Table 1.
Maternal and child characteristics of offspring with and without IQ data at 8 years of age and according to maternal dietary clusters in pregnancya
| Confoundersb | Without IQ data | With IQ datac | Fruit and vegetables | Meat and potatoes | White bread and coffee | ||
|---|---|---|---|---|---|---|---|
| Continuous | Mean (SD) | Mean (SD) | p valued | Mean (SD) | Mean (SD) | Mean (SD) | p valuee |
| Prepregnancy BMI | 22.9 (4.0) | 22.9 (3.7) | .329 | 22.4 (3.2)g | 22.6 (3.5)g | 23.7 (4.2)h | <.001 |
| Child's diet at 7 years (kJ) | 7,743 (1,930) | 7,637 (1,776) | .010 | 7,610 (1,700)g | 7,984 (2,282)h | 7,461 (2,486)i | <.001 |
| Child's age at 8 year clinic (months) | – | 103.4 (3.3) | – | 103.3 (3.1)g | 103.3 (3.1)g | 103.7 (3.7)h | <.001 |
| Categorical | n (%) | n (%) | p valuef | n (%) | n (%) | n (%) | p valuee |
|---|---|---|---|---|---|---|---|
| Maternal education | <.001 | <.001 | |||||
| Low | 2,146 (39.9) | 1,430 (21.7) | 662 (15.0)g | 719 (29.5)h | 2,195 (42.8)h | ||
| Middle | 1,856 (34.5) | 2,299 (34.9) | 1,304 (29.6)g | 961 (39.5)h | 1,890 (36.9)h | ||
| High | 1,383 (25.7) | 2,854 (43.3) | 2,442 (55.4)g | 754 (31.0)h | 1,041 (20.3)h | ||
| Housing | <.001 | <.001 | |||||
| Mortgaged/owned | 3,364 (65.0) | 5,454 (84.2) | 3,681 (85.0)g | 1,856 (78.4)h | 3,281 (66.1)i | ||
| Public/social housing | 988 (19.1) | 504 (7.8) | 206 (4.8)g | 262 (11.1)h | 1,024 (20.6)i | ||
| Other | 826 (15.9) | 522 (8.1) | 441 (10.2)g | 248 (10.5)h | 659 (13.3)i | ||
| Crowding at home (person/room) | <.001 | <.001 | |||||
| ≤0.75 | 3,425 (67.5) | 5,187 (80.9) | 3,585 (83.8)g | 1,769 (75.6)h | 3,258 (66.9)i | ||
| >0.75 | 1,650 (32.5) | 1,226 (19.1) | 691 (16.2)g | 571 (24.4)h | 1,614 (33.1)i | ||
| Partner | <.001 | <.001 | |||||
| No | 219 (4.2) | 104 (1.6) | 82 (1.9)g | 49 (2.1)g | 192 (3.8)h | ||
| Yes | 5,011 (95.8) | 6,431 (98.4) | 4,279 (98.1)g | 2,339 (97.9)g | 4,824 (96.2)h | ||
| Maternal age at birth of child (years) | <.001 | <.001 | |||||
| <20 | 350 (6.5) | 113 (1.7) | 64 (1.4)g | 98 (4.0)h | 301 (5.8)i | ||
| ≥20 to <30 | 3,411 (62.9) | 3,440 (52.1) | 2,052 (46.5)g | 1,477 (60.6)h | 3,322 (64.3)i | ||
| ≥30 | 1,659 (30.6) | 3,049 (46.2) | 2,301 (52.1)g | 864 (35.4)h | 1,543 (29.9)i | ||
| Maternal smoking in pregnancy | <.001 | <.001 | |||||
| Nonsmoker | 2,268 (43.6) | 3,632 (55.8) | 2,476 (57.0)g | 1,258 (52.9)h | 2,166 (43.5)i | ||
| Stopped | 1,564 (30.1) | 1,994 (30.7) | 1,455 (33.5)g | 695 (29.2)h | 1,408 (28.3)i | ||
| Still smoking | 1,370 (26.3) | 877 (13.5) | 414 (9.5)g | 425 (17.9)h | 1,408 (28.3)i |
| Categorical | n (%) | n (%) | p valuef | n (%) | n (%) | n (%) | p valuee |
|---|---|---|---|---|---|---|---|
| Maternal alcohol use in pregnancy | <.001 | <.001 | |||||
| Nondrinker | 513 (9.9) | 384 (5.9) | 241 (5.5)g | 177 (7.4)h | 479 (9.6)i | ||
| Stopped | 1,909 (36.8) | 2,485 (38.1) | 1,715 (39.4)g | 846 (35.5)h | 1,833 (36.9)i | ||
| Still drinking | 2,769 (53.3) | 3,648 (56.0) | 2,396 (55.1)g | 1,361 (57.1)h | 2,660 (53.5)i | ||
| Parity (number of deliveries) | <.001 | <.001 | |||||
| 0 | 2,207 (42.9) | 3,003 (46.6) | 2,216 (51.4)g | 921 (39.1)h | 2,073 (42.1)i | ||
| 1 | 1,795 (34.9) | 2,313 (35.9) | 1,383 (32.1)g | 968 (41.1)h | 1,757 (35.7)i | ||
| ≥2 | 1,146 (22.2) | 1,133 (17.5) | 716 (16.5)g | 468 (19.9)h | 1,095 (22.2)i | ||
| Ethnic origin | <.001 | <.001 | |||||
| White | 5,138 (96.4) | 6,443 (98.2) | 4,252 (97.2)g | 2,380 (98.6)h | 4,949 (97.0)g | ||
| Black | 79 (1.5) | 46 (0.7) | 42 (1.0)g | 12 (0.5)h | 71 (1.4)g | ||
| Asian | 112 (2.1) | 71 (1.1) | 81 (1.8)g | 22 (0.9)h | 80 (1.6)g | ||
| Breastfeeding | <.001 | <.001 | |||||
| Yes | 2,766 (67.1) | 5,073 (81.9) | 3,513 (87.7)g | 1,550 (73.2)h | 2,776 (66.2)i | ||
| No | 1,358 (32.9) | 1,124 (18.1) | 493 (12.3)g | 569 (26.8)h | 1,420 (33.8)i | ||
| Sex | <.001 | .717 | |||||
| Male | 2,898 (53.5) | 3,290 (49.8) | 2,283 (51.7)g | 1,245 (51.1)g | 2,660 (51.5)g | ||
| Female | 2,522 (46.5) | 3,311 (50.2) | 2,133 (48.3)g | 1,194 (48.9)g | 2,506 (48.5)g | ||
| Child dietary patterns | <.001 | <.001 | |||||
| Plant based | 469 (22.1) | 1,482 (26.2) | 1,123 (35.2)g | 321 (19.5)h | 507 (17.2)i | ||
| Traditional British | 500 (23.6) | 1,407 (24.8) | 735 (23.1)g | 442 (26.8)h | 730 (24.7)i | ||
| Processed | 1,149 (54.3) | 2,779 (49.0) | 1,328 (41.7)g | 885 (53.7)h | 1,715 (58.1)i |
Note. BMI = body mass index; SD = standard deviation.
a
Data without imputation.
b
The left portion presents the confounding variable data for mothers whose children did not have IQ data and the right portion the data for mothers of children with IQ data.
c
At least one IQ data (verbal or performance).
d
p values refer to Student's t test.
e
p values refer to analysis of variance test.
f
p values refer to chi‐square test.
g, h, i Where superscripts differ, there is a difference among variables according to the dietary clusters (Tukey–Kramer method).