Iron status among infants 8-26 months of age in Vancouver and socio-cultural/dietary predictors of risk for iron deficiency anemia

Abstract The feeding practices of Chinese and Caucasian infants may place them at risk for IDA and its deleterious consequences. It is currently recommended that dietary assessment is used to screen 'high risk' infants for risk of IDA however, dietary instruments to assess iron nutrition among Caucasian and Chinese infants are not available. The purpose of this study was to develop and assess the utility of dietary instruments for identifying Caucasian and Chinese infants ages 8-26 mths with poor iron status. Letters describing the study were sent to 1585 parents of potentially eligible infants identified through birth lists and 613 of these parents were contacted by telephone. Of these, 148 infants 8-26 mths of age, n=84 Caucasian, n=48 Chinese completed the study. Capillary blood samples were collected and analyzed for hemoglobin (Hgb), serum ferritin and soluble transferrin receptors (sTfR). A 191-item food frequency questionnaire (FFQ) was developed to provide a comprehensive assessment of the dietary intakes and sources of energy, iron and other dietary factors influencing iron absorption. Feeding history and current diet were assessed using a Socio-Cultural and Infant Feeding Questionnaire, a 3day food record (3d-FR) and the interviewer-administered FFQ. The 3d-FR and FFQ were analyzed for dietary intakes and sources of energy, iron (total, heme and non-heme), vitamin C, calcium and dietary fibre using Food Processor®. The FFQ measures of total and heme iron intakes showed criterion validity compared with sTfRrferritin ratio (i=-0.33 and -0.27, respectively, PO.001), and relative validity compared with 3d-FR measures of total and heme iron intakes (r=0.65 and 0.72, respectively, PO.OOl). The prevalence of IDA (Hgb <110 g/L + serum ferritin <12 ug/L) was higher at ages 8-12 than 13-26 mths in Caucasian (15% vs. 4%) and Chinese (6% vs. 0%) infants (P=0.001). Low iron stores (serum ferritin £12 ug/L without IDA) was found in 30% of Caucasian and 19% of Chinese infants. The types and quantities of complementary foods fed, most notably the introduction of meats later than 9 mths of age, and subsequent low intakes of meats, in a predominandy breast milk diet were associated with the high prevalence of poor iron status among Caucasian infants. Four key dietary patterns were associated with poor iron status: 1) a history of no iron-fortified formula or supplemental iron; 2) cows' milk fed prior to 9 mths of age; 3) >800 g/day cows' milk/milk products; and 4) <30 g/day meats. Primary prevention initiatives should be targeted to 8-12 mth old Caucasian infants and include ways to ensure adequate intakes of heme iron or alternatives to this, and avoidance of early introduction or excessive quantities of cows' milk. Brief dietary-screening tools for detection of infants at risk for IDA are presented but need to be field-tested in future research.The feeding practices of Chinese and Caucasian infants may place them at risk for IDA and its deleterious consequences. It is currently recommended that dietary assessment is used to screen 'high risk' infants for risk of IDA however, dietary instruments to assess iron nutrition among Caucasian and Chinese infants are not available. The purpose of this study was to develop and assess the utility of dietary instruments for identifying Caucasian and Chinese infants ages 8-26 mths with poor iron status. Letters describing the study were sent to 1585 parents of potentially eligible infants identified through birth lists and 613 of these parents were contacted by telephone. Of these, 148 infants 8-26 mths of age, n=84 Caucasian, n=48 Chinese completed the study. Capillary blood samples were collected and analyzed for hemoglobin (Hgb), serum ferritin and soluble transferrin receptors (sTfR). A 191-item food frequency questionnaire (FFQ) was developed to provide a comprehensive assessment of the dietary intakes and sources of energy, iron and other dietary factors influencing iron absorption. Feeding history and current diet were assessed using a Socio-Cultural and Infant Feeding Questionnaire, a 3day food record (3d-FR) and the interviewer-administered FFQ. The 3d-FR and FFQ were analyzed for dietary intakes and sources of energy, iron (total, heme and non-heme), vitamin C, calcium and dietary fibre using Food Processor®. The FFQ measures of total and heme iron intakes showed criterion validity compared with sTfRrferritin ratio (i=-0.33 and -0.27, respectively, PO.001), and relative validity compared with 3d-FR measures of total and heme iron intakes (r=0.65 and 0.72, respectively, PO.OOl). The prevalence of IDA (Hgb <110 g/L + serum ferritin <12 ug/L) was higher at ages 8-12 than 13-26 mths in Caucasian (15% vs. 4%) and Chinese (6% vs. 0%) infants (P=0.001). Low iron stores (serum ferritin £12 ug/L without IDA) was found in 30% of Caucasian and 19% of Chinese infants. The types and quantities of complementary foods fed, most notably the introduction of meats later than 9 mths of age, and subsequent low intakes of meats, in a predominandy breast milk diet were associated with the high prevalence of poor iron status among Caucasian infants. Four key dietary patterns were associated with poor iron status: 1) a history of no iron-fortified formula or supplemental iron; 2) cows' milk fed prior to 9 mths of age; 3) >800 g/day cows' milk/milk products; and 4) <30 g/day meats. Primary prevention initiatives should be targeted to 8-12 mth old Caucasian infants and include ways to ensure adequate intakes of heme iron or alternatives to this, and avoidance of early introduction or excessive quantities of cows' milk. Brief dietary-screening tools for detection of infants at risk for IDA are presented but need to be field-tested in future research.