Refined carbohydrate-rich diet is associated with long-term risk of dementia and Alzheimer's disease in apolipoprotein E ε4 allele carriers

Introduction: In animal models, refined carbohydrates (RF) worsen Alzheimer's disease (AD). However, the long-term effects of high RF intake on the risk of dementia and AD are poorly described in epidemiological studies. Moreover, the interaction between RF and the apolipoprotein E epsilon 4 allele (APOE-epsilon 4) is unknown. Our study investigated whether RF-rich diets are associated with the risk of dementia and AD. Methods: The glycemic load (GL) was quantified in 2777 elderly participants from the French Three-City Study to estimate RF intake. Then, the associations between GL and risk of dementia and AD, and the interaction with APOE-epsilon 4 over a 12-year period were assessed using proportional hazards models. Results: After adjustment for potential confounders, high afternoon-snack GL was associated with increased dementia and AD risk in APOE-epsilon 4 carriers (hazard ratio = 1.27 [1.03-1.56]). Discussion: This study highlights that RF-rich diets are a risk factor for dementia and AD in APOE-epsilon 4 carriers.