Aimin Wang1, Jing Han2, Yunxia Jiang2, Dongfeng Zhang3. 1. School of Nursing, the Medical College of Qingdao University, Qingdao, People's Republic of China. Electronic address: wangaiminqy@126.com. 2. School of Nursing, the Medical College of Qingdao University, Qingdao, People's Republic of China. 3. Department of Epidemiology and Health Statistics, the Medical College of Qingdao University, Qingdao, People's Republic of China.
Abstract
OBJECTIVE: Whether vitamin A and β-carotene as nutrients are protective factors against cataracts remains unclear. Thus, the aim of this study was to summarize the evidence from epidemiologic studies of vitamin A and β-carotene with the risk for cataract. METHODS: Pertinent studies were identified by a search of PubMed, Web of Science, Google Scholar, and Wan Fang Med Online. A fixed- or random-effects model was used based on heterogeneity test. Meta-regression and "leave-one-out" analysis were used to explore potential sources of between-study heterogeneity. Publication bias was estimated using Egger's regression asymmetry test. RESULTS: Twenty-two articles were included in this meta-analysis. The relative risk (RR; 95% confidence interval [CI]) for cataract for the highest versus lowest category of serum β-carotene levels was 0.827 (95% CI, 0.736-0.930), and the association was significant between β-carotene intake and cataract risk (RR, 0.937; 95% CI, 0.880-0.997). Significant association of cataract risk with vitamin A intake was found overall (RR, 0.831; 95% CI, 0.757-0.913). However, no significant association was found between serum vitamin A and cataract risk (RR, 0.925; 95% CI, 0.675-1.266; I(2) = 63.1%), but an inverse association was observed with risk for cataract with serum vitamin A after sensitivity analysis (RR, 0.765; 95% CI, 0.654-0.894; I(2) = 29.1%). CONCLUSIONS: Greater vitamin A and β-carotene intakes might be inversely associated with risk for cataract.
OBJECTIVE: Whether vitamin A and β-carotene as nutrients are protective factors against cataracts remains unclear. Thus, the aim of this study was to summarize the evidence from epidemiologic studies of vitamin A and β-carotene with the risk for cataract. METHODS: Pertinent studies were identified by a search of PubMed, Web of Science, Google Scholar, and Wan Fang Med Online. A fixed- or random-effects model was used based on heterogeneity test. Meta-regression and "leave-one-out" analysis were used to explore potential sources of between-study heterogeneity. Publication bias was estimated using Egger's regression asymmetry test. RESULTS: Twenty-two articles were included in this meta-analysis. The relative risk (RR; 95% confidence interval [CI]) for cataract for the highest versus lowest category of serum β-carotene levels was 0.827 (95% CI, 0.736-0.930), and the association was significant between β-carotene intake and cataract risk (RR, 0.937; 95% CI, 0.880-0.997). Significant association of cataract risk with vitamin A intake was found overall (RR, 0.831; 95% CI, 0.757-0.913). However, no significant association was found between serum vitamin A and cataract risk (RR, 0.925; 95% CI, 0.675-1.266; I(2) = 63.1%), but an inverse association was observed with risk for cataract with serum vitamin A after sensitivity analysis (RR, 0.765; 95% CI, 0.654-0.894; I(2) = 29.1%). CONCLUSIONS: Greater vitamin A and β-carotene intakes might be inversely associated with risk for cataract.