Factors affecting iron stores in infants 4-18 months of age.
OBJECTIVE
To determine the effects of dietary, physiological or environmental factors on body iron levels in infants aged 4-18 months.


METHODS
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.


METHODS
The city of Norwich, UK and some of its suburbs.


METHODS
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 < 0.001)) and body weight (-ve (P < 0.005)). In the 8 month old infants intake of cow's milk (-ve (P < 0.05)), belonging to a smoking household (-ve (P < 0.05)) and quantity of commercial babyfood consumed (+ve (P < 0.05)) were significant. In this age group there was a gender effect (girls > boys (P < 0.01)) and the gender effect remained at 12 months (girls > boys (P < 0.05)), but at 18 months only non-haem iron intake was a significant factor (-ve (P < 0.05)).


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.
Wharf
S G
SG
Institute of Food Research, Norwich Research Park, Colney, Norwich, NR4 7UA, Norfolk, UK.
Fox
T E
TE
Fairweather-Tait
S J
SJ
Cook
J D
JD
D000367:Age Factors; D000818:Animals; D001724:Birth Weight; D001835:Body Weight; D004739:England; D004777:Environment; D004909:Erythrocyte Indices; D005260:Female; D005293:Ferritins / Q000097:blood*; D006400:Hematocrit; D006454:Hemoglobins / Q000032:analysis / Q000378:metabolism*; D006801:Humans; D007223:Infant; D007225:Infant Food; D007227:Infant Nutritional Physiological Phenomena; D007501:Iron / Q000032:analysis / Q000097:blood*; D019266:Iron, Dietary / Q000008:administration & dosage*; D008297:Male; D008892:Milk / Q000009:adverse effects; D009752:Nutritional Status; D012044:Regression Analysis; D012737:Sex Factors; D011795:Surveys and Questionnaires
D006454:Hemoglobins; D019266:Iron, Dietary; D005293:Ferritins; D007501:Iron