Objective: The hypothesis of carotenoid having a preventive role in diabetes is suggested by their antioxidant properties. In this report, we investigated the relationship between baseline total plasma carotenoid levels and 9-year onset of dysglycemia (impaired fasting glucose or type 2 diabetes) in a healthy elderly population.
Research design and methods: The Epidemiology of Vascular Ageing Study is a 9-year longitudinal study including 1,389 volunteers aged 59-71 years. Fasting plasma glucose was measured at baseline and at 2, 4, and 9 years after inclusion. The relationship between plasma carotenoid at baseline and incidence of dysglycemia was determined by Cox proportional hazards regression analysis adjusting for potential confounders.
Results: At 9 years, 127 incident cases of dysglycemia had occurred. Risk of dysglycemia was significantly lower in participants with plasma carotenoid in the highest quartile (Q4) compared with participants in the lowest quartile (Q1) (Q4 vs. Q1: relative risk 0.26 [95% CI 0.14-0.49], P < 10(-4); Q3 vs. Q1: 0.55 [0.34-0.89], P = 0.01; and Q2 vs. Q1: 0.82 [0.51-1.31], P = 0.40). After controlling for sociodemographic variables, lifestyle habits, cardiovascular disease, blood pressure, BMI, and lipid profile, risk of dysglycemia remained significantly lower in participants in the highest quartile of total plasma carotenoid compared with participants in the lowest quartile (Q4 vs. Q1: 0.42 [0.22-0.82], P = 0.01; Q3 vs. Q1: 0.69 [0.41-1.15], P = 0.16; and Q2 vs. Q1: 0.80 [0.48-1.32], P = 0.38).
Conclusions: This study prospectively confirms that plasma carotenoid levels have an independent relationship to onset of dysglycemia.