Prevalence and incidence of periodic limb movements during sleep in <scp>São Paulo</scp> , <scp>Brazil</scp> : results from the <scp>EPISONO</scp> cohort

Periodic limb movements in sleep (PLMS) are characterised by repetitive and involuntary movements of the limbs during sleep. When these movements exceed 15 events/h, they are considered clinically significant and can disrupt sleep quality and contribute to various health risks. The aim of this study was to investigate the prevalence, incidence, and remission of PLMS in a representative sample from São Paulo, Brazil. Data from the 2007 (and its 2015 follow-up) and 2018 editions of the São Paulo Epidemiologic Sleep Study (EPISONO) study were used. PLMS prevalence rates were determined for 2007 and 2018, while incidence and remission rates were evaluated between 2007 and 2015. In 2007, the prevalence of PLMS was 9.02% (95% confidence interval [CI] 7.28-10.76%), which increased to 15.60% (95% CI 13.04-18.17%) by 2018. The incidence of new PLMS cases from 2007 to 2015 was 6.54% (95% CI 4.60-8.4%), with a remission rate of 50.82% (95% CI 38.27-63.37%). Ageing significantly influenced the increase in both the prevalence and severity of PLMS over time. Individuals with African ancestry had lower odds of PLMS compared to those of Caucasian ancestry (odds ratio 0.25, 95% CI 0.10-0.60; p = 0.002). Our study revealed that the prevalence of PLMS in São Paulo, a city with a racially mixed population, was significantly lower than in population samples with Caucasian ancestry. The observed increase in PLMS prevalence over a decade was potentially linked to population ageing and lifestyle changes. These findings highlight the importance of ongoing research into the long-term health implications of PLMS and its role in sleep disorders.