SERUM-FREE AND TOTAL INSULIN-LIKE GROWTH-FACTOR-I, INSULIN-LIKE-GROWTH-FACTOR BINDING PROTEIN-1 AND INSULIN-LIKE-GROWTH-FACTOR BINDING PROTEIN-3 LEVELS IN HEALTHY ELDERLY INDIVIDUALS - RELATION TO SELF-REPORTED DUALITY OF HEALTH AND DISABILITY

Background: Little is known about the influence of the free insulin-li ke growth factor-I/insulin-like growth factor binding protein (IGF-I/I GFBP) system on the quality of health and on disability in the elderly population. Design: In a cross-sectional population based study of 21 8 healthy elderly subjects (age 55-80 yrs) fasting free and total insu lin-like growth factor (IGF-I), insulin-like growth factor binding pro tein-1 (IGFBP-1) and insulin-like growth factor binding protein-3 (IGF BP-3) levels were measured. Subjective quality of health was assessed by asking all participants whether they judged the quality of their he alth as better, the same or worse than that of their peers. Disability was determined by the Disability Index of the Stanford Health Questio nnaire. Results: Mean serum-free IGF-I levels were significantly lower in the 21 subjects who experienced their health as worse than those o f their peers, compared to the 181 subjects who experienced their heal th as better or the same as their peers 0.069 (SE 0.009) vs. 0.093 nmo l/l (SE 0.004) (p = 0.04). Mean IGFBP-1 levels were significantly high er in subjects, who felt less healthy than their peers 1.23 (SE 0.26) vs. 0.73 nmol/l (SE 0.82) (p = 0.01). Free and total IGF-I, IGFBP-1 an d IGFBP-3 levels, were not different in subjects with the lowest and t he highest Disability Index Score. Conclusion: Low free IGF-I and high IGFBP-1 levels are associated with a decreased self-reported quality of health, but are not related to physical disability in the elderly.