The overall objective of this application is to characterize current patterns and determinants of iron status in women of reproductive age (12-49 years), using nationally representative data from the recently completed (1988-94) NHANES III. Iron status will be defined in terms of biochemical indicators: serum ferritin, transferrin saturation, erythrocyte porphyrin, mean corpuscular volume and hemoglobin.
The Specific Aims i nclude the identification of subgroups at risk for iron deficiency or excess, quantification of trends in iron status over the past 20 years by comparison to results from previous NHANES surveys and assessment of the contributions of supplement use and dietary sources (especially fortified products) to iron intake and status. Dietary data will be based on 24 hour recall and food frequency questionnaires. The sociodemographic correlates of iron deficiency and excess will be identified using multivariate techniques such as logistic regression and general linear models. Sample weights and Strata and Pseudo Primary Sampling Units will be used for calculating variance estimates using the program SUDAAN, which can account for the complex study design of the HANES datasets. Similarly, all the final logistic and ordinary least squares models will also be tested using SUDAAN. The investigators state that this project will help ascertain whether iron deficiency remains a major public health problem in the United States. It will provide an up-to-date picture of iron status among women, including the prevalence of iron excess, which is regarded as an emerging health problem. High iron stores are perceived to increase the risks of hereditary hemochromatosis and chronic disease. Although causality cannot be established due to the limitations of the NHANES, the examination of the strength and direction of the associations of iron excess with predisposing factors for and/or chronic disease is expected to improve significantly current understanding of this emerging area of concern and will be useful for identifying groups at risk and for guiding future research. The investigators state that in summary, the project is expected to provide information that can be used to examine policy options and develop guidelines to ensure adequate but safe iron status for women of reproductive age.
