Toronto—More than a million Americans suffer a concussion each year, and a disproportionate number of those are older adults.

An article in JAMA Neurology points out that the extent of complications after mild traumatic brain injury is uncertain—including lingering mood disorders or a chronic neuropsychiatric disorder—and that pharmacologic options are limited.

That’s why a new study led by University of Toronto researchers is so important. The study team conducted a large extended population-based double cohort study following 28,815 patients after a concussion. Results indicate that the 5-year incidence of dementia was substantial but that use of statins—commonly prescribed to lower cholesterol levels—was associated with a significantly reduced risk of subsequent dementia.

The Canadian study ran from April 1, 1993, to April 1, 2013, (enrollment) and continued until March 31, 2016 (follow-up), with analysis through March 21, 2019. Participants were older adults in Ontario diagnosed as having a concussion. Excluded were severe cases resulting in hospitalization, individuals with a prior diagnosis of dementia or delirium, and those who died within 90 days.

Patients suffering concussion had a median age of 76 years, and 61.3% were women. About a fourth of them, 25.4%, were taking statins. Over a mean follow-up of 3.9 years, 4,727 patients subsequently developed dementia; researchers calculated that as an incidence of one case per six patients.

Results indicate that patients who received a statin had a 13% reduced risk of dementia compared with patients who did not receive a statin (relative risk, 0.87; 95% CI, 0.81-0.93; P <.001).

“The decreased risk of dementia associated with statin use applied to diverse patient groups, remained independent of other cardiovascular medication use, intensified over time, was distinct from the risk of subsequent depression, and was not observed in patients after an ankle sprain,” study authors write.

The researchers add that although older adults had a substantial long-term risk of dementia after a concussion but that they found “a modest reduction among patients receiving a statin.”

While the authors say their study suggests a potential long-term protective association between statin use and the risk of dementia after a concussion that justifies future research, they also suggest that a randomized trial might not be possible, noting that “we know of no practical method to randomize patients to receive a statin immediately before a concussion. Therefore, analytic observational research may provide the best available data for the immediate future.”

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