Obese women less likely to have low serum ferritin levels, Nicaragua

Iron deficiency is common in developing countries also experiencing increases in overweight and obesity. Data on how weight status is associated with iron deficiency, assessed by serum ferritin, are inconsistent. This analysis examines the association between weight status and serum ferritin among reproductive age (15-49y) women in Nicaragua, considering the effect of α1-acid glycoprotein (AGP), a marker of inflammation. We analyzed data from the 2004-05 Nicaragua Integrated Surveillance System for Nutrition Interventions. We categorized body mass index (BMI) as normal weight: 18.5–24.9kg/m²; overweight: 25.0–29.9kg/m²; and obese: ≥30kg/m². Three logistic regression models were analyzed with low serum ferritin (LSF; <15 µg/L) as the dependent variable and weight status (normal weight reference) as the independent variable, controlling for: (1) age, rural/urban residence, and education, (2) model 1 plus AGP, and (3) model 1 restricted to women with AGP <1.0 g/L. Prevalences of overweight and obesity were 31.8% and 19.2%, respectively, and 27.6% had LSF. In model 1, odds of LSF was 0.74, 95% CI: (0.52, 1.05) among overweight women and 0.42, 95% CI: (0.26, 0.65) among obese women. In model 2, AGP was significantly independently associated with LSF (OR=0.56, 95% CI: 0.34, 0.92) while the OR for overweight and obesity were largely unchanged. Excluding women with elevated AGP did not appreciably affect the relationship between BMI and LSF (model 3). Overall, in this population of reproductive age women, obese women were less likely to have LSF levels, and this was independent of inflammation, as measured by AGP.