[Prevalence of restless legs syndrome]

Restless legs syndrome (RLS) is a common movement disorder wherein sensory motor symptoms are observed in the limbs mainly during sleep and quiet wakefulness. The diagnostic criteria for RLS were established in 1995 by the International RLS Study Group (IRLSSG) and revised in 2003. The prevalence of RLS in Europe and North America was reported to be between 5% and 12%. On the other hand, the prevalence of RLS in Asia was lesser than that in Europe and North America: it was estimated to be less than 4%. This difference might be associated with vacial, cultural, and language differences. Genetic factors are known to contribute to the etiology of RLS in up to two-thirds of these patients. Furthermore, RLS might complicate an already existing medical condition. The development of secondary RLS is associated with renal failure, iron deficiency, frequent blood donation, Parkinson disease, neuropathy, as well as pregnancy. Generally, these medical condition are more frequently complicated in patient with RLS than in healthy controls. However, there is no conclusive evidence to prove an association between these medical conditions and RLS. Genetic contribution, environmental factors and other covariates such as gender, age, iron deficiency, as well as medical conditions play an important role in the development of RLS. In conclusion, epidemiological evidence suggests that both the primary and secondary forms of RLS are common neurological disorders. Future epidemiological studies are required to determine the potential risk factors contributing to the development of this disorder.