Background: Experimental models and observational studies suggest that vitami n E supplementation may prevent cardiovascular disease and cancer. However, seve ral trials of high dosage vitamin E supplementation show...Background: Experimental models and observational studies suggest that vitami n E supplementation may prevent cardiovascular disease and cancer. However, seve ral trials of high dosage vitamin E supplementation showed non statistically significant increases in total mortality. Purpose: To perform a meta analysis of the dose response relationship between vitamin E supplementation and total mortality by using data from randomized, controlled trials. Patients: 135 967 p articipants in 19 clinical trials. Of these trials, 9 tested vitamin E alone and 10 tested vitamin E combined with other vitamins or minerals. The dosages of vi tamin E ranged from 16.5 to 2000 IU/d (median, 400 IU/d). Data Sources:PubMed se arch from 1966 through August 2004, complemented by a search of the Cochrane Cli nical Trials Data base and review of citations of published reviews and meta analyses. No language restrictions were applied. Data Extraction: 3 investigato rs independently abstracted study reports. The investigators of the original pub lications were contacted if required information was not available. Data Synthes is: 9 of 11 trials testing high dosage vitamin E (≥ 400 IU/d) showed increased risk (risk difference >0) for all cause mortality in comparisons of vitamin E versus control. The pooled all cause mortality risk difference in high dosag e vitamin E trials was 39 per 10 000 persons (95% CI, 3 to 74 per 10 000 perso ns; P = 0.035). For low dosage vitamin E trials, the risk difference was 16 per 10 000 persons (CI, - 41 to 10 per 10 000 persons; P >0.2). A dose respo nse analysis showed a statistically significant relationship between vitamin E d osage and all cause mortality, with increased risk of dosages greater than 150 IU/d. Limitations: High dosage (≥ 400 IU/d) trials were often small and were performed in patients with chronic diseases. The generalizability of the findin gs to healthy adults is uncertain. Precise estimation of the threshold at which risk increases is difficult. Conclusion: High dosage (≥ 400 IU/d) vitamin E s upplements may increase all cause mortality and should be avoided.展开更多
文摘Background: Experimental models and observational studies suggest that vitami n E supplementation may prevent cardiovascular disease and cancer. However, seve ral trials of high dosage vitamin E supplementation showed non statistically significant increases in total mortality. Purpose: To perform a meta analysis of the dose response relationship between vitamin E supplementation and total mortality by using data from randomized, controlled trials. Patients: 135 967 p articipants in 19 clinical trials. Of these trials, 9 tested vitamin E alone and 10 tested vitamin E combined with other vitamins or minerals. The dosages of vi tamin E ranged from 16.5 to 2000 IU/d (median, 400 IU/d). Data Sources:PubMed se arch from 1966 through August 2004, complemented by a search of the Cochrane Cli nical Trials Data base and review of citations of published reviews and meta analyses. No language restrictions were applied. Data Extraction: 3 investigato rs independently abstracted study reports. The investigators of the original pub lications were contacted if required information was not available. Data Synthes is: 9 of 11 trials testing high dosage vitamin E (≥ 400 IU/d) showed increased risk (risk difference >0) for all cause mortality in comparisons of vitamin E versus control. The pooled all cause mortality risk difference in high dosag e vitamin E trials was 39 per 10 000 persons (95% CI, 3 to 74 per 10 000 perso ns; P = 0.035). For low dosage vitamin E trials, the risk difference was 16 per 10 000 persons (CI, - 41 to 10 per 10 000 persons; P >0.2). A dose respo nse analysis showed a statistically significant relationship between vitamin E d osage and all cause mortality, with increased risk of dosages greater than 150 IU/d. Limitations: High dosage (≥ 400 IU/d) trials were often small and were performed in patients with chronic diseases. The generalizability of the findin gs to healthy adults is uncertain. Precise estimation of the threshold at which risk increases is difficult. Conclusion: High dosage (≥ 400 IU/d) vitamin E s upplements may increase all cause mortality and should be avoided.
