ASSOCIATION OF INSULIN-LIKE GROWTH-FACTOR-I WITH BODY-COMPOSITION, WEIGHT HISTORY, AND PAST HEALTH BEHAVIORS IN THE VERY OLD - THE FRAMINGHAM HEART-STUDY

OBJECTIVES: We examined correlates of insulin-like growth factor-I (IG F-I), an indicator of growth hormone levels, to identify factors assoc iated with higher levels of IGF-I in old age. DESIGN: Nested study of cross-sectional correlates and early-life predictors of IGF-I level. S ETTING: A longitudinal cohort study, the Framingham Heart Study. PARTI CIPANTS: A total of 790 men and women (mean age 78.5, range 72-94), wh o had weight, waist and hip circumferences measured at the time of IGF -I measurement. MEASUREMENTS: Association of IGF-I with weight, fat di stribution, functional status, nutritional indicators, and past health behaviors was assessed. We also examined IGF-I in relation to body co mposition derived from dual energy X-ray absorptiometry. RESULTS: ICE- I levels declined with age in both men and women. However, low IGF-I d id not show expected associations with low lean mass and increased bod y fat. Current functional status and grip strength were not associated with IGF-I. Low IGF-I was associated with weight loss in men; the str ongest associations were with indicators of poorer nutritional status in both men and women. Levels of IGF-I in old age did not vary by past health behaviors. CONCLUSION: Although IGF-I declined with age, these data from the Framingham Heart Study did not show expected cross-sect ional associations of weight, body fat, and lean mass. The strongest a ssociations were between IGF-I and nutritional indicators. These resul ts suggest caution may be warranted with regard to use of IGF-I as an indicator of growth hormone.