Journal of Nutrition
August 2002 (Volume 132, Number 8)
Low Income Postpartum Women Are at Risk of Iron Deficiency
Bodnar LM, Cogswell ME, Scanlon KS
Journal of Nutrition. 2002;132(8):2298-2302
The aim of this study was 2-fold -- first, to estimate the prevalence of postpartum iron deficiency, iron-deficiency anemia, and anemia in the United States, and second, to compare the prevalence of iron deficiency among postpartum women with that of women of childbearing age who have never been pregnant.
Data from the Third National Health and Nutrition Examination Survey 1988-1994 (NHANES III) was used for this study. This survey used a stratified, multistage probability design to select participants from the civilian non-institutionalized population of the United States. Data were collected via household interviews and physical examinations in mobile centers. Iron deficiency was defined as abnormal values for > 2 of 3 iron status measures (serum ferritin, free erythrocyte protoporphyrin, transferrin saturation). The postpartum period was determined by the number of months after the last pregnancy. A poverty index ratio was defined as the total household income divided by the poverty threshold in the interview year. A low income was defined as a poverty index of 0% to 130%.
A total of 680 postpartum women and 587 never pregnant women aged 20-40 years were studied. Iron-deficiency prevalence for women 0-6, 7-12, and 13-24 months postpartum were 12.7%, 12.4%, and 7.8%, respectively, and 6.5% among never-pregnant women. The risk of iron deficiency among women with a poverty index of > 130% who were 0-6, 7-12, and 13-24 months postpartum was 4.1%, 3.1%, and 2.0% times as great as for never-pregnant women, with the 95% CI being 2.0% to 7.1%, 1.3% to 6.5%, and 0.8% to 4.1%, respectively.
The authors conclude that low-income postpartum women have a substantially greater iron deficiency risk than never-pregnant women and that more attention should be given to preventing iron deficiency among low-income women during and after pregnancy.
Clinical Commentary
The strength of this study lies in the number of subjects studied and the use of a well-established, well-respected national survey. Iron deficiency is one of the most common nutritional deficiencies among US women of child-bearing age and is associated with impaired cognitive function[1] and reduced work capacity.[2] Since pregnant women require ~1000 mg of total body iron, mainly for supplying oxygen to the fetus and increasing maternal red cell mass, they are at a particular risk of developing iron deficiency if not supplemented during pregnancy.
The results of this study provide evidence that disparities in iron deficiency exist by income status in the postpartum period. Clearly, efforts should be directed at determining the most effective ways in which iron deficiency among low-income women can be reduced.
References
1. Bruner AB, Joffe A, Duggan AK, Casella JF, Brandt J. Randomised study of cognitive effects of iron supplementation in non-anaemic iron-deficient adolescent girls. Lancet. 1996;348:992-996.
2. Scholtz BD, Gross R, Schultnik W, Sastroamidjojo S. Anaemia is associated with reduced productivity of women workers even in less-physically strenuous tasks. Br J Nutr. 1997;77:47-57.