Purpose: We investigated the prevalence, natural course, and associated risk factors of habitual snoring (HS) and restless legs syndrome (RLS) over a period of 10 years among an aging population from their early sixties to their seventies.
Methods: A population-based follow-up study among all persons born in 1935 and living in the city of Oulu in northern Finland was conducted. In this study, we examined subjects who had participated in two subsequent surveys conducted in 1996-1998 and 2007-2008. The data were gathered by questionnaires, as well as by laboratory and clinical measurements.
Results: Altogether 457 (55%) of the 838 eligible subjects participated in both surveys. The prevalence of both RLS and HS decreased during the 10 years from 21% to 15% and from 26% to 19%, respectively. Half of those who snored in 1996-1998 stopped snoring in 10 years time, and half of those who suffered from restless legs at least three times per week in 1996-1998 suffered from this syndrome never or less than once a week in 2007-2008. The 10-year incidence of new cases of both HS and RLS was 7%. Male gender predicted best the incidence of new HS in 10 years, while the Zung sum score as a marker of depressive symptoms and waist circumference predicted RLS.
Conclusions: Overall, the prevalence of both HS and RLS seems to diminish during aging. The causes behind this still remain unknown and should be investigated with more sophisticated methods.