The Effect of Diabetes and Hypertension on Cognition: Mechanisms that Impair & Protect

Authors: Turk K*

Volume 2, Issue 1

Abstract

Comorbid hypertension and diabetes adversely impact memory, increase cognitive decline, and increase risk of developing dementia of the Alzheimer’s type. Given population aging and rising obesity rates, both conditions are expected to increase in the near future. The cognitive reserve hypothesis suggests that education may buffer negative effects of hypertension or diabetes on cognition. In line with this hypothesis, the goal of this study was to determine whether educational attainment moderates the effect of diabetes and hypertension on cognition, using the 2008 wave of the Health and Retirement Study (n=10,258 adults aged 65 and above). Further, this study seeks to elucidate the deleterious mechanisms on the brain caused by hypertension and diabetes. The mean age of the sample was 74.6 years; 58% were female, and average education was 12.26 years. Hierarchical ordinary least squares multiple regression techniques were used. Results show diabetics who take oral medications (especially in combination with insulin) score lower on cognition than non-diabetics. The analyses controlled for age, sex, race, self-rated health, ADLs, smoking status, alcohol use, income, and exercise. The study found that education (measured in years but not in degree categories) moderates the effect of diabetes on cognition for diabetics using both oral medications and insulin (t=2.13, p>.038). Thus, it lends very limited if any support to the cognitive reserve hypothesis. It also raises concerns about potential cognitive side effects diabetes medications.

Keywords: Alzheimer’s disease; Blood pressure; Hypertension; Diabetes

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