Punch drunk

A new study in the British Medical Journal concludes that “there is no strong evidence to associate chronic traumatic brain injury with amateur boxing,” 

The authors systematically reviewed 36 observational studies of amateur boxers published over the past 50 years. But they acknowledge that the general quality of the studies is very poor, so, despite the conclusion, their findings are actually inconclusive.

In an accompanying editorial, neurologist and sports physician Paul McRory notes that boxers’ careers are much shorter now than they were in the first half of the last century. Boxers today are therefore exposed far less to head impacts – the main risk factor in traumatic brain injury – than they were in the past.

But traumatic brain injury is an “invisible” injury that occurs as a result of the cumulative effects of head impacts. It can go undetected for years, and it is impossible to determine how many – or how few – blows to the head can be experienced before such injuries occur.

There is little doubt that the repeated blows to the head experienced by boxers can cause traumatic brain injury – the multiple concussions suffered by boxers can lead to punch drunk syndrome (also known as dementia pugilistica, boxer’s dementia, or chronic traumatic encephalopathy), a condition which affects up to 20% of professional boxers.

However, the possible risk to amateurs is difficult to ascertain. The protective head gear worn by amateurs reduces cuts and bruises to the head, but the extent to which it reduces the jarring of the brain within the skull is unclear. And, although the length of amateur bouts in the U.K. has been reduced from three rounds of three minutes to four rounds of two minutes, the rules differ from one country to another.

Professional boxing is banned in Norway, Cuba, Iran and North Korea. The British Medical Association (BMA) has been calling for a complete ban on boxing in the U.K. – both amateur and professional – since the early 1980s, and has extended that call in a report published last month.

For more information, see this 1993 report, The Boxing Debate, by the BMA.



3 thoughts on “Punch drunk

  1. they acknowledge that the general quality of the studies is very poor, so, despite the conclusion, their findings are actually inconclusive.

    They must have figured out early on that their data sources were “very poor.” Why continue on and publish?

  2. Well, if existing data is poor, then saying so out loud can push those with better data to publish.
    Another comment: Yes, TBI is an ‘invisible injury’. However, the evidence for multiple concussions leading to cognitive impairment is weak – there’s evidence it occurs for some, but certainly not most, and there’s no evidence that a single concussion generally does this. The MRI/CT scan data seems to be normal for about 90% of people, (with some difficulty identifying how many abnormalities are pre-existing). Similarly, cognitive test data, although typically abnormal in the first few days, returns to normal, for over 90% of people, by 3 months.
    Finally, the US navy study, looking at WW2 veterans, found no increase in dementia in those who experienced mild brain injuries, 50 years after the fact (although it was clearly demonstrated for those with severe brain injuries).
    The BMJ paper suggests the APOE e4 allele is a risk factor for decline, just as it seems to be a risk factor for cognitive decline in other conditions.

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