What is the evidence base for dysmenorrhoea and vitamin E?
Dr Martin Dawes considers the evidence for dysmenorrhoea
and vitamin E
A patient attends having read an article about vitamin E and dysmenorrhoea. Dysmenorrhoea affects more than 40 per cent of women and as many as 20 per cent of them may have such severe symptoms as to need to have time off work.
The first task is to identify for this patient what is the specific problem. In her case it is the severity of pain. My structured question is then: 'In women with dysmenorrhoea does vitamin E reduce the severity of the pain?' To identify the drug names I checked the BNF for vitamin E and found alphatocopheryl.
For most of the searches I first looked for the problem (ie, dysmenorrhoea) and then separately looked for the therapy. I then combined these two searches.
How good is the evidence?
The Cochrane review1 was helpful at defining the scope of research, which was small. The Spanish trial (cited in the Cochrane library article) was a cross-over placebo-controlled study combining ibuprofen with vitamin E compared with ibuprofen alone. A cross-over study is when each individual takes the control medication and then the experimental medication, or vice versa. The regimen was 100mg daily for 20 days before menses plus ibuprofen at beginning of painful menstruation compared with just ibuprofen at onset of pain. Women were treated for two cycles (one cycle of each treatment).
They found that 23 out of 26 women (88 per cent) on ibuprofen and vitamin E compared with 17 out of 24 women (71 per cent) on ibuprofen alone had pain relief. But the confidence interval is wide so this result may not be seen in general.
There is another randomised controlled trails of vitamin E in women with dysmenorrhoea2 published more recently in 2001. This group first sampled 1,000 students aged 16 to 18 in Iran. From this sample 50 girls were randomised to receive either vitamin E or placebo. The study was double blinded so that neither the girls nor the health centre knew which they were getting. There was concealment of the randomisation process. On vitamin E the median pain score fell from 5.5 to 3.5 while on placebo it fell from 5.4 to 4.3. There is no assessment as to whether this drop in median score is larger enough to be clinically significant. The critical appraisal of this article can be found at www.emcats.com.
Advice for the patient
So after looking at this question, what can I tell my patient? The evidence for this drug is not impressive. Partly that is because large trials have not been undertaken. Is it likely to be harmful? No, the side-effects occur after taking 1g per day. In every patient the individual response to therapy differs. If my patient wants to try it then I would not advise against it. But I would provide her with other alternative conventional choices.
1 Wilson, M.L. and P.A. Murphy, Herbal and dietary therapies for primary and secondary dysmenorrhoea (Cochrane Review). Cochrane Database Syst Rev, 2001;3:CD002124
2 Ziaei, S., et al, A randomised placebo-controlled trial to determine the effect of vitamin E in treatment of primary dysmenorrhoea.
How I conducted the research
Source of Search Trials Second search Trials Trials found
evidence term found term about therapy found combining terms
Cochrane Dysmenorrhea 10 reviews Vitamin E or 118 reviews Three review
and alpha and and two trials
360 trials tocopheryl 1,712 trials
Best Dysmenorrhea two trials Vitamin E or 31 trials No trials
Evidence 5 (not MESH term) Alpha
Clinical Chapter on One trial
Evidence dysmenorrhea (Spanish,
PubMed Dysmenorrhea or 215 trials (Vitamin E) or 820 Three trials
(clinical query) dysmenorrhoea (alpha tocopheryl)
or (alpha tocopherol)