Table 2

Baseline characteristics according to RLS status in the PHS (n=19 182)

No RLS (n=17 809)RLS (n=1373)p Value
Demographic information
 Mean age, years (SD)66.6 (8.7)67.8 (8.9)<0.01
 Ethnicity, n (%)
  White16 091 (90.8)1288 (94.2)<0.01
 Geographic location, n (%)0.16
  Northeast3983 (22.4)299 (21.8)
  Southeast5137 (28.8)359 (26.2)
  Midwest4547 (25.5)375 (27.3)
  West4031 (22.6)329 (24.0)
  Other111 (0.6)11 (0.8)
CVD risk factors, n (%)
 History of hypertension8596 (48.3)703 (51.2)0.04
 History of diabetes1200 (6.7)138 (10.1)<0.01
 History of cholesterol ≥240 mg/dl8387 (47.1)686 (50.0)0.04
 BMI categories (kg/m2)<0.01
  <257550 (42.5)519 (37.8)
  25–29.98197 (46.1)665 (48.5)
  ≥302038 (11.5)189 (13.8)
 Smoking status0.17
  Never9763 (54.9)719 (52.4)
  Past7543 (42.4)617 (45.0)
  Current495 (2.8)37 (2.7)
 Alcohol consumption<0.01
  Rarely/never3120 (17.5)292 (21.3)
  1–3 times/month2171 (12.2)157 (11.4)
  1–6 times/week6631 (37.3)514 (37.4)
  ≥1 times/day5862 (33.0)410 (29.9)
 Exercise<0.01
  Rarely/never6174 (34.8)536 (39.2)
  ≤1/week455 (2.6)39 (2.9)
  2–4 times/week7917 (44.6)594 (43.4)
  5–7 times/week3204 (18.1)200 (14.6)
 Parental history of myocardial infarction1910 (10.7)137 (10.0)0.39
Other covariates, n (%)
 History of migraine2157 (12.1)202 (14.7)<0.01
 History of depression1709 (9.8)219 (16.1)<0.01
 History of Parkinson's disease207 (1.2)20 (1.5)0.33
 Iron supplementation use298 (1.9)25 (2.1)0.73
 Sleep duration ≥8 h5254 (32.7)431 (34.9)0.11
 Snoring0.24
  Never4382 (26.9)338 (27.0)
  A few nights6604 (40.6)482 (38.5)
  Most nights5283 (32.5)433 (34.6)
  • Percentages may not add up to 100% due to rounding or missing values.

  • BMI, body mass index; CVD, cardiovascular disease; PHS, Physician's Health Study; RLS, restless legs syndrome.