October - December 2021, Volume 17, Issue 4

Stojanovic M, Popevic M, Pekic S, Doknic M, Miljic D, Medic-Stojanoska M, Topalov D, Stojanovic J, Milovanovic A, Petakov M, Damjanovic S , Popovic V

Serum Insulin-Like Growth Factor-1 (Igf-1) Age-Specific Reference Values for Healthy Adult Population of Serbia

Acta Endo (Buc) 2021, 17 (4): 462-471
doi: 10.4183/aeb.2021.462

Context. Insulin-like growth factor-1 (IGF-1) is main serum surrogate marker of growth hormone (GH) secretion, used in diagnostics and treatment of GH deficiency (GHD) and acromegaly. Regional, ethnic, racial or nutritional factors obscure cross-population applicability of IGF-1 reference values. Establishment of population- and assayspecific reference values requires sizable representative cohort of healthy subjects. Subjects and Methods. In representative sample of healthy adult population of Serbia (N=1200, 21-80 years, 1:1 male:female) serum IGF-1 was analyzed by Siemens Immulite 2000 assay under uniform laboratory conditions. Upper and lower limit of reference range (5th - 95th percentile) were calculated for each of the 12 quinquennial age intervals. IGF-1 distribution was normalized and standard deviation score (SDS) calculated by Logarithmic and LMS methods. Results. IGF-1 and age correlated significantly, with most prominent decline at 21-50 years, followed by a plateau up to age of 70. Gender differences were not significant overall. Plateau in age-related IGF-1 decline was less prominent in women. Correlations of IGF-1 with body mass index (BMI) or waist to hip ratio (WHR) were insignificant. Superior IGF-1 SDS transformation was achieved with LMS method, while logarithmic method was simpler to use. Conclusions. Normative age-specific serum IGF- 1 reference values were established on a representative cohort of healthy adults in Serbia. Our results support recommendations against necessity for gender-specific or BMI- and WHR-specific reference ranges. Populationbased data serve to generate IGF-1 SDS, which is valuable in rational application of consensus guidelines, proper longitudinal follow-up, advancement in efficacy and safety and personalization of treatment targets.

Keywords: normative data, Southeast Europe, normal healthy population, SD-score, population-based, IGF-1, Growth hormone.

Correspondence: Assistant Professor Marko Stojanovic MD, PhD, University Clinical Center of Serbia, Clinic for Endocrinology, Diabetes and Metabolic Diseases, Department of Neuroendocrinology, Dr Subotica 13, Belgrade, 11000, Serbia, E-mail: markostoj@yahoo.com