RLS prevalence according to age
We conducted logistic regression analysis for RLS prevalence according to headache diagnosis in 5 age groups. Subjects with migraine showed increased ORs for RLS in the 19–29 age group (OR = 6.6 95 % CI = 1.2–36.8, p = 0.029) and the 40–49 age group (OR = 6.7, 95 % CI = 1.5–33.5, p = 0.016) compared to non-headache controls. For subjects with non-migraine headaches, the 30–39 age group (OR = 4.6, 95 % CI = 1.8–12.0, p = 0.002) and the 40–49 age group (OR = 3.7, 95 % CI = 1.0–13.5, p = 0.046) showed increased ORs for RLS compared to non-headache controls. Migraineurs and non-migraine headache subjects failed to show increased ORs for RLS compared to non-headache controls in the 50–59 and 60–69 age groups (Table 2). We further divided our participants into 2 age groups (aged <50 years and aged ≥50 years) and compared the association between migraine and RLS. Migraineurs showed an increased OR for RLS compared to non-headache controls in aged <50 years (OR = 6.9, 95 % CI = 2.9–16.2, p < 0.001) but failed to show in aged ≥50 years (OR = 1.1, 95 % CI = 0.3–3.9, p = 0.883). For non-migraine headache subjects, an increased OR for RLS compared to non-headache controls was observed in aged <50 years (OR = 3.9, 95 % CI = 2.1–7.4, p < 0.001) but not in aged ≥50 years (OR = 1.5, 95 % CI = 0.9–2.4, p = 0.099).