BackgroundUnderweight, defined as a body mass index (BMI) 2), normal weight (18.5-24.9 kg/m2), or overweight (≥25.0 kg/m2). The outcomes were all-cause dementia and Alzheimer's disease (AD) dementia.ResultsA total of 607 patients (median age, 74 years) were included: 58 underweight, 389 normal weight, and 160 overweight. During a median follow-up of 4.7 years, 39 patients developed dementia and 30 developed AD dementia. Kaplan-Meier analysis showed that underweight group had a significantly higher incidence of all-cause dementia (p = 0.002) and AD dementia (p = 0.009) compared with the other groups. Cox regression hazard analysis adjusted for age and sex revealed that underweight had a higher risk of all-cause dementia (hazard ratio, 3.38; 95% confidence interval, 1.49-7.67) compared with normal weight. In exploratory analysis, the association between underweight and all-cause dementia remained significant after adjustment for additional confounders, medial temporal atrophy, and white matter hyperintensities.ConclusionsUnderweight in older adults was associated with increased risk of all-cause dementia independent of age, sex, confounding factors, brain atrophy and white matter hyperintensities. These findings warrant confirmation in larger cohorts.Clinical Trial RegistrationUMIN000026671.
Kitagawa et al. (Thu,) studied this question.