Greater prevalence of iron deficiency in overweight and obese children and adolescents

Abstract

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.