Insulin-like growth factor I promoter polymorphism, risk of stroke, and survival after stroke: the Rotterdam study

摘要

textabstractBACKGROUND AND PURPOSE: Low levels of insulin-like growth factor I (IGF-I) predispose to atherosclerosis and may therefore increase the risk of stroke. Low levels have also been found to influence the outcome of cardiovascular and cerebrovascular disease. A polymorphism in the promoter region of the IGF-I gene influences IGF-I levels. Non-carriers of the 192 bp allele have lower levels of IGF-I compared with 192 bp allele carriers. We studied the IGF-I polymorphism in relation to the risk of stroke and survival after stroke.METHODS: We studied 6808 subjects of the Rotterdam Study, who were followed for the occurrence of stroke and death after stroke. Subjects were grouped according to the 192 bp allele of IGF-I into non-carriers, heterozygotes, and homozygotes. The risk of stroke and survival after stroke was studied using Cox regression analysis, adjusting for age and sex, with homozygotes for the wildtype allele as the reference.RESULTS: Non-carriers had a relative risk of 0.8 (95% CI: 0.6 to 1.0) for the occurrence of any stroke and 0.7 (95% CI: 0.5 to 1.0) for ischaemic stroke. For non-carriers, the relative risk of death after any stroke was 1.5 (95% CI: 1.0 to 2.2). After an ischaemic stroke, this relative risk was 1.5 (95% CI: 0.9 to 2.6) and after a haemorrhagic stroke 5.2 (95% CI: 1.3 to 21.5).CONCLUSIONS: Our study suggests that IGF-I is a significant determinant of survival after stroke.