Positive Health Online

Abstract

JIANG and COLLEAGUES, 1 School of Public Health, Xi'an Jiaotong University Health Science Center, Xi'an, China; 2 The First Affiliated Hospital, Xi'an Jiaotong University College of Medicine, Xi'an, China; 3 Center for Population Health Research, Division of Health Sciences, University of South Australia, Adelaide, South Australia, Australia; 4 Key Laboratory of Environment and Genes Related to Diseases (Xi'an Jiaotong University), Ministry of Education of China, Xi'an, China set out to conduct a meta-analysis of randomized controlled trials (RCTs) and cohort studies of dietary vitamin and carotenoid intake and age-related cataract (ARC) risk.

Background

Existing studies suggest that dietary vitamins and carotenoids might be associated with a reduced risk of age-related cataract (ARC), although a quantitative summary of these associations is lacking.

Methodology

The MEDLINE, EMBASE, ISI Web of Science, and Cochrane Library databases were searched from inception to June 2018. The adjusted RRs and corresponding 95% CIs for the associations of interest in each study were extracted to calculate pooled estimates. Dose-response relations were assessed with the use of generalized least-squares trend estimation.

Results

We included 8 RCTs and 12 cohort studies in the meta-analysis. Most vitamins and carotenoids were significantly associated with reduced risk of ARC in the cohort studies, including vitamin A (RR: 0.81; 95% CI: 0.71, 0.92; P = 0.001), vitamin C (RR: 0.80; 95% CI: 0.72, 0.88; P < 0.001), vitamin E (RR: 0.90; 95% CI: 0.80, 1.00; P = 0.049), β-carotene (RR: 0.90; 95% CI: 0.83, 0.99; P = 0.023), and lutein or zeaxanthin (RR: 0.81; 95% CI: 0.75, 0.89; P < 0.001). In RCTs, vitamin E (RR: 0.97; 95% CI: 0.91, 1.03; P = 0.262) or β-carotene (RR: 0.99; 95% CI: 0.92, 1.07; P = 0.820) intervention did not reduce the risk of ARC significantly compared with the placebo group. Further dose-response analysis indicated that in cohort studies the risk of ARC significantly decreased by 26% for every 10-mg/d increase in lutein or zeaxanthin intake (RR: 0.74; 95% CI: 0.67, 0.80; P < 0.001), by 18% for each 500-mg/d increase in vitamin C intake (RR: 0.82; 95% CI: 0.74, 0.91; P < 0.001), by 8% for each 5-mg/d increase in β-carotene intake (RR: 0.92; 95% CI: 0.88, 0.96; P < 0.001), and by 6% for every 5 mg/d increase in vitamin A intake (RR: 0.94; 95% CI: 0.90, 0.98; P < 0.001).

Conclusion

Higher consumption of certain vitamins and carotenoids was associated with a significant decreased risk of ARC in cohort studies, but evidence from RCTs is less clear.

References

Hong Jiang  1 , Yue Yin  1 , Chang-Rui Wu  2 , Yan Liu  1 , Fang Guo  1 , Ming Li  3 , Le Ma  1   4. Dietary vitamin and carotenoid intake and risk of age-related cataract. Am J Clin Nutr. 109(1):43-54. doi: 10.1093/ajcn/nqy270. Jan 1 2019.

Comment

The above research demonstrated that higher consumption of certain vitamins and carotenoids – vitamin A, vitamin C, vitamin E, β-carotene, lutein or zeaxanthin – was associated with a significantly decreased with of age-related cataract (ARC),