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

Pediatric Obesity: Impact and Surgical Management

The incidence of children in the United States who are overweight or obese is increasing at an alarming rate, and many obesity-related complications are now being described in children. There appears to be no current pharmacologic treatment or surgical procedure that is both safe and effective for millions of obese children. Bariatric surgery may be useful, however, in carefully selected obese children with associated serious comorbidities unresponsive to medical or dietary interventions. The complications of pediatric obesity are discussed, as well as current medical and surgical management of this disorder.

Serum Iron and Body Fat Distribution in a Multiethnic Cohort of Adults Living in New York City

OBJECTIVE

To examine the relationship between serum iron and body composition in a multiracial adult cohort.

METHODS

The analysis consisted of 670 participants on whom blood analysis and anthropometric data were available. The participants were recruited as part of the Rosetta Study (1990-2000), which was designed to assess body composition in a multiethnic cohort of healthy adults. Fasting iron level was measured as part of a biochemistry panel. Dual x-ray absorptiometry was used to assess fat mass. Anthropometric measures included waist circumference and body mass index (BMI; calculated as kg/m(2)) as an index of abdominal adiposity and overall body fatness, respectively.

RESULTS

In the study cohort the mean age was 54+/-17 years and 60.9% were overweight or obese (BMI > or =25). Men had higher serum iron levels (94.91+/-34.52 microg/dL [16.99+/-6.18 micromol/L] vs 82.17+/-32.62 microg/dL [14.71+/-5.84 micromol/L]) and larger waist circumference (91.98+/-11.87 cm vs 85.24+/-12.37 cm) compared with women (P<0.001). Iron was inversely correlated with BMI (r=-0.23, P<0.001), waist circumference (r=-0.19, P<0.05), and fat mass (r=-0.19, P<0.05) among Hispanic women but not among African-American, white, or Asian women or in men of any race/ethnic group.

CONCLUSIONS

The results of this study show an inverse association of measures of body fat distribution and total fat mass with serum iron level in Hispanic women. Studies designed to explore how micronutrients are used by the body at varying degrees of body fatness could provide useful information on the micronutrient-related comorbidities of obesity.

Effect of ferroportin Q248H polymorphism on iron status in African children

BACKGROUND

Iron deficiency is common in African children, but genetic variations affecting susceptibility have not been identified. The Q248H mutation in ferroportin, a cellular iron exporter regulated by iron status and inflammation, may be associated with high iron stores in African adults.

OBJECTIVE

The study examined the prevalence of iron deficiency in African children in an area where malaria transmission is low to absent and investigated whether ferroportin Q248H provides protection from iron deficiency.

DESIGN

Complete blood counts, serum markers of iron status and inflammation, and ferroportin Q247H were measured in 208 preschool children in Harare, Zimbabwe. Iron deficiency was defined by serum ferritin and C-reactive protein (CRP) concentrations (definition 1) or by ferritin and the ratio of transferrin receptor to log10 ferritin (definition 2).

RESULTS

Q248H was present in 40 children (38 heterozygotes, 2 homozygotes), elevated CRP was present in 26 (12.5%), and iron deficiency was present in 50 (24.0%) (definition 1) or 55 (26.4%) (definition 2). The interaction between ferroportin Q248H and CRP was significant for ferritin concentrations (P = 0.027) in a 2-factor analysis of variance model. With elevated CRP, the estimated geometric mean (SE range) ferritin concentration was 74 (52-106) microg/L for Q248H heterozygotes but 24 (20-30) microg/L for wild-type subjects (P = 0.016). With normal CRP, the ferritin concentration was 16 (14-19) microg/L whether or not the mutation was present. After adjustment for age and weight-for-height z score, the odds ratio (OR) for iron deficiency in Q248H heterozygotes was not significant according to definition 1 (OR: 0.53; 95% CI: 0.18, 1.40; P = 0.222) or definition 2 (OR: 0.39; 95% CI: 0.14, 1.07; P = 0.068).

CONCLUSIONS

Any effect of Q248H in protecting against iron deficiency may be observable in children exposed to repeated inflammatory conditions. Further studies of iron status and ferroportin Q248H in African children are needed.

Concentrations of calcium, copper, iron, magnesium, potassium, sodium and zinc in adult female hair with different body mass indexes in Taiwan

We investigated concentrations of calcium, copper, iron, magnesium, potassium, sodium and zinc using atomic absorption spectroscopy in the hair of four groups of adult females (n = 392), ranging in age from 20 to 50 years, with different body mass index (BMI): BMI < 18, slim group; BMI 18-25, normal group; BMI 26-35, overweight or obese group; and BMI>35, morbidly obese group. We found that the group with BMI < 18 had the highest ratios for [Ca]/[Mg], [Fe]/[Cu] and [Zn]/[Cu], but the lowest ratio for [K]/[Na] in hair. On the contrary, the group with BMI > 35 had the highest ratio for [K]/[Na], but the lowest for [Fe]/[Cu] and [Zn]/[Cu] in hair. Furthermore, when we compared concentrations of Ca, Cu, Fe, Mg, K, Na and Zn between the groups with BMI < 18 and BMI > 35, we found that there were significant differences (p < 0.05) in zinc concentrations between these two groups. In addition, there were significant differences in Ca, Cu, Mg, K and Na concentrations, with p < 0.01 at least. From this point of view, we suggest that hair concentrations of Ca, Cu, Fe, Mg, K, Na and Zn may be correlated with adult female BMI, but further studies are needed.

Serum ferritin and risk of the metabolic syndrome in U.S. adults

OBJECTIVE

We examined the relationship among iron stores, the metabolic syndrome, and insulin resistance.

RESEARCH DESIGN AND METHODS

We conducted a cross-sectional study of 6,044 adults >20 years of age who participated in the Third National Health and Nutrition Examination Survey. Metabolic syndrome was defined as the presence of at least three of the following: elevated blood pressure, low HDL cholesterol, elevated serum triglycerides, elevated plasma glucose, and abdominal obesity. Insulin resistance was estimated using homeostasis model assessment (for insulin resistance), fasting insulin, and triglyceride-to-HDL cholesterol ratio.

RESULTS

After excluding individuals with likely hemochromatosis, mean serum ferritin values in premenopausal women, postmenopausal women, and men were 33.6, 93.4, and 139.9 microg/l, respectively. Metabolic syndrome was more common in those with the highest compared with the lowest levels of serum ferritin in premenopausal women (14.9 vs. 6.4%, P = 0.002), postmenopausal women (47.5 vs. 28.2%, P < 0.001), and men (27.3 vs. 13.8%, P < 0.001). Insulin resistance also increased across quartiles of serum ferritin for men and postmenopausal women and persisted after adjustment for age, race/ethnicity, C-reactive protein, smoking, alcohol intake, and BMI.

CONCLUSIONS

Elevated iron stores were positively associated with the prevalence of the metabolic syndrome and with insulin resistance.

Overweight children and adolescents: a risk group for iron deficiency

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.