Long-term study links amateur boxing to earlier onset of dementia
Using data from an ongoing long-term health study spanning 35 years, researchers have found men who participated in amateur boxing in their youth are almost three times more likely to suffer from Alzheimer’s-like cognitive impairment in their senior years compared to those who did not box when young.
"Professional boxing is known to cause chronic traumatic brain injury – but there has been little to no long-term research on this issue in amateur boxing,” says lead author Peter Elwood. "Our study therefore provides some of the best available evidence suggesting that amateur boxing is associated with clinically measurable long-term brain injury, manifested as earlier onset Alzheimer's-like impairment.”
To investigate any potential long-term effects from boxing while young the new research looked at data from a valuable observational study known as the Caerphilly Cohort Study. This project began in 1979, enrolling several thousand men and tracking the relationship between lifestyle and health over several decades.
The men were aged between 45 and 59 at the beginning of the study and were followed for 35 years, completing a battery of tests every five years. At the 35-year mark in the study all participants completed comprehensive cognitive testing to assess dementia and Alzheimer’s disease.
Earlier in the study, when the participants were being assessed while in their mid-60s, they were asked several questions about their boxing experiences while young and whether they had suffered any head injuries during their lives. The degree of boxing each subject may have experienced was not explicitly measured. Instead, the participants were asked the question: “When you were younger did you ever box seriously as a sport?”
“Although the inclusion of 'serious' in the question about boxing is somewhat vague," the researchers note in the study, "it certainly will have eliminated men who toyed casually with the sport, and although the identification of men who had boxed was retrospective, serious boxing is not a sport which is likely to have been forgotten."
A sample of 1,123 men was ultimately used in the new study, and 73 of those subjects self-reported “serious” boxing in their youth. One third of those amateur boxers were found to have some degree of cognitive impairment in their senior years, compared to one fifth of those men who had not boxed.
Amateur boxers were three-times as likely to display nonvascular cognitive impairment, a form of dementia generally considered to be an early-stage of Alzheimer’s disease, compared to non-boxers. And the former boxers displayed signs of dementia an average of five years earlier than those who didn’t box.
The researchers are cautious to point out this is a small sample size (of only 73 self-reported amateur boxers) and the study is only observational, so no direct causality can be determined. But the findings are unique as there simply hasn’t been any study on the long-term effects of boxing when young.
Elwood does note the boxing reported in this study most likely took place in the mid-20th century, when the sport lacked the safety measures often seen today. Nevertheless, he does suggest there are extra preventative measures that could be instituted in the 21st century to prevent any potential long-term cognitive impairment from the sport.
"Over the years the introduction of increasingly tight controls in the amateur sport, with shorter bouts and mandatory headgear, means that the chances of serious brain injury are much reduced – but there is still a true long-term impact of boxing,” says Elwood. "Banning blows to the head would seem to be an acceptable preventive measure, as this need not reduce the competitive aspect of the sport but would preserve its undoubted considerable physical and social benefits."
The new study was published in the Clinical Journal of Sport Medicine.
Source: Cardiff University