Association between insulin-like growth factor-1 and cardiovascular events: a systematic review and dose-response meta-analysis of cohort studies.

Background: Insulin-like growth factor-1 (IGF-1) has increasingly been reported as linked to cardiovascular (CV) events; however, reported results have been inconsistent, and no meta-analysis has been undertaken to quantitatively assess this association.

Methods: We searched PubMed, Embase, and Web of Science databases for cohort articles published up to December 1, 2020. Fixed or random-effects models were used to estimate the summary relative risks (RRs) and 95% confidence intervals (CIs) of CV events in relation to IGF-1. Restricted cubic splines were used to model the dose-response association.

Results: We identified 11 articles (thirteen cohort studies) covering a total of 22,995 participants and 3040 CV events in this meta-analysis. The risk of overall CV events reduced by 16% from the highest to the lowest IGF-1 levels (RR 0.83, 95% CI 0.72-0.95), while the occurrence of CV events reduced by 28% (RR 0.72, 95% CI 0.56-0.92), but not for CV deaths, however (RR 1.00, 95% CI 0.65-1.55). We also found linear associations between IGF-1 levels and CV events. With each per 45 μg/mL IGF-1 increase, the pooled RRs were 0.91 (95% CI 0.86-0.96), 0.91 (95% CI 0.85-0.97) and 0.91 (95% CI 0.84-0.98) for overall CV events, for the occurrence of CV events, and for CV deaths, respectively.

Conclusions: Our findings based on cohort studies support the contention that any increase in IGF-1 is helpful in reducing the overall risk of CV events. As an important biomarker for assessing the likelihood of CV events, IGF-1 appears to offer a promising prognostic approach for aiding prevention.