Reacción a "Untreated sleep apnoea is associated with an increased risk of Parkinson's disease, according to data from US war veterans"

This study, based on millions of medical records of US veterans, shows that people with untreated obstructive sleep apnoea have a higher risk of being diagnosed with Parkinson's disease in subsequent years, and that this risk appears to be lower in those receiving continuous positive airway pressure (CPAP) treatment. For an observational study, the methodological quality is very high: the sample size is enormous, the follow-up is relatively long, and the authors adjust for many factors that could distort the association. Overall, it is an important piece of work that reinforces the idea that sleep-disordered breathing can have long-term consequences for brain health. At the same time, we must be cautious when generalising the results: these are US veterans, mostly men, with very specific characteristics (more head injuries, more exposure to toxins, more psychiatric disorders) that could increase the risk of both sleep apnoea and Parkinson's disease. Although the statistical analysis takes many of these comorbidities into account, there may still be some residual confusion, which is why it is important for other studies, in populations more similar to the general population, to confirm these findings. The authors are well aware of this. 

What I find most critical when disseminating these results is to correctly interpret what it means to “increase” or “decrease” the risk of Parkinson's disease in the following years. It is not a question of whether or not the disease will ever develop, but rather of whether the onset of the disease is brought forward or delayed. In other words, untreated sleep apnoea could cause the disease to appear earlier in people who were already vulnerable — or who already had the disease in its prodromal phase — and CPAP could delay that moment slightly. That “little” (one to two years, according to the figures in the article) can undoubtedly be very important for the individual and for healthcare systems, but unfortunately it does not mean avoiding the disease altogether. In any case, the underlying message is clear: sleeping well is not a luxury, but a basic pillar of long-term brain health.