All HCW with de novo headache  HCW without pre-existing headache  HCW with pre-existing headache  P value
(n=158)  (n=93)  (n=65)
Days with headache/month (SD)  13.2 (7.2)  13.0 (7.4)  13.5 (7.1)  0.746
Days with headache/week (SD)  3.8 (1.7)  3.8 (1.7)  3.9 (1.7)  0.827
Mean pain level, VAS (SD)  5.9 (1.5)  5.8 (1.5)  6.1 (1.4)  0.08
Duration time (hours)    0.008
 1–4  74 (47.4%)  52 (57.1%)  22 (33.8%)
 4–8  46 (29.5%)  23 (25.3%)  23 (35.4%)
 8–12  21 (13.5%)  12 (13.2%)  9 (13.8%)
 >12  15 (9.6%)  4 (4.4%)  11 (16.9%)
Analgesic response    0.342
 Good or very good  97 (61.4%)  61 (65.6%)  36 (55.4%)
 Regular  46 (29.1%)  23 (24.7%)  23 (35.4%)
 Bad or very bad  15 (9.5%)  9 (9.7%)  6 (9.2%)
Headache impact on HCW (SD)
 Occupational  4.0 (2.6)  3.5 (2.6)  4.6 (2.5)  0.02
 Family  4.4 (2.7)  4.1 (2.6)  4.9 (2.5)  0.084
 Personal  5.0 (2.6)  4.7 (2.7)  5.5 (2.4)  0.049
 Social  4.8 (2.8)  4.4 (2.8)  5.4 (2.7)  0.021