Obesity,Age,and Oxidative Stress in Middle-Aged and Older Women

Abstract

Recent evidence suggests that urinary F₂-isoprostanes (F₂-IsoPs) are more accurate markers of oxidative stress than other available biomarkers. Most previous studies used unmetabolized F₂-IsoPs as a biomarker. Few previous studies measured 15-F_2t-IsoP-M, a metabolite of one of the most common F₂-IsoPs, 15-F_2t-IsoP. Unlike 15-F_2t-IsoP, 15-F_2t-IsoP-M is not subject to autoxidation and renal production. To our knowledge, no study has compared the associations of age and body mass index (BMI) with F₂-IsoPs to those with 15-F_2t-IsoP-M. Urinary levels of F₂-IsoPs and 15-F_2t-IsoP-M were measured using gas chromatography–mass spectrometry for 845 healthy women aged 40–70 years. Both F₂-IsoPs and 15-F_2t-IsoP-M were elevated among smokers. The level of 15-F_2t-IsoP-M increased with age, particularly after menopause, and with BMI. In contrast, F₂-IsoPs decreased with age, regardless of menopausal status, and was not related to BMI. The association of 15-F_2t-IsoP-M with age or menopausal status did not differ by BMI category, and the association with BMI was also independent of age or menopausal status. 15-F_2t-IsoP-M appears to be a valuable biomarker of oxidative stress in age- and obesity-related diseases. Antioxid. Redox Signal. 14, 2453–2460.