67404
document
Effects of iron supplements and perinatal factors on fetal hemoglobin disappearance in LBW infants . BACKGROUND The homeostatic mechanisms of iron metabolism and erythropoiesis in infants are unclear . Infants synthesize both fetal hemoglobin ( HbF ) and adult hemoglobin ( HbA ) , and it is not known how the hemoglobin switch is regulated . We hypothesized that iron supplements to infants affect the disappearance of HbF . METHODS We randomized 285 low-birth-weight infants ( 2,000-2,500 g ) into three intervention groups receiving 0 , 1 , or 2 mg/kg/d of iron supplements from 6 wk to 6 mo of age . In the present secondary analysis , we analyzed iron status , total hemoglobin ( Hb ) , and HbF fraction at 6 wk , 12 wk , and at 6 mo and calculated absolute levels of HbF . RESULTS We observed dose-dependent increased levels of Hb in iron-supplemented groups at 6 mo of age . However , for absolute HbF concentration , there was no similar effect of intervention . Mean ( SD ) HbF was 81.2 ( 16.8 ) , 37.0 ( 13.8 ) , and 8.1 ( 5.6 ) g/l at 6 wk , 12 wk , and 6 mo , respectively , similar in all groups . In linear regression analyses , postconceptional age turned out as the major predictor of HbF , independent of gestational age at birth . CONCLUSION Our hypothesis was rejected . Instead , we confirmed a close correlation to postconceptional age , supporting a genetically programmed switch , insensitive to most environmental factors including birth .
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Intervention_Pharmacological
iron supplements
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Outcome_Physical
analyzed iron status , total hemoglobin ( Hb ) , and
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Outcome_Other
levels
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Outcome_Other
intervention .
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Participant_Condition
LBW
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Participant_Age
infants
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Participant_Sample-size
285
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Participant_Condition
low-birth-weight