The association of prediagnostic circulating levels of cardiometabolic markers, testosterone and sex hormone‐binding globulin with risk of breast cancer among normal weight postmenopausal women in the <scp>UK</scp> Biobank

Emerging evidence suggests that normal weight postmenopausal women with a relative excess of body fat are at increased breast cancer risk. However, little is known about the associations between obesity-related blood markers and risk among these individuals. In this prospective study comprising 58 629 (body mass index 18.5 kg/m2 24.9 kg/m2) who were enrolled in UK Biobank cohort 2006 2010, we examined glycated hemoglobin, triglycerides, high-density lipoprotein cholesterol, C-reactive protein (CRP), testosterone sex hormone-binding globulin (SHBG) cancer. A total 1268 cases ascertained during median follow-up period 7 years. Women CRP, free (FT) levels highest quintile had compared to those lowest (HRQ5 vs Q1: 1.35, 95% confidence interval [CI]: 1.12-1.63, HR Q5 1.47, CI: 1.20-1.80 1.53, 1.23-1.90, respectively), whereas SHBG reduced (HR 0.70, 0.56-0.88). These attenuated but persisted after additional adjustment for BMI, (whole [kg]/height [m2]) or waist circumference mutual testosterone, CRP and/or SHBG. Our association relatively high low