IGF-I concentrations are positively associated with carotid artery atherosclerosis in women

BACKGROUND. Alterations in the growth hormone (GH)/insulin-like growth factor I (IGF-I) axis are associated with increased cardiovascular morbidity and mortality, but previous studies have yielded conflicting results. In addition, the T1169A polymorphism in the GH1 gene has been associated with IGF-I levels. AIMS. To investigate whether IGF-I concentrations and the T1169A polymorphism of the GH1 gene are associated with cardiovascular risk factors and the intima media thickness (IMT) of the carotid artery. METHODS. Fasting plasma IGF-I concentrations (n=1008) were measured in a large population-based OPERA (Oulu Project Elucidating Risk of Atherosclerosis) cohort. Genotype variants were determined by the restriction fragment length polymorphism method. RESULTS. Low IGF-I concentrations associated with several cardiovascular risk factors including age, adiposity, and high triglyceride, fasting insulin and C-reactive protein concentrations in the analysis of all subjects. In the multivariate models, however, IGF-I concentrations were positively associated with the mean IMT of women (beta=0.127, P=0.009) whereas the association in men was weaker and negative (beta=-0.088, P=0.034). The 1169A allele was associated with low low-density lipoprotein cholesterol in both sexes and with low systolic blood pressure levels in women. CONCLUSIONS. IGF-I concentrations were associated with several traditional cardiovascular risk factors. The observed gender difference in the association between IGF-I concentrations and carotid artery atherosclerosis warrants further study. The GH1 1169A allele may be associated with a favourable metabolic profile.