Determinants of circulating insulin-like growth factor I and insulin-like growth factor binding protein 3 concentrations in a cohort of Singapore men and women

Abstract

Variation in the circulating concentrations of the insulin-like growth factor (IGF) system has been implicated in the etiology of chronic diseases including cancer (prostate, breast, colon, and lung), heart disease, type 2 diabetes, and osteoporosis. We searched for sociodemographic, anthropometric, reproductive, lifestyle, and dietary determinants of IGF-I and insulin-like growth factor binding protein (IGFBP) -3 serum concentrations. Serum samples were collected in a Singapore Chinese cohort with a mean age of 61 years. Subject information was assessed during an in-person interview. Radioimmunometrically measured IGF-I and IGFBP-3 concentrations were available for 312 men and 326 postmenopausal women ages 50 years or older. Mean IGF-I concentrations were 144 ng/ml and 121 ng/ml for men and women, respectively (gender difference, P < 0.0001), and mean IGFBP-3 concentrations were 3710 ng/ml and 4147 ng/ml for men and women, respectively (gender difference, P < 0.0001). IGF-I and IGFBP-3 decreased with age (P for trend