Restless legs syndrome in women: a review

Correlates of Nonanemic Iron Deficiency in Restless Legs Syndrome

Objective: Iron deficiency anemia (IDA) is a well-known cause of secondary restless legs syndrome (RLS). Iron deficiency without anemia (IDNA) is insidious, and its association with RLS is less evaluated. We investigate prevalence and features of IDNA in a consecutive cohort of patients with RLS.

Methods: We included sequential primary RLS patients and RLS patients with IDA. We also recruited age- and gender-matched healthy controls. RLS mimics and other comorbidities were carefully excluded.

Results: One-hundred and ninety-six RLS patients without anemia, 26 RLS patients with IDA, and 63 controls were included. 42.3% of RLS patients without anemia had iron deficiency. Women were much more susceptible for IDNA with a relative risk of 5.51 (p < 0.0001). Women with IDNA and RLS had younger age both at interview and at RLS onset compared to women with RLS without iron deficiency (NID) (P < 0.01). IDNA RLS patients showed a tendency to higher risk of severe/very severe tiredness or sleepiness during the day as compared to NID RLS patients. Furthermore, IDNA RLS patients had longer duration of RLS (P < 0.01 in men, P < 0.05 in women) and younger age at onset (only in men, P < 0.05) compared to IDA RLS patients.

Conclusion: IDNA is frequent in RLS and iron deficiency may be severe despite a normal hemoglobin level. Women are at much higher risk for IDNA, and IDNA in women presents some specific clinical features. Features of IDNA RLS are different from IDA RLS. Regular screening of peripheral iron parameters even in patients with normal blood counts is recommended for timely optimal management.

Ethnic differences in the prevalence and predictors of restless legs syndrome between Hispanics of Mexican descent and non-Hispanic Whites in San Diego county: a population-based study

STUDY OBJECTIVES

To investigate the prevalence and predictors of RLS in Hispanics of Mexican descent (HMD) and non-Hispanic whites (NHW).

DESIGN

A population-based random digit dialing telephone questionnaire.

SETTING

San Diego County California

PARTICIPANTS

1,754 HMD and 1,913 NHW adults ≥ 18 years of age able to participate in a telephone interview in English or Spanish.

INTERVENTIONS

None.

MEASUREMENTS AND RESULTS

RLS was defined by the presence of all 4 criteria of the International Restless Legs Study Group. Sleepiness was measured by the Epworth Sleepiness Scale. Acculturation was evaluated using the Short Acculturation Scale for Hispanics. Risk factors for RLS were by self-report. The survey was conducted in the subject's language of choice. RLS prevalence was significantly lower in HMD than in NHW (14.4% vs.18.3%, p = 0.002). High acculturation HMD had a significantly greater RLS prevalence than the low acculturation group (17.4% vs. 12.8%, p = 0.008). Predictors of RLS varied between HMD and NHW. Female gender (OR 1.40, 95% CI 1.04, 1.90, p = 0.027), smoking (OR 1.82, 95% CI 1.27, 2.61, p = 0.001), and acculturation (OR 1.47, 95% CI 1.10, 1.97, p = 0.009) were independent predictors of RLS in HMD, while only older age (OR 1.01, 95% CI 1.0, 1.02) was an independent predictor of RLS for NHW.

CONCLUSION

The prevalence of RLS was significantly lower in HMD than in NHW, and significantly greater in high acculturation HMD. Our data suggest that risk factors for RLS vary by race/ethnicity and acculturation is an independent risk for RLS in HMD.

Restless legs syndrome: A qualitative analysis of psychosocial suffering and interdisciplinary attention

The aim of this study is to investigate psychosocial factors related to the diagnosis and treatment of patients with restless legs syndrome. Fifteen patients were interviewed at the Neuro-Sono Outpatient Clinic, Universidade Federal de São Paulo. The results were submitted to a qualitative analysis. We identified four content categories: illness description, illness history, illness experience, and relationships. Lack of control over the body and lack of recognition by professionals produce stigma and lead patients to suffering. The research underscores the relevance of psychosocial factors to the diagnosis and treatment of patients with restless legs syndrome and the importance of having interdisciplinary teams when attending patients with restless legs syndrome.

