雅思阅读的真题机经：磁疗_雅思英语阅读

雅思阅读的真题机经：磁疗

　　Efficacy

　　Several studies have been conducted in recent years to investigate what, if any, role static magnetic fields may play in health and healing. Unbiased studies of magnetic therapy are problematic, since magnetisation can be easily detected, for instance, by the attraction forces on ferrous objects; because of this, effective blinding of studies is difficult. Incomplete or insufficient blinding tends to exaggerate treatment effects, particularly where any such effects are small. Health claims such as longevity and cancer treatment are implausible and unsupported by any research. More mundane health claims, most commonly pain relief, also lack any credible proposed mechanism, and clinical research is not promising.

　　Pain

　　Effects of magnet therapy on pain relief beyond non-specific placebo response have not been adequately demonstrated. A 2008 systematic review of magnet therapy for all indications found no evidence of an effect for pain relief. It reported that small sample sizes, inadequate randomization, and difficulty with allocation concealment all tend to bias studies positively and limit the strength of any conclusions. In 2009 the results of a randomized double-blind placebo-controlled crossover trial on the use of magnetic wrist straps for osteoarthritis were published, addressing a gap in the earlier systematic review. This trial showed that magnetic wrist straps are ineffective in the management of pain, stiffness and physical function in osteoarthritis. The authors concluded that reported benefits are most likely attributable to non-specific placebo effects.