(P30-005-25) Impact of Hormonal Contraceptives on Iron (Fe) Status in Females of Reproductive Age

Objectives: Iron (Fe) status is influenced by physiological and lifestyle factors. Prior research using the FeGenes dataset revealed significantly higher Fe status indicators in East Asian (EA) compared to Northern European (NE) adults; which was driven by an enhanced Fe absorption and altered hormonal milieu in those of EA ancestry. Contraceptive use might contribute to these differences, as hormonal contraceptive (HC) use is known to reduce menstrual blood loss. This study aims to assess the impact of HC use on Fe-related biomarkers among a cohort of reproductive-aged females.

Methods: This study population consisted of all females (n=255) enrolled in the FeGenes study (n total=504). Participants were healthy, premenopausal, non-pregnant, non-lactating females between the ages of 18-50 years without obesity or chronic diseases. To increase sample size and isolate the effects of HC, participants were grouped by contraceptive use as: HC users (n=72) or non-hormonal contraceptive users (NHC) (comprised of those taking non-hormonal contraceptives, unspecified forms of contraceptives, or no contraceptives (n=183)). Fe status and inflammatory biomarkers (serum ferritin, CRP, IL-6, sTfR, transferrin (Tf)) were assessed using immunoassays, with data presented as geometric means or means ± SD. Statistical analyses included adjustments for ancestry and BMI.

Results: The ancestry composition varied significantly between groups with 66.2% NE and 33.8% EA in the HC group and 44.0% NE and 56.0% EA in the NHC group (P=0.003). Tf was higher in the HC vs. NHC group (293.1 ± 49.6 vs. 267.0 ± 39.1 mg/dL) (P=0.0001). A greater proportion of women in the HC group had CRP levels>5 mg/L compared with those in the NHC group (18.3%vs 6.5%) (P=0.0004). Hemoglobin concentrations were higher for HC users (13.2 ± 1.0 vs. 13.0 ± 0.9 g/dL) (P=0.003), but the difference was no longer significant after controlling for ancestry group.

Conclusions: Higher serum CRP and Tf concentrations were found among those using HC even after controlling for BMI and ancestry group. Use of HC did not significantly affect hemoglobin or other Fe status biomarkers. Mechanisms responsible for higher CRP and Tf in those using HC warrant further investigation.

Funding Sources: This work was supported by The National Institute of Diabetes and Digestive and Kidney Health (NIDDK) Grant R01DK122216.