LBMON65 Generation Of Serum Insulin Like Growth Factor -1 (IGF-1) Normative Data According To Age, Tanner Staging & Bone Age In Healthy Indian Children And Adolescents With Two Different Assays: The Germinative Study

Abstract

Abstract Context To diagnose and monitor GH-related disorders, serum IGF-I is a cornerstone, but Indian ethnicity based data, following consensus criteria for establishment of normative data are not available. Objectives To generate normative IGF-I data for chronological age (CA), Tanner stage and bone age (BA) [Greulich & Pyle (GP)] for both genders. Setting and Participants: We conducted a cross-sectional epidemiological study for Indian children (age 5-18 years) that included 2226 apparently normal subjects (1145 males; 1081 females). We used robust clinical exclusion criteria initially and later statistically we removed outliers separately for Age,Tanner Stage & Bone age using software SPSS 26. 0. Outcome Measures:: Serum IGF-I (ng/ml) using the Roche ECLIA & Immunodiagnostic Systems & Immunoassay System (IDS iSYS) were measured and normative data for 2.5th, 5th,10th, 25th, 50th (median), 75th, 90th, 95th and 97.5th centiles were generated. Results Age- and gender-specific serum IGF-I normative data generated from a uniquely large cohort reflected various patterns. With Roche assay, females (n=910) had IGF-I median peak at 13 years (356.85) [BA (n=804) at 14 years (401.5 ng/mL)] and & Tanner (n = 936) stage IV (368) while males (n=959) had median peak at 14 years (329.5) [BA (n=906) at 15 years (351 ng/mL)] & Tanner (n = 986) stage III (311. 0). With IDS iSYS assay, females had IGF-I median peak at Age (n=913) 13 years (397.5), Tanner (n=941) stage IV (418.5) and GP BA (n=843) 14 years (448.5) and males had median peak at Age (n=974) 14 years (376), Tanner (n=1003) stage III (367) and GP BA (n=909) 15-16 years (383). Females had earlier rise & peak and higher IGF-I values with both assays. In Tanner-specific data maximum difference noticed between stage II and III in both genders with both assays. On comparison of both assays, IGF-1 median peak was achieved at similar ages and Tanner stage but all the values are higher with IDS iSYS assay. When reviewed published literature on Caucasians, females had IGF-I median peak at 15 years (300.1) and Tanner stage III (382.8) and males had median peak at 15 years (318.3) and Tanner stage IV (439). The Indian & Caucasian IGF-1 normative data clearly demonstrates that every ethnicity has a unique pattern of growth. Conclusions The normative data on serum IGF-I are ethnicity-specific and it will improve the diagnostic utility of IGF-I in evaluation and management of growth disorders in Indian Children. Using both age- and Tanner stage-specific normative data simultaneously can improve diagnostic work-up. Presentation: Monday, June 13, 2022 12:30 p.m. - 2:30 p.m.