BY SARAH OWENS
Patients who underwent truncal vagotomy, which denervates multiple organs, including the stomach, liver, gall bladder, and pancreas, appeared to have a decreased risk of Parkinson's disease (PD). And the evidence suggests truncal vagotomy may delay the onset of PD, according to a new study published online on April 26, 2017 ahead of the print edition of Neurology.
The authors were interested in exploring the evidence of Parkinson's disease pathology in the gut based on human and animal studies. In pathologic studies, Lewy-type pathology has been found in the gut of people with prodomal Parkinson's disease. Their interest in examining the effect of vagotomy was spurred by mouse models, in which vagal surgery was observed to stop the spread of PD-like pathology.
The authors of the study, led by Bojing Liu, MSc, of the department of medical epidemiology and biostatistics at the Karolinska Institute in Stockholm, Sweden, noted that the association was not significant overall for other types of vagotomy. The findings offer "suggestive evidence for a potential protective effect of truncal, but not selective, vagotomy against PD development," they wrote.
The PD risk reduction was strongest at more than five years and more than 10 years after vagotomy, but the association was attenuated at more than 20 years after vagotomy. These temporal patterns, the study authors suggested, support "the possibility that PD pathology may start at multiple sites of the peripheral nervous system" and that truncal vagotomy may delay, rather than entirely prevent, the onset of PD.
For the study, researchers gathered data from nationwide health registries in Sweden and matched 9,430 patients who underwent vagotomy between 1970 and 2010 with 377,200 reference individuals by sex and year of birth. Of the patients who underwent vagotomy, 3,445 underwent a truncal vagotomy, and 5,978 underwent a selective vagotomy,which denervates only the stomach and preserves innervation to the antrum and pylorus.
They followed up the participants from the date of vagotomy until diagnosis of PD, death, emigration out of Sweden, or the end of 2010 (whichever occurred first), using the Swedish Patient Register to identify all vagotomies and all cases of incident PD.
They found that among 4,390 total cases of incident PD over 7.3 million person-years, the incidence of PD was 61.8 per 100,000 person-years among participants who underwent vagotomy and 67.5 per 100,000 person-years among the reference participants. There was no overall association between vagotomy and PD risk, but patients who underwent truncal, rather than selective, vagotomy appeared to have a lower PD risk (HR 0.78, 95% CI 0.37-0.93), although the difference did not reach statistical significance.
The researchers noted several limitations to their study. Among them, the nationwide registry likely included misclassifications, especially of Parkinson's diagnosis and the timing of diagnosis; and they were unable to fully control for all confounders, including individual Parkinson's disease risk factors like smoking, coffee intake, and genetics.
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