High prevalence of anaemia among African migrants in Germany persists after exclusion of iron deficiency and erythrocyte polymorphisms.

Objectives: Haematological parameters differ between individuals of African and European ancestry. However, respective data of first-generation African migrants are virtually absent. We assessed these in Ghanaian migrants living in Berlin, compared them with reference data from Germany and Ghana, and estimated the role of iron deficiency (ID) and erythrocyte polymorphisms in anaemia.

Methods: A total of 576 Ghanaians (median age, 45 years) were analysed. Blood counts were performed, haemoglobinopathies and glucose-6-phosphate dehydrogenase (G6PD) deficiency were genotyped, and concentrations of ferritin and C-reactive protein were measured to define ID.

Results: Most individuals had resided in Germany for more than a decade (median, 18 years). By WHO definition, anaemia was present in 30.9% of females and 9.4% of males. Median haemoglobin (Hb) levels were lower than among Germans (women, -0.8 g/dl, men, -0.7 g/dl). However, applying reference values from Ghana, only 1.9% of the migrants were considered anaemic. Alpha-thalassaemia, Hb variants and G6PD deficiency were observed in 33.9%, 28.3% and 23.6%, respectively. ID was highly prevalent in women (32.0%; men, 3.9%). The population fraction of anaemia cases attributable to ID was 29.0% (alpha-thalassaemia, 13.6%; G6PD deficiency, 13.5%). Nevertheless, excluding ID, alpha-thalassaemia, G6PD deficiency and sickle cell disease, anaemia prevalence remained high (women, 18.4%; men, 6.5%), and was also high when applying uncensored thresholds proposed for African Americans (females, 19.3%; males, 7.8%).

Conclusions: Iron deficiency and erythrocyte polymorphisms are common among first-generation Ghanaian migrants but explain only part of the increased prevalence of anaemia. Common Hb thresholds for the definition of anaemia may not be appropriate for this group.