Frequencies for Each of the Responses and Missing Data for Categorical Predictor, Control, and Outcome Variables Before Data Imputation (N = 5107)
| Variable . | N (%) . |
|---|---|
| Sex of child | |
| Male | 2608 (51.1) |
| Female | 2499 (48.9) |
| Missing | 0 (0.0) |
| Wave 1 child still breastfeeding | |
| Yes | 2007 (39.3) |
| No | 3096 (60.6) |
| Missing | 4 (0.1) |
| Child was breastfed at any time | |
| Yes | 4685 (91.7) |
| No | 418 (8.2) |
| Missing | 4 (0.1) |
| Mother’s trimester 1 d per wk drinking alcohol | |
| 0 or occasional | 3934 (77) |
| 1 | 141 (2.8) |
| 2 | 85 (1.7) |
| 3 | 32 (0.6) |
| 4 | 17 (0.3) |
| 5 | 12 (0.2) |
| 6 | 5 (0.1) |
| 7 | 4 (0.1) |
| Missing | 877 (17.2) |
| Mother’s trimester 2 d per wk drinking alcohol | |
| 0 or occasional | 3823 (74.9) |
| 1 | 206 (4.0) |
| 2 | 118 (2.3) |
| 3 | 48 (0.9) |
| 4 | 19 (0.4) |
| 5 | 9 (0.2) |
| 6 | 5 (0.1) |
| 7 | 3 (0.1) |
| Missing | 876 (17.2) |
| Mother’s trimester 3 d per wk drinking alcohol | |
| 0 or occasional | 3802 (74.4) |
| 1 | 190 (3.7) |
| 2 | 133 (2.6) |
| 3 | 54 (1.1) |
| 4 | 24 (0.5) |
| 5 | 14 (0.3) |
| 6 | 6 (0.1) |
| 7 | 5 (0.1) |
| Missing | 879 (17.2) |
| Pregnancy: average No. drinks on drinking d | |
| 0 or none | 2597 (50.9) |
| 1 or 2 | 1560 (30.5) |
| 3 or 4 | 56 (1.1) |
| 5 or 6 | 7 (0.1) |
| 7–10 | 3 (0.1) |
| 11 or more | 5 (0.1) |
| Missing | 879 (17.2) |
| Mother’s level of education | |
| Never attended or still attending school | 4 (0.1) |
| ≤Year 8 | 83 (1.6) |
| Year 9 or Eq | 161 (3.2) |
| Year 10 or Eq | 820 (16.1) |
| Year 11 or Eq | 539 (10.6) |
| Year 12 or Eq | 1813 (35.5) |
| Bachelor degree | 998 (19.5) |
| Graduate diploma or certificate | 319 (6.2) |
| Postgraduate degree | 361 (7.1) |
| Missing | 9 (0.2) |
| Combined family income (Australian dollars) | |
| ≥$2400 per wk or ≥$124 800 per y | 384 (7.5) |
| $2200–$2399 per wk or $114 400–$124 799 per y | 106 (2.1) |
| $2000–$2199 per wk or $104 000–$114 399 per y | 158 (3.1) |
| $1500–$1999 per wk or $78 000–$103 999 per y | 674 (13.2) |
| $1000–$1499 per wk or $52 000–$77 999 per y | 1295 (25.4) |
| $800–$999 per wk or $41 600–$51 999 per y | 685 (13.4) |
| $700–$799 per wk or $36 400–$41 599 per y | 367 (7.2) |
| $600–$699 per wk or $31 200–$36 399 per y | 287 (5.6) |
| $500–$599 per wk or $26 000–$31 199 per y | 266 (5.2) |
| $400–$499 per wk or $20 800–$25 999 per y | 273 (5.3) |
| $300–$399 per wk or $15 600–$20 799 per y | 231 (4.5) |
| $200–$299 per wk or $10 400–$15 599 per y | 78 (1.5) |
| $100–$199 per wk or $5200–$10 399 per y | 17 (0.3) |
| $50–$99 per wk or $2600–$5199 per y | 7 (0.1) |
| $1–$49 per wk or $1–$2599 per y | 1 (<0.1) |
| Nil income | 2 (<0.1) |
| Negative income | 4 (0.1) |
| Missing | 272 (5.3) |
| Mother’s frequency of drinking alcohol (modified AUDIT-C question 1) | |
| Never | 387 (7.6) |
| Not in the last y | 414 (8.1) |
| Monthly or less | 1234 (24.2) |
