Glycemic Load and Risk of Alzheimer's Disease

Objective: to explore the relation of glycemic load (GL) with Alzheimer's disease (AD) risk.

Design: Cohort study.

Setting: Cohort of elderly subjects in New York City.

Participants: 939 persons 65 years and older without dementia followed for an average of 6.3 years.

Measurements: Glycemic index, carbohydrate and calorie intake were measured using a semi-quantitative food frequency questionnaire (SFFQ). GL was calculated as the product of carbohydrate intake and glycemic index and adjusted for energy intake. AD was ascertained with standard research criteria.

Results: Cox regression was used to relate GL quartiles to AD using time from SFFQ to AD as the time-to-event variable. There was no association between GL and AD after adjustment for age, gender, education, ethnic group, and presence of diabetes. There was no evidence of modification by age, gender, APOE-e4, and presence of diabetes. The only dietary variable associated with a higher risk of AD was total calories (HR of AD for a one-log unit increase =2.2; 95% CI: 1.4,3.5) after adjustment for age, gender, ethnic group, education, diabetes, and APOE-e4.

Conclusion: GL is not associated with a higher risk of AD in the elderly. Our data does not support the popular practice of low carbohydrate diets for the prevention of AD in the elderly.