Scientists have identified the most clear genetic link yet to obesity in the general population. People with two copies of a particular gene variant have a 70 per cent higher risk of being obese than those with no copies.
Scientists from the Peninsula Medical School, Exeter, and the University of Oxford first identified a genetic link to obesity through a study of people with type 2 diabetes.
This study was part of the Wellcome Trust Case Control Consortium, which is searching for genetic variations that may predispose people to or protect them from major diseases.
The researchers identified a strong association between an increase in body mass index and a variation of the gene FTO.
The researchers then tested a further 37 000 samples for this gene from Bristol, Dundee and Exeter as well as a number of other regions in the UK and Finland.
The study found that people carrying one copy of the FTO allele have a 30 per cent increased risk of being obese compared to a person with no copies. However, a person carrying two copies of the allele has a 70 per cent increased risk of being obese, being on average 3 kg heavier than a similar person with no copies. Among white Europeans, approximately one in six people carries both copies of the allele.
The researchers currently do not know why people with copies of the FTO allele have an increased BMI and rates of obesity.
The research is published online in the journal Science.