Table 1.
Baseline characteristics of the study population.
| Stratum 1 (n = 529) | Stratum 2 (n = 262) | p | |||
|---|---|---|---|---|---|
| Mean | SD | Mean | SD | ||
| Age, years | 30.40 | 5.07 | 30.21 | 5.28 | 0.613 |
| Weight, Kg | 64.83 | 11.31 | 67.17 | 13.60 | 0.017 |
| Pre–pregnancy BMI, Kg/m2 | 24.66 | 4.13 | 25.82 | 5.08 | 0.001 |
| Gestational weight gain, Kg | 11.11 | 8.17 | 9.69 | 9.47 | 0.030 |
| % (n) | % (n) | ||||
| Smoking | 16.6 (88) | 20.2 (53) | 0.214 | ||
| Parity | 62.3 (329) | 55.7 (146) | 0.075 | ||
| Planned pregnancy | 79.8 (422) | 80.5 (211) | 0.801 | ||
| Use of hormonal contraception | 18.3 (97) | 18.1 (47) | 0.929 | ||
| Pre–pregnancy BMI | |||||
| Underweight | 1.3 (7) | 2.3 (6) | 0.314 | ||
| Normal weight | 60.9 (322) | 51.5 (135) | 0.012 | ||
| Overweight | 25.7 (136) | 27.9 (73) | 0.518 | ||
| Obesity | 12.1 (64) | 18.3 (48) | 0.018 | ||
| HFE gene mutation | 31.7 (130) | 32.53 (68) | 0.834 | ||
| HFE genotype | |||||
| WT/WT | 67.3 (280) | 66.2 (141) | 0.779 | ||
| C282Y/WT | 3.8 (16) | 2.8 (6) | 0.506 | ||
| Carrier of H63D mutation | 27.4 (114) | 29.1 (62) | 0.652 | ||
| Carrier of S65C mutation | 1.4 (6) | 1.9 (4) | 0.679 | ||
| Family socioeconomic status | |||||
| Low | 16.4 (87) | 15.6 (41) | 0.774 | ||
| Middle | 66.7 (353) | 67.6 (177) | 0.816 | ||
| High | 16.8 (89) | 16.8 (44) | 0.991 | ||
| Maternal ethnic origin | |||||
| Caucasian | 82.8 (405) | 82.9 (203) | 0.991 | ||
| Asian | 0.2 (1) | 0.8 (2) | 0.221 | ||
| Arab | 7.8 (38) | 8.2 (20) | 0.853 | ||
| Black | 1.8 (9) | 0.4 (1) | 0.114 | ||
| Latin American | 7.4 (36) | 7.7 (19) | 0.849 | ||
| Adherence to Mediterranean diet | |||||
| Low–Middle | 64.7 (342) | 71.0 (186) | 0.075 | ||
| High | 35.3 (187) | 29.0 (76) | 0.075 | ||
BMI: body mass index; WT: wild type. Sample size HFE genotype = 629; sample size maternal ethnic origin = 734.