Context: IGF-1 plays a role in bone metabolism. Although IGF-1 and bone mass both decrease with advancing age, their relationship in older individuals remains to be elucidated.
Objective: The objective was to investigate associations of serum IGF-1 cross-sectionally with quantitative ultrasound and bone mineral density (BMD), and longitudinally with 3-year change in BMD and 10-year fracture risk in older individuals.
Design, setting, and patients: The study included 627 men and 656 women aged ≥ 65 years from the Longitudinal Aging Study Amsterdam, an ongoing, population-based cohort study.
Main outcome measures: Main outcome measures included baseline serum IGF-1 concentration; baseline quantitative ultrasound of the heel, including broadband ultrasound attenuation and speed of sound; BMD measured at several body sites at baseline and after 3 years; and prospective fracture incidence over 10 years. Associations were adjusted for relevant confounders.
Results: Women, but not men, in the lowest quintile of IGF-1 concentration had lower broadband ultrasound attenuation (B = -4.53; P = .03) and a greater 3-year decrease in total hip BMD (B = -0.02; P = .05), than women in the highest quintile of IGF-1. Moreover, compared to women in the highest quintile of IGF-1, women in the combined lowest four quintiles of IGF-1 had an increased 10-year fracture risk (hazard ratio = 1.98; P = .05).
Conclusions: Associations of lower IGF-1 with lower BUA, greater 3-year decrease in BMD, and increased 10-year fracture risk were only observed in women, not in men. These results support previous findings of gender differences in the relationship between IGF-1 and bone in older individuals.