Serum inhibin-b in fertile men is strongly correlated with low but not high sperm counts: a coordinated study of 1,797 European and US men  Niels Jørgensen, M.D., Ph.D., Fan Liu, Ph.D., Anna-Maria Andersson, Ph.D., Matti Vierula, Ph.D., D. Stewart Irvine, M.D., Ph.D., Jacques Auger, M.D., Ph.D., Charlene K. Brazil, B.S., Erma Z. Drobnis, Ph.D., Tina K. Jensen, M.D., Ph.D., Pierre Jouannet, M.D., James W. Overstreet, M.D., Ph.D., J. Bruce Redmon, M.D., Amy Sparks, Ph.D., Jorma Toppari, M.D., Ph.D., Christina Wang, M.D., Niels E. Skakkebæk, M.D., Shanna H. Swan, Ph.D.  Fertility and Sterility  Volume 94, Issue 6, Pages 2128-2134 (November 2010) DOI: 10.1016/j.fertnstert.2009.12.051 Copyright © 2010 American Society for Reproductive Medicine Terms and Conditions

Figure 1 The solid black line and the two dotted black lines closest to this represent the calculated average inhibin-b levels according to hour of blood sampling and the 95% confidence intervals, respectively. The dotted lines highest and lowest represent 95% of the data set. (A) shows the entire data set and (B), a higher magnification that more clearly shows the decreasing inhibin-b level during the day. Fertility and Sterility 2010 94, 2128-2134DOI: (10.1016/j.fertnstert.2009.12.051) Copyright © 2010 American Society for Reproductive Medicine Terms and Conditions

Figure 2 The associations between time-adjusted inhibin-b values and nontransformed sperm concentrations (A) and total sperm counts (B) are shown as a function (solid black line esimates and dotted lines 95% confidence interval) of inhibin-b adjusted for the time of day of the blood drawing. Sperm counts increased steeply with increasing time-adjusted inhibin-b values up to approximately 150 pg/mL, followed by a less steep increase up to approximately 300 pg/mL where after an additional increase in time-adjusted inhibin-b was not reflected by a further increase in sperm counts. Fertility and Sterility 2010 94, 2128-2134DOI: (10.1016/j.fertnstert.2009.12.051) Copyright © 2010 American Society for Reproductive Medicine Terms and Conditions