Weight changes in the early stages of Parkinson's disease may be associated with changes in thinking skills

Weight changes in the early stages of Parkinson's disease may be associated with changes in thinking skills

People who gain or lose weight soon after being diagnosed with Parkinson's disease are more likely to show changes in their thinking skills than people who maintain their weight, according to a study published in the October 19, 2022 online edition of Neurology®, according to the medical journal of the American Academy of Neurology.

Early weight loss is a common symptom in people with Parkinson's disease. It could be a sign that people are at risk of cognitive decline.”

Jin-Sun Jun, MD, study author, Kangnam Sacred Heart Hospital in Seoul, Republic of Korea

The study involved 358 people who had recently been diagnosed with Parkinson's disease and had not yet started taking Parkinson's medications. They were on average 61 years old and had received the diagnosis an average of two years previously. They were compared with 174 people who did not have Parkinson's disease.

Weight gain or loss was defined as a change of more than 3% of body weight in the first year of the study. Weight maintenance was defined as no change or change of no more than 3%. In total, 98 people lost weight, 59 gained weight, and 201 maintained their weight.

Participants took tests of their thinking skills at the start of the study and every year thereafter for up to eight years. They also conducted tests for other non-motor symptoms that can occur in people with Parkinson's disease, such as depression, anxiety and sleep problems.

People with Parkinson's disease who lost weight had their general thinking scores decline faster than people with Parkinson's disease who maintained their weight. Both groups started the test with an average score of 27. The scores of those who lost weight fell 0.19 points faster per year than those of those who maintained their weight. The thinking skills with the greatest declines were related to verbal fluency, which is a measure of executive function.

In contrast, Parkinson's patients who gained weight had their scores on a processing speed test fall more slowly than those who maintained their weight.

There was no association between weight change and other non-motor symptoms.

Among people who did not have Parkinson's disease, there was no association between weight changes and thinking skills test results.

"These results highlight the potential importance of weight management in the early stages of Parkinson's disease," said Jun. "Further studies are needed to determine whether interventions to prevent weight loss can slow cognitive decline in Parkinson's patients."

The study does not prove that changing weight leads to changes in thinking skills; it just shows an association.

Limitations of the study were that researchers could not examine whether the effect of weight change on thinking skills was the same in underweight or obese people. They also couldn't take into account whether the weight change was intentional or unintentional.

The study was supported by the Hallym University Research Fund.

Source:

American Academy of Neurology

Reference:

Kim, R., et al. (2022) Association between early weight change and cognitive decline in patients with Parkinson's disease. Neurology. doi.org/10.1212/WNL.0000000000201404.

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