| 2–3 times a mo | 582 (11.4) |
| Once a wk | 590 (11.6) |
| 2–3 times a wk | 604 (11.8) |
| 4–6 times a wk | 303 (5.9) |
| Every d | 91 (1.8) |
| Missing | 902 (17.7) |
| Mother’s average No. drinks when drinking (modified AUDIT-C question 2) | |
| 0 | 387 (7.6) |
| 1 or 2 | 2484 (48.6) |
| 3 or 4 | 611 (12.0) |
| 5 or 6 | 184 (3.6) |
| 7–10 | 64 (1.3) |
| ≥11 | 17 (0.3) |
| Missing | 1360 (26.6) |
| Mother’s frequency of drinking ≥5 drinks in 1 sitting (modified AUDIT-C question 3) | |
| Not in the last y | 2879 (56.4) |
| Monthly or less | 1022 (20.0) |
| 2 or 3 times a mo | 148 (2.9) |
| Once a wk | 95 (1.9) |
| 2–3 times a wk | 46 (0.9) |
| 4–6 times a wk | 7 (0.1) |
| Every d | 1 (0.1) |
| Missing | 909 (17.8) |
| Head injury wave 3a | |
| Yes | 7 (0.1) |
| No | 4379 (85.7) |
| Missing | 721 (14.1) |
| Head injury wave 4a | |
| Yes | 19 (0.4) |
| No | 4223 (82.7) |
| Missing | 865 (16.9) |
| Head injury wave 5a | |
| Yes | 24 (0.5) |
| No | 4024 (78.8) |
| Missing | 1059 (20.7) |
| Head injury wave 6a | |
| Yes | 28 (0.5) |
| No | 3670 (71.9) |
| Missing | 1409 (27.6) |
| Learning difficulty wave 3 | |
| Yes | 84 (1.6) |
| No | 4302 (84.2) |
| Missing | 721 (14.1) |
| Learning difficulty wave 4 | |
| Yes | 25 (0.5) |
| No | 4217 (82.6) |
| Missing | 865 (16.9) |
| Learning difficulty wave 5 | |
| Yes | 92 (1.8) |
| No | 3955 (77.4) |
| Missing | 1060 (20.8) |
| Learning difficulty wave 6 | |
| Yes | 107 (2.1) |
| No | 3670 (71.9) |
| Missing | 1409 (27.6) |
| Variable . | N (%) . |
|---|---|
| Sex of child | |
| Male | 2608 (51.1) |
| Female | 2499 (48.9) |
| Missing | 0 (0.0) |
| Wave 1 child still breastfeeding | |
| Yes | 2007 (39.3) |
| No | 3096 (60.6) |
| Missing | 4 (0.1) |
| Child was breastfed at any time | |
| Yes | 4685 (91.7) |
| No | 418 (8.2) |
| Missing | 4 (0.1) |
| Mother’s trimester 1 d per wk drinking alcohol | |
| 0 or occasional | 3934 (77) |
| 1 | 141 (2.8) |
| 2 | 85 (1.7) |
| 3 | 32 (0.6) |
| 4 | 17 (0.3) |
| 5 | 12 (0.2) |
| 6 | 5 (0.1) |
| 7 | 4 (0.1) |
| Missing | 877 (17.2) |
| Mother’s trimester 2 d per wk drinking alcohol | |
| 0 or occasional | 3823 (74.9) |
| 1 | 206 (4.0) |
| 2 | 118 (2.3) |
| 3 | 48 (0.9) |
| 4 | 19 (0.4) |
| 5 | 9 (0.2) |
| 6 | 5 (0.1) |
| 7 | 3 (0.1) |
| Missing | 876 (17.2) |
| Mother’s trimester 3 d per wk drinking alcohol | |
| 0 or occasional | 3802 (74.4) |
| 1 | 190 (3.7) |
| 2 | 133 (2.6) |
| 3 | 54 (1.1) |
| 4 | 24 (0.5) |
| 5 | 14 (0.3) |
| 6 | 6 (0.1) |
| 7 | 5 (0.1) |
| Missing | 879 (17.2) |
| Pregnancy: average No. drinks on drinking d | |
| 0 or none | 2597 (50.9) |
| 1 or 2 | 1560 (30.5) |
| 3 or 4 | 56 (1.1) |
| 5 or 6 | 7 (0.1) |
| 7–10 | 3 (0.1) |
| 11 or more | 5 (0.1) |
| Missing | 879 (17.2) |
| Mother’s level of education | |
| Never attended or still attending school | 4 (0.1) |
| ≤Year 8 | 83 (1.6) |
| Year 9 or Eq | 161 (3.2) |
| Year 10 or Eq | 820 (16.1) |
| Year 11 or Eq | 539 (10.6) |
