ABSTRACT
BACKGROUNDS: The efficacy of vitamin E in prevention of diabetes-related complications differs by Haptoglobin (Hp) genotype. OBJECTIVE: To examine the role of Hp genotype in the relationship of vitamin E intake with brain volume in cognitively normal elderly patients with type 2 diabetes. METHODS: Brain volumes for the superior, middle, and inferior frontal gyri and for the middle temporal gyrus were generated from structural T1 MRI in 181 study participants (Hp 1-1: nâ=â24, Hp 2-1: nâ=â77, Hp 2-2: nâ=â80). Daily vitamin E intake was assessed using the Food Frequency Questionnaire. Analyses of covariance, controlling for demographic and cardiovascular variables was used to evaluate whether the association of daily vitamin E intake with brain volume was modified by Hp genotype. RESULTS: Average age was 70.8 (SDâ=â4.2) with 40% females, and mean Mini-Mental State Examination score of 28.17 (SDâ=â1.90). A significant interaction was found between vitamin E intake and Hp genotype in inferior frontal gyrus' volume; pâ=â0.0108. For every 1 microgram increase in vitamin E intake, the volume of the inferior frontal gyrus decreased by 0.955% for Hp 1-1 (pâ=â0.0348), increased by 0.429% for Hp 2-1 (pâ=â0.0457), and by 0.077% for Hp 2-2 (pâ=â0.6318). There were no significant interactions between vitamin E intake and Hp genotype for the middle (pâ=â0.6011) and superior (pâ=â0.2025) frontal gyri or for the middle temporal gyrus (pâ=â0.503). CONCLUSIONS: The effect of dietary vitamin E on the brain may differ by Hp genotype. Studies examining the impact of vitamin E on brain-related outcomes should consider Hp genotype.