Associations of Serum Carotenoids With Risk of Cardiovascular Mortality Among Individuals With Type 2 Diabetes: Results From NHANES

<a><b>Objective:</b> Although carotenoids have been suggested to exhibit antioxidant properties, some experiment studies reported that β-carotene may show prooxidant effects under certain conditions. Current evidence regarding the cardiovascular effects of carotenoids among patients with type 2 diabetes (T2D) is scarce. This study aimed to prospectively examine the associations of individual serum carotenoid concentrations with cardiovascular mortality among adults with T2D.</a> <p><b>Methods: </b><a>This analysis included 3107 individuals with T2D from the Third </a><a>National Health and Nutrition Examination Survey</a> (NHANES III) and NHANES 2001–2006. <a>Cardiovascular mortality was ascertained by linkage to National Death Index records through 31 December 2015.</a> Cox proportional hazards regression models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs).</p> <p><b>Result:</b> <a>During an average of 14 years of follow-up, 441 cardiovascular deaths occurred.</a> After multivariate adjustment including lifestyles, dietary factors, <a>glucose control, </a>and other major carotenoids, higher serum β-carotene concentrations were significantly associated with an elevated risk of cardiovascular mortality <a>in a dose-response manner</a>. Comparing extreme quartiles of β-carotene, the multivariable-adjusted HR (95% CI) was 2.47 (1.62, 3.76) for cardiovascular mortality (<i>P </i>_trend=0.002); and per one-unit increment in natural log-transformed serum<a> β-carotene </a>was associated with a 46% higher risk of cardiovascular mortality (<i>P</i>=0.001). Other individual carotenoids (α-carotene, β-cryptoxanthin, lycopene, and lutein/zeaxanthin) were not significantly associated with risk of cardiovascular mortality. Consistent results were observed when stratifying by age, sex, race, body mass index, smoking status, diabetes duration, and HbA_1c levels.</p> <p><b>Conclusion:</b> <a>Higher concentrations of serum</a><a> </a><a>β-carotene</a>, but not other individual carotenoids, were significantly associated with an increased risk of cardiovascular mortality among individuals with T2D. <a></a><a></a><a>Our findings, if replicated, underscore the need to estimate the optimal serum β-carotene concentrations in individuals with T2D.</a></p>