Background: F2-isoprostanes (F2-IsoP) are oxidant stress biomarkers that are higher in HIV-infected women than men. We explored whether the effect of hemoglobin (Hgb), serum iron, or anemia on F2-IsoP is different between HIV-infected women and men.
Methods: Plasma F2-IsoP were quantified by gas chromatography/mass spectrometry; clinical and laboratory data were collected at enrollment or from the medical record. Multivariable linear regression was used to assess associations between F2-IsoP and Hgb, anemia as a dichotomous variable, and serum iron with adjustment for age, sex, race, body mass index, CD4+ lymphocyte count, self-reported current smoking status, and antiretroviral therapy.
Results: Compared with men, women had lower Hgb [median: 12.7 (interquartile range: 11.8–13.9) vs. 14.9 (13.7–15.8) g/dL, P < 0.001], lower iron levels [75 (47–97) vs. 90 (69–121) µg/dL, P = 0.004], more anemia (29% vs. 10%, P < 0.001), and higher levels of F2-IsoP [42 (32–62) vs. 36 (25–46) pg/mL, P < 0.001]. The relationship between iron and F2-IsoP differed significantly between men and women (interaction P = 0.02). Men had a 21% (95% confidence interval: 8 to 36) increase in F2-IsoP per interquartile increase in iron (P = 0.001), whereas no relationship was seen among women [−4% (−17 to 13, P = 0.65].
Conclusions: Although women have overall higher F2-IsoP than men, a relationship between circulating F2-IsoP and iron levels was observed in men but not in women with HIV infection. The association between female sex and higher F2-IsoP is not explained by iron or Hgb levels because the association persists when controlling for these factors. The role of iron in oxidant stress and sex-specific differences among HIV-infected individuals require further study.