Swedish scientists have found that a variation of the FTO gene linked to an increased risk of obesity may also be associated with an increased risk of Alzheimer’s disease and dementia. Their study also found carrying both the risky FTO allele with another gene known to be associated with Alzheimer’s disease increases the risk of dementia by 50%. The findings were announced earlier today at the Alzheimer’s Association International Conference on Alzheimer’s Disease in Honolulu, Hawaii.

Over nine years, researchers followed 1,003 elderly subjects who initially presented no signs of dementia. The found that those people carried two copies of the A variant of the FTO gene had a 58% increased risk for Alzheimer’s disease and a 48% increased risk for developing dementia. The FTO A allele, which occurs at a frequency of about 45% in Central and Western Europeans and 52% in West Africans, has been previously shown to correlate with increased BMI and increased risk for obesity in both children and adults. The Swedish researchers found that those individuals who carried two copies of FTO A as well as the e4 allele of the gene APOE saw their risk factor for dementia double. It’s estimated that about 25% of people carry at least one copy of the APOE e4 allele.

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