is the head of the parliamentary panel.
In a nationally representative survey of 1.1 million homes, Prabhath Jha and others found that smoking reduced median survival of women by eight years and six years for men. This was published in prestigious New England Journal of Medicine (2011). A search of smoking and lung cancer in Google scholar finds 25300 articles, with more specifics pointing to 196-9870 articles. At least 1000 epidemiological studies show large relative risks 20:1 suggesting that risk is 20 times or higher for those who smoke. Tobacco is the single largest avoidable cause of premature death, a recognised carcinogen and the largest source of particulate indoor air pollution. It is a major cause of deaths and diseases due to second-hand smoke. A dose-response relationship indicates the higher propensity to get lung cancer with each extra cigarette smoked. In India, NCDs account for 60 per cent of all deaths, making them the leading cause of death. Tobacco use is the chief risk factor for causing NCDs.
Resulted by smoking and other shared risk factors such as physical inactivity and unhealthy food, India’s NCDs burden results in 40 per cent of all hospital stays and roughly 35 per cent of all recorded outpatient visits. With increased proportion of ageing population in India, we are going to be in a precarious state.
You get diabetes due to eating sugar, rice, potatoes. Why don’t you write warnings for all these things as well,” says Gupta.
Those who have diabetes are advised not to eat high sugar containing foods and not vice versa. This shows the despondency to use unfounded statements to defend the use of tobacco, a tactic used by tobacco moguls to engage more people to use tobacco in low and middle-income countries such as India. Tobacco provides instant euphoria, causes diseases over a period of time and results in premature death. Tobacco industry propagates wrong information to target non-users, they support activists who advocate that tobacco use is a matter of individual choice and state should not interfere. Tobacco is very potent as the users hook on to it after taking few puffs. The adverse marketing and surrogate advertisements influence teenagers and young adults to start using tobacco and they would never be able to quit. The honourable MPs should desist from making such statements and instead work on curbing tobacco use, and win the overly prolonged war against tobacco.
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