Table 3.
Multivariable analyses of the association between ethnicity and ferritin, iron deficiency, and iron overload during early pregnancy
| Total (n 4737) | Dutch (n 3112) | Turkish (n 474) | Moroccan (n 352) | Cape Verdean (n 244) | Surinamese-Hindustani (n 212) | Surinamese-Creole (n 170) | Antillean (n 173) |
|---|---|---|---|---|---|---|---|
| Serum ferritin (SDS) | |||||||
| β (95 % CI) | β (95 % CI) | β (95 % CI) | β (95 % CI) | β (95 % CI) | β (95 % CI) | ||
| Basic model | Ref | −0⋅7 (−0⋅8, −0⋅6)** | −0⋅7 (−0⋅8, −0⋅6)** | −0⋅3 (−0⋅4, −0⋅2)** | −0⋅8 (−0⋅9, −0⋅7)** | 0⋅0 (−0⋅2, 0⋅1) | −0⋅1 (−0⋅3, −0⋅0) |
| se model | Ref | −0⋅5 (−0⋅6, −0⋅4)** | −0⋅5 (−0⋅6, −0⋅4)** | −0⋅1 (−0⋅3, −0⋅0) | −0⋅7 (−0⋅8, −0⋅6)** | 0⋅1 (−0⋅0, 0⋅3) | 0⋅0 (−0⋅1, 0⋅2) |
| LS model | Ref | −0⋅7 (−0⋅8, −0⋅6)** | −0⋅7 (−0⋅8, −0⋅5)** | −0⋅2 (−0⋅4, −0⋅1)** | −0⋅7 (−0⋅9, −0⋅6)** | 0⋅0 (−0⋅2, 0⋅1) | −0⋅1 (−0⋅3, 0⋅0) |
| Full model | Ref | −0⋅6 (−0⋅7, −0⋅5)** | −0⋅5 (−0⋅6, −0⋅4)** | −0⋅1 (−0⋅3, −0⋅0) | −0⋅7 (−0⋅8, −0⋅5)** | 0⋅1 (−0⋅0, 0⋅3) | 0⋅0 (−0⋅1, 0⋅2) |
| Iron deficiency | |||||||
| OR (95 % CI) | OR (95 % CI) | OR (95 % CI) | OR (95 % CI) | OR (95 % CI) | OR (95 % CI) | ||
| Basic model | 1⋅0 | 5⋅1 (3⋅7, 7⋅1)** | 5⋅2 (3⋅7, 7⋅3)** | 2⋅0 (1⋅2, 3⋅4)* | 5⋅5 (3⋅6, 8⋅3)** | 1⋅1 (0⋅5, 2⋅4) | 1⋅5 (0⋅8, 2⋅9) |
| se model | 1⋅0 | 3⋅8 (2⋅6, 5⋅5)** | 3⋅7 (2⋅5, 5⋅5)** | 1⋅6 (0⋅9, 2⋅8) | 4⋅9 (3⋅2, 7⋅7)** | 0⋅9 (0⋅4, 2⋅0) | 1⋅2 (0⋅6, 2⋅4) |
| LS model | 1⋅0 | 4⋅3 (3⋅0, 6⋅2)** | 3⋅8 (2⋅6, 5⋅7)** | 1⋅6 (0⋅9, 2⋅8) | 4⋅6 (3⋅0, 7⋅1)** | 0⋅9 (0⋅4, 2⋅1) | 1⋅3 (0⋅6, 2⋅6) |
| Full model | 1⋅0 | 3⋅6 (2⋅4, 5⋅3)** | 3⋅1 (2⋅0, 4⋅8)** | 1⋅5 (0⋅8, 2⋅6) | 4⋅4 (2⋅8, 7⋅0)** | 0⋅8 (0⋅4, 1⋅9) | 1⋅1 (0⋅5, 2⋅3) |
| Iron overload | |||||||
| OR (95 % CI) | OR (95 % CI) | OR (95 % CI) | OR (95 % CI) | OR (95 % CI) | OR (95 % CI) | ||
| Basic model | 1⋅0 | 0⋅1 (0⋅1, 0⋅3)** | 0⋅1 (0⋅0, 0⋅3)** | 0⋅4 (0⋅2, 0⋅9) | 0⋅2 (0⋅1, 0⋅5)* | 1⋅4 (0⋅8, 2⋅3) | 0⋅8 (0⋅4, 1⋅5) |
| se model | 1⋅0 | 0⋅2 (0⋅1, 0⋅5)** | 0⋅2 (0⋅1, 0⋅6)* | 0⋅6 (0⋅3, 1⋅3) | 0⋅2 (0⋅1, 0⋅6)* | 2⋅1 (1⋅2, 3⋅6)* | 1⋅1 (0⋅6, 2⋅2) |
| LS model | 1⋅0 | 0⋅1 (0⋅1, 0⋅3)** | 0⋅1 (0⋅0, 0⋅3)** | 0⋅5 (0⋅2, 1⋅0) | 0⋅2 (0⋅1, 0⋅5)* | 1⋅3 (0⋅8, 2⋅2) | 0⋅8 (0⋅4, 1⋅5) |
| Full model | 1⋅0 | 0⋅2 (0⋅1, 0⋅4)** | 0⋅2 (0⋅0, 0⋅5)* | 0⋅6 (0⋅3, 1⋅3) | 0⋅2 (0⋅1, 0⋅6)* | 1⋅8 (1⋅0, 3⋅2) | 1⋅0 (0⋅5, 2⋅0) |
Values indicate betas (β, reflecting change in ferritin SDS) or odds ratios (ORs) with 95 % confidence interval (95 % CI), derived from linear (for serum ferritin SDS as a continuous variable) and logistic regression models (for iron deficiency and iron overload as categorical outcomes) based on multiple imputed data, reported per ethnic group compared with the Dutch (reference) group. Normal serum ferritin (15–150 μg/l). Iron deficiency is defined as serum ferritin <15 μg/l (yes/no), and iron overload as serum ferritin >150 μg/l (yes/no). The basic model was adjusted for age, gestational age at iron blood sampling and C-reactive protein. The socioeconomic (se) model was adjusted for the factors in the basic model and for income, education and parity. The lifestyle (LS) model was adjusted for the factors in the basic model and dietary iron intake, iron supplement use, folic acid supplement use, body mass index, smoking during pregnancy and psychological distress. The full model included all these determinants named (see Supplementary Figure S2). Values that are significant are indicated in bold (P < 0⋅05), with * (P < 0⋅01) or ** (P < 0⋅001).