Independent effect of body mass index variation on amyloid-β positivity

Abstract

Objectives: The relationship of body mass index (BMI) changes and variability with amyloid-β (Aβ) deposition remained unclear, although there were growing evidence that BMI is associated with the risk of developing cognitive impairment or AD dementia. To determine whether BMI changes and BMI variability affected Aβ positivity, we investigated the association of BMI changes and BMI variability with Aβ positivity, as assessed by PET in a non-demented population.

Methods: We retrospectively recruited 1,035 non-demented participants ≥50 years of age who underwent Aβ PET and had at least three BMI measurements in the memory clinic at Samsung Medical Center. To investigate the association between BMI change and variability with Aβ deposition, we performed multivariable logistic regression. Further distinctive underlying features of BMI subgroups were examined by employing a cluster analysis model.

Results: Decreased (odds ratio [OR] = 1.68, 95% confidence interval [CI] 1.16-2.42) or increased BMI (OR = 1.60, 95% CI 1.11-2.32) was associated with a greater risk of Aβ positivity after controlling for age, sex, APOE e4 genotype, years of education, hypertension, diabetes, baseline BMI, and BMI variability. A greater BMI variability (OR = 1.73, 95% CI 1.07-2.80) was associated with a greater risk of Aβ positivity after controlling for age, sex, APOE e4 genotype, years of education, hypertension, diabetes, baseline BMI, and BMI change. We also identified BMI subgroups showing a greater risk of Aβ positivity.

Conclusion: Our findings suggest that participants with BMI change, especially those with greater BMI variability, are more vulnerable to Aβ deposition regardless of baseline BMI. Furthermore, our results may contribute to the design of strategies to prevent Aβ deposition with respect to weight control.

Keywords: Alzheimer’s disease; BMI change; BMI variability; amyloid-β (Aβ); body mass index (BMI).

FIGURE 1

Body mass index (BMI) patterns of representative participants in each group. Group 1 had a constant pattern of both BMI change and variability. Group 2 showed a constant BMI change and some variability. Group 3 was a cluster with increasing BMI changes and high variability. Group 4 was a cluster with a decreasing BMI changes and high variability. The graphs on the right are spaghetti plots representing the BMI pattern of all patients in each group, and a blue line representing the trend of the group. BMI, body mass index.