Insulin growth factor-1 correlates with higher bone mineral density and lower inflammation status in obese adult subjects.

ABSTRACT

PURPOSE: Obesity is a severe public health problem worldwide, leading to an insulin-resistant state in liver, adipose, and muscle tissue, representing a risk factor for type 2 diabetes mellitus, cardiovascular diseases, and cancer. We have shown that abdominal obesity is associated with homeostasis derangement, linked to several hormonal and paracrine factors. Data regarding potential link between GH/IGF1 axis, bone mineral density, and inflammation in obesity are lacking. Thus, aim of this study was to evaluate correlation among IGF-1, BMD, and inflammation in obese individuals. METHODS: The study included 426 obese subjects, mean age 44.8 ± 14 years; BMI 34.9 ± 6.1. Exclusion criteria were chronic medical conditions, use of medications affecting bone metabolism, hormonal and nutritional status, recent weight loss, and prior bariatric surgery. Patients underwent measurements of BMD and body composition by DEXA and were evaluated for hormonal, metabolic profile, and inflammatory markers. RESULTS: In this population, IGF-1 was inversely correlated with abdominal FM% (p < 0.001, r 2 = 0.12) and directly correlated with osteocalcin (OSCA) (p < 0.002, r 2 = 0.14). A negative correlation was demonstrated between IGF-1 levels and nonspecific inflammatory index, such as fibrinogen (p < 0.01, r 2 = 0.04) and erythrocyte sedimentation rate (p < 0.0001, r 2 = 0.03). IGF-1 was directly correlated with higher BMD, at both lumbar (p < 0.02, r 2 = 0.03) and femoral site (p < 0.04, r 2 = 0.03). CONCLUSIONS: In conclusion, our results show that higher levels of serum IGF-1 in obese patients correlate with lower inflammatory pattern and better skeletal health, as demonstrated by higher BMD and osteocalcin levels. These results lead to speculate the existence of a bone-adipose-muscle interplay modulating energy homeostasis, glucose, bone metabolism, and chronic inflammation in individuals affected by abdominal obesity.