Table 1. Baseline characteristics of participants according to tertiles of iron intake, SU.VI.MAX cohort, france, 1994–2007a.
| Tertile 1 (n=1548) | Tertile 2 (n=1549) | Tertile 3 (n=1549) | Pb | |
|---|---|---|---|---|
| Age, y | 47.2 ± 6.6 | 46.7 ± 6.6 | 47.1 ± 6.5 | 0.9 |
| Children, n | 2.0 ± 1.1 | 1.9 ± 1.2 | 1.9 ± 1.1 | 0.2 |
| Height, cm | 160.9 ± 5.7 | 161.9 ± 5.9 | 162.7 ± 5.9 | 0.3 |
| Body mass index, kg/m2 | 23.2 ± 3.8 | 23.0 ± 3.7 | 23.1 ± 3.8 | 0.8 |
| Menopause, yes | 486 (31.4) | 436 (28.1) | 475 (30.7) | 0.1 |
| Hormonal treatment for menopause, yes | 458 (29.6) | 436 (28.1) | 479 (30.9) | 0.2 |
| Intervention group of the initial trial | 0.4 | |||
| Antioxidant supplementation group | 751 (48.5) | 765 (49.4) | 788 (50.9) | |
| Placebo group | 797 (51.5) | 784 (50.6) | 761 (49.1) | |
| Family history of breast cancerc, yes | 146 (9.4) | 135 (8.7) | 124 (8.0) | 0.4 |
| Smoking status | 0.07 | |||
| Never | 920 (59.4) | 891 (57.5) | 868 (56.0) | |
| Former | 406 (26.2) | 462 (29.8) | 472 (30.5) | |
| Current | 222 (14.3) | 196 (12.7) | 209 (13.5) | |
| Physical activity | 0.02 | |||
| Irregular | 419 (27.1) | 377 (24.3) | 394 (25.4) | |
| < 1 h/d walking or equivalent | 489 (31.6) | 563 (36.3) | 569 (36.7) | |
| ≥ 1 h/d walking or equivalent | 640 (41.3) | 609 (39.3) | 586 (37.8) | |
| Educational level | <.0001 | |||
| Primary | 353 (22.8) | 263 (17.0) | 231 (14.9) | |
| Secondary | 609 (39.3) | 628 (40.5) | 595 (38.4) | |
| University | 586 (37.9) | 658 (42.5) | 723 (46.7) | |
| Alcohol intake, g/d | 5.2 ± 6.8 | 10.0 ± 10.9 | 17.0 ± 17.1 | <.0001 |
| Energy intake, kcal/d | 1392 ± 312 | 1777 ± 313 | 2088 ± 424 | <.0001 |
| Dietary iron, mg/d | 7.7 ± 1.3 | 10.6 ± 0.7 | 14.4 ± 2.3 | <.0001 |
| Total lipids, g/d | 63.0 ± 17.0 | 80.4 ± 17.9 | 95.7 ± 23.6 | <.0001 |
| Eicosapentaenoic acid (EPA), g/d | 0.1 ± 0.1 | 0.1 ± 0.1 | 0.1 ± 0.1 | <.0001 |
| Docosahexaenoic acid (DHA), g/d | 0.2 ± 0.2 | 0.2 ± 0.2 | 0.2 ± 0.2 | <.0001 |
SU.VI.MAX, Supplémentation en Vitamines et Minéraux Antioxydants.
a
Values are means ± SDs or N (%). Cut-offs for tertiles of total dietary iron intake were 9.3 and 11.9 mg/d.
b
P value for the comparison between tertiles of iron intake using χ2 tests or Fisher tests (P-trend) as appropriate. All statistical tests were 2-sided.
c
Among first-degree relatives.