Insulin-like growth factors and subsequent risk of mortality in the United States.

Although numerous studies have explored the relation of insulin-like growth factor (IGF)-I and IGF-binding protein (BP) 3 with cancer and cardiovascular disease, only two previous studies are known to have looked at the association of IGF-I and IGF-BP3 with risk of mortality. The objective of this US study was to examine the risk of all-cause, heart disease, and cancer mortality associated with IGF-I and IGF-BP3 levels using data from the Third National Health and Nutrition Examination Survey (NHANES III) and NHANES III Mortality Study (n = 6,061) (1988-2000). The authors constructed proportional hazards models with age as the time scale to determine the association of baseline IGF-I and IGF-BP3 levels with subsequent mortality. After adjustment for baseline measures, there was no increased risk of all-cause, heart disease, or cancer mortality for the lower quartiles of IGF-I compared with the highest quartile. The adjusted relative hazard of all-cause mortality for the lowest quartile of IGF-BP3 compared with the highest quartile was 1.57 (95% confidence interval: 0.98, 2.52), and the trend for risk was significant (p = 0.0364), but there was no increased risk of heart disease or cancer mortality. Results suggest that the association of IGF-I and IGF-BP3 with mortality may differ from associations with incidence of disease.