Management and interpretation of heterogeneous observational data: Using insulin-like growth factor-I data from the NordiNet® International Outcome Study

Burns, 2009, The First International Standard for Insulin-like Growth Factor-1 (IGF-1) for immunoassay: preparation and calibration in an international collaborative study, Growth Horm. IGF. Res., 19, 457, 10.1016/j.ghir.2009.02.002 Brabant, 2003, Serum insulin-like growth factor I reference values for an automated chemiluminescence immunoassay system: results from a multicenter study, Horm. Res., 60, 53 Krebs, 2008, Five commercially available insulin-like growth factor I (IGF-I) assays in comparison to the former Nichols Advantage IGF-I in a growth hormone treated population, Clin. Chem. Lab. Med., 46, 1776, 10.1515/CCLM.2008.349 Brugts, 2008, Normal values of circulating insulin-like growth factor-I bioactivity in the healthy population: comparison with five widely used IGF-I immunoassays, J. Clin. Endocrinol. Metab., 93, 2539, 10.1210/jc.2007-2454 Clemmons, 2011, Consensus statement on the standardization and evaluation of growth hormone and insulin-like growth factor assays, Clin. Chem., 57, 555, 10.1373/clinchem.2010.150631 Bidlingmaier, 2009, Pitfalls of insulin-like growth factor I assays, Horm. Res., 71, 30 Friedrich, 2008, Reference ranges of serum IGF-1 and IGFBP-3 levels in a general adult population: results of the Study of Health in Pomerania (SHIP), Growth Horm. IGF. Res., 18, 228, 10.1016/j.ghir.2007.09.005 Elmlinger, 2004, Reference ranges for two automated chemiluminescent assays for serum insulin-like growth factor I (IGF-I) and IGF-binding protein 3 (IGFBP-3), Clin. Chem. Lab. Med., 42, 654, 10.1515/CCLM.2004.112 Bidlingmaier, 2011, A new automated chemiluminescence immunoassay system to measure insulin-like growth factor I (IGF-I): validation and establishment of reference values [abstract], Endocr. Rev., 32, 1 Hoybye, 2013, Clin. Epidemiol., 5, 119, 10.2147/CLEP.S42602 Lee, 2012, Int. J. Pediatr. Endocrinol., 2012, 22, 10.1186/1687-9856-2012-22 Savendahl, 2012, Gender influences short-term growth hormone treatment response in children, Horm. Res. Paediatr., 77, 188, 10.1159/000337570 McLean, 1991, A unified approach to mixed linear models, Am. Stat., 45, 54 Bidlingmaier, 2014, Reference intervals for insulin-like growth factor-1 (igf-i) from birth to senescence: results from a multicenter study using a new automated chemiluminescence IGF-I immunoassay conforming to recent international recommendations, J. Clin. Endocrinol. Metab., 99, 1712, 10.1210/jc.2013-3059 Juul, 1994, Serum insulin-like growth factor-I in 1030 healthy children, adolescents, and adults: relation to age, sex, stage of puberty, testicular size, and body mass index, J. Clin. Endocrinol. Metab., 78, 744 Frystyk, 2010, The current status of IGF-I assays—a 2009 update, Growth Horm. IGF. Res., 20, 8, 10.1016/j.ghir.2009.09.004