IGF1 and fibromyalgia: Despite IGF-1 levels are influenced by age, gender, nutrition, body mass index, chronic stress and concomitant psychiatric medication, and a low sensibility stays (between 37% and 48%, when standardized by age and gender for a controlled population) [18], a subset of fibromyalgia patients with low IGF-1 serum levels (cut-off 150 ug/dL for -2SD, as in our study) but with normal insulin tolerance test has been identified [7].