Sex, Age, and Lower Cognitive Scores Among Factors That Predict Weight Loss in Parkinson’s, Study Reports

Weight loss is common in Parkinson’s disease and can affect quality of life.

A study has identified factors that can predict weight loss in patients who are in the early stages of Parkinson’s. They include being a woman, being older, having posture problems, having low cognitive scores, and using levodopa as a dopamine replacement therapy.

The findings were reported in an article titled “Predictors of weight loss in early treated Parkinson’s disease from the NET‑PD LS‑1 cohort” that was published in the Journal of Neurology.

Researchers had previously observed an association between body mass index and Unified Parkinson’s Disease Rating Scale (UPDRS) motor and total scores. UPDRS is used to evaluate the severity of Parkinson’s. It focuses on behavior, mood, daily life activities, and motor symptoms.

Factors that predict weight loss in Parkinson’s patients hadn’t been studied in large patient populations before. So researchers examined information on 1,619 people in the early stages of the disease. They were part of a long-term clinical trial sponsored by the National Institute of Neurological Disorders and Stroke.  NET-PD LS1 was a double-blind, multicenter, randomized, placebo-controlled study.

Investigators analyzed patients’ weight change between the start of the trial and at 12, 24, 36, 48, 60, and 72 months.

On average, participants lost only 0.6 kg per year. Being a woman, being older, having more weight at the start of the study, having higher UPDRS scores at the beginning of the trial, having difficulty eating and drinking, having posture problems, having lower cognitive scores, and taking levodopa at the start of the study were all associated with weight loss.

Surprisingly, difficulty swallowing, involuntary muscle movements, depression, constipation, and self-reported anorexia, vomiting, or nausea were not significantly associated with weight loss.

Overall, patients experienced little weight loss in their first six years of dopamine replacement therapy, although posture problems and using levodopa were both predictors of early weight loss. Another finding was that patients receiving levodopa had an average weight loss of 0.28 kg more per year than those on dopamine agonists only. Also, older participants lost weight at a faster rate.

Despite its interesting results, the study had several limitations that prevent it from being generalized to the Parkinson’s population as a whole, researchers said.

“First, the study enrolled only patients with early Parkinson’s disease, and weight loss is likely to become more significant as the disease progresses,” researchers wrote. “Studying prospective predictors of weight loss in a more advanced population would be helpful for clinicians [doctors] trying to manage this symptom.

“Second, the duration of follow-up (a mean of 4.1 years from the study’s start) may not have been adequate to capture gradual weight loss,” the team said. “Third, participants enrolled in the NET-PD LS-1 study were not representative of the PD [Parkinson’s] population as a whole, given that participants were in general younger, healthier and better educated than average.”

To better comprehend weight loss in Parkinson’s, researchers called for a follow-up study measuring dietary intake, appetite, sense of smell, and other features.