Study: Body composition associated with neurodegenerative disease, brain aging

Key takeaways:

• Higher rates of neurodegenerative disease were linked to “central obesity” and “arm-dominant fat distribution.” 
• Body composition improvement and addressing CVD may mitigate neurodegenerative disease risk.

Body composition patterns associated with weight and fat distribution were strongly correlated with neurodegenerative disease and brain aging, mediated by cardiovascular disease, according to research published in Neurology.

“This study highlights the potential to lessen people’s risk of developing these diseases by improving their body composition,” Huan Song, MD, PhD, a professor at the West China Hospital of Sichuan University in Chengdu, China, said in a related release.

Song and colleagues sought to examine examines the associations between seven different kinds of body composition and the risk of neurodegenerative diseases with cardiovascular disease (CVD) as a mediator in a cohort of midlife to older adults compiled by the U.K. Biobank from 2006 to 2010.

Their retrospective analysis included more than 412,000 individuals (mean age, 56 years; 55.1% female) with the necessary body composition measurements at the time of recruitment but without record of neurological disease at time of examination or extreme values in body composition measurement.

All who met inclusion criteria were followed from 5 years after recruitment until April 1, 2023.

The primary outcome for the study was incidence of any neurodegenerative disease, with secondary outcomes of incidence of specific neurodegenerative conditions such as Alzheimer’s disease, Parkinson’s disease, dementia or other vascular disease of that type. All cases were determined by review of inpatient hospital or death records.

The researchers employed multivariable Cox regression models to assess associations between different components and major patterns of body composition with the risk of neurodegenerative disease. They also conducted mediation analysis to determine if CVD contributed to these associations.

Song and colleagues additionally followed a subset of 40,790 participants, utilizing MRI-derived data, to assess relationships between body composition patterns and brain aging biomarkers such as atrophy and cerebral small vessel disease.

According to results, 8,224 new cases of neurodegenerative diseases (primary causes, n = 6,274; vascular causes, n = 1,194) were identified over an average follow-up of 9.1 years, with 2,427 cases of PD, 2,933 cases of AD and 6,076 all-cause dementia cases.

Data showed that lower rates of neurodegenerative disease carried associations with body condition patterns such as “fat-to-lean mass,” “muscle strength,” “bone density,” and “leg-dominant fat distribution” (HR = 0.74–0.94).

Conversely, higher rates of neurodegenerative disease were associated with patterns such as “central obesity” and “arm-dominant fat distribution” (HR = 1.13–1.18).

The researchers additionally reported that roughly 10.7% to 35.3% of the observed associations between body composition and neurodegenerative disease were mediated by CVDs, particularly cerebrovascular issues. Analysis of the study subcohort yielded positive association with brain aging biomarkers and composition patterns “central obesity,” “muscle strength,” and “arm-dominant fat distribution.”

“Our findings highlight the potential for improvement in body composition and early interventions in CVDs as a target in mitigating the future risk of neurodegenerative diseases,” Song said in the release.

Reference:

Does your body composition affect your risk of dementia or Parkinson’s? https://www.aan.com/PressRoom/Home/PressRelease/5189. Published July 24, 2024. Accessed July 25, 2024.