Table 2

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, caloric intake, weekly physical activity level, and reproductive factors

n (%)IGF-I in ng/mlIGF-II in ng/mlIGF BP-3 in ng/mlIGF-I/IGF BP-3IGF-II/IGF BP-3
Men
 Caloric intakea
  Low45 (21)174.4 (74.7)539.0 (131.6)3557 (968)4.8 (1.8)0.58 (0.12)
  Medium75 (36)159.4 (51.6)541.2 (136.7)3604 (989)4.5 (1.3)0.57 (0.13)
  High90 (43)161.0 (58.3)554.3 (123.2)3726 (934)4.4 (1.3)0.57 (0.11)
  P for trend0.260.370.300.050.78
 Weekly physical activityb
  High22 (10)167.1 (67.4)604.7 (156.7)3934 (796)4.3 (1.6)0.57 (0.11)
  Low188 (90)164.7 (62.0)537.9 (125.3)3593 (975)4.6 (1.5)0.58 (0.12)
  P for trend0.870.020.120.290.90
Women
 Caloric intakea
  Low56 (33)131.7 (50.5)641.9 (158.4)3733 (783)3.5 (1.2)0.65 (0.16)
  Medium57 (33)133.0 (71.5)633.0 (204.3)3815 (899)3.4 (1.6)0.62 (0.17)
  High58 (34)134.0 (66.6)642.2 (136.1)3786 (991)3.4 (1.4)0.65 (0.12)
  P for trend0.850.990.760.740.91
 Weekly physical activityb
  High10 (6)109.5 (53.9)719.4 (142.9)3542 (768)3.0 (0.9)0.76 (0.11)
  Low161 (94)134.4 (63.6)634.0 (168.2)3793 (899)3.5 (1.4)0.63 (0.12)
  P0.230.120.390.270.008
 Age at menopause
  <50 years111 (65)126.8 (59.8)636.5 (163.2)3733 (922)3.3 (0.4)0.65 (0.15)
  ≥50 years58 (35)145.3 (68.9)642.5 (179.5)3854 (826)3.7 (1.4)0.63 (0.15)
  P0.070.830.400.180.38
 Report of miscarriage
  Yes56 (33)134.3 (61.9)655.3 (168.5)3864 (825)3.4 (1.4)0.64 (0.15)
  No115 (67)132.2 (64.1)631.1 (167.4)3737 (923)3.5 (1.4)0.64 (0.15)
  P0.840.380.380.880.99
 Parity
  Parous150 (88)133.7 (65.3)644.2 (171.7)3743 (889)3.5 (1.4)0.65 (0.12)
  Nulliparous21 (12)127.5 (46.3)602.5 (133.1)4034 (892)3.1 (1.1)0.56 (0.15)
  P0.680.290.160.300.01
  • a Daily caloric intake was divided based on tertiles of consumption: among women, low was defined as <1375 calories, medium as 1375–1908 calories, and high as >1908 calories. Among men, low was defined as <1793 calories, medium as 1793–2395 calories, and high as >2395 calories.

  • b High weekly physical activity was defined as self-report of one or more weekly episodes of “active sports” or “jogging or running.”