Sex-specific associations of serum insulin-like growth factor-1 with bone density and risk of fractures in Chinese patients with type 2 diabetes

Summary: We evaluated the associations of serum insulin-like growth factor-1 (IGF-1) with bone mineral density (BMD) and risk of fractures in Chinese patients with type 2 diabetes (T2D). We found positive associations between IGF-I and BMD and negative associations between IGF-I and all three modified 10-year probabilities of MOFs and HFs in men, but not in women. Introduction: The objective was to investigate the associations of serum insulin-like growth factor-1 (IGF-1) with bone mineral density (BMD) and risk of fractures in Chinese patients with type 2 diabetes (T2D) in each gender. Methods: This was a cross-sectional, retrospective study that included men over 50 years and postmenopausal women with T2D without medical conditions or medications known to significantly affect BMD or serum IGF-I levels. Data of IGF-1, bone metabolism markers, lumbar spine (LS), femoral neck (FN), and total hip (TH) BMD were obtained; 10-year probability of major osteoporotic fractures (MOFs) and hip fractures (HFs) was calculated and modified with rheumatoid arthritis, femoral neck T-score, and age. Correlations of IGF-1 levels with bone metabolism and risk of fractures were statistically analyzed in men and women, respectively. Results: A total of 391 patients, including 226 men and 165 women, were included. The age, serum fasting C-peptide, glycosylated hemoglobin (HbA1c), bone formation marker, and all three modified 10-year probabilities of MOFs and HFs were higher in women than those in men (all p < 0.05). The levels of 25 hydroxyvitamin D (25OHD), IGF-1, and BMD were lower in women than those in men (all p < 0.05). In men, IGF-1 was positively correlated with FN and TH BMD (FN BMD: r = 0.267, p < 0.001; TH BMD: r = 0.235, p < 0.001) and negatively correlated with all three modified 10-year probabilities of MOFs (RA-modified MOFs: r = - 0.289, p < 0.001; age-modified MOFs: r = - 0.237, p < 0.001; FN T-score−modified MOFs: r = - 0.280, p < 0.001) and HFs (RA-modified HFs: r = - 0.291, p < 0.001; age-modified HFs: r = - 0.271, p < 0.001; FN T-score−modified HFs: r = - 0.270, p < 0.001), while no significant correlations were found between serum IGF-I and BMD and three modified 10-year probability in women. Conclusions: According to this study, we found sex differences in the associations of serum IGF-1 with BMD and risk of fractures in Chinese patients with T2D. These results suggested that increasing serum IGF-1 might be a clinical target for protecting fractures in T2D, especially in men.