Association between circulating insulin-like growth factor 1 and risk of all-cause and cause-specific mortality

Insulin-like growth factor 1 (IGF1) is an important growth factor modulating development, homeostasis, and aging. However, whether and how circulating IGF1 concentrations influence early death risk in the general population remains largely unknown.

We included 380 997 participants who had serum IGF1 measurement and no history of cancer, cardiovascular disease (CVD), or diabetes at baseline from UK Biobank, a prospective cohort study initiated in 2006-2010. Restricted cubic splines and Cox proportional hazards regression models were used to assess the association between baseline IGF-1 concentrations and all-cause and cause-specific mortality.

Over a median follow-up of 8.8 years, 10 753 of the participants died, including 6110 from cancer and 1949 from CVD. Dose-response analysis showed a U-shaped relationship between IGF1 levels and mortality. Compared to the fifth decile of IGF1, the lowest decile was associated with 39% (95% CI: 29-50%), 20% (95% CI: 8-34%), and 39% (95% CI: 14-68%) higher risk of all-cause, cancer, and CVD mortality, respectively, while the highest decile was associated with 17% (95% CI: 7-28%) and 38% (95% CI: 11-71%) higher risk of all-cause and CVD mortality, respectively. The results remained stable in detailed stratified and sensitivity analyses.

Our findings indicate that both low and high concentrations of serum IGF1 are associated with increased risk of mortality in the general population. Our study provides a basis for future interrogation of underlying mechanisms of IGF1 in early death occurrence and possible implications for mitigating the risk.