To the Editor In the article by Wills and coauthors,1 it is hypothesized that a lower body mass index (BMI) in Parkinson disease (PD) is associated with shorter survival based on the extrapolation from the association found in Huntington disease and amyotrophic lateral sclerosis. However, it is important to clarify whether this research hypothesis is based on an expected association between undernutrition and survival (BMI is considered a diagnostic criteria for undernutrition) or between the BMI-related anthropometric measurements per se and survival.
Cardoso R, Miranda D, Ferreira JJ. Association Between Body Mass Index and Parkinson Disease. JAMA Neurol. 2016;73(7):891-892. doi:10.1001/jamaneurol.2016.1242