Subject characteristics by SES group
| All (n=412) | Lower SES (n=264) | Higher SES (n=148) | p Value | |
|---|---|---|---|---|
| Infant age, mean±SD, weeks | 8.9±6.6 | 8.6±6.7 | 9.3±6.3 | 0.17 (NS) |
| Infant gender, n male (%) | 210 (51.1) | 131 (49.6) | 79 (53.7) | 0.42 (NS) |
| Parent age, mean±SD, year | 26.8±6.0 | 25.0±5.1 | 29.9±6.2 | <0.01 |
| Parent gender, n female (%) | 410 (99.5) | 262 (99.2) | 148 (100) | 0.29 (NS) |
| Marital status, n (%) | ||||
| Married | 89 (21.7) | 22 (8.3) | 67 (45.9) | <0.01 |
| Separated/divorced | 14 (3.4) | 9 (3.4) | 5 (3.4) | 0.99 (NS) |
| Never married | 307 (74.9) | 233 (88.3) | 74 (50.7) | <0.01 |
| Parent highest education completed, n (%) | ||||
| <8th grade | 1 (0.2) | 1 (0.4) | 0 (0) | 0.46 (NS) |
| Grade 9–11 | 41 (10.0) | 39 (14.8) | 2 (1.4) | <0.01 |
| Grade 12 | 163 (39.8) | 134 (50.8) | 29 (19.9) | <0.01 |
| Some college/technical/vocational school | 100 (24.4) | 69 (26.1) | 31 (21.2) | 0.27 (NS) |
| Technical or vocational school | 25 (6.1) | 11 (4.2) | 14 (9.6) | 0.03 |
| Four year college | 46 (11.2) | 8 (3.0) | 38 (26.0) | <0.01 |
| Postgraduate | 34 (8.3) | 2 (0.8) | 32 (21.9) | <0.01 |
| Healthcare provider recommended exclusive supine sleep position, n (%) | 279 (67.7) | 185 (70.1) | 94 (63.5) | 0.17 (NS) |
| Senior caregiver present in home, n (%) | 126 (30.6) | 100 (37.9) | 26 (17.6) | <0.01 |
| Parent observed infant placed prone in birth hospital, n (%) | 17 (4.1) | 12 (4.5) | 5 (3.4) | 0.57 (NS) |
| Sleep position, n (%) | ||||
| Supine exclusively | 259 (62.9) | 162 (61.4) | 97 (65.5) | 0.40 (NS) |
| Side exclusively | 35 (8.5) | 24 (9.1) | 11 (7.4) | 0.56 (NS) |
| Prone exclusively | 39 (9.5) | 26 (9.8) | 13 (8.8) | 0.72 (NS) |
| Supine occasionally | 328 (79.6) | 206 (78.0) | 122 (82.4) | 0.29 (NS) |
| Side occasionally | 96 (23.3) | 63 (23.9) | 33 (22.3) | 0.72 (NS) |
| Prone occasionally | 60 (14.6) | 38 (14.4) | 22 (14.9) | 0.90 (NS) |
SES, socioeconomic status.