Body mass index in patients with Parkinson's disease: a systematic review

Body mass index (BMI) has been found to have an impact on neurodegenerative diseases such as Parkinson's disease (PD). Several studies suggested that patients with PD have a lower BMI compared with controls. However, some studies indicated the differences between patients and controls as statistically insignificant. We performed this meta-analysis to clarify the relationship between BMI and PD based on the studies published from 1975 to April 2023 in the PubMed, Embase, and Cochrane Library databases. In total, 18 case-control studies met the inclusion criteria for meta-analysis. We found a statistically significant difference in mean BMI between patients with PD and healthy controls {standardized mean difference (SMD) [95% confidence interval (CI)] = -0.36 (-0.43, -0.29), P < 0.05}. Regarding sex, seven studies were included in the meta-analysis for female/male patients with PD. The mean BMI was significantly different between males with PD and healthy males [SMD (95% CI) = -0.34 (-0.47, -0.22), P < 0.05]. Moreover, the mean BMI of females with PD was significantly different from that of corresponding healthy females [SMD (95% CI) = -0.44 (-0.57, -0.30), P < 0.05]. The meta-analysis demonstrates a significantly lower BMI in patients with PD, but no gender differences, when compared with their respective healthy individuals.NEW & NOTEWORTHY The meta-analysis demonstrates a significantly lower body mass index in patients with PD, but no gender differences, when compared with their respective healthy individuals.