Table 4

Mean plasma concentrations (SDs) of IGF-I, IGF-II, and IGF BP-3, and the ratios of IGF-I and IGF-II to IGF BP-3 by HRT use and selected smoking characteristics in women

no HRT (n = 80)HRT (n = 90)no HRTHRTP
IGF-I in ng/ml
 Smoking status
  Never148114.6 (59.4)91.6 (46.7)0.35
  Former2841157.8 (72.4)115.0 (52.9)0.006
  Current3841165.4 (61.7)119.1 (55.9)0.0008
 Current smokers, pack-yearsa
  Low1016179.1 (66.4)105.6 (38.5)0.007
  Medium1515170.6 (67.4)136.5 (67.5)0.18
  High1310149.0 (51.6)114.6 (59.2)0.15
  P for trend0.240.55
 Former smokers, pack-yearsa
  Low1318168.1 (78.8)122.9 (63.1)0.09
  Medium912172.2 (68.9)113.8 (49.0)0.03
  High611114.1 (53.3)103.3 (38.7)0.64
  P for trend0.190.34
 Current smokers, number of cigarettes smoked daily
  1–19915160.5 (48.8)102.1 (38.5)0.004
  20–392319164.4 (70.5)127.9 (63.7)0.09
  ≥4067176.8 (48.2)131.6 (63.9)0.18
  P for trend0.640.18
IGF BP-3 in ng/ml
 Smoking status
  Never1483435 (1013)3378 (1005)0.90
  Former28414007 (792)3816 (966)0.39
  Current38413824 (834)3734 (868)0.64
 Current smokers, pack-yearsa
  Low10163479 (682)3602 (725)0.67
  Medium15153879 (1015)4072 (949)0.59
  High13104026 (667)3436 (867)0.25
  P for trend0.130.84
 Former smokers, pack-yearsa
  Low13184121 (639)3851 (868)0.35
  Medium9124104 (632)3946 (1209)0.73
  High6113615 (1237)3614 (880)0.99
  P for trend0.250.58
 Current smokers, number of cigarettes smoked daily
  1–199153766 (907)3624 (696)0.67
  20–3923193819 (844)3911 (928)0.74
  ≥40673928 (822)3486 (1054)0.42
  P for trend0.720.98
IGF-I/IGF BP-3
 Smoking status
  Never1483.2 (1.0)2.6 (0.9)0.21
  Former28413.9 (1.6)3.0 (1.1)0.01
  Current38414.3 (1.5)3.2 (1.2)0.0003
 Current smokers, pack-yearsa
  Low10165.1 (2.0)3.0 (1.1)0.002
  Medium15154.3 (1.4)3.3 (1.2)0.04
  High13103.6 (0.8)3.2 (1.2)0.40
  P for trend0.010.53
 Former smokers, pack-yearsa
  Low13184.1 (1.9)3.2 (1.4)0.13
  Medium9124.2 (1.5)2.8 (0.9)0.02
  High6113.1 (1.0)2.8 (0.9)0.65
  P for trend0.280.42
 Current smokers, number of cigarettes smoked daily
  1–199154.2 (1.1)2.8 (1.0)0.005
  20–3923194.2 (1.7)3.2 (1.2)0.03
  ≥40674.6 (1.6)3.7 (1.2)0.27
  P for trend0.720.11
IGF-II in ng/ml
 Smoking status
  Never148606.5 (236.4)584.1 (170.6)0.81
  Former2841688.8 (200.0)646.8 (151.8)0.33
  Current3841649.2 (151.1)609.7 (146.1)0.24
 Current smokers, pack-yearsa
  Low1016608.9 (131.9)658.8 (69.4)0.29
  Medium1515633.1 (185.3)605.5 (186.5)0.69
  High1310698.9 (113.7)537.3 (150.1)0.008
  P for trend0.150.04
 Former smokers, pack-yearsa
  Low1318738.7 (258.8)666.0 (159.7)0.34
  Medium912653.1 (106.9)662.2 (130.5)0.87
  High611634.2 (155.1)598.5 (163.0)0.67
  P for trend0.250.28
 Current smokers, number of cigarettes smoked daily
  1–19915634.3 (139.4)653.5 (74.3)0.71
  20–392319653.8 (163.3)612.2 (170.5)0.43
  ≥4067645.4 (141.0)509.0 (160.0)0.11
  P for trend0.780.04
IGF-II/IGF BP3
 Smoking status
  Never1480.67 (0.21)0.65 (0.08)0.76
  Former28410.65 (0.18)0.65 (0.14)0.97
  Current38410.64 (0.13)0.62 (0.15)0.53
 Current smokers, pack-yearsa
  Low10160.67 (0.17)0.70 (0.11)0.57
  Medium15150.61 (0.10)0.56 (0.17)0.33
  High13100.66 (0.13)0.59 (0.14)0.25
  P for trend0.940.04
 Former smokers, pack-yearsa
  Low13180.66 (0.22)0.65 (0.13)0.88
  Medium9120.60 (0.13)0.65 (0.11)0.40
  High6110.68 (0.14)0.63 (0.17)0.58
  P for trend0.960.67
 Current smokers, number of cigarettes smoked daily
  1–199150.65 (0.18)0.69 (0.11)0.51
  20–3923190.64 (0.11)0.59 (0.18)0.33
  ≥40670.63 (0.15)0.55 (0.14)0.35
  P for trend0.0.
  • a Pack-years were divided into tertiles based on the distribution of all smokers: low was defined as ≤32.5 pack-years, medium as >32.5 to <56.25 pack-years, and high as ≥56.25 pack-years.