Naeini 2014.
Methods | 2‐arm, parallel group, randomised, controlled trial, 1 year duration | |
Participants |
Location: Iran. Single centre. Setting of recruitment and treatment: Tehran University, School of Nutritional Sciences and Dietetics. Sample size:
Participant (baseline) characteristics:
Inclusion criteria:
Exclusion criteria:
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Interventions |
Active intervention: 300 mg of vitamin E (Dl‐alpha‐ tocopherol acetate) plus 400 mg vitamin C (ascorbic acid) daily for a year. Comparator: Placebo. |
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Outcomes |
Outcomes of interest in the review: Overall cognitive function: MMSE. |
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Source of Funding | This study was supported by Institute of Nutritional Sciences, University of Vienna and the Vice‐chancellor for Research, Tehran University of Medical Sciences (TUMS), Iran, by a Grant (No. 11126). | |
Declaration of Interest | "The authors declare that there are no conflicts of interest". | |
Notes | ||
Risk of bias | ||
Bias | Authors' judgement | Support for judgement |
Random sequence generation (selection bias) | Unclear risk | Quote: "The MCI subjects were divided to two groups according to their gender (male or female), each of them were further divided to three age groups including 60‐65, 65‐70, and 70‐75 years. The subjects within each of these six groups were then further divided to two equally numbered supplemented or placebo subgroups by simple randomization". Comment: Insufficient information about sequence generation process. |
Allocation concealment (selection bias) | Unclear risk | Comment: No information – allocation concealment not described. |
Blinding of participants and personnel (performance bias) All outcomes | Unclear risk | Described as "double‐blind". Quote: “One group consumed 300 mg of vitamin E (Dl‐alpha‐ tocopherol acetate) plus 400 mg vitamin C (ascorbic acid) per day, and the second group consumed placebo with the identical condition over the 1‐year intervention period". Comment: Unclear from this whether appearance of supplements and placebo were identical. |
Blinding of outcome assessment (detection bias) All outcomes | Low risk | Quote: "Evaluation of cognitive function by MMMSE was blindly performed by an expert psychologist." Comment: Blinded outcome assessor. |
Incomplete outcome data (attrition bias) All outcomes | Unclear risk | Quote: “Of the 761 volunteers, 296 were found to have MCI and selected for the next part of the study. From these, 40 did not continue with the study due to the problems tolerating the supplementations (14 subjects), 1 subject died, and 25 subjects abstained to continue participation due to personal reasons. 148 were randomised to each group and 256 subjects completed the study.” 21/148 in the vitamins group and 19/148 in the placebo group did not complete. Comment: The participants who did not complete the trial (40/296, 13.5%) were not included in the analysis. Reason for exclusion was not described based on the allocated group. |
Selective reporting (reporting bias) | Low risk | Comment: Outcomes specified in the methods section were reported. No access to trial protocol. |
Other bias | Low risk | No other risks identified. |