Association of carotenoids with risk of gastric cancer: A meta-analysis

Background & aims: Prior studies on carotenoids and gastric cancer risk have generated inconsistent results. We performed a meta-analysis of observational studies to summarize the evidence regarding the relation of carotenoids and gastric cancer risk. Methods: A comprehensive search was performed to identify all observational studies providing quantitative estimates between gastric cancer risk and carotenoids. The fixed or random effect model was selected based on the homogeneity test among studies in the highest vs. lowest categorical analyses. Results: 13 published case control studies with 14 results including 3919 cases and 7400 controls, and 8 cohort studies involving 1972 cases of gastric cancer and 96,691 participants, met the inclusion criteria. For case control studies, only intake of beta-carotene and alpha-carotene were significantly associated with a reduced gastric cancer risk. The summary OR(95%CI) for beta-carotene, alpha-carotene, lycopene and lutein were 0.52(0.46-0.59), 0.59(0.37-0.92), 0.88(0.55-1.41) and 0.85(0.56-1.30) respectively. In contrast, the summary RR(95%CI) for beta-carotene, alpha-carotene, lycopene and lutein were 0.72(0.50-1.03), 0.79(0.58-1.07), 0.80(0.60-1.07) and 0.95(0.77-1.18), respectively. Conclusion: Although data from case control studies suggested that beta-carotene, alpha-carotene were inversely associated with risk of gastric cancer, there was no conclusive evidence on this association because of inconsistencies between case control and cohort studies. (C) 2015 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.