Dementia

Dementia Risk Linked to High Body Mass Index

A high midlife body mass index (BMI) was associated with an increased risk for dementia later in life, according to a recent study. However, the researchers also noted that weight loss due to metabolic changes during pre-clinical dementia may mask this correlation.

The researchers used data from 39 cohort studies, which included a total of 1,349,857 participants who were dementia-free at baseline, for their study. Participants’ BMI was assessed at baseline and dementia was determined using linkage to electronic health records.
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When BMI was assessed at 10, 10 to 20, and >20 years prior to dementia diagnosis, the hazard ratios (HRs) per 5-kg/m2 increase in BMI for dementia were 0.71 (95% CI= 0.66-0.77), 0.94 (0.89-0.99), and 1.16 (10.5-1.27), respectively.

“The findings of this study are consistent with the hypothesis that the BMI-dementia association is attributable to two processes: a direct (causal) effect and reverse causation as a result of weight loss during the preclinical dementia phase,” the researchers concluded.

—Melissa Weiss

Reference:

Kivimäki M, Luukkonen R, Batty GD, et al. Body mass index and risk of dementia: analysis of individual-level data from 1.3 million individuals [published online November 20, 2017]. Alzheimer's & Dementia. http://dx.doi.org/10.1016/j.jalz.2017.09.016.