Iron status markers in 224 indigenous Greenlanders: influence of age, residence and traditional foods

OBJECTIVE: To evaluate iron status in indigenous Greenlanders and its relationship to gender, age and intake of traditional Greenlandic foods. Methods: Serum ferritin, serum transferrin saturation and haemoglobin were evaluated in a population survey in 1993-1994 comprising 224 Greenlandic individuals (109 men) aged 19-82 yr. The participants were residents in the capital Nuuk (n=73) with a predominantly Western style of living, the town Ilulissat (n=60) with a mixture of Western and Greenlandic style of living, and the small town Uummannaq (n=91) with a predominantly Greenlandic style of living. Consumption of traditional foods was assessed by questionnaire. RESULTS: Intake of traditional foods was more prevalent among elderly than among young individuals and more frequent in Uummannaq than in Ilulissat and Nuuk. Ferritin levels were higher in men than in women (p<0.0001). Median ferritin levels were lowest in Nuuk (men, 92 microg/L; women, 40 microg/L), higher in Ilulissat (men, 104 microg/L; women, 69 microg/L) and in Uummannaq (men, 118 microg/L; women, 46 microg/L) (p<0.001). The prevalence of iron load (ferritin >200 microg/L) was lowest in Nuuk (men: 13.8%, women: 2.3%) intermediate in Ilulissat (men, 11.1%; women, 9.1%) and highest in Uummannaq (men, 32.1%; women, 21.1%). The prevalence of iron depletion (ferritin <16 microg/L) was high in Nuuk (men, 0%; women, 20.5%), and lower in Ilulissat (men, 3.7%; women, 6.1%) and in Uummannaq (men, 0%; women, 10.5%). The prevalence of iron deficiency anaemia (ferritin <13 microg/L and Hb <5th percentile for iron-replete men and women) was 0.92% in men and 0.87% in women. Correlations between age and ferritin were lowest in Nuuk (men, r(s)=0.26, p=0.2; women, r(s)=0.50, p=0.001) intermediary in Ilulissat (men, r(s)=0.37, p=0.06; women, r(s)=0.73, p<0.0001) and highest in Uummannaq (men, r(s)=0.59, p<0.0001; women, rs=0.74, p<0.0001). Intake of traditional foods was correlated with ferritin in men (r(s)=0.29, p=0.01) and women (r(s)=0.40, p<0.0001). CONCLUSION: The observed differences in estimated body iron stores in Greenlanders from the three residential areas can be explained by differences in the dietary intake of haem iron.