Biochemical analyses
BLOOD
Blood samples were collected fasting between 8:00 and 10:00 AM. AMH was measured by a sensitive immunoassay (Immunotech, Beckman Coulter Ltd., Marseilles, France) with an inter-assay coefficient of variation (CV) < 12%. Inhibin B was measured by a specific two-sided enzyme-linked immunoassay (inhibin B genII; Beckman Coulter, Brea, United States of America) with a CV < 11%. FSH and LH were measured by a time-resolved immuno-fluorometric assay (Delfia; Wallac, Turku, Finland) with CV < 4% for both. Testosterone and estradiol levels were measured using radio-immunoassay platforms from Siemens (Los Angeles, USA) and Pantex (Santa Monica, United States of America), with CV < 13% for both. Serum 25-hydroxyvitamin D (25OHD) was measured by isotope dilution liquid chromatography-tandem mass spectrometry with CV < 10%. Except for 25OHD at baseline, all blood analyses were conducted on frozen serum samples from day 1 and day 150 and analyzed after study completion to avoid intraassay variation (year 2015).