Factors affecting iron stores in infants 4–18 months of age

Objectives To determine the effects of dietary, physiological or environmental factors on body iron levels in infants aged 4-18 months.Design The daily iron intake of the infants was measured from a diet history obtained by interview using a standardised question sheet, previously validated against weighed intake (minimum 3 days) in an independent sample of 8 and 18 month old infants. Capillary blood samples were analyzed for haemoglobin, mean cell volume, haematocrit, zinc protoporphyrin and plasma ferritin concentration. Ferritin values were log-transformed prior to analysis to give a better approximation to the normal distribution and forward stepwise multiple linear regression was carried out using SPSS.Setting The city of Norwich, UK and some of its suburbs.Subjects One hundred and eighty-one healthy infants in age groups 4, 8, 12 and 18 months.Results Main determinants of iron stores in the 4 month old infants were birth weight (+ve (P boys (P boys (P Conclusions At 4 months of age birth weight and body weight exert the greatest influence on iron stores, whereas by 8 months components of the weaning diet have an effect (commercial babyfood (+ve), cow's milk (-ve)); there is also a gender effect (girls > boys), possibly reflecting the different growth rate between boys and girls. At 12 and 18 months the only significant factors are gender (girls > boys) and non-haem iron intake (-ve) respectively.