Ethnic differences in adverse iron status in early pregnancy: a cross-sectional population-based study

Abstract

We studied ethnic differences in terms of iron status during pregnancy between Dutch women and other ethnicities and explore to what extent these differences can be explained by environmental factors. This cross-sectional population-based study (2002-2006) was embedded in the Generation R study and included a total of 4737 pregnant women from seven ethnic groups (Dutch, Turkish, Moroccan, Cape Verdean, Surinamese-Hindustani, Surinamese-Creole and Antillean). Ethnicity was defined according to the Dutch classification of ethnic background. Ferritin, iron and transferrin were measured in early pregnancy. The overall prevalence of iron deficiency was 7 %, ranging from 4 % in both Dutch and Surinamese-Creoles, to 18 % in Turkish, Moroccan and Surinamese-Hindustani women. Iron overload was most prevalent in Surinamese-Creole (11 %) and Dutch (9 %) women. Socioeconomic factors accounted for 5-36 % of the differences. Income was the strongest socioeconomic factor in the Cape Verdean and Surinamese-Hindustani groups and parity for the Turkish and Moroccan groups. Lifestyle determinants accounted for 8-14 % of the differences. In all groups, the strongest lifestyle factor was folic acid use, being associated with higher iron status. In conclusion, in our population, both iron deficiency and iron overload were common in early pregnancy. Our data suggest that ethnic differences in terms of socioeconomic and lifestyle factors only partly drive the large ethnic differences in iron status. Our data support the development of more specific prevention programmes based on further exploration of socioeconomic inequities, modifiable risk and genetic factors in specific ethnic subgroups, as well as the need for individual screening of iron status before supplementation.

Keywords: Ferritin; Haemoglobin; Iron overload; Iron-deficiency anaemia.

Fig. 1.

Oaxaca-Blinder decomposition explaining differences in early pregnancy. Relative contributions of determinants to the lower mean maternal serum ferritin concentration in early pregnancy as compared to the Dutch reference group. Basic determinants: age, gestational age at iron blood sampling, C-reactive protein; socioeconomic determinants: monthly household income, education, parity; lifestyle determinants: dietary iron intake, iron supplementation, folic acid supplement use, pre-pregnancy body mass index, smoking during pregnancy, psychological distress (see also Supplementary Table S3).