Plasma tocopherols and risk of cognitive impairment in an elderly Italian cohort

• Published in: The American journal of clinical nutrition 2008-05, Vol.87 (5), p.1306-1313
• Main Authors: Ravaglia, Giovanni, Forti, Paola, Lucicesare, Anna, Pisacane, Nicoletta, Rietti, Elisa, Mangialasche, Francesca, Cecchetti, Roberta, Patterson, Christopher, Mecocci, Patrizia
• Format: Article
• Language: English
• Subjects: 5-nitro-gamma-tocopherol; Aged; Aged, 80 and over; alpha-tocopherylquinone; Antioxidants - metabolism; Biological and medical sciences; biomarkers; blood plasma; Chemical compounds; Cholesterol - blood; cognition; Cognition Disorders - blood; Cognition Disorders - complications; Cognition Disorders - epidemiology; Cohort Studies; Confidence Intervals; dementia; Dementia - blood; Dementia - epidemiology; Dementia - etiology; Disease Progression; elderly; elderly nutrition; Feeding. Feeding behavior; Female; Fundamental and applied biological sciences. Psychology; Humans; Incidence; Italy - epidemiology; Learning disabilities; Male; metabolites; Multivariate Analysis; Nutrition; Odds Ratio; Older people; oxidation; Plasma; Prevalence; risk assessment; Risk Factors; tocopherols; Tocopherols - blood; Vertebrates: anatomy and physiology, studies on body, several organs or systems; Vitamin E; Vitamin E - analogs & derivatives; Vitamin E - blood
• ISSN: 0002-9165; 1938-3207
• DOI: 10.1093/ajcn/87.5.1306

BACKGROUND: Evidence that vitamin E may preserve cognitive function in elderly subjects is conflicting. The most abundant and most investigated form of vitamin E in humans is α-tocopherol, but other antioxidant tocopherols (β, γ, and δ) exist in nature. OBJECTIVE: We aimed to investigate plasma concentrations of the natural tocopherols and the tocopherol oxidation markers α-tocopherylquinone (αTQ) and 5-nitro-γ-tocopherol (5NGT) in relation to cognitive function in the elderly. DESIGN: Baseline plasma tocopherols and their oxidation markers were measured in 761 elderly Italian subjects from a population-based cohort assessed in 1999-2000 for mild cognitive impairment (MCI) and dementia. In 2003-2004, information about cognitive status was collected for 615 of the 666 subjects without baseline cognitive impairment. Tocopherols and oxidation markers were analyzed as plasma absolute values divided by serum total cholesterol because lipids affect their blood availability. Analyses were adjusted for sociodemographic, genetic, lifestyle, and medical confounders. RESULTS: Compared with the corresponding lowest tertile, the risk of prevalent dementia was higher for the highest tertile of δ-tocopherol[divide sign]cholesterol [odds ratio (OR): 3.87; 95% CI: 1.46, 10.27] and αTQ[divide sign]cholesterol (4.02; 1.45, 11.14), but the risk of incident dementia was not directly associated with plasma vitamin E metabolites. A U-shaped association, with lower risk for intermediate tertiles, was found for prevalent MCI with 5NGT[divide sign]cholesterol (0.39; 0.17, 0.91) and for incident dementia with γ-tocopherol[divide sign]cholesterol (hazard ratio: 0.42; 95% CI: 0.22, 0.84). CONCLUSIONS: Plasma concentrations of some non-α-tocopherol forms of vitamin E are associated with cognitive impairment in elderly people. However, the associations depend on concurrent cholesterol concentration and need further investigation.