Cycle-phase dependent associations between CRP, leptin, and reproductive hormones in an urban, Canadian sample

Objectives: To assess the relationships among reproductive hormones, follicular development, inflammation, and adiposity in a sample of urban, Canadian women. Materials and Methods: Participants (n = 41) had blood collected every 3 days through one interovulatory interval (IOI) to measure estradiol, progesterone, LH, FSH, leptin, and C-reactive protein (CRP). Participants underwent daily transvaginal ultrasound examinations during the IOI to quantify all follicles > 2 mm. CRP and leptin tertiles were used to compare conditions of high and low inflammatory processes and adiposity, respectively. Results: Luteal phase estradiol, luteal phase LH, and follicular phase progesterone were lower among individuals in the highest CRP tertile (adjusted r²= 0.63, 0.70, 0.76, respectively). Luteal and follicular phase follicle diameter was greatest in the high CRP tertile (adjusted r²= 0.68, 0.71). Follicular phase progesterone was lowest among individuals in the highest leptin tertile, and follicular phase FSH was lowest among individuals in the lowest leptin tertile (adjusted r²= 0.54, 0.45). Luteal phase follicle diameter was highest among those in the moderate leptin tertile (adjusted r²= 0.49). Discussion: This study is a first comprehensive assessment of the relationship between multiple ovarian function components and inflammatory biomarkers. The results are interpreted to mean that inflammatory and energetic stressors produce differential effects depending on population, adiposity, and cycle phase. Am J Phys Anthropol 160:389–396, 2016.