One in six seniors developed dementia after a concussion, according to a new study by researchers at ICES and Sunnybrook Health Sciences Centre. While concussions predict an increased long-term dementia risk, it is modestly lower for older adults receiving a statin (cholesterol lowering drug).
The study published today in JAMA Neurology examined 28,815 adults over age 65 years who had not been previously diagnosed with dementia before they suffered a concussion over a 20 year period in Ontario (1993 to 2013). The researchers then followed each individual for up to five years to determine the long-term risk of developing dementia.
“I work at Canada's largest trauma centre and treat many patients after a serious injury. I am not scared by broken bones, liver lacerations, or messy bleeding. I am always worried, however, about brain injury even if the CT scan looks normal and the patient seems just a bit stunned,” says Dr. Donald Redelmeier, lead investigator, ICES senior scientist, and a physician at Sunnybrook Health Sciences Centre.
The researchers found that one in six patients developed dementia, which far exceeded the population norm. The increased risk of dementia occurred regardless of wealth status and was particularly high for older patients after the age of 80. The increased risk was distinct to concussions and not found with other types of injury such as a sprained ankle.
“The concussions occurred from everyday activities and no drug seemed to improve recovery, with one exception. Namely, patients receiving a statin had a 13 per cent lower risk of dementia than patients who did not receive a statin. No other cardiac or non-cardiac drug that was studied lowered the risk of dementia after a concussion,” adds Redelmeier. “The protection from statins is interesting yet modest”
The researchers add that the lower risk of dementia after a concussion associated with taking statins did not depend on the dose. Patients who started the statin after the concussion still showed a benefit. One explanation is that statins might ease the damage from a concussion by improving the circulation in tiny blood vessels throughout the brain.
The study suggests a potential long-term protective association between statins and the risk of dementia following a concussion. This finding may encourage older patients who are already prescribed a statin or who are at risk for a concussion to consistently take their medication. The researchers stress, however, that the study was not a randomized trial and correlation might not mean causality.
The researchers recommend more concussion prevention at all ages including driving safely, walking with proper footwear, using protective gear, staying sober, and avoiding reckless situations. “A way to avoid getting dementia when you are older is to avoid having a concussion when you are younger”, says Redelmeier.
Author block: Donald A. Redelmeier, Fizza Manzoor and Deva Thiruchelvam.
The report “Statins and risk of dementia following a concussion,” is published in the May 20 issue of JAMA Neurology.
ICES is an independent, non-profit research institute that uses population-based health information to produce knowledge on a broad range of healthcare issues. Our unbiased evidence provides measures of health system performance, a clearer understanding of the shifting healthcare needs of Ontarians, and a stimulus for discussion of practical solutions to optimize scarce resources. ICES knowledge is highly regarded in Canada and abroad, and is widely used by government, hospitals, planners, and practitioners to make decisions about care delivery and to develop policy. In October 2018, the institute formerly known as the Institute for Clinical Evaluative Sciences formally adopted the initialism ICES as its official name. For the latest ICES news, follow us on Twitter: @ICESOntario
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