The impact of altitude on the prevalence and characteristics of Restless Legs Syndrome
Date
2023
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
University of the Witwatersrand, Johannesburg
Abstract
Restless Legs Syndrome (RLS) is a neurological sensory disorder, characterised by the irresistible urge to move due to unpleasant, deep-seated paresthesias in the legs. The urge to move usually occurs in the evening, when an individual is at rest and the sensations experienced are alleviated with movement. The prevalence of RLS in a general population ranges from 2.5 to 10%, from studies across the globe. Differences in RLS prevalence have been noted between different ethnic groups, with individuals of European ancestry exhibiting greater prevalence of RLS compared to individuals of Asian and African ancestry. The aetiology of RLS is unclear; however, there is evidence of central nervous system iron dysregulation. Low partial pressure of oxygen at high altitude, which is a large distance above sea level, may exacerbate iron dysregulation which may account for the greater prevalence of RLS at high compared to low altitude, which is an area at sea level. However, the impact of altitude on the prevalence of RLS requires further investigation and is the aim of this study. To investigate the effect of altitude on the prevalence and characteristics of RLS, a questionnaire was administered to the general South African population at two altitudes: low altitude (Durban, South Africa) and higher altitude, (1753m above sea level, Johannesburg, South Africa). The survey was completed by 1291 participants (416 at low altitude and 875 at higher altitude). Using an online questionnaire, data were collected on demographic characteristics (including age, sex and ethnicity), the Cambridge-Hopkins RLS questionnaire (to assess the presence/absence of RLS), self-reported iron deficiency, subjective measures of sleep, measures of daytime sleepiness (using the Epworth Sleepiness Scale) and levels of fatigue (using the Fatigue Assessment Scale). RLS was significantly more prevalent at the higher altitude (n = 69, 7.9%) compared to low altitude (n = 20, 4.8%), which may be due to an increase in iron dysregualtion at high altitude, resulting from the low partial pressure of oxygen. Factors associated with RLS also were exacerbated at higher altitude; these include increased RLS severity (p = 0.003), increased daytime sleepiness (p = 0.04) and decreased self-reported iron levels (p = 0.03) in individuals with RLS at higher altitude compared with low altitude. RLS was less prevalent in individuals with African ancestry than in those with European ancestry at the higher altitude (p = 0.0025). However, RLS was more prevalent in individuals with African ancestry than in those with Indian ancestry at low altitude (p = 0.0004). My data therefore support that altitude appears relevant to the pathophysiology of RLS, with high altitude presenting as a risk factor for RLS and exacerbating some characteristics of RLS
Description
A Dissertation submitted in fulfillment of the requirements for the degree of Master of Science to the Faculty of Health Science, School of Physiology Johannesburg, 2023
Keywords
Restless Legs Syndrome, Altitude
Citation
Munian, Pariska. (2024). The impact of altitude on the prevalence and characteristics of Restless Legs Syndrome [Master’s dissertation, University of the Witwatersrand, Johannesburg]. WireDSpace.