Person: ÖZEN, AHMET OĞUZHAN
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ÖZEN
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AHMET OĞUZHAN
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Publication Metadata only Serum IGF-I and IGFBP-3 levels of Turkish children during childhood and adolescence: Establishment of reference ranges with emphasis on puberty(KARGER, 2006) BEREKET, ABDULLAH; Bereket, A; Turan, S; Omar, A; Berber, M3Aims/Methods: We established age- and sex-related reference ranges for serum insulin-like growth factor-I (IGF-I) and insulin-like growth factor binding protein-3 (IGFBP-3) levels in 807 healthy Turkish children (428 boys, 379 girls), and constructed a model for calculation of standard deviation scores of IGF-I and IGFBP-3 according to age, sex and pubertal stage. Results: Serum IGF-I and IGFBP-3 concentrations tended to be higher in girls compared to boys of the same ages, but the differences were statistically significant only in pubertal ages (9-14 years) for IGF-I and only in prepubertal ages for IGFBP-3 (6-8 years) (p < 0.05). Peak IGF-I concentrations were observed earlier in girls than boys (14 vs. 15 years, Tanner stage IV vs. V) starting to decline thereafter. IGFBP-3 levels peaked at age 13 and at Tanner stage IV in both sexes with a subsequent fall. Serum levels of IGF-I and IGFBP-3 increased steadily with age in the prepubertal stage followed by a rapid increase in IGF-I in the early pubertal stages. A relatively steeper increase in IGF-I but not in IGFBP-3 levels was observed at age 10-11 years in girls and at 12-13 years in boys which preceded the reported age of pubertal growth spurt. At late pubertal stages, both IGF-I and IGFBP-3 either did not change or decreased by increasing age. Interrelationships between growth factors and anthropometric measurements have been described, and the physiologic consequences of these have been discussed in detail. Conclusions: Differences in the pattern of IGF-I and IGFBP-3 in the present paper and those reported in other studies emphasize the importance of locally established reference ranges. Establishment of this reference data and a standard deviation score prediction model based on age, sex and puberty will enhance the diagnostic power and utility of IGF-I and IGFBP-3 in evaluating growth disorders in our population. Copyright (c) 2006 S. Karger AG, Basel.Publication Metadata only The effect of economic status on height, insulin-like growth factor (IGF)-I and IGF binding protein-3 concentrations in healthy Turkish children(NATURE PUBLISHING GROUP, 2007) BEREKET, ABDULLAH; Turan, S.; Bereket, A.; Furman, A.; Omar, A.; Berber, M.; Ozen, A.; Akbenlioglu, C.; Haklar, G.Objectives: The effect of economic status (ES) on growth, insulin-like growth factor (IGF)-I and IGF-binding protein (IGFBP)-3 in healthy children is not well characterized. We aimed to study the interrelationship between height, weight, IGF-I, IGFBP-3, mid-parental height (MPH) and ES. Design/ subjects: Eight hundred and fourteen healthy children (428 boys, 386 girls; age 3 -18 years) were classified according to income of the families as low, middle and high. Standard deviation scores (SDSs) of height, weight, MPH, IGF-I and IGFBP-3 were compared between the groups. The combined effect of these parameters and ES on height SDS was investigated with complex statistical models. Results: There was a significant trend for height and weight SDSs to increase with higher income levels in boys, but not in girls. Body mass index (BMI) SDSs were similar in three groups. There was a general trend for MPH SDS to increase with income levels in both sexes. In boys, IGF-I SDS was significantly higher in high ES group than low ES. In girls, IGFBP-3 SDSs were significantly higher in high ES group than in middle ES group. For both genders, height SDS was highly correlated with weight SDS and moderately correlated with BMI SDS, MPH SDS and IGF-1 SDS. All correlations were significant and positive. Complex models showed that MPH (19%), IGF-I (13%) and ES (3%) in boys, and MPH (16%) and IGF-I (7%) in girls have significant contribution to height SDSs. Conclusions: ES per se, independent of overt malnutrition, affects