Received on February 24, 2008
Accepted on July 22, 2008

Endocrinology and Metabolism

Plasma Insulin-Like Growth Factor 1 and Binding-Protein 3 and Risk of Myocardial Infarction in Women: A Prospective Study

¹ Department of Epidemiology, Harvard School of Public Health, Harvard University, Boston, MA
² Channing Laboratory, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA
³ Department of Oncology, McGill University, Montreal, Canada
⁴ Department of Epidemiology, Harvard School of Public Health, Harvard University, Boston, MA; Channing Laboratory, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, and Division of Preventive Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA
⁵ Department of Epidemiology, Harvard School of Public Health, Harvard University, Boston, MA, and Channing Laboratory, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA

^* To whom correspondence should be addressed. E-mail: john_page{at}post.harvard.edu.

BACKGROUND: The aim of this study was to prospectively evaluate relationships between plasma concentrations of insulin-like growth factor 1 (IGF1) and insulin-like growth factor binding protein 3 (IGFBP3) and subsequent myocardial infarction (MI) in women.

METHODS: We used case-control sampling to select study participants from women who had already been selected for inclusion in the prospective Nurses' Health Study cohort. Blood samples were collected from 32 826 women in 1989–1990. During the follow-up period from sample collection through June 1998, MI (fatal and nonfatal) was diagnosed in 245 women. Cases were matched to controls 1:2 by age, cigarette-smoking status, and month and fasting status at the time of blood collection. Conditional logistic regression was used to adjust for potential confounders (menopausal status, parental history of MI, postmenopausal hormone use, diabetes mellitus, hypertension, hypercholesterolemia, aspirin use, alcohol use, body mass index, and physical activity).

RESULTS: Multivariable adjusted analyses did not reveal a statistically significant linear relationship between IGF1 or IGFBP3 concentrations or their molar ratio and risk of MI. Women in the highest IGF1 quartile had a multivariable-adjusted rate ratio of 1.46 (95% CI 0.79, 2.72; P for trend = 0.46) for MI, compared with those in the lowest. The corresponding rate ratios (95% CI) for IGFBP3 and the IGF1:IGFBP3 mol/L ratio were 1.24 (0.71, 2.17) and 1.29 (0.70, 2.37), respectively.

CONCLUSIONS: We did not observe a monotonic relationship between IGF1 or IGFBP3 and MI among predominantly postmenopausal women. Future studies are warranted to evaluate these relationships in other demographic groups including younger women.