Abstract
Objective. To examine the relation between the plasma concentration of antioxidant micronutrients and endometrial cancer risk in Korean women. Design. Hospital-based case–control study. Setting. Seven tertiary medical institutes in Korea. Population. Incidence of 28 endometrial cancer cases were identified and 140 age-matched controls selected for the same period.Methods. Preoperative plasma concentrations of β-carotene, lycopene, zeaxanthin plus lutein, retinol, α-tocopherol, and γ-tocopherol were measured by reverse-phase, gradient high-pressure liquid chromatography. Conditional logistic regression was used to evaluate micronutrient effect after adjustment for body mass index (BMI), menopause, parity, oral contraceptive use, smoking status, and alcohol consumption status.Main outcome measures. Effect of micronutrients on endometrial cancer risk.Results. The mean concentration of plasma β-carotene (p=0.001), lycopene (p=0.008), zeaxanthin plus lutein (p=0.031), retinol (p=0.048), and γ-tocopherol (p=0.046) were significantly lower in endometrial cancer patients than in controls. Plasma levels of β-carotene (p for trend=0.0007) and lycopene (p for trend=0.007) were inversely associated with endometrial cancer risk across tertiles. Women in the highest tertile of plasma β-carotene and lycopene had a 0.12-fold (95% confidence intervals (CIs) 0.03–0.48) and 0.15-fold (95% CIs 0.04–0.61) decreased risk of endometrial cancer compared to women in the lowest tertile, respectively. Other micronutrients such as zeaxanthin plus lutein (p for trend=0.142), retinol (p for trend=0.108), α-tocopherol (p for trend=0.322), and γ-tocopherol (p for trend=0.087) showed no association with endometrial cancer risk.Conclusions. Plasma levels of β-carotene and lycopene are inversely associated with the risk of endometrial cancer in Korean women.