Neurology: Body mass index, abdominal obesity, and Parkinson's disease incidence in French women from the E3N cohort study

Previous studies on the relationship between body mass index (BMI) and Parkinson's disease (PD) have yielded inconsistent results, most likely due to the reverse explanation
of weight loss in the prodromal symptom stage.
Recently, a study published in Neurology used lagged analysis to examine the relationship between BMI and abdominal obesity and PD incidence to elucidate potential reverse causality and compare BMI trajectories in patients with previously diagnosed and matched controls
.

The study used data from the E3N cohort study and followed French women for 29 years (1990-2018).

BMI (kg/m²) is calculated based on self-reported weight and height up to 11 times; Measure up to 6 waist circumference (WC) and hip circumference
.
Diagnoses of Parkinson's disease are validated
based on medical records and drug claims databases.
Multivariate time-varying COX proportional hazard model was used to estimate hazard ratio (HR) and 95% confidence interval (CI), classified by body mass index (underweight < 18.
5; normal = [18.
5~25.
0; overweight = [25.
0~30.
0]; Obesity ≥=30.
0).

In the primary analysis, risk exposure lagged by 5 years; Longer lag times (10, 15, 20 years)
were used in sensitivity analyses.
Multiple logistic models using multivariate generalized estimation equations were used to examine trajectories
of BMI classes in nested case-control studies.

In this large cohort of women with long-term follow-up, even when measured 20 years before diagnosis, consistent with the results of Mendelian randomized studies, obesity was associated with
a lower risk of Parkinson's disease.
This analysis highlights the importance of
hysteresis analysis in explaining reverse causation.
These findings warrant further study to understand the mechanism of
this inverse association.

Sources: Portugal B, Artaud F, Domenighetti C, et al.
Body Mass Index, Abdominal Adiposity, and Incidence of Parkinson Disease in French Women From the E3N Cohort Study [published online ahead of].
print, 2022 Oct 3].
Neurology.
2022; 10.
1212/WNL.
0000000000201468.
doi:10.
1212/WNL.
0000000000201468