Cross-posted from Nature Medicine’s news blog, Spoonful of Medicine. By Roxanne Khamsi.

PARIS — A massive review of the medical records of nearly 300,000 US veterans lends weight to the notion that traumatic brain injury might contribute to the risk of cognitive impairment later in life. Neurologist Kristine Yaffe of the University of California–San Francisco and her colleagues reviewed seven years’ worth of data from the files of the former military troops, and found that these types of head injuries were linked to a doubled risk of dementia.

Yaffe, who presented the findings here today at the Alzheimer’s Association International Conference, says that it’s the largest analysis of its kind to date. All of the 281,540 veterans included in the analysis were aged 55 years or older and free of dementia at check-up visits before 2001. However, during seven years of follow up, 2% of the older veterans had a diagnosis of traumatic brain injury (TBI). Of those with TBI, 15.3% developed dementia, as opposed to 6.8% of those who were free of this type of head injury. After adjusting for other possible contributing factors, such as post-traumatic stress disorder — which previous research has hinted might contribute to impaired cognitive function — the scientists calculated that TBI is linked to a 2.3-fold increased risk of dementia.

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