Table 1  Baseline conditions and mask and Personal Protective Equipment (PPE) usage among healthcare workers
Total  De novo headache  P value
No  Yes
N= 261  (n=103)  (n=158)
Age, years (SD)  42.9 (10.7)  40.8 (11.4)  44.4 (10.1)  0.009
Female gender  208 (79.7%)  73 (31.1%)  135 (64.9%)  0.004
Occupation    0.0001
 Doctor  112 (42.9%)  61(54.5%)  51 (45.5%)
 Nurse  95 (36.4%)  33 (34.7%)  62(65.3%)
 Others  54 (20.7%)  9(16.7%)  45(83.3%)
Work shift    <0.0001
 Mornings and 24-hour duties  89 (34.1%)  51 (57.3%)  38 (42.7%)
 Rotating shifts  91 (34.9%)  26 (28.6%)  65 (71.4%)
 Others  81 (31.0%)  26 (32.1%)  55 (67.9%)
Type of face mask    0.029
 Surgical mask  208 (79.7%)  89 (42.8%)  119 (57.2%)
 N95/FFP2  53 (20.3%)  14 (26.4%)  39 (73.6%)
Number of hours worn per day (SD)  6.9 (2.3)  6.8 (2.4)  7.0 (2.2)  0.474
Use of another PPE:    0.203
 Face shield  54 (20.7%)  21 (38.9%)  33 (61.1%)
 Protective eyewear  33 (12.6%)  13 (39.4%)  20 (60.6%)
 Complete PPE  46 (17.6%)  16 (34.8%)  30 (65.2%)
Confirmed COVID-19  12 (4.6%)  4 (33.3%)  8 (66.7%)  0.161
Pre-existing headache  110 (42.1%)  45 (40.9%)  65 (59.1%)  0.683
Comorbidity
 Allergy  34 (13.0%)  16 (47.1%)  18(52.9%)  0.331
 Asthma  17 (6.5%)  11 (64.7%)  6 (35.3%)  0.028
 Tobacco  41 (15.7%)  8 (19.5%)  33 (80.5%)  0.004
 Arterial hypertension  18 (6.9%)  9 (50.0%)  9 (50.0%)  0.789
 Cardiopathy  1 (0.4%)  0 (0.0%)  1 (100%)  0.419
 Dyslipidaemia  14 (5.4%)  7 (50.0%)  7 (50.0%)  0.76
 Diabetes  2 (0.8%)  1 (50.0%)  1 (50.0%)  0.76
 Thyroid disease  28 (10.7%)  9 (32.1%)  19 (67.9%)  0.402
 Anxiety  26 (10.0%)  6 (23.1%)  20 (76.9%)  0.072
 Others  16 (6.1%)  4 (25.0%)  12 (75.0%)  0.222
Other symptoms
 Sleep disturbance  79 (30.3%)  11 (13.9%)  68 (86.1%)  0.0001
 Loss of concentration  73 (28.0%)  14 (19.2%)  59 (80.8%)  0.0001
 Irritability  74 (28.4%)  18 (24.3%)  56 (75.7%)  0.002
 Photophobia  31 (11.9%)  8 (25.8%)  23 (74.2%)  0.097
 Sonophobia  24 (9.2%)  6 (25.0%)  18 75.0%)  0.128
 Sickness/vomiting  24 (9.2%)  11 (45.8%)  13 (54.2%)  0.503
FFP2, filtering face pieces; N95, 95% particle filtering capacity.