1. ¹INSERM U. 330, Université de Bordeaux 2, Bordeaux Cedex, France
2. ²Laboratoire de Biochimie et de Biologie Moléculaire, Université de Bordeaux 2, 146 rue Léo Saignat, Bordeaux Cedex, France
3. ³Centre de Gériatrie Henri Choussat, Hopital Xavier-Arnozan, CHU de Bordeaux, Pessac, France

Correspondence: C Helmer, INSERM U 330 (Case 11), Université de Bordeaux II, 146 rue Léo Saignat, 33076 Bordeaux Cedex, France. E-mail: catherine.helmer@isped.u-bordeaux2.fr

^†Contributors: CH analysed the data and wrote the first draft of the manuscript. LD and MJT did the biochemical analyses. CH, EP, LL, IB-M, SL, JFD, and PB-G contributed to the data interpretation. JFD, PB-G, LL, and EP were responsible for the study concept and design. JFD, PB-G and IB-M obtained funding. PB-G and LL supervised the study. All authors made a critical revision of the manuscript.

Received 24 September 2002; Revised 20 December 2002; Accepted 5 January 2002.

Abstract

Objective: To analyse the relation between antioxidant vitamins A, E, and malondialdehyde (MDA) lipoperoxidation product plasma concentrations with incident dementia.

Design: A nested case–control within the PAQUID (Personnes Agées QUID) cohort.

Setting: The PAQUID population-based prospective cohort in southwestern France.

Subjects: Among 626 subjects with blood collection at baseline, 46 developed a dementia during the follow-up and were considered to be cases. Each case was matched (on age and sex) to three controls.

Results: Plasma vitamin E concentrations were lower among cases (mean value at 22.62 mol/l (s.d.: 7.38) vs 24.99 (s.d.: 6.73 among controls). The same trend was observed for vitamin A concentrations, but the difference was not significant. On the contrary, MDA concentrations tended to be higher (mean value 1.35 mol/l (s.d.: 0.53) vs 1.23 (s.d.: 0.44)) among cases. In logistic regression models, plasma values were split into tertiles. Adjusted for confounders, the risk of dementia was significantly increased in the lowest vitamin E tertile (21.0 mol/l) (OR=3.12, P=0.033) compared to the highest one (25.5 mol/l). The risk of Alzheimer's disease was also increased, with borderline significance (OR=3.06, P=0.053). Risks associated with vitamin A were nonsignificant. Similarly, there was a trend to an increased risk of dementia in the highest tertile of MDA (OR=1.67, P=0.31).

Conclusions: These results suggest that subjects with low plasma vitamin E concentrations are at a higher risk of developing a dementia in subsequent years.