Background: There is inconclusive evidence from observational studies to suggest that people who eat a diet rich in antioxidant vitamins (carotenoids, vitamins C and E) or minerals (selenium and zinc) may be less likely to develop age-related macular degeneration (AMD).

Objectives: To examine the evidence as to whether or not taking antioxidant vitamin or mineral supplements prevents the development of AMD.

Search methods: We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2011, Issue 12), MEDLINE (January 1950 to January 2012), EMBASE (January 1980 to January 2012), Open Grey (System for Information on Grey Literature in Europe) (www.opengrey.eu/), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). There were no date or language restrictions in the electronic searches for trials. The electronic databases were last searched on 26 January 2012.

Selection criteria: We included all randomised controlled trials (RCTs) comparing an antioxidant vitamin and/or mineral supplement (alone or in combination) to control.

Data collection and analysis: Both review authors independently assessed risk of bias in the included studies and extracted data. One author entered data into RevMan 5 and the other author checked the data entry. We pooled data using a fixed-effect model.

Main results: We included four RCTs in this review; 62,520 people were included in the analyses. The trials were conducted in Australia, Finland and the USA and investigated vitamin E and beta-carotene supplements. Overall the quality of the evidence was high. People who took these supplements were not at decreased (or increased) risk of developing AMD. The pooled risk ratio for any antioxidant supplement in the prevention of any AMD was 0.98 (95% confidence interval 0.89 to 1.08) and for advanced AMD was 1.05 (95% CI 0.80 to 1.39). Similar results were seen when the analyses were restricted to beta-carotene and alpha-tocopherol alone.

Authors' conclusions: There is accumulating evidence that taking vitamin E or beta-carotene supplements will not prevent or delay the onset of AMD. There is no evidence with respect to other antioxidant supplements, such as vitamin C, lutein and zeaxanthin, or any of the commonly marketed multivitamin combinations. Although generally regarded as safe, vitamin supplements may have harmful effects and clear evidence of benefit is needed before they can be recommended. People with AMD should see the related Cochrane review 'Antioxidant vitamin and mineral supplements for slowing the progression of age-related macular degeneration' written by the same review team.

/pdf/antioxidant-vitamin-and-mineral-supplements-for-preventing-1tlre0ldgx.pdf

Antioxidant vitamin and mineral supplements for preventing age-related macular degeneration.

Clinical trials: Design, conduct, and analysis

Background
Antipsychotic (neuroleptic) medication is used extensively to treat people with chronic mental illnesses. Its use, however, is associated with adverse effects, including movement disorders such as tardive dyskinesia (TD) – a problem often seen as repetitive involuntary movements around the mouth and face. Vitamin E has been proposed as a treatment to prevent or decrease TD.

Objectives
To determine the effects of vitamin E for people with schizophrenia or other chronic mental illnesses who also developed neuroleptic-induced TD.

Search methods
We searched the Cochrane Schizophrenia Group Trials Register (March 2010), inspected references of all identified studies for further trials and contacted authors of trials for additional information.

Selection criteria
We included reports if they were controlled trials dealing with people with neuroleptic-induced TD and schizophrenia who had been randomly allocated to either vitamin E or to a placebo or no intervention.

Data collection and analysis
We independently extracted data from these trials and we estimated risk ratios (RR) or mean differences (MD), with 95% confidence intervals (CI). We assumed that people who dropped out had no improvement.

Main results
The review now includes 11 poorly reported randomised trials (total 427 people). There was no clear difference between vitamin E and placebo for the outcome of 'clinically relevant improvement in TD' (6 trials, 256 people, RR 0.95 CI 0.89 to 1.02). For the outcome of 'any improvement in TD symptoms', again, we found no clear difference between groups (7 trials, 311 people, RR 0.86 CI 0.75 to 1.00). However, people allocated to placebo showed more deterioration of their symptoms compared with those given vitamin E (5 trials, 98 people, RR 0.38 CI 0.16 to 0.9). There was no difference in the incidence of adverse effects (9 trials, 203 people, RR 1.29 CI 0.51 to 3.24) or leaving the study early (medium term 6 trials, 173 people, RR 1.29 CI 0.72 to 2.3). There is no trial-based information regarding the effect of vitamin E for those with early onset of TD.

Authors' conclusions
Small trials of limited quality suggest that vitamin E may protect against deterioration of TD. There is no evidence that vitamin E improves symptoms of this problematic and disfiguring condition once established. New and better trials are indicated in this under-researched area, and, of the many adjunctive treatments that have been given for TD, vitamin E would be a good choice for further evaluation.

/pdf/vitamin-e-for-neuroleptic-induced-tardive-dyskinesia-piqpi4s144.pdf

Vitamin E for neuroleptic-induced tardive dyskinesia.

Background Several short-term, controlled trials have documented the efficacy of vitamin E in treating tardive dyskinesia. However, the persistent nature of the disease prompted us to perform a multicenter, longer-term trial of vitamin E. Methods The study was a prospective, randomized, 9-site trial of up to 2 years of treatment with d -vitamin E (1600 IU/d) vs matching placebo. One hundred fifty-eight subjects with tardive dyskinesia who were receiving neuroleptic medications were enrolled. The blinded assessments performed were clinical (Abnormal Involuntary Movements Scale, Barnes Akathisia Scale, and Modified Simpson-Angus [for Extrapyramidal Symptoms] Scale) and electromechanical assessments of movement disorders, psychiatric status (Brief Psychiatric Rating Scale), and functioning (Global Assessment of Functioning). There were no significant differences in baseline demographic characteristics or in study assessments between the group that received vitamin E and the group that received placebo. Results Vitamin E was well tolerated and subject compliance with medication was good and similar between treatment groups. One hundred seven subjects (70% of those receiving vitamin E and 66% of subjects receiving placebo) completed at least 1 year of treatment. There were no significant effects of vitamin E on total scores or subscale scores for the AIMS, electromechanical measures of dyskinesia, or scores from the other 4 scales. Conclusion This long-term, randomized trial of vitamin E vs placebo found no evidence for efficacy of vitamin E in the treatment of tardive dyskinesia.

https://jamanetwork.com/journals/jamapsychiatry/articlepdf/205277/yoa8239.pdf

Vitamin E Treatment for Tardive Dyskinesia

Relationship of neuromotor disturbances to psychosis symptoms in first-episode neuroleptic-naive schizophrenia patients.

Nine VA Medical Centers are participating in a 2-year double-blind placebo controlled study of antioxidant treatment for tardive dyskinesia (TD) conducted by the Department of Veteran Affairs Cooperative Studies Program. One of the principal outcome measures of this study is the score derived from the instrumental assessment of upper extremity dyskinesia. Dyskinetic hand movements are quantified by assessing the variability associated with steady-state isometric force generated by the patient. In the present report, we describe the training procedures and results of a multi-center reliability assessment of this procedure. Data from nine study centers comprising 45 individual patients with six trials each (three from left hand and three from right hand) were reanalyzed by an independent investigator and the results were subjected to reliability assessment. For the statistic of interest (average coefficient of variation over trials 2 and 3 for each hand, then take the larger of these two values), we found very high intraclass correlation coefficients for reliability over all patients across sites (ICC = 0.995). We also calculated the reliability of the measures across trials within patient for each combination of hand (right, left, dominant), rater group (site, control), and trials set (all three, trials 2 and 3). For a given hand and trial set, the reliability of the site raters was similar to that of the control. This study demonstrates that instrumental measures for the assessment of dyskinesia are reliable and can be implemented in multi-center studies with minimal training.

Kathlene Tracy

Papers

Reliability of an instrumental assessment of tardive dyskinesia: results from VA Cooperative Study #394