Of the 2,695 participants, 1,273 (47.2 %) subjects had had at least 1 attack of headache, and 143 subjects (5.3 %) met the ICHD-2 criteria for migraine. So, 1,130 subjects were classified as having non-migraine headaches and 1,422 subjects were classified as non-headache controls. One hundred forty two (5.3 %) subjects positively responded at all 4 questions from the IRLSSG criteria and were classified as having RLS (Table 1).