Risk Factors Contributing to Racial/Ethnic Disparities in Iron Deficiency in US Women

Abstract

Abstract Objectives Iron deficiency (ID) in women of reproductive age can negatively impact women's health, pregnancy outcomes and the health and development of their infants. Disparities in rates of iron deficiency by race and ethnicity in the US are persistent, but their causes are not well understood. This study was conducted to describe risk factors for ID and sources of racial/ethnic disparities in ID burden. Methods Adult women ages 20–49 years (N = 1,069) from the National Health and Nutrition Examination Survey 2015–16 who completed the questionnaire and laboratory examinations were included in the analysis. Risk factors for ID (serum ferritin (SF) < 12 µg/L) were examined in three domains: diet (total iron intake, total vitamin C intake, Healthy Eating Index (HEI) score), sociodemographic and acculturation (race/ethnicity, age, place of birth, interview language), and health (BMI, depression symptoms). Prevalence of ID overall and in subgroups were assessed in mean models accounting for the survey design. Associations of risk factors with ID were examined in logistic regression models using survey commands in SAS. Results In total, 153 women (11.3%) had ID. Prevalence of ID was highest in Mexican American (20.5%, n = 213) and non-Hispanic Black women (19.9%, n = 234) and lower in other Hispanic (13.5%, n = 136) and non-Hispanic, non-Black women (7.7%, n = 486) (p < 0.001). Non-US birth and Spanish language interview were associated with 67% (p = 0.01) and 77% (p = 0.001), respectively, greater risk of ID. Low iron intake and Healthy Eating Index (HEI) were not associated with risk of ID in this sample, while vitamin C intake was inversely associated with risk of ID (β (95% CI): 1.81 (1.0–3.29), p = 0.0. Finally, neither BMI nor depression symptoms was associated with ID in this sample. Stratified and multivariable analyses will be conducted in the 2015–16 and 2017–18 NHANES surveys combined to explore risk factors by race/ethnicity. Conclusions Sociodemographic and lifestyle characteristics are predictive of ID risk in US women. Planned analyses will generate race/ethnicity-specific risk profiles and identify actionable targets for intervention to reduce racial/ethnic disparities in ID prevalence. Funding Sources None.