title: A cross-sectional study of different patterns of oral contraceptive use among premenopausal women and circulating IGF-1: implications for disease risk.
abstract: BACKGROUND
  Insulin-like growth factor-1 (IGF-1) is important in normal growth, development, and homeostasis. Current use of oral contraceptives (OC) decreases IGF-1 concentrations; however, the effect of past use, age/timing of use, and type of OC used on IGF-1 levels is unknown. OC are the most commonly used form of birth control worldwide. Both IGF-1 and OC use have been linked to premenopausal breast and colorectal cancers, osteoporosis and cardiovascular disease (CVD). Understanding the effects of different patterns of OC use on IGF-1 levels may offer insight into its influence on disease risk in young women.
  
  
  METHODS
  In a cross-sectional study of 328 premenopausal women ages 18 to 21 and 31 to 40 we examined the relationship between different patterns of OC use and circulating IGF-1 using adjusted linear regression analysis. Information on OC use was obtained through an interviewer administered questionnaire. Plasma IGF-1 was assessed with enzyme linked immunosorbent assay (ELISA).
  
  
  RESULTS
  Among women aged 18 to 21, ever OC use was significantly associated with decreased IGF-1 levels compared to never use (β = -57.2 ng/ml, 95% confidence interval (CI): -88.7, -25.8). Among women aged 31 to 40, past users who first used OC at 25 years of age or older (β = 43.8 ng/ml, 95% CI: 8.8, 78.8), in the last 15 years (β = 35.1 ng/ml, 95% CI: 9.3, 61.0) or after 1995 (β = 46.6 ng/ml, 95% CI: 13.4, 79.8) had significantly higher IGF-1 levels compared to never users.
  
  
  CONCLUSIONS
  This is the first study to highlight the long term effects of OC use after cessation on IGF-1 levels among premenopausal women, which previously were thought to be transitory. Future studies of past use and IGF-1 levels are required and must consider age/timing of use and type/generation of OC used. Additional studies are needed to confirm the potential mediation of IGF-1 levels in the links between OC use and health outcomes.
authors: Prosserman Center for Health Research, Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Canada. blackmore@lunenfeld.ca
authors: Kristina M
authors: KM
authors: Blackmore
authors: Jody
authors: J
authors: Wong
authors: Julia A
authors: JA
authors: Knight
references: Med Phys. 2010 Feb;37(2):419-26
references: 20229850
references: Endocr Rev. 2008 Aug;29(5):535-59
references: 18436706
references: Contraception. 2000 Nov;62(5):259-69
references: 11172797
references: Cancer Causes Control. 2003 Feb;14(1):65-74
references: 12708727
references: Contraception. 2003 Jul;68(1):11-7
references: 12878281
references: JAMA. 2000 Jul 5;284(1):72-8
references: 10872016
references: Eur J Cancer Prev. 2001 Oct;10(5):443-52
references: 11711759
references: Cancer Epidemiol Biomarkers Prev. 2000 Apr;9(4):345-9
references: 10794477
references: Lancet. 2004 Apr 24;363(9418):1346-53
references: 15110491
references: Endocr Relat Cancer. 2007 Sep;14(3):721-32
references: 17914102
references: CMAJ. 2001 Oct 16;165(8):1023-9
references: 11699697
references: Epidemiol Rev. 1995;17(2):265-86
references: 8654511
references: J Endocrinol. 1994 Feb;140(2):165-9
references: 7513340
references: J Bone Miner Metab. 2008;26(2):159-64
references: 18301972
references: Hum Reprod Update. 2009 Sep-Oct;15(5):489-98
references: 19414526
references: Horm Res. 2002;58 Suppl 3:49-55
references: 12435898
references: J Natl Cancer Inst. 2000 Oct 4;92(19):1592-600
references: 11018095
references: Eur J Cancer. 2000 Jun;36(10):1224-8
references: 10882860
references: Cancer Epidemiol Biomarkers Prev. 2001 Apr;10(4):377-84
references: 11319179
references: Lancet. 1996 Jun 22;347(9017):1713-27
references: 8656904
references: Br J Cancer. 2001 Mar 2;84(5):722-7
references: 11237397
references: Cancer Epidemiol Biomarkers Prev. 2005 Jan;14(1):2-19
references: 15668470
references: Mayo Clin Proc. 2006 Oct;81(10):1290-302
references: 17036554
references: Am J Obstet Gynecol. 1999 Mar;180(3 Pt 1):530-6
references: 10076123
references: Br J Sports Med. 2006 Jan;40(1):11-24
references: 16371485
references: Eur J Nutr. 2005 Mar;44(2):105-13
references: 15309428
references: Ann Intern Med. 1997 Oct 15;127(8 Pt 1):596-603
references: 9341057
references: J Clin Endocrinol Metab. 1996 Nov;81(11):3986-92
references: 8923848
references: Mayo Clin Proc. 2008 Jan;83(1):86-90; quiz 90-1
references: 18174010
references: Cancer Epidemiol Biomarkers Prev. 2004 Dec;13(12):2264-7
references: 15598790
references: Am Fam Physician. 1999 Nov 1;60(7):2073-84
references: 10569509
references: J Clin Endocrinol Metab. 2005 Nov;90(11):5937-41
references: 16131586
references: J Clin Endocrinol Metab. 2005 Jul;90(7):3863-70
references: 15814774
references: Endocr Rev. 1995 Feb;16(1):3-34
references: 7758431
references: Cancer Causes Control. 2001 Dec;12(10):951-8
references: 11808715
references: Cancer Epidemiol Biomarkers Prev. 2005 Sep;14(9):2147-53
references: 16172224
references: Circulation. 2002 Aug 20;106(8):939-44
references: 12186797
references: Clin Endocrinol (Oxf). 2008 Sep;69(3):347-58
references: 18462260
references: Endocr Relat Cancer. 2006 Jun;13(2):273-8
references: 16728563
references: Bone. 2007 Feb;40(2):444-50
references: 16965947