Table 1. Characteristics of the mothers and their children (N=7,857)1.
| Maternal caffeine intake during pregnancy2 | ||||||
|---|---|---|---|---|---|---|
| Total group N=7,857 |
<2 units N=4,804 |
2-3.9 units N=2,447 |
4-5.9 units N=496 |
>6 units N=110 |
P-value3 | |
| Maternal characteristics | ||||||
| Age, median (95% range), years | 30.4 (19.3, 39.2) | 29.3 (18.7, 38.8) | 31.5 (20.5, 39.9) | 32.6 (21.2, 40.3) | 32.8 (22.2, 40.8) | <0.001 |
| Height, mean (SD), cm | 167.4 (7.4) | 166.6 (7.4) | 168.4 (7.2) | 169.4 (7.3) | 167.9 (7.1) | <0.001 |
| Pre-pregnancy weight, median (95% range), kg | 64.0 (48.0, 99.0) | 63.0 (48.0, 100.0) | 65.0 (49.0, 95.0) | 65.0 (49.0, 100.1) | 67.5 (48.1, 100.3) | 0.076 |
| Pre-pregnancy BMI, median (95% range), kg/m2 | 22.6 (17.9, 35.0) | 22.6 (17.8, 35.6) | 22.6 (18.1, 34.1) | 22.6 (18.0, 35,5) | 22.8 (18.4, 33.0) | 0.108 |
| Education, No. (%) | ||||||
| Primary | 421 (5.9) | 295 (6.8) | 106 (4.8) | 18 (4.0) | 2 (1.9) | <0.001 |
| Secondary | 3,070 (43.3) | 2,021 (46.8) | 814 (36.6) | 176 (39.5) | 59 (56.7) | |
| Higher | 3,600 (50.8) | 2,003 (46.4) | 1,302 (58.6) | 252 (56.5) | 43 (41.3) | |
| Parity, No. nulliparous (%) | 4,405 (56.4) | 2,838 (59.5) | 1,278 (52.4) | 243 (49.2) | 46 (42.2) | <0.001 |
| Ethnicity, No. European (%) | 4,485 (58.5) | 2,387 (51.1) | 1,636 (67.9) | 378 (77.6) | 84 (77.1) | <0.001 |
| Folic acid supplementation use, No. Yes (%) | 4,375 (71.3) | 2,558 (69.1) | 1,466 (75.1) | 302 (75.7) | 49 (61.3) | <0.001 |
| Smoking during pregnancy, No. Yes (%) | 1,336 (18.6) | 645 (14.7) | 493 (22.0) | 144 (31.7) | 54 (51.4) | <0.001 |
| Alcohol consumption during pregnancy, No. Yes (%) | 2,672 (37.6) | 1,339 (30.7) | 1,062 (48.0) | 215 (48.8) | 56 (54.4) | <0.001 |
| Gestational diabetes, No. Yes (%) | 80 (1.1) | 48 (1.0) | 25 (1.1) | 7 (1.5) | 0 (0.0) | N/A4 |
| Pre-eclampsia, No. Yes (%) | 153 (2.1) | 99 (2.2) | 37 (1.6) | 16 (3.4) | 1(1.0) | 0.072 |
| Gestational hypertension, No Yes (%) | 293 (3.9) | 187 (4.1) | 87 (3.7) | 15 (3.2) | 4 (3.8) | 0.775 |
| Child characteristics | ||||||
| Males, No. (%) | 3,957 (50.4) | 2,452 (51.1) | 1,176 (48.1) | 267 (53.8) | 62 (56.4) | 0.018 |
| Gestational age at birth, median (95% range), weeks | 40.1 (35.7, 42.3) | 40.1 (35.6, 42.3) | 40.1 (36.0, 42.3) | 40.3 (33.3, 42.4) | 40.2 (33.3, 42.5) | 0.001 |
| Birth weight, median (95% range), g | 3435 (2242, 4490) | 3420 (2250, 4450) | 3460 (2260, 4520) | 3490 (2144, 4567) | 3380 (1980, 4300) | <0.001 |
| Ever breastfeeding, No. Yes (%) | 5,282 (91.9) | 3,131 (92.1) | 1,733 (92.0) | 353 (90.7) | 65 (87.8) | 0.467 |
| Introduction of solid foods, No. before 6 months (%) | 3,859 (89.5) | 2,208 (88.9) | 1,321 (90.0) | 282 (91.6) | 48 (92.3) | 0.349 |
| Age at 6 year follow-up measurement, median (95% range), years | 6.0 (5.6, 7.9) | 6.0 (5.6, 8.0) | 6.0 (5.6, 7.8) | 6.0 (5.5, 7.4) | 6.1 (5.6, 7.5) | 0.042 |
| Television watching, No. More than 2 hours/day (%) | 934 (19.2) | 588 (21.0) | 284 (17.3) | 47 (13.4) | 15 (23.4) | 0.001 |
| Body mass index at 6 years, median (95% range), kg/m2 | 15.9 (13.6, 21.3) | 15.9 (13.6, 21.3) | 15.7 (13.7, 20.9) | 16.0 (13.8, 21.4) | 16.2 (13.9, 21.0) | 0.001 |
| Overweight at 6 years, No. Yes (%) | 991 (17.8) | 633 (19.2) | 280 (15.4) | 63 (17.1) | 15 (18.8) | 0.008 |
| Total body fat mass, median (95% range), % | 24.0 (16.3, 38.8) | 24.1 (16.2, 39.2) | 23.9 (16.6, 38.2) | 24.0 (16.3, 38.2) | 23.2 (15.8, 41.6) | 0.198 |
| Android/gynoid fat mass ratio, median (95% range) | 0.24 (0.16, 0.42) | 0.24 (0.16, 0.42) | 0.24 (0.16, 0.42) | 0.24 (0.16, 0.43) | 0.25 (0.17, 0.43) | 0.197 |
| Abdominal preperitoneal fat area, median (95% range), cm2 | 0.39 (0.16, 1.21) | 0.40 (0.16, 1.27) | 0.39 (0.16, 1.15) | 0.39 (0.15, 1.03) | 0.33 (0.14, 1.19) | 0.002 |
| Insulin, median (95% range), (pmol/L) | 115 (17, 402) | 115 (16, 395) | 114 (18, 408) | 132 (16, 467) | 91 (14, 369) | 0.015 |
| C-peptide median (95% range), (nmol/L) | 0.96 (0.30, 2.14) | 0.97 (0.30, 2.15) | 0.95 (0.32, 2.09) | 1.06 (0.26, 2,48) | 0.88 (0.36, 2,16) | 0.039 |
1
Values represent means (SD), median (95% range) or number of subjects (valid %).
2
1 unit of caffeine intake represents the equivalent of 1 cup of coffee (90 mg caffeine).
3
Differences in subject characteristics between the groups were tested using One-Way ANOVA for continuous variables and Chi-square tests for proportions.
4
Not available as a result of small numbers.