Evaluation of insulin like growth factor-1 (IGF-1) level and its impact on muscle and bone mineral density in frail elderly male.

Decrease in IGF-1 level is a major endocrine dysregulation that has been implicated in frailty, disability, and mortality in older adults. Our aim was to clarify the effect of IGF-1 on muscle and bone mineral density (BMD) in frail males. One hundred elderly males were included and divided into frail group (n=50) and robust group (n=50) based on the study of osteoporotic fractures (SOF) frailty index. Anthropometric measures, femoral BMD, and serum IGF-1 level were measured. Our results showed that the IGF-1 level was significantly lower in the frail males in comparison to the robust with mean value 37.1±24.2 versus 68.5±18.4ng/ml (P<0.05). Receiver operating curve (ROC) analysis of the IGF-1 level revealed that sensitivity was 88.5%, specificity was 100%, cutoff value was 46.5ng/ml and area under the curve (AUC) was 0.897 (P<0.05). Participants with low IGF-1 percentile had significantly higher odds ratio of being frail compared to those with high IGF-1 percentile (odds ratio=12.8, 95% CI: 4.2-38.8, P-value<0.05). Subjects with low IGF-1 percentile had 13.5 times the odds of having an abnormal BMD than those with middle IGF-1 percentile (95% CI: 3.4-53.3, P<0.05). In multivariate analysis BMD, mid arm circumference (MAC), mid calf circumference (MCC), and handgrip strength were significantly affected by IGF-1 percentiles with age and co-morbid diseases adjustment. Male subjects with a low IGF-1 level may be at risk of being frail and having abnormal BMD. 16.8% and 15% of variability in MCC and BMD may be attributed to IGF-1 level respectively.