Magnetic bracelets: a paradise for charlatans

I find it always nice to see that people appreciate my work. Yet sometimes I am a little surprised to realise what some commercially interested firms make of it. Recently I came across a website that proudly used my research for advertising the use of magnetic bracelets against pain. Here is the text in question:

The extra strong magnets make this magnetic bracelet the fastest acting pain reliever. While wearing this magnetic bracelet customers with wrist and hand pain report significant pain relief….

What is a magnetic bracelet and what are the benefits? Magnetic bracelets are a piece of jewelry, worn for the therapeutic benefits of the magnetic field. Magnetic bracelets has been used successfully by many people for pain relief of inflammatory conditions such as arthritis, tendinitis and bursitis.

A randomized, placebo controlled trial with three parallel groups, came to the conclusion : Pain from osteoarthritis of the hip and knee decreases when wearing magnetic bracelets. It is uncertain whether this response is due to specific or non-specific (placebo) effects. Tim Harlow, general practitioner, Colin Greaves, research fellow, Adrian White, senior research fellow, Liz Brown, research assistant, Anna Hart, statistician, Edzard Ernst, professor of complementary medicine.

The entrepreneurs seem to have forgotten a few things which we tried to make clear in our paper:

• this article was published in the Christmas issue of the BMJ which specialises in publishing unusual and odd findings with a high entertainment value,
• in our paper, we point out that “the contamination of group B with stronger magnets prevented a more objective estimation of any-placebo effect”,
• and stressed that “there were problems with the weak magnets”,
• and that “a per-specification analysis suggested (but could not confirm) a specific effect of magnetic bracelets over and above placebo”.

Most importantly, this was just one trial, and surely one swallow does not make a summer! We should always consider the totality of the reliable evidence. Being conscientious researchers, at the time, we did exactly that and conducted a systematic review. Here is the abstract in its full beauty:

BACKGROUND:

Static magnets are marketed with claims of effectiveness for reducing pain, although evidence of scientific principles or biological mechanisms to support such claims is limited. We performed a systematic review and meta-analysis to assess the clinical evidence from randomized trials of static magnets for treating pain.

METHODS:

Systematic literature searches were conducted from inception to March 2007 for the following data sources: MEDLINE, EMBASE, AMED (Allied and Complementary Medicine Database), CINAHL, Scopus, the Cochrane Library and the UK National Research Register. All randomized clinical trials of static magnets for treating pain from any cause were considered. Trials were included only if they involved a placebo control or a weak magnet as the control, with pain as an outcome measure. The mean change in pain, as measured on a 100-mm visual analogue scale, was defined as the primary outcome and was used to assess the difference between static magnets and placebo.

RESULTS:

Twenty-nine potentially relevant trials were identified. Nine randomized placebo-controlled trials assessing pain with a visual analogue scale were included in the main meta-analysis; analysis of these trials suggested no significant difference in pain reduction (weighted mean difference [on a 100-mm visual analogue scale] 2.1 mm, 95% confidence interval -1.8 to 5.9 mm, p = 0.29). This result was corroborated by sensitivity analyses excluding trials of acute effects and conditions other than musculoskeletal conditions. Analysis of trials that assessed pain with different scales suggested significant heterogeneity among the trials, which means that pooling these data is unreliable.

INTERPRETATION:

The evidence does not support the use of static magnets for pain relief, and therefore magnets cannot be recommended as an effective treatment. For osteoarthritis, the evidence is insufficient to exclude a clinically important benefit, which creates an opportunity for further investigation.

So, would I, on the basis of the current best evidence, recommend magnetic bracelets to people who suffer from pain? No! In my view, only charlatans would do such a thing.