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Medline ® Abstracts for References 8,9

of 'Iron requirements and iron deficiency in adolescents'

Greater prevalence of iron deficiency in overweight and obese children and adolescents.
Pinhas-Hamiel O, Newfield RS, Koren I, Agmon A, Lilos P, Phillip M
Int J Obes Relat Metab Disord. 2003;27(3):416.
OBJECTIVE: To assess whether overweight children and adolescents, who often have poor dietary habits, are at increased risk of iron deficiency (ID).
METHODS: The study sample included 321 children and adolescents followed in two endocrine centers in Israel between 1999 and 2001. The subjects were divided into three groups on the basis of body mass index (BMI) for age and gender as follows: group 1-BMI below 85th percentile (normal weight); group 2-BMI above 85th, but below 97th percentile (overweight); and group 3-BMI above 97th percentile (obese). ID was defined as iron levels<8 micromol/l (45 mcg/dl), and iron-deficiency anemia (IDA) was defined as ID and hemoglobin level below 2 standard deviation score (SDS) for the mean for age and gender.
RESULTS: Iron levels below 8 micromol/l (45 mcg/dl) were noted in 38.8% of the obese children and 12.1% of the overweight children, compared with 4.4% of the normal-weight group (P<0.001). There was a significant negative correlation of low iron levels with BMI SDS (r=-0.44, P<0.001), but not with age or gender. Among the children with ID, 26.6% also had IDA. Groups 1, 2, and 3 accounted for 6.7%, 35%, and 58.3% of the children with IDA, respectively.
CONCLUSIONS: ID is common in overweight and obese children. A significantly greater proportion of obese than normal-weight children have IDA. Insufficient dietary intake of iron, whether absolute or relative to body mass, and increased iron needs may be a result of unbalanced nutrition or repeated short-term restrictive diets. Because of potentially harmful effects of ID, obese children should be routinely screened and treated as necessary.
Pediatrics Endocrinology and Metabolism, Schneider Children's Medical Center, Petah-Tikva, Israel. orithami@sheba.health.gov.il
Overweight children and adolescents: a risk group for iron deficiency.
Nead KG, Halterman JS, Kaczorowski JM, Auinger P, Weitzman M
Pediatrics. 2004;114(1):104.
BACKGROUND: The prevalence of obesity has increased at an epidemic rate, and obesity has become one of the most common health concerns in the United States. A few small studies have noted a possible association between iron deficiency and obesity.
OBJECTIVE: To investigate the association between weight status, as measured by body mass index (BMI), and iron deficiency in a nationally representative sample of children and adolescents.
DESIGN: National Health and Nutrition Examination Survey III (1988-1994) provides cross-sectional data on children 2 to 16 years of age. Recorded measures of iron status included transferrin saturation, free erythrocyte protoporphyrin levels, and serum ferritin levels. Children were considered iron-deficient if any 2 of these values were abnormal for age and gender. With the use of age- and gender-specific BMI percentiles, at risk for overweight was defined as a BMI of>or =85th percentile and<95th percentile, and overweight was defined as a BMI of>or =95th percentile. The prevalence of iron deficiency was compared across weight groups. Logistic regression was used to estimate the association between iron status and overweight, controlling for age, gender, ethnicity, poverty status, and parental education level.
RESULTS: In this sample of 9698 children, 13.7% were at risk for overweight and 10.2% were overweight. Iron deficiency was most prevalent among 12- to 16-year-old subjects (4.7%), followed by 2- to 5-year-old subjects (2.3%) and then 6- to 11-year-old subjects (1.8%). Overweight 2- to 5-year-old subjects (6.2%) and overweight 12- to 16-year-old subjects (9.1%) demonstrated the highest prevalences of iron deficiency. Overall, the prevalence of iron deficiency increased as BMI increased from normal weight to at risk for overweight to overweight (2.1%, 5.3%, and 5.5%, respectively), and iron deficiency was particularly common among adolescents (3.5%, 7.2%, and 9.1%, respectively). In a multivariate regression analysis, children who were at risk for overweight and children who were overweight were approximately twice as likely to be iron-deficient (odds ratio: 2.0; 95% confidence interval: 1.2-3.5; and odds ratio: 2.3; 95% confidence interval: 1.4-3.9; respectively) as were those who were not overweight.
CONCLUSIONS: In this national sample, overweight children demonstrated an increased prevalence of iron deficiency. Given the increasing numbers of overweight children and the known morbidities of iron deficiency, these findings suggest that guidelines for screening for iron deficiency may need to be modified to include children with elevated BMI.
Section of General Pediatrics, Department of Pediatrics, Yale University, New Haven, Connecticut 06520-8064, USA. kgnead@alumni.middlebury.edu