Validation of the post sleep questionnaire for assessing subjects with restless legs syndrome: results from two double-blind, multicenter, placebo-controlled clinical trials

BACKGROUND

Because of the subjective nature of Restless Legs Syndrome (RLS) symptoms and the impact of these symptoms on sleep, patient-reported outcomes (PROs) play a prominent role as study endpoints in clinical trials investigating RLS treatments. The objective of this study was to validate a new measure, the Post Sleep Questionnaire (PSQ), to assess sleep dysfunction in subjects with moderate-to-severe RLS symptoms.

METHODS

Pooled data were analyzed from two 12-week, randomized, placebo-controlled trials of gabapentin enacarbil (N = 540). At baseline and Week 12, subjects completed the PSQ and other validated health surveys: IRLS Rating Scale, Clinical Global Impression of Improvement (CGI-I), Profile of Mood States (POMS), Medical Outcomes Study Scale-Sleep (MOS-Sleep), and RLS-Quality of Life (RLSQoL). Pooled data were used post hoc to examine the convergent, divergent, known-group validity and the responsiveness of the PSQ.

RESULTS

Convergent validity was demonstrated by significant correlations between baseline PSQ items and total scores of IRLS, POMS, RLSQoL, and the MOS-Sleep Scale (p ≤ 0.007 each). Divergent validity was demonstrated through the lack of significant correlations between PSQ items and demographic characteristics. Correlations (p < 0.0001) between RLS severity groups and PSQ items demonstrated known-group validity. Mean changes in investigator- and subject-rated CGI-I scores for each PSQ item (p < 0.0001) demonstrated the PSQ's responsiveness to patient change as reported by their care provider.

CONCLUSIONS

Although these analyses were potentially limited by the use of clinical trial data and not prospective data from a study conducted solely for validation purposes, the PSQ demonstrated robust psychometric properties and is a valid instrument for assessing sleep and sleep improvements in subjects with moderate-to-severe RLS symptoms.

TRIAL REGISTRATION

This study analyzed data from two registered trials, NCT00298623 and NCT00365352.

Mechanisms of sex difference: a historical perspective

OBJECTIVE

The history of the discovery of mechanisms contributing to sex difference helps to better appreciate gender factors in a variety of disease states. The objective of this article is to illustrate four mechanisms of sex differences in disease incidence: X-linkage (including inactivation, escape from inactivating, skewed inactivation), sex-specific exposure to disease-producing pathogens, fetal microchimerism, and iron depletion.

METHODS

This is a historic review.

RESULTS

An emphasis on sex difference led to the uncovering of four different mechanisms by which illness rates differ in men and women.

CONCLUSIONS

Research into many disease states can benefit from a focus on potential mechanisms that yield sex differences in illness susceptibility, progression, and outcome.

Prevalence and impact of sleep disorders and sleep habits in the United States

PURPOSE

Epidemiologic studies on sleep disorders in the USA have mostly focused on specific disorders in specific groups of individuals. Most studies on sleep habits and sleep-related difficulties have focused on children and adolescents. The authors describe the prevalence of the three common physician-diagnosed sleep disorders (insomnia, sleep apnea, and restless legs syndrome (RLS)) by age, gender, and race in the US population. In addition, the authors describe the sleep habits and sleep-related difficulties in carrying routine daily activities. The authors also investigate the impact of the sleep disorders on performing routine daily activities.

METHODS

Data from the 2005-2006 National Health and Nutrition Examination Survey for 6,139 individuals over the age of 16 was analyzed for sleep-related parameters.

RESULTS

The prevalence was highest for sleep apnea (4.2%), followed by insomnia (1.2%) and RLS (0.4%). Hispanics and Whites reported longer sleep duration than Blacks by 24 to 30 min. The predominant sleep habits were snoring while sleeping (48%), feeling unrested during the day (26.5%), and not getting enough sleep (26%). Difficulty concentrating (25%) or remembering (18%) were the main sleep-related difficulties in our sample. Insomnia, sleep apnea, and RLS had the highest impact on concentration and memory.

CONCLUSIONS

Our findings suggest that the prevalence of sleep disorders in the USA is much lower than previously reported in the literature suggesting under diagnosis of sleep disorders by primary care physicians.

Movement disorders

Abnormal involuntary movements are major features of a large group of neurologic disorders, some of which are neurodegenerative and pose a significant diagnostic and treatment challenge to treating physicians. This article presents a concise review of clinical features, pathogenesis, epidemiology, and management of seven of the most common movement disorders encountered in a primary care clinic routinely. The disorders discussed are Parkinson disease, essential tremor, restless legs syndrome, Huntington disease, drug-induced movement disorder, Wilson disease, and Tourette syndrome.