Insulin‐like growth factor‐1 positively associated with bone formation markers and creatine kinase in adults with general physical activity

Background The Insulin‐like growth factor‐1 (IGF‐1) is primarily synthesized by hepatocytes in a growth hormone (GH)‐dependent manner, it is also produced by bone and muscle. The effects of exercise on the associations between IGF‐1 levels and bone turnover markers (BTM) were found in the previous studies. However, the associations between the levels of IGF‐1 and BTM, liver function tests, and skeletal muscle markers in adults with general physical activity were not clear. Methods Ninety‐four participants were recruited from healthy survey. Blood samples were collected to analyze the levels of IGF‐1, total protein (TP), albumin (Alb), total bilirubin (T‐Bil), direct bilirubin (D‐Bil), aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), bone alkaline phosphatase (BALP), lactate dehydrogenase (LDH), creatine kinase (CK), creatinine (CRTN), and glucose. Urine samples were collected to analyze the CRTN and deoxypyridinoline (Dpd) levels. Results The positively significant associations were found between the IGF‐1 levels and the levels of ALP, BALP, and CK, respectively. No significant associations were found between the IGF‐1 levels and the levels of TP, Alb, A/G, T‐Bil, D‐Bil, AST, ALT, LDH, glucose, urinary CRTN, urinary Dpd, and Dpd/CRTN ratios, respectively. Conclusion The serum IGF‐1 levels associated with the levels of skeletal muscle and bone formation markers (BFM), not the bone resorption markers under general physical activity in the healthy adults. The physician needs to consider the effects of bone formation and skeletal muscle markers on the IGF‐1 levels in the management of IGF‐1‐related disorders. In the healthy adults with general physical activity, the associations of the biomarkers of skeletal muscles, liver function and bone modulation with the circulating IGF‐1 levels were found: (1) The positively significant associations were found between the IGF‐1 levels and the levels of ALP, BALP and CK, respectively. (2) No significant associations were found between the IGF‐1 levels and the levels of AST, ALT, urinary CRTN, urinary Dpd, and Dpd/CRTN ratios respectively. (3) In conclusion, the serum IGF‐1 levels associated with the levels of skeletal muscle and bone formation markers, not the markers of bone resorption and liver function.