| Year 12 or Eq | 1813 (35.5) |
| Bachelor degree | 998 (19.5) |
| Graduate diploma or certificate | 319 (6.2) |
| Postgraduate degree | 361 (7.1) |
| Missing | 9 (0.2) |
| Combined family income (Australian dollars) | |
| ≥$2400 per wk or ≥$124 800 per y | 384 (7.5) |
| $2200–$2399 per wk or $114 400–$124 799 per y | 106 (2.1) |
| $2000–$2199 per wk or $104 000–$114 399 per y | 158 (3.1) |
| $1500–$1999 per wk or $78 000–$103 999 per y | 674 (13.2) |
| $1000–$1499 per wk or $52 000–$77 999 per y | 1295 (25.4) |
| $800–$999 per wk or $41 600–$51 999 per y | 685 (13.4) |
| $700–$799 per wk or $36 400–$41 599 per y | 367 (7.2) |
| $600–$699 per wk or $31 200–$36 399 per y | 287 (5.6) |
| $500–$599 per wk or $26 000–$31 199 per y | 266 (5.2) |
| $400–$499 per wk or $20 800–$25 999 per y | 273 (5.3) |
| $300–$399 per wk or $15 600–$20 799 per y | 231 (4.5) |
| $200–$299 per wk or $10 400–$15 599 per y | 78 (1.5) |
| $100–$199 per wk or $5200–$10 399 per y | 17 (0.3) |
| $50–$99 per wk or $2600–$5199 per y | 7 (0.1) |
| $1–$49 per wk or $1–$2599 per y | 1 (<0.1) |
| Nil income | 2 (<0.1) |
| Negative income | 4 (0.1) |
| Missing | 272 (5.3) |
| Mother’s frequency of drinking alcohol (modified AUDIT-C question 1) | |
| Never | 387 (7.6) |
| Not in the last y | 414 (8.1) |
| Monthly or less | 1234 (24.2) |
| 2–3 times a mo | 582 (11.4) |
| Once a wk | 590 (11.6) |
| 2–3 times a wk | 604 (11.8) |
| 4–6 times a wk | 303 (5.9) |
| Every d | 91 (1.8) |
| Missing | 902 (17.7) |
| Mother’s average No. drinks when drinking (modified AUDIT-C question 2) | |
| 0 | 387 (7.6) |
| 1 or 2 | 2484 (48.6) |
| 3 or 4 | 611 (12.0) |
| 5 or 6 | 184 (3.6) |
| 7–10 | 64 (1.3) |
| ≥11 | 17 (0.3) |
| Missing | 1360 (26.6) |
| Mother’s frequency of drinking ≥5 drinks in 1 sitting (modified AUDIT-C question 3) | |
| Not in the last y | 2879 (56.4) |
| Monthly or less | 1022 (20.0) |
| 2 or 3 times a mo | 148 (2.9) |
| Once a wk | 95 (1.9) |
| 2–3 times a wk | 46 (0.9) |
| 4–6 times a wk | 7 (0.1) |
| Every d | 1 (0.1) |
| Missing | 909 (17.8) |
| Head injury wave 3a | |
| Yes | 7 (0.1) |
| No | 4379 (85.7) |
| Missing | 721 (14.1) |
| Head injury wave 4a | |
| Yes | 19 (0.4) |
| No | 4223 (82.7) |
| Missing | 865 (16.9) |
| Head injury wave 5a | |
| Yes | 24 (0.5) |
| No | 4024 (78.8) |
| Missing | 1059 (20.7) |
| Head injury wave 6a | |
| Yes | 28 (0.5) |
| No | 3670 (71.9) |
| Missing | 1409 (27.6) |
| Learning difficulty wave 3 | |
| Yes | 84 (1.6) |
| No | 4302 (84.2) |
| Missing | 721 (14.1) |
| Learning difficulty wave 4 | |
| Yes | 25 (0.5) |
| No | 4217 (82.6) |
| Missing | 865 (16.9) |
| Learning difficulty wave 5 | |
| Yes | 92 (1.8) |
| No | 3955 (77.4) |
| Missing | 1060 (20.8) |
| Learning difficulty wave 6 | |
| Yes | 107 (2.1) |
| No | 3670 (71.9) |
| Missing | 1409 (27.6) |
Head injuries noted at earlier waves were automatically recorded at all later waves.