Background: Because brain oxidative stress is a cause of cognitive impairment, selenium, which is an antioxidant, may protect against cognitive decline. The aim of the study was to examine whether declining selenium levels over time are associated with cognitive decline in a cohort of community-dwelling French elderly.
Methods: During 1991–1993, 1389 subjects (age 60–71 years) were recruited into a 9-year longitudinal study with 6 waves of follow-up. Cognitive functions were evaluated by neuropsychologic tests. To take into account the entire set of cognitive measurements and the within-subject correlations between measures, we analyzed mixed linear and logistic models to study associations between selenium change and cognitive decline.
Results: After controlling for potential confounders, cognitive decline was associated with decreases of plasma selenium over time. Among subjects who had a decrease in their plasma selenium levels, the greater the decrease in plasma selenium, the higher the probability of cognitive decline. Among subjects who had an increase in their plasma selenium levels, cognitive decline was greater in subjects with the smallest selenium increase. There was no association between short-term (2-year) selenium change and cognitive changes.
Conclusion: Selenium status decreases with age and may contribute to declines in neuropsychologic functions among aging people.
From *Inserm E361 Université Montpellier1, Montpellier, France; †NVMC, UFR de Pharmacie, Université J. Fourrier, Grenoble, France; ‡Inserm, U708, Université Paris 6, Paris, France; and §Département de Biologie intégrée, CHU de Grenoble, Grenoble, France.
Submitted 6 December 2005; accepted 31 July 2006.
N. Tasnime Akbaraly was supported by a grant from the French Alzheimer's Disease Association.
The EVA study was carried out under an agreement between Inserm and the Merck, Sharp and Dohme-Chibret Laboratories (West Point, PA) and was supported by EISAI Laboratory (France).
Correspondence: N. Tasnime Akbaraly, Inserm E0361, Hôpital La Colombière, 39 Avenue Charles Flahault, BP 34493, 34093 Montpellier Cedex 5, France. E-mail: firstname.lastname@example.org.