Worldwide estimation of restless legs syndrome: a systematic review and meta-analysis of prevalence in the general adult population

This systematic review, meta-analysis and meta-regression assessed the prevalence of restless legs syndrome (RLS) in the general adult population. Studies identified in Scopus, PubMed, Web of Science, and PsycInfo between January 2000 and February 2022 were included if they used a case-control or cross-sectional design and reported data regarding the prevalence of RLS. The protocol was pre-registered in the International Prospective Register of Systematic Reviews (PROSPERO; CRD42022300709). A total of 97 studies including 483,079 participants from 33 different countries met the eligibility criteria. The Newcastle Ottawa Scale was used to evaluate the methodological quality, and the fill-and-trim method was used to correct probable publication bias, while the jack-knife method was performed to assess small study effect. The corrected overall pooled prevalence of RLS was 3% (95% confidence interval [CI] 1.4%-3.8%). The pooled prevalence of RLS syndrome was affected by methodological quality (no data from non-respondents in the included studies), gender (higher among women), study design (lower prevalence in case-control versus cohort and cross-sectional studies). The figures for corrected pooled prevalence among men, women, alcohol consumers and smokers were 2.8% (95% CI 2%-3.7%); 4.7% (95% CI 3.2%-6.3%); 1.4% (95% CI 0%-4.2%); and 2.7% (95% CI 0%-5.3%), respectively. The prevalence among male and female participants was lower in community-based versus non-community-based studies. Moreover, the prevalence was higher in developed versus developing countries and among elders versus adults. In conclusion, RLS is a common disorder in the general adult population, with a higher prevalence in women; however, prevalence data are affected by study design and quality.

Restless legs syndrome: Over 50 years of European contribution

Restless legs syndrome (RLS) is a sensorimotor neurological disorder characterised by an urge to move the limbs with a circadian pattern (occurring in the evening/at night), more prominent at rest, and relieved with movements. RLS is one of the most prevalent sleep disorders, occurring in 5%-10% of the European population. Thomas Willis first described RLS clinical cases already in the 17th century, and Karl-Axel Ekbom described the disease as a modern clinical entity in the 20th century. Despite variable severity, RLS can markedly affect sleep (partly through the presence of periodic leg movements) and quality of life, with a relevant socio-economic impact. Thus, its recognition and treatment are essential. However, screening methods present limitations and should be improved. Moreover, available RLS treatment options albeit providing sustained relief to many patients are limited in number. Additionally, the development of augmentation with dopamine agonists represents a major treatment problem. A better understanding of RLS pathomechanisms can bring to light novel treatment possibilities. With emerging new avenues of research in pharmacology, imaging, genetics, and animal models of RLS, this is an interesting and constantly growing field of research. This review will update the reader on the current state of RLS clinical practice and research, with a special focus on the contribution of European researchers.

Severity and frequency of restless legs syndrome in patients with familial Mediterranean fever

Objective:

Restless legs syndrome (RLS) is a common sensory motor disorder. RLS an urge to move the extremities that may be accompanied by dysesthesias, and significantly affects quality of life of affected patients. The frequency of RLS is higher in different systemic inflammatory diseases. Familial Mediterranean fever (FMF) is an inherited inflammatory disease characterized by attacks of polyserositis, arthritis, and fever. The prevalence of RLS in patients with FMF is unknown. This study aimed to evaluate the prevalence rate of RLS in a sample of patients with FMF and compare this prevalence with that of a matched normal population.

Method:

A total of 60 patients with FMF and 60 healthy controls were studied. All participants underwent a neurological examination. Diagnostic criteria as proposed by the International Restless Legs Syndrome Study Group (IRLSSG) were used to define RLS. The IRLSSG rating scale for the severity of RLS was applied to determine the severity of symptoms.

Results:

The prevalence of RLS was not significantly different between patients and controls. Although the mean International Restless Legs Syndrome Rating Scale (IRLSRS) scores tended to be higher in patients compared with controls, this difference was not significant. When each item of the severity scale was compared between the two groups, significantly higher scores were found in some items of the IRLSRS in patients with FMF compared with controls.

Conclusion:

According to this result, RLS symptoms in patients with FMF were more frequent and lasted longer than those in controls.

Serum zinc levels in patients with iron deficiency anemia and its association with symptoms of iron deficiency anemia

Iron deficiency anemia (IDA) is a major public health problem especially in underdeveloped and developing countries. Zinc is the co-factor of several enzymes and plays a role in iron metabolism, so zinc deficiency is associated with IDA. In this study, it was aimed to investigate the relationship of symptoms of IDA and zinc deficiency in adult IDA patients. The study included 43 IDA patients and 43 healthy control subjects. All patients were asked to provide a detailed history and were subjected to a physical examination. The hematological parameters evaluated included hemoglobin (Hb); hematocrit (Ht); red blood cell (erythrocyte) count (RBC); and red cell indices mean corpuscular volume (MCV), mean corpuscular hemoglobin (МСН), mean corpuscular hemoglobin concentration (МСНС), and red cell distribution width (RDW). Anemia was defined according to the criteria defined by the World Health Organization (WHO). Serum zinc levels were measured in the flame unit of atomic absorption spectrophotometer. Symptoms attributed to iron deficiency or depletion, defined as fatigue, cardiopulmonary symptoms, mental manifestations, epithelial manifestations, and neuromuscular symptoms, were also recorded and categorized. Serum zinc levels were lower in anemic patients (103.51 ± 34.64 μ/dL) than in the control subjects (256.92 ± 88.54 μ/dL; <0.001). Patients with zinc level <99 μ/dL had significantly more frequent mental manifestations (p < 0.001), cardiopulmonary symptoms (p = 0.004), restless leg syndrome (p = 0.016), and epithelial manifestations (p < 0.001) than patients with zinc level > 100 μ/dL. When the serum zinc level was compared with pica, no statistically significant correlation was found (p = 0.742). Zinc is a trace element that functions in several processes in the body, and zinc deficiency aggravates IDA symptoms. Measurement of zinc levels and supplementation if necessary should be considered for IDA patients.