Table 1.
Univariate findings of sudden infant death syndrome
| Variables | Proportion (%) of: | Odds ratio (95% CI) | p | |
| Cases | Controls | |||
| SLEEPING ENVIRONMENT FACTORS* | ||||
| Position when put down to sleep: | ||||
| • supine | 2/35 (5.7) | 16/145 (11.0) | 1.00 (reference) | |
| • side | 33/35 (94.3) | 123/145 (84.8) | 2.15 [0.47; 9.80] | 0.325 |
| • prone | 0/35 (0) | 6/145 (4.1) | 0.00 | 0.999 |
| Sleeping surface: | ||||
| • crib | 15/35 (42.9) | 113/145 (77.9) | 1.00 (reference) | |
| • bassinet | 19/35 (54.3) | 16/145 (11.0) | 8.95 [3.80; 21.05] | <0.001 |
| • full-sized bed (parental or sofa) | 1/35 (2.9) | 16/145 (11.0) | 0.47 [0.05; 3.81] | 0.480 |
| Substandard infant mattress** | 25/35 (71.4) | 66/145 (45.5) | 3.09 [1.38; 6.89] | 0.006 |
| Waterproof cloth over the mattress | 18/35 (51.4) | 45/145 (31.0) | 2.35 [1.11; 4.98] | 0.025 |
| Use of a pillow# | 32/35 (91.4) | 135/145 (93.1) | n/a | 0.268 |
| Wearing ≥4 togs | 24/35 (68.6) | 31/145 (21.4) | 8.02 [3.55; 18.16] | <0.001 |
| Wearing a cap | 17/35 (48.6) | 24/145 (16.6) | 4.76 [2.15; 10.54] | <0.001 |
| Type of bedding: | ||||
| • medium warmth type | 18/35 (57.1) | 62/145 (42.7) | 1.00 (reference) | |
| • warm type | 14/35 (40.0) | 80/145 (55.2) | 0.54 [0.25; 1.16] | 0.114 |
| • unknown type | 1/35 (2.9) | 3/145 (2.1) | 1.03 [0.10; 10.50] | 0.978 |
| Bed sharing with parent(s) for the whole night # | 0/35 (0) | 20/145 (13.8) | n/a | 0.010 |
| Sleeping in a room alone# | 32/35 (91.4) | 135/145 (93.1) | n/a | 0.268 |
| INFANT FACTORS | ||||
| Male sex | 23/35 (65.7) | 86/145 (59.3) | 1.32 [0.61; 2.85] | 0.487 |
| Birth weight < 2500.0 g# | 5/35 (14.3) | 2/145 (1.4) | n/a | 0.003 |
| Gestation ≤36 weeks# | 3/35 (8.6) | 2/145 (1.4) | n/a | 0.051 |
| Any neonatal problem# | 3/35 (8.6) | 12/145 (8.3) | n/a | 0.589 |
| Any congenital anomaly# | 2/35 (5.7) | 12/145 (8.3) | n/a | 0.463 |
| Twins birth# | 0/35 (0) | 1/145 (0.7) | n/a | 0.810 |
| Bottle feeding of the birth | 7/35 (20.0) | 7/144 (4.9) | 4.89 [1.59; 15.05] | 0.006 |
| No dummy when sleeping | 18/35 (51.4) | 57/145 (39.3) | 1.63 [0.78; 3.43] | 0.194 |
| MATERNAL FACTORS | ||||
| Unplanned pregnancy | 30/35 (85.7) | 59/145 (40.7) | 8.75 [3.21; 23.85] | <0.001 |
| Late (month 4–9) or no prenatal care | 16/35 (45.7) | 24/144 (16.7) | 4.25 [1.91; 9.41] | <0.001 |
| Previous stillbirth# | 2/35 (5.7) | 18/144 (12.5) | n/a | 0.204 |
| Previous interruption of pregnancy# | 3/35 (8.6) | 12/145 (8.3) | n/a | 0.589 |
| Previous infant death# | 1/35 (2.9) | 4/144 (2.8) | n/a | 0.668 |
| ≥2 previous live births | 26/35 (74.3) | 74/144 (51.4) | 2.73 [1.19; 6.24] | 0.017 |
| SOCIOECONOMIC FACTORS | ||||
| Maternal age ≤20 y or ≥35 y | 15/35 (42.9) | 24/145 (16.6) | 3.78 [1.69; 8.41] | 0.001 |
| Paternal age ≤20 y or ≥35 y | 12/33 (36.4) | 21/135 (15.6) | 3.10 [1.33; 7.25] | 0.009 |
| Maternal education ≤12 y | 25/35 (71.4) | 43/145 (29.7) | 5.93 [2.62; 13.40] | <0.001 |
| Paternal education ≤12 y | 19/33 (57.6) | 56/143 (39.2) | 2.11 [0.98; 4.54] | 0.057 |
| Single mother*** | 7/35 (20.0) | 11/145 (7.6) | 3.04 [1.09; 8.54] | 0.034 |
| No waged income | 9/33 (27.3) | 15/141 (10.6) | 3.15 [1.24; 8.02] | 0.016 |
| Renting or living with parents | 16/35 (45.7) | 70/145 (48.3) | 0.90 [0.43; 1.89] | 0.785 |
| Worse than fair housing conditions# | 10/35 (28.6) | 4/144 (2.8) | n/a | <0.001 |
| Overcrowding**** # | 32/35 (91.4) | 110/144 (76.4) | n/a | 0.035 |
| Worse than fair self-perceived economic family status | 25/35 (71.4) | 16/145 (11.0) | 20.16 [8.21; 49.51] | <0.001 |
| PARENTAL LIFESTYLE FACTORS | ||||
| Maternal smoking during pregnancy | 10/35 (28.6) | 8/145 (5.5) | 6.85 [2.46; 19.05] | <0.001 |
| Paternal smoking during pregnancy | 26/35 (74.3) | 73/145 (50.3) | 2.85 [1.25; 6.50] | 0.013 |
| Exposure to smoking during pregnancy (one or both of parents smoked) | 28/35 (80.0) | 73/145 (50.3) | 3.94 [1.62; 9.61] | 0.003 |
*Variables are for routine practices.
**Includes pallet, twisted plaid, pillow
***Includes mothers who were divorced, widowed, unmarried and living separately from the father of infant.
****Living >1 person per room.
#Fisher's exact test is carried out, hence odds ratio not applicable (n/a).