Impact of Overweight and Obesity on Functional and Clinical Outcomes of Early Parkinson's Disease

ObjectiveTo determine whether being overweight or obese contributes to disease progression and functional status in Parkinson's disease (PD).DesignCohort study using data from the Parkinson Progression Markers Initiative (PPMI).Setting and ParticipantsA total of 399 drug-naive patients with early PD were classified into normal weight (body mass index of 18.5–24.9, n = 139), overweight (25.0–29.9, n = 167), and obese (30.0 or more, n = 93) groups.MethodsThe primary outcome was the development of functional dependency. Functional dependency was defined as a Schwab and England score of less than 80% at any time point that remained throughout follow-up. The secondary outcomes were the changes in the Movement Disorders Society Unified Parkinson Disease Rating Scale motor score measured in the off-medication state and the Montreal Cognitive Assessment score across visits.ResultsOver a 5-year follow-up period, the incidence of functional dependency was higher in the obese group than in the normal weight group (P = .001). No difference was observed between the overweight and normal weight groups (P = .429). The multivariable Cox model confirmed that obesity, but not overweight, increased the risk of dependency (hazard ratio 2.63, 95% confidence interval 1.32–5.23, P = .006). The increase in the Movement Disorders Society Unified Parkinson Disease Rating Scale motor score was greater in the obesity (P < .001) and overweight (P = .004) groups than in the normal weight group. Changes in the Montreal Cognitive Assessment score did not differ among the groups (P = .978).Conclusions and ImplicationsWe found that obesity is related to an increased risk of functional dependency and rapid motor progression in patients with early PD. Although being overweight did not increase the risk of dependency, this condition was associated with rapid motor progression.