There's been a lot of media coverage recently about the high incidence of dementia in retired NFL pros. One report using a phone survey of retired NFL players revealed that the incidence of dementia or memory-related problems was 19 times higher than normal for men ages 30 to 49. Repeated head trauma is thought to create conditions that significantly increases the chances of developing dementia. A number of states are even enacting legislation that sets certain criteria for removing high school football players after any head injury with prompt and proper medical evaluation.
While these concerns are legitimate, I think the NFL officials are missing a very important piece of the puzzle, and that's the very high incidence of obstructive sleep apnea in current and retired pro football players. One recent Mayo Clinic study showed that 60% of all retired linemen and 46% of all other positions were found to have significant obstructive sleep apnea. Amongst active players in 2003, the overall numbers were 14% and 34% with linemen.
If you look at what happens to the brain with repeated episodes of hypoxia during apneas, then you'll see that the implications are profound. Untreated patients with sleep apnea are found to have multiple areas of dead or non-functioning brain tissues. Another similar study showed multiple areas of microscopic strokes, called lacunar infarcts. Chronic hypoxia in mice resulted in brain biopsy studies revealing amyloid plaques (similar to what we see with Alzheimer's disease).
So with this logic, it makes sense that repeated concussions in someone with untreated obstructive sleep apnea is more likely to suffer from the cumulative effects of head trauma compared with someone without sleep apnea. As with everything else in medicine, diseases never exist alone in a vacuum. It would be interesting if they did a study looking at the incidence of obstructive sleep apnea in these ex-players with dementia. I'm willing to bet a very high percentage will have undiagnosed obstructive sleep apnea. Another, more costly and ambitious study would be to screen all current NFL players for sleep apnea and follow them for years (or decades) while undergoing proper treatment, measuring their rate of progression to developing dementia.
What do you think about this issue? Should be continue treating medical conditions in isolation, or look at other co-morbid conditions that can aggravate the original diagnosis? Please enter your comments in the text area below.