Association between body weight change in late life and risk of dementia: A population‐based cohort study

Abstract

AbstractBackgroundAdiposity 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 incidence of dementia.MethodWithin 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.ResultDuring the follow‐up (median 5.78 years), 102 incident dementia cases were identified. 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]). BMI and weight loss/gain were dose‐dependently related to dementia risk. These associations became stronger among participants carrying an ApoE ɛ4 allele or with diabetes. No significant associations between moderate BMI and weight loss/gain and dementia were detected.ConclusionBoth large bodyweight loss and gain are associated with almost 3‐fold higher risk of dementia. ApoE ɛ4 and diabetes appear to play a role in this association.