Researchers from the University of California report that individuals with a higher proportion of muscle mass may have a lower chance of developing Alzheimer’s disease. The findings appear in BMJ Medicine.
Earlier work has linked low muscle mass with a greater risk of Alzheimer’s, but it wasn’t clear whether muscle loss drives the disease or results from it.
In the new study, investigators examined data from 450,000 medical records in the British Biobank. They used bioimpedance analysis to assess muscle and fat tissue in the arms and legs. This technique measures how electrical current travels through fat and muscle, helping to estimate body composition because fat and lean tissue conduct electricity at different speeds.
The body measurements were adjusted for age, sex, and 584 genetic variants known to influence muscle mass. Taken together, these genetic variants explained about 10% of the observed differences in lean muscle mass among participants. The researchers employed Mendelian randomization to minimize the impact of lifestyle factors such as diet and physical activity, since genetic variants are not affected by these choices and can help reveal potential causal relationships.
On average, individuals with greater genetically determined muscle mass showed a small but statistically meaningful reduction in the risk of Alzheimer’s disease. Higher lean mass also correlated with better performance on cognitive tasks in other assessments. The study suggests there may be a causal link between higher muscle mass and lower Alzheimer’s risk, independent of other factors.
Additionally, the analysis found no evidence that fat mass influences Alzheimer’s risk. The authors caution that these results are not ready for clinical use and more research is needed before applying them in medical practice.
Obesity has previously been linked to a higher risk of Alzheimer’s disease. This connection is thought to involve increased beta-amyloid protein, which can drive obesity-related inflammation and insulin resistance, potentially contributing to Alzheimer’s pathology in fat tissue.
While muscle health appears promising as a potential modifier of dementia risk, the study emphasizes that maintaining overall health through balanced nutrition and regular activity remains important. The authors encourage further work to confirm these findings in diverse populations and to explore practical strategies for preserving muscle mass across age groups, with the aim of reducing dementia risk in broader communities.
Overall, the research adds to the growing interest in how body composition relates to brain health. It underscores the need for ongoing investigations that can translate genetic insights into clear, evidence-based guidance for prevention and care.