Table 1.
Main characteristics of participants in the study
| Total | Bronchiolitis | Number of episodes of bronchiolitis | |||||||
|---|---|---|---|---|---|---|---|---|---|
| N = 907 | N = 652 | N = 255 | N = 652 | N = 162 | N = 93 | ||||
| Variable | Category | N (%) | No | Yes | P | 0 | 1 | > 1 | p |
| Maternal age (years) | mean ± sd | 33.7 ± 5.2 | 33.84 (0.20) | 33.36 (0.32) | 0.213 | 33.84 (0.20) | 33.55 (0.41) | 33.04 (0.54) | 0.348 |
| Maternal educational level | Primary studies | 215 (22.7) | 144 (72.36) | 55 (27.64) | 0.643 | 144 (72.36) | 30 (15.08) | 25 (12.56) | 0.290 |
| Secondary studies | 112 (11.8) | 79 (72.48) | 30 (27.52) | 79 (72.48) | 23 (21.10) | 7 (6.42) | |||
| foundation degree | 272 (28.7) | 180 (68.97) | 81 (31.03) | 180 (68.97) | 48 (18.39) | 33 (12.64) | |||
| University studies | 350 (36.9) | 249 (73.67) | 89 (26.33) | 249 (73.67) | 61 (18.05) | 28 (8.28) | |||
| Maternal occupation | working | 660 (69.6) | 451 (71.36) | 181 (28.64) | 0.911 | 451 (71.36) | 121 (19.15) | 60 (9.49) | 0.655 |
| unemployed | 163 (17.2) | 116 (73.89) | 41 (26.11) | 116 (73.89) | 24 (15.29) | 17 (10.83) | |||
| Inactive | 116 (12.2) | 79 (72.48) | 30 (27.52) | 79 (72.48) | 15 (13.76) | 15 (13.76) | |||
| Student | 10 (1.1) | 6 (66.67) | 3 (33.33) | 6 (66.67) | 2 (22.22) | 1 (11.11) | |||
| Smoking in pregnancy | No | 830 (87.5) | 571 (72.10) | 221 (27.90) | 0.711 | 571 (72.10) | 140 (17.68) | 81 (10.23) | 0.922 |
| Yes | 119 (12.5) | 81 (70.43) | 34 (29.57) | 81 (70.43) | 22 (19.13) | 12 (10.43) | |||
| Cigarettes/day | mean ± sd | 0.12 (0.01) | 0.13 (0.02) | 0.712 | 0.12 (0.01) | 0.14 (0.03) | 0.13 (0.03) | 0.923 | |
| Pregnancy duration | < 34 weeks | 16 (1.7) | 10 (50.00) | 10 (50.00) | 0.038 | 10 (50.00) | 5 (25.00) | 5 (25.00) | 0.020 |
| 34–36 weeks | 36 (3.8) | 24 (63.16) | 14 (36.84) | 24 (63.16) | 6 (15.79) | 8 (21.05) | |||
| ≥37 weeks | 897 (94.5) | 618 (72.79) | 231 (27.21) | 618 (72.79) | 151 (17.79) | 80 (9.42) | |||
| Type of delivery | Vaginal | 653 (67.4) | 446 (73.00) | 165 (27.00) | 0.062 | 446 (73.00) | 105 (17.18) | 60 (9.82) | 0.216 |
| Instrumental vaginal | 80 (8.3) | 60 (78.95) | 16 (21.05) | 60 (78.95) | 11 (14.47) | 5 (6.58) | |||
| Caesarean section | 236 (24.4) | 146 (66.36) | 74 (33.64) | 146 (66.36) | 46 (20.91) | 28 (12.73) | |||
| Newborn gender | Male | 490 (50.6) | 312 (68.27) | 145 (31.73) | 0.015 | 312 (68.27) | 83 (18.16) | 62 (13.57) | 0.003 |
| female | 479 (49.4) | 340 (75.56) | 110 (24.44) | 340 (75.56) | 79 (17.56) | 31 (6.89) | |||
| Sibling pregnancy | No | 929 (95.9) | 631 (72.70) | 237 (27.30) | 0.010 | 631 (72.70) | 155 (17.86) | 82 (9.45) | 0.001 |
| Yes | 40 (4.1) | 21 (53.85) | 18 (46.15) | 21 (53.85) | 7 (17.95) | 11 (28.21) | |||
| Newborn weight | < 2500 | 83 (8.6) | 54 (66.67) | 27 (33.33) | 0.474 | 54 (66.67) | 15 (18.52) | 12 (14.81) | 0.474 |
| 2500–4000 g | 808 (93.4) | 545 (72.67) | 205 (27.33) | 545 (72.67) | 130 (17.33) | 75 (10.00) | |||
| > 4000 g | 78 (8.1) | 53 (69.74) | 23 (30.26) | 53 (69.74) | 17 (22.37) | 6 (7.89) | |||
| Attending daycare | No | 763 (78.7) | 556 (73.84) | 197 (26.16) | 0.006 | 556 (73.84) | 121 (16.07) | 76 (10.09) | 0.015 |
| Yes | 132 (13.6) | 79 (60.31) | 52 (39.69) | 79 (60.31) | 37 (28.24) | 15 (11.45) | |||
| Unknown | 74 (7.6) | 17 (73.91) | 6 (26.09) | 17 (73.91) | 4 (17.39) | 2 (8.70) | |||
| Breastfeeding durationa (months) | mean ± sd | 5.9 ± 5.2 | 6.22 (0.21) | 5.26 (0.33) | 0.014 | 6.22 (0.21) | 5.54 (0.41) | 4.79 (0.54) | 0.026 |
aAny breastfeeding