Summary of a report on assessment of the iron nutritional status of the United States population. Expert Scientific Working Group.

This report summarizes the evaluations by an Expert Scientific Working Group of the iron nutritional status of the US population based on biochemical data for persons aged 1 through 74 yr in the second National Health and Nutrition Examination Survey, 1976-1980. Three approaches were used for estimating the prevalence of impaired iron status. The first (ferritin model) required that at least two of three indicators be abnormal: serum ferritin, transferrin saturation, erythrocyte protoporphyrin. A second approach (MCV model), using mean corpuscular volume rather than ferritin, also required that at least two of the three indicators be abnormal. Finally, the change in median hemoglobin concentration (hemoglobin percentile shift) was determined after exclusion of individuals with one or more abnormal iron status values. The range of prevalence estimates was fairly low with the exception of children aged 1-2 yr, males aged 11-14 yr, and females aged 15-44 yr. The associations of impaired iron status with hemoglobin levels, inflammatory disease, and socioeconomic and demographic variables were examined. Data on iron overload were also assessed.