Time to revive popeye? : Secular trends in the prevalence of iron deficiency among US toddlers: 1976-2002

Background: Iron deficiency (ID) and iron-deficiency anemia affect 2.4 million and 490,000 US children, respectively. Striking racial/ethnic disparities in ID prevalence have been documented for toddlers. But, no studies have examined national secular trends in ID in toddlers. Objective: To examine secular trends in ID among US children 1-3 years old. Methods: Time-trend analyses of NHANES II-IV (1976-2002) were performed for a nationally representative sample of children 1-3 years old. Iron status measures included transferrin saturation, free erythrocyte protoporphyrin, and serum ferritin. Chi-square tests were performed to evaluate changes in ID prevalence by race/ethnicity, weight-for-height status, and poverty. Multivariate analyses were performed to adjust for NHANES survey wave, race/ethnicity, age, gender, birthweight, weight-for-height status, poverty, and blood lead level. Results: Between 1976-2002, there was no change in the prevalence of ID (9%) in US toddlers. ID prevalence remained unchanged in Latino (15%) and white (6%) toddlers but decreased from 15% to 6% among African-American toddlers (p=.006). For all 3 survey waves, racial/ethnic disparities in ID persisted between Latino and white toddlers with a disparity ratio of at least 2 (p<.03). The ID prevalence remained high (20-25%) in overweight toddlers, significantly higher than in at-risk for overweight (11%) and normal-weight (8%) toddlers (p<.03). ID prevalence decreased from 22% to 9% in toddlers in poor households (p=.001), but remained unchanged in toddlers in households at/above the federal poverty threshold (7%). In multivariate analyses, Latino toddlers (OR, 2.2; 95% CI, 1.4-3.4) and overweight toddlers (OR, 3.0; 95% CI, 1.8-4.8) had higher odds of ID. Conclusions: There has been no change in the prevalence of ID among US toddlers in the last 26 years. Racial/ethnic disparities in ID prevalence persist between Latino and white toddlers. The ID prevalence has remained consistently high in overweight toddlers, higher than in at-risk for overweight and normal-weight toddlers. Implications for Policy, Delivery, or Practice: Efforts to reduce the prevalence of ID in infancy and early childhood are urgently needed and should target Latino and overweight toddlers.