Carrying two copies of a common variant of a particular gene doubles your chances of developing diabetes and puts you in a similar risk category to being clinically obese, according to a collaborative study led by UCL (University College London) researchers.

The collaborative team led by UCL Professor Steve Humphries studied the TCF7L2 gene, which was discovered to be implicated in diabetes earlier this year by a group working in Iceland. The new study followed healthy middle-aged men in the UK for 15 years, and found that carrying a common variant of the gene increased their risk of developing diabetes by 50 per cent. Carrying two copies of the variant gene increased the risk two-fold, to nearly 100 per cent. In the population as a whole, the impact of this gene on the risk of developing diabetes is as big as the problem of being clinically obese (having a body mass index over 30).