How Risky is Smoking? Your Genes May Tell.

This is from The New York Times:

The Respiragene test looks at 20 spots in a person’s genome where DNA varies among people. It uses that data, as well as nongenetic information like the person’s smoking history, to compute a risk score… The average smoker has a lifetime risk of lung cancer of about 10 percent, which is about 20 times as high as that of a nonsmoker. This would imply that smokers found to be at highest risk from the genetic test would have a near certainty of getting cancer.

Comments (7)

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  1. Bruce says:

    The question is: Can a gene test tell us when IT IS SAFE TO SMOKE?

  2. Ken says:

    I agree with Bruce. Is the only information you can get negative?

  3. Devon Herrick says:

    That is an interesting argument. I suspect smokers would be less apt to quit if they knew they weren’t likely to get lung cancer. Yet, smoking also causes heart disease and emphysema.

  4. Bart I. says:

    Pollack assumes that you can simply multiply the risk factors in order to find an implied aggregate value (20 x 10 x 0.5% = 100%). This seems questionable.

    Maybe the risk is additive instead: say 10% for smoking plus 5% for the worst genes = 15% for a smoker with bad genes.

    Or maybe you should multiply the negative risk, 0.9 x 0.95 = 0.855 that they won’t develop cancer.

  5. Dr Robert Young says:

    I am the clinician who developed this test (MD PhD) and wish to help clarify the points raised in this debate. Andy Pollack has indeed misunderstood the relevance of the test results. He has incorrectly interchanged lifetime risk (a form of absolute risk)with relative risk (risk between 2 specified groups)based on cross-sectional data.

    Someone at very high lung cancer risk does not have 100% likelihood of getting lung cancer just as someone at the moderate (lower)risk maintains a residual risk of lung cancer (not no risk). This test is not a license to smoke just as serum cholesterol level is not a license to indulge in poor diet nor is it a 100% predictor of heart attack.

    First, the quoted lifetime risk for a smoker getting lung cancer is 10-15% but this is only an average and dependent on a number of variables. This figure is misleadingly applied to all smokers, but in the absence of risk testing, suffices as an average only. The Respiragene test helps to refine this risk of lung cancer among smokers with the aim to enlighten and empower them with personalised information relevant to their circumstances.

    Second, in our cross-sectional data comparing healthy unaffected smokers with smokers with lung cancer (but similar age, smoking exposure and gender) we are able to assign smokers to a moderate, high and very high risk based on their “risk score” calculated from the presence of validated genetic and clinical variables. Our studies show that about 50% of healthy smokers (and subsequent studies show 50% of random smokers) are in the moderate (“lower risk” group). This group still has residual risk for lung cancer (much like BRCA1-gene test negative woman maintain an 8-10% lifetime risk of breast cancer).

    Therefore the Respiragene test does not tell you it is safe to smoke because (a) there are many causes of death from smoking apart from lung cancer which smokers are well aware of thanks to public health measures, and(b)there is no data to support the idea that undertaking tests of risk like this will maintain the smoking habit. In fact we have conducted 2 surveys of over 188 smokers that shows they are not demotivated from quitting after getting genetic risk test results. If a similar concern applied to the dietary management of diabetics (where future risk is used to motivate better dietary choice), we wouldn’t test diabetics for their risk of heart disease (eg cholesterol and blood pressure) or glucose control, for fear they were normal.

    Contrary to the comments of Mr Herrick (possibly a non-smoker?), smokers are actually looking for reasons and help to quit – studies consistently show that 70% of smokers have tried to quit in the preceding 12 months. This test might help them succeed much like speeding tickets help deter the majority of motorists from speeding.

    Dr Rob Young

  6. I have not had a puff in over a year. The nastiest aspect concerning stopping might be the starting few weeks. Luckily for me that stuff went away quickly and stuff got easier day-to-day on account of the electronic cigarette. Please don’t stop trying. Simply keep trying and you will, no doubt realise success forever.

  7. Carlos Kelly says:

    lung cancer is almost alway caused by heavy cirgarette smoking;~*