Genetic Testing Not Appropriate For Type 2 Diabetes

BMJ editors are chastizing the press for inflating the usefulness of recent gene discoveries for type 2 diabetes. Various news stories implied or said outright that people would be more inclined to change their lifestyle if they knew that they carried a gene variant that increased their risk of developing diabetes.

Right. Do they have any idea how stubborn people are?

Even if this discovery led to a 100% effective intervention that specifically targeted the effects of the genetic variant, 45% of the general population would need to receive this intervention to prevent 21% of diabetes cases, they [BMJ editors] explain. An intervention that specifically targets the effects of TCF7L2 variants would therefore need to be cheap, harmless, and burdenless to warrant such substantial overtreatment.

Alternatively, the genetic test could identify people at high risk who would benefit from appropriate advice on diet and physical activity. But many carriers would find their risk increased from 33% to only 38%. Would these figures provide enough incentive for them to change their lifestyles, they ask?

All this is true, but it’s also true of other risk factors as well, like diet. For instance, how many times have we heard conflicting evidence about coffee?

Estimating risk in epidemiologic studies is not a precise science. When we discover genes or other exposures that appear to have a strong effect on our health, the next logical step would be to understand the mechanism by which they act. But, it doesn’t hurt to tell people to develop healthy lifestyle habits because of or in spite of their genes.

Medical News Today, September 11, 2006

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