Twin study shows genetic and early-life environmental factors involved in the association
TUESDAY, May 3 (HealthDay News) -- Being overweight or obese in midlife may increase the risk of dementia, Alzheimer's disease (AD), and vascular dementia (VaD), according to a study published in the May 3 issue of Neurology.
Weili L. Xu, M.D., Ph.D., from the Karolinska Institutet in Stockholm, Sweden, and colleagues investigated the long-term impact of being overweight (body mass index [BMI], >25 to 30 kg/m²) or obese (BMI, >30kg/m²) in midlife on dementia, AD, and VaD, and the role of genetic and early-life environmental factors in this association. A total of 8,534 twin individuals (aged 65 or older), who were part of the Swedish Twin Registry, with midlife weight and height data, were evaluated to identify dementia cases. Two analyses were performed: a generalized estimating equation (GEE) model using unmatched case-controls for all twins, and conditional logistic regression for dementia-discordant twin pairs in a co-twin matched case-control approach, accounting for lifespan vascular disorders and diabetes.
The investigators found that 350 individuals were diagnosed with dementia, and 114 individuals had questionable dementia. A total of 29.8 percent of participants were overweight and obese at midlife. In adjusted GEE models, midlife overweight or obesity was associated with dementia (odds ratio [OR], 1.71 and 3.88, respectively). The association was attenuated in the conditional logistic regression analysis of 137 dementia-discordant twin pairs. There was a statistically significant difference in the ORs between the two analyses.
"Both overweight and obesity at midlife independently increase the risk of dementia, AD, and VaD. Genetic and early-life environmental factors may contribute to the midlife high adiposity-dementia association," the authors write.
One author disclosed financial ties to the pharmaceutical industry.
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