Article

In recent years, there has been a major shift in our understanding of the course
of Parkinson's disease (PD) from a disease of the brain to a disease of long
latency, characterized by the progressive emergence of multiple non-motor
symptoms, including hyposmia, constipation, depression, anxiety, rapid eye
movement (REM) sleep behavior disorder and excessive daytime sleepiness, as well
as subtle motor signs, before the typical motor signs appear. Epidemiological
studies have made major contributions by allowing better characterization of
subsequent PD risk in relation to non-motor symptoms. Such findings have profound
implications for the conduct of epidemiological studies examining risk and
protective factors in PD, and the interpretation of their findings. Given the
length of the prodromal period, reverse causation in particular is a major
concern with many reported associations. One striking feature of PD etiology,
compared with other diseases, is the presence of numerous inverse associations.
If these associations are truly causal, they would have major implications for
disease prevention and for slowing disease progression. However, whether these
associations are truly causal remains to be demonstrated in future studies.
Experimental studies play an important role by offering a better understanding of
the underlying mechanisms. Well-designed epidemiological studies using innovative
approaches will also be key in elucidating whether these intriguing associations
are causal or a consequence of reverse causation.
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Langue : ANGLAIS