Association Between Body Weight Change In Late Life And Risk Of Dementia: A Population-based Cohort Study

Background. Adiposity in midlife is a modifiable risk factor for dementia. However, the effect of adiposity in late-life on dementia remains unclear. We investigated the association of body mass index (BMI) and weight changes after age 60 with the incident dementia. Methods. Within the Swedish National Study on Aging and Care-Kungsholmen, 1,673 dementia-free participants with data on BMI/weight both at baseline and the 6-year follow-up were followed to detect subsequent incident dementia cases. BMI change was assessed as the percentage of the difference between BMI at baseline and the initial 6-year follow-up and categorized into large (>10%) or moderate (5–10%) loss, stable (≤5%), and moderate (5–10%) or large (>10%) gain. Weight change (difference between weight at baseline and the 6-year follow-up) was categorized into large (>7.5 kg) or moderate (2.5–7.5 kg) loss, stable (≤2.5 kg), and moderate (2.5–7.5 kg) or large (> 7.5 kg) gain. Dementia was diagnosed following the DSM-IV criteria. Data were analyzed using Cox regression models. Results. During the follow-up (median 5.78 years), 102 incident dementia cases developed. BMI/weight change showed U-shaped associations with dementia. Compared with stable BMI, the hazard ratios (95% confidence intervals) of dementia were 2.93 (1.72−4.91) for large BMI loss and 2.61 (1.09−5.54) for large BMI gain. Similar results were observed for a large weight loss (2.92 [1.67−5.07]) or gain (2.95 [1.16−6.53]). These associations became stronger among participants carrying an ApoE ɛ4 allele. Conclusion. Both large bodyweight loss and gain are associated with a higher risk of dementia, especially among ApoE ɛ4 carriers.