TABLE 2.
Pregnancies, n | Cycles at risk, n | Age adjusted FR (95% CI) | Multivariable2 FR (95% CI) | Mutually adjusted multivariable3 FR (95% CI) | |
---|---|---|---|---|---|
Snart Foraeldre, n = 1693 | |||||
Total iron, mg/d | |||||
<10 | 419 | 2348 | 1.00 (Ref.) | 1.00 (Ref.) | — |
10–11.9 | 606 | 3088 | 1.08 (0.97, 1.21) | 1.10 (0.98, 1.24) | — |
≥12 | 114 | 730 | 0.92 (0.76, 1.11) | 0.98 (0.81, 1.20) | — |
Heme iron, mg/d | |||||
<0.5 | 205 | 1125 | 1.00 (Ref.) | 1.00 (Ref.) | 1.00 (Ref.) |
0.5–0.9 | 737 | 4025 | 1.02 (0.89, 1.17) | 0.99 (0.86, 1.14) | 0.99 (0.86, 1.14) |
≥1.0 | 197 | 1016 | 1.05 (0.88, 1.25) | 1.01 (0.85, 1.22) | 1.00 (0.83, 1.20) |
Nonheme iron, mg/d | |||||
<9 | 319 | 1801 | 1.00 (Ref.) | 1.00 (Ref.) | 1.00 (Ref.) |
9–10.9 | 668 | 3495 | 1.07 (0.95, 1.21) | 1.12 (0.99, 1.27) | 1.12 (0.99, 1.27) |
≥11 | 152 | 870 | 1.02 (0.85, 1.22) | 1.11 (0.92, 1.34) | 1.11 (0.92, 1.34) |
PRESTO, n = 2969 | |||||
Total iron, mg/d | |||||
<10 | 377 | 2832 | 1.00 (Ref.) | 1.00 (Ref.) | — |
10–11.9 | 608 | 4310 | 1.06 (0.94, 1.19) | 0.98 (0.87, 1.10) | — |
≥12 | 831 | 5258 | 1.16 (1.04, 1.30) | 1.06 (0.94, 1.19) | — |
Heme iron, mg/d | |||||
<0.5 | 776 | 5262 | 1.00 (Ref.) | 1.00 (Ref.) | 1.00 (Ref.) |
0.5–0.9 | 837 | 5543 | 1.00 (0.91, 1.09) | 1.03 (0.94, 1.12) | 1.03 (0.94, 1.13) |
≥1.0 | 203 | 1595 | 0.87 (0.76, 1.01) | 1.01 (0.87, 1.17) | 1.01 (0.87, 1.18) |
Nonheme iron, mg/d | |||||
<9 | 293 | 2168 | 1.00 (Ref.) | 1.00 (Ref.) | 1.00 (Ref.) |
9–10.9 | 573 | 4116 | 1.03 (0.91, 1.18) | 0.96 (0.84, 1.09) | 0.96 (0.84, 1.09) |
≥11 | 950 | 6116 | 1.14 (1.01, 1.29) | 1.01 (0.89, 1.14) | 1.01 (0.89, 1.15) |
FR, fecundability ratio.
Adjusted for age, vocational training/education, BMI, physical activity, smoking, alcohol consumption, use of oral contraceptives, parity, cycle regularity and length, doing something to improve chances of conception, use of iron and vitamin C supplements, multivitamin use, dietary vitamin C (continuous), and total energy (continuous). The PRESTO models are also adjusted for race/ethnicity
Also adjusted for dietary heme or nonheme iron intake, respectively.