Table 1.
Demographic and other characteristics by arm of randomization
| Variable | Medical mask (% and 95% CI) (n = 492) | N95 non‐fit (% and 95% CI) (n = 488) | P value | N95 fit (% and 95% CI) (n = 461) | P value |
|---|---|---|---|---|---|
| Sex (male) | 57/492 | 40/488 | 0·08 | 45/461 | 0·36 |
| 11·6 (8·8–14·4) | 8·2 (5·8–10·6) | 9·8 (7·1–12·5) | |||
| Age (mean) | 32·7 (31·8–33·5) | 33 (32·2–33·8) | 0·52 | 35·3 (34·4–36·2) | <0·01 |
| Education* | 189/492 | 180/488 | 0·62 | 155/461 | 0·12 |
| 38·4 (34·1–42·7) | 36·9 (32·6–41·2) | 33·6 (29·3–37·9) | |||
| Current smoker | 18/492 | 17/488 | 0·88 | 13/461 | 0·47 |
| 3·7 (2·0–5·3)) | 3·5 (1·9–5·1) | 2·8 (1·3–4·3) | |||
| Anyone smoking in family | 187/492 | 216/488 | 0·05 | 213/461 | 0·01 |
| 38·0 (33·7–42·3) | 44·3 (39·9–48·7) | 46·2 (41·7–50·8) | |||
| Four or more people of family | 89/492 | 122/488 | 0·01 | 113/461 | 0·02 |
| 18·1 (14·7–21·5) | 25·0 (21·2–28·8) | 24·5 (20·6–28·4) | |||
| Four or more adults in family | 67/492 | 100/488 | <0·01 | 90/461 | 0·01 |
| 13·6 (10·6–16·7) | 20·5 (16·9–24·1) | 19·5 (15·9–23·1) | |||
| One child in family** | 201/485 | 209/464 | 0·26 | 197/457 | 0·61 |
| 41·4 (37·1–45·8) | 45·0 (40·5–49·6) | 43·1 (38·6–47·7) | |||
| No children in family** | 278/485 | 244/464 | 0·14 | 254/457 | 0·59 |
| 57·3 (52·9–61·7) | 52·6 (48·0–57·1) | 55·6 (51·0–60·1) | |||
| Influenza vaccination in 2008 | 109/492 | 105/488 | 0·81 | 44/461 | <0·01 |
| 22·2 (18·5–25·8) | 21·5 (17·9–25·2) | 9·5 (6·9–12·2) | |||
| Influenza vaccination in 2007 | 107/492 | 105/488 | 0·93 | 68/461 | <0·01 |
| 21·7 (18·1–25·4) | 21·5 (17·9–25·2) | 14·8 (11·5–18·0) | |||
| Previous mask wearing | |||||
| At work | 469/492 | 475/488 | 0·09 | 431/461 | 0·22 |
| 95·3 (93·5–97·2) | 97·3 (95·9–98·8) | 93·5 (91·2–95·7) | |||
| At home | 3/492 | 4/488 | 0·7 | 6/461 | 0·27 |
| 0·6 (0–1·3) | 0·8 (0–1·6) | 1·3 (0·3–2·3) | |||
| Public transport | 7/492 | 11/488 | 0·33 | 19/461 | 0·01 |
| 1·4 (0·4–2·5) | 2·3 (0·9–3·6) | 4·1 (2·3–5·9) | |||
| Staff (doctors) | 154/492 | 144/488 | 0·54 | 166/461 | 0·12 |
| 31·3 (27·2–35·4) | 29·5 (25·5–33·6) | 36·0 (31·6–40·4) | |||
| Undertake handwashing after touching a patient | 435/491 | 424/483 | 0·7 | 382/460 | 0·01 |
| 88·6 (85·8–91·4) | 87·8 (84·9–90·7) | 83·0 (79·6–86·5) | |||
| Sick contact in household during trial | 13/296 | 21/376 | 0·48 | 7/283 | 0·21 |
| 4·4 (2·1–6·7) | 5·6 (3·3–7·9) | 2·5 (0·7–4·3) | |||
| Hospital level (level 2) | 0/492 | 48/488 | <0·01 | 319/461 | <0·01 |
| 0 | 9·8 (7·2–12·5) | 69·2 (65·0–73·4) | |||
| High‐risk procedure | 201/492 | 171/488 | 0·06 | 108/461 | <0·01 |
| 40·9 (36·5–45·2) | 35·0 (30·8–39·3) | 23·4 (19·6–27·3) | |||
*Undergraduate and above.
**Cases without data are not included.