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

Objectives: The relationship of body mass index (BMI) changes and variability with amyloid-beta (A beta) 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 A beta positivity, we investigated the association of BMI changes and BMI variability with A beta 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 A beta 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 A beta 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 A beta 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 A beta 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 A beta positivity. Conclusion: Our findings suggest that participants with BMI change, especially those with greater BMI variability, are more vulnerable to A beta deposition regardless of baseline BMI. Furthermore, our results may contribute to the design of strategies to prevent A beta deposition with respect to weight control.