Prediagnostic levels of serum micronutrients in relation to risk of gastric cancer in Shanghai, China.

Data on blood levels of specific carotenoids and vitamins in relation to gastric cancer are scarce. Little is known about the relationship between prediagnostic serum levels of carotenoids other than beta-carotene and risk of gastric cancer especially in non-Western populations. Prediagnostic serum concentrations of alpha-carotene, beta-carotene, beta-cryptoxanthin, lycopene, lutein/zeaxanthin, retinol, alpha-tocopherol, gamma-tocopherol, and vitamin C were determined on 191 cases and 570 matched controls within a cohort of 18,244 middle-aged or older men in Shanghai, China, with a follow-up of 12 years. High serum levels of alpha-carotene, beta-carotene, and lycopene were significantly associated with reduced risk of developing gastric cancer (all Ps for trend </= 0.05); the odds ratios (95% confidence intervals) for the highest versus the lowest quartile of alpha-carotene, beta-carotene, and lycopene were 0.38 (0.13-1.11), 0.54 (0.32-0.89), and 0.55 (0.30-1.00), respectively. Increased serum level of vitamin C was significantly associated with reduced risk of gastric cancer among men who neither smoked cigarettes over lifetime nor consumed >/=3 drinks of alcohol per day; the odds ratios (95% confidence intervals) for the second, third, and fourth quartile categories were 0.69 (0.28-1.70), 0.36 (0.14-0.94), and 0.39 (0.15-0.98), respectively, compared with the lowest quartile of vitamin C (P for trend = 0.02). There were no statistically significant relationships of serum levels of beta-cryptoxanthin, lutein/zeaxanthin, retinol, alpha-tocopherol, and gamma-tocopherol with gastric cancer risk. The present study implicates that dietary carotenes, lycopene, and vitamin C are potential chemopreventive agents for gastric cancer in humans.