Head injury increases dementia risk in veterans

A study of US war veterans has revealed that those who experienced head injuries were 60% more likely to go on to develop dementia than those that did not sustain brain injury.

Posted on 26th June 2014

A study of US war veterans has revealed that those who experienced head injuries were 60% more likely to go on to develop dementia than those that did not sustain brain injury. The research is published on the 25 June in the journal Neurology.

The researchers looked at the medical records of 188,764 US military veterans with an average age of 68, who did not have dementia at the start of the study. The research team collected information from veteran medical records about the types of head injuries they had received, as well as information of other physical and mental health conditions such as diabetes, cerebrovascular disease, post-traumatic stress disorder and depression. The team also made estimates of education level and socioeconomic background, based on census data and postal address.

Of the 188,764 medical records analysed, 1,229 veterans had sustained a head injury, also known as traumatic brain injury (TBI). Of these, 196 went on to develop dementia in the 9 year follow-up, a greater proportion than those who did not experience TBI. When other factors that may contribute to the risk of dementia, such as age, education level, diabetes and depression, were taken into account, it was found that brain injury increased the likelihood of developing dementia by 60% compared to those with no history of head trauma.

The research also showed that veterans with a previous TBI developed dementia, on average, 2 years before those with no record of TBI. As well as looking at dementia generally, the study looked at the different forms of dementia. The findings showed that the risk of Alzheimer’s disease, vascular dementia and dementia with Lewy bodies were all increased in veterans with a previous TBI. There were too few cases of frontotemporal dementia to make an accurate assessment of risk.

Dr Simon Ridley, Head of Research at Alzheimer’s Research UK, the UK’s leading dementia research charity, said:

“This study adds to the growing evidence that traumatic brain injuries increase the risk of developing dementia later in life. While the number of medical records analysed in this study was large, the number of veterans who experienced head injuries and developed dementia was relatively small. The medical records used in this study also did not provide information on the timing or number of head injuries received. Larger studies will be needed to draw firmer conclusions and tease apart how head injuries may con tribute to different forms of dementia.

“It is still unclear whether knocks to the head in everyday life may impact our dementia risk. Understanding the risk factors for dementia is important as it means that steps could be taken to protect brain health for as long as possible. Current evidence suggests that a balanced diet, regular exercise, not smoking and keeping blood pressure and cholesterol in check could all help to maintain a healthy brain as we get older.”

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