Adjusted for age, site, race (white vs. nonwhite), body mass index, alcohol use, caffeine intake, smoking status, physical activity, cognitive function, history of stroke, history of diabetes, history of myocardial infarction or congestive heart failure, use of benzodiazepines, use of dopaminergics, education, apnea-hypopnea index. Test for interaction, F[2,979]=3.13. Test for trend from a linear regression model, t[N=447]=3.06.
Abbreviations, IRSS=International RLS Study Group Severity Scale; PLMI=periodic limb movement index.