- Association between serum insulin-like growth factor-I levels and thyroid disorders in a population-based study. Völzke, H., Friedrich, N., Schipf, S., Haring, R., Lüdemann, J., Nauck, M., Dörr, M., Brabant, G., Wallaschofski, H. J. Clin. Endocrinol. Metab. (2007)