Table 1

Mean plasma concentrations (SDs) of IGF-I, IGF-II, and IGF BP-3, and the molar ratios of IGF-I and IGF-II to IGF BP-3 by gender, HRT use, height, and BMI

n (%)IGF-I in ng/mlIGF-II in ng/mlIGF BP-3 in ng/mlIGF-I/IGF BP-3IGF-II/IGF BP-3
Women171 (100)137.1 (65.5)640.0 (165.3)3778 (891)3.4 (1.4)0.64 (0.15)
 HRT within 6 months
  Yes90 (53)114.8 (53.8)624.3 (150.7)3739 (923)3.0 (1.1)0.63 (0.14)
  No80 (47)153.9 (67.1)a655.6 (185.4)a3819 (864)a3.9 (1.5)a0.65 (0.16)a
  P<0.00010.230.56<0.00010.56
 Height in feet and inchesNo HRTHRTNo HRTHRT
  <5′4”65 (38)139.6 (63.0)106.9 (44.2)614.9 (170.6)3651 (898)3.6 (1.4)3.0 (1.0)0.64 (0.17)
  5′4” to 5′7”83 (49)155.7 (66.5)119.7 (63.4)657.3 (165.4)3832 (865)3.9 (1.3)3.1 (1.2)0.65 (0.14)
  ≥5′8”23 (13)192.6 (72.0)b118.1 (39.8)641.4 (166.0)3941 (960)5.0 (2.2)3.0 (0.8)0.61 (0.13)
  P for trend0.010.640.260.100.020.380.49
 BMI in kg/m2No HRTHRTNo HRTHRT
  <2575 (44)169.6 (70.6)c114.8 (57.2)669.0 (149.6)3779 (898)4.4 (1.8)c3.0 (1.2)0.67 (0.12)
  25–3061 (36)146.1 (51.8)c107.4 (48.4)608.9 (182.4)3758 (772)3.7 (1.0)c2.9 (1.0)0.61 (0.18)
  ≥3035 (20)138.1 (73.6)c135.2 (55.7)627.4 (171.2)3812 (1078)3.5 (1.3)c3.3 (0.8)0.63 (0.13)
  P for trend0.300.610.170.570.080.600.02
Men210 (100)164.9 (62.4)a544.9 (130.1)a3629 (962)a4.6 (1.5)0.58 (0.12)
 Height in feet and inches
  <5′8”36 (19)150.0 (74.1)516.9 (140.1)3380 (1216)4.5 (1.5)0.61 (0.15)
  5′8” to 6′134 (64)169.3 (59.6)556.8 (126.1)3674 (889)4.6 (1.5)0.58 (0.11)
  ≥6′40 (19)163.6 (59.6)530.4 (132.1)3696 (941)4.5 (1.6)0.54 (0.12)
  P for trend0.130.500.010.980.0003
 BMI in kg/m2
  <2563 (30)171.2 (55.1)577.2 (118.4)3725 (833)4.7 (1.7)0.60 (0.12)
  25–30108 (51)166.9 (65.4)543.2 (130.8)3611 (1053)4.6 (1.4)0.58 (0.11)
  ≥3039 (19)149.5 (64.2)497.5 (134.1)3521 (894)4.3 (1.5)0.54 (0.13)
  P for trend0.100.0050.350.110.02
  • a To compare mean IGF levels of men and women without recent use of HRT, we used the Student t test to test for significance. The P for IGF-I was 0.16; for IGF-II, P < 0.0001; for IGF BP-3, P = 0.12; for the molar ratio of IGF-I. IGF BP-3, P = 0.0009; and for the molar ratio of IGF-II:IGF BP-3, P = 0.0004.

  • b When we compared mean levels of IGF-I of men and women without recent use of HRT by height, the P = 0.56 for those shorter than 5′8” and P = 0.24 for those 5′8” and taller. When we compared molar ratios of IGF-I to IGF BP-3 for men and women without recent use of HRT by height, the P = 0.006 for those shorter than 5′8” and P = 0.79 for those 5′8” and taller. When we compared molar ratios of IGF-II to IGF BP-3 for men and women without recent use of HRT by height, the P = 0.12 for those shorter than 5′8” and P = 0.08 for those 5′8” and taller.

  • c When we compared mean levels of IGF-I of men and women without recent use of HRT by BMI categories, the P = 0.90 for those with BMI <25, the P = 0.10 for those with BMI 25–30, and for those with BMI ≥30, P = 0.53. When we compared molar ratios of IGF-I to IGF BP-3 for men and women without recent use of HRT by BMI categories, the P = 0.56 for those with BMI <25, the P = 0.0008 for those with BMI 25–30, and for those with BMI ≥30, P = 0.03. When we compared molar ratios of IGF-II to IGF BP-3 for men and women without recent use of HRT by BMI categories, the P = 0.001 for those with BMI <25, the P = 0.41 for those with BMI 25–30, and for those with BMI ≥30, P = 0.01.