The association of serum insulin-like growth factor-I with mortality, cardiovascular disease, and cancer in the elderly: a population-based study.

Abstract

Numerous studies have investigated the effect of serum IGF-I concentration on aging and different aging-related diseases, e.g. cardiovascular disease (CVD) and cancer. Decreased as well as increased levels have been reported to be associated with reduced life expectancy in humans. This study investigates the association of serum IGF-I concentration with all-cause and cause-specific mortality of community-dwelling older persons and the development of CVD and cancer. Data were used from the Longitudinal Aging Study Amsterdam (LASA), an ongoing multidisciplinary cohort study in the general Dutch population of older persons (≥65 yr old) where serum IGF-I was measured (n = 1273). The mortality information was ascertained using the International Classification of Diseases, 10th revision, and the presence or absence of CVD and cancer by self-reports with a follow-up of 11.6 yr. We measured all-cause, CVD, and cancer mortality and nonfatal CVD and cancer. Fully adjusted Cox proportional hazards models demonstrated an increased risk of all-cause mortality for older persons with IGF-I values in the lowest quintile as compared to the middle quintile [hazard ratio (HR), 1.28; 95% confidence interval (CI), 1.01-1.63]. A more than 2-fold increased risk of CVD mortality was revealed for both low-normal (HR, 2.39; 95% CI, 1.22-4.66) and high-normal (HR, 2.03; 95% CI, 1.02-4.06) IGF-I values. Significant associations of serum IGF-I with nonfatal CVD and fatal and nonfatal cancer were not observed. Results suggest a U-shaped relationship between IGF-I level and mortality, with fatal CVD as the most critical outcome in community-dwelling older persons.