Iron status in Danish men 1984-94:: a cohort comparison of changes in iron stores and the prevalence of iron deficiency and iron overload

Background and objectives: From 1954 to 1987, flour in Denmark was fortified with 30 mg carbonyl iron per kg. This mandatory fortification was abolished in 1987. The aim of this study was to compare iron status in Danish men before and after abolition of iron fortification. Methods : Iron status (serum ferritin, haemoglobin), was assessed in population surveys in Copenhagen County during 1983-84 comprising 1324 Caucasian men (1024 non-blood-donors, 300 blood donors) and in 1993-94 comprising 1288 Caucasian men (1103 non-blood-donors, 185 donors), equally distributed in age cohorts of 40, 50, 60 and 70 yr. Results : In the 1984 survey median serum ferritin values in the four age cohorts in non-blood-donors were 136, 141, 133 and 111 mug/L, and in the 1994 survey 177, 173, 186 and 148 mug L-1, respectively. The difference was significant in all age groups (P<0.001). There was no significant difference between the two surveys concerning the prevalence of small iron stores (ferritin 16-32 mug L-1), depleted iron stores (ferritin <16 mug L (-1)) or iron-deficiency anaemia (ferritin <13 mug L-1 and Hb <5th percentile for iron-replete men). However, from 1984 to 1994, the prevalence of iron overload (ferritin >300 mug L-1) increased from 11.3% to 18.9% (P <0.0001). During the study period there was an increase in body mass index (P<0.0001), alcohol consumption (P<0.03) and use of non-steroid anti-inflammatory drugs (NSAID) (P<0.0001), and a decrease in the use of vitamin-mineral supplements (P<0.04) and in the prevalence of tobacco smoking (P<0.0001). In contrast, median ferritin in blood donors showed a significant fall from 1984 to 1994 (103 vs. 74 mug L (-1),P<0.02). Conclusion : Abolition of iron fortification reduced the iron content of the Danish diet by an average of 0.24 mg MJ(-1), and the median dietary iron intake in men from 17 to 12 mg d(-1). From 1984 to 1994, body iron stores and the prevalence of iron overload in Danish men increased significantly, despite the abolition of food iron fortification. The reason appears to be changes in dietary habits, with a lower consumption of dairy products and eggs, which inhibit iron absorption, and a higher consumption of alcohol, meat, and poultry, containing haem iron and enhancing iron absorption. The high prevalence of iron overload in men may constitute a health risk.