A recent study published in the Journal of Alzheimer’s disease states that low body mass index (BMI) in clinically normal older adults may be linked with greater cortical amyloid burden in them.

The current study involved clinically normal older adults (N=280; age: 62–90 years). The participants were physically examined and their medical history was obtained. They underwent assessments, including Pittsburgh compound B (PiB) positron emission tomography (PET) amyloid imaging, and apolipoprotein E ɛ4 (APOE4) genotyping. In the primary analysis, the association between BMI and PiB retention was obtained using a general linear model. In the secondary analysis, association of PiB with BMI subdivisions (normal, overweight, obese), APOE4 carriers, and BMI×APOE4 interaction were evaluated.

The results demonstrated that greater PiB retention was associated with lower BMI (p=0.02). Besides, greater PiB retention was also associated with APOE4 carrier status (p = 0.02) and normal BMI (p = 0.01), as opposed to overweight or obese BMI. The BMI×APOE4 interaction was also found to be significant (p = 0.04).

In conclusion, lower BMI in clinically normal older adults may be associated with greater cortical amyloid burden. Thus, the findings suggest that BMI may play a role at the preclinical stage of Alzheimer’s disease. However, further research is required to prove this association.