Plasma Carotenoids Are Inversely Associated With Dementia Risk in an Elderly French Cohort.

BACKGROUND

Although intake of fruits and vegetables has been associated with a decreased risk of dementia, studies focusing on nutrients underlying this association are lacking. Our objective was to analyze the relation between plasma carotenoids and the risk of dementia and Alzheimer's disease (AD) in French elderly community dwellers.

METHODS

The study population consisted of 1,092 nondemented older participants, from the Three-City-Bordeaux cohort followed for up to 10 years (range: 1.8-10.8 years, median: 9.5 years). Dementia and AD were diagnosed by a committee of neurologists. The concentration of plasma carotenoids (beta-carotene, alpha-carotene, lycopene, lutein, zeaxanthin, and beta-cryptoxanthin) was determined at baseline. Longitudinal analyses of the association between each plasma carotenoid, either crude or expressed as a ratio to plasma lipids (total cholesterol + triglycerides), and the risk of dementia or AD were performed by multivariate Cox models.

RESULTS

During follow-up, 199 dementia cases, including 132 AD, occurred. After adjustment for sociodemographic data, diet quality, and clinical variables, including baseline cognitive performances, only higher lutein concentration, considered as a function of plasma lipids, was consistently significantly associated with a decreased risk of all-cause dementia and AD (hazard ratio = 0.808, 95% confidence interval = 0.671-0.973, p = .024 and hazard ratio = 0.759, 95% confidence interval = 0.600-0.960, p = .021, respectively for +1 SD).

CONCLUSION

This large cohort of older participants suggests that maintaining higher concentrations of lutein in respect to plasma lipids may moderately decrease the risk of dementia and AD.