Women’s Health
Correlates of iron deficiency in non-pregnant women of reproductive age 15-49 years, NHANES 2021-2023 Mollie Killion* Mollie Killion Killion Killion Killion Centers for Disease Control and Prevention
Background: Iron deficiency (ID) is prevalent but frequently undiagnosed in women of reproductive age (WRA), leading to morbidity despite availability of effective treatment. Using a physiologically-based (PB) approach, the threshold to identify early iron-deficient erythropoiesis is higher than the current CDC 1998 threshold, which is based on limited data and expert opinion.
Objectives: We estimated ID prevalence among non-pregnant WRA using inflammation-adjusted serum ferritin (SF). We compared the CDC guideline (CDC-ID) and PB SF (PB-ID) thresholds. We also identified correlates associated with PB-ID.
Methods: Using NHANES 2021–2023, we estimated ID prevalence classified as CDC-ID (SF<15 µg/L) and PB-ID (SF<25 µg/L). We used quasibinomial log-link models to estimate adjusted prevalence ratios (aPR, 95%CI), identifying underlying, immediate, and biological correlates associated with PB-ID, with alpha of p<0.05. Analyses used R survey package and phlebotomy weights.
Results: CDC-ID prevalence was 23.1% and PB-ID was 40.0%. Age 15–19 was associated with increased PB-ID prevalence compared to age 31–40 (aPR 1.4; 95%CI: 1.0, 1.9). Compared to non-Hispanic White, Mexican American and Other Hispanic race/ethnicity were associated with higher PB-ID prevalence (1.4; 1.0, 2.0 & 1.5; 1.1, 1.9, respectively). Having regular menstruation and BMI > 30 kg/m2 were also positively associated with PB-ID (2.5; 1.6, 4.0 & 1.3; 1.0, 1.6) compared to no regular menstruation and normal BMI. Alcohol use, iron intake, food security status, poverty level, health insurance status, and education were not associated with PB-ID.
Conclusion: ID prevalence among WRA in the U.S. is high, with meaningful differences (17 percentage points) between prevalence based on CDC versus PB thresholds. Predominantly biological correlates were associated with PB-ID. Understanding factors associated with ID can help identify WRA at risk of ID-related adverse outcomes and inform updated screening guidance.