Research Reports - The risk of Parkinson's disease after mild traumatic brain injury
Arch Phys Med Rehabil. 2014 Mar;95
Marras C(1), Hincapié CA(2), Kristman VL(3), Cancelliere C(4), Soklaridis S(5), Li A(6), Borg J(7), af Geijerstam JL(7), Cassidy JD(8)
OBJECTIVE: To synthesize the best available evidence on the risk of Parkinson's
disease (PD) after mild traumatic brain injury (MTBI).
DATA SOURCES: MEDLINE and other databases were searched (1990-2012) with terms
including "craniocerebral trauma" and "parkinsonian disorders." Reference lists
of eligible articles and relevant systematic reviews and meta-analyses were also
STUDY SELECTION: Controlled clinical trials, cohort studies, and case-control
studies were selected according to predefined criteria. Studies had to have a
minimum of 30 concussion cases.
DATA EXTRACTION: Eligible studies were critically appraised using a modification
of the Scottish Intercollegiate Guidelines Network criteria. Two reviewers
independently reviewed and extracted data from accepted studies into evidence
DATA SYNTHESIS: Evidence was synthesized qualitatively according to modified
Scottish Intercollegiate Guidelines Network criteria. Sixty-five studies were
eligible and reviewed, and 5 of these with a low risk of bias were accepted as
scientifically admissible and form the basis of our findings. Among these
admissible studies, the definitions of MTBI were highly heterogeneous. One study
found a significant positive association between MTBI and PD (odds ratio, 1.5;
95% confidence interval, 1.4-1.7). The estimated odds ratio decreased with
increasing latency between MTBI and PD diagnosis, which suggests reverse
causality. The other 4 studies did not find a significant association.
CONCLUSIONS: The best available evidence argues against an important causal
association between MTBI and PD. There are few high-quality studies on this
topic. Prospective studies of long duration would address the limitations of
recall of head injury and the possibility of reverse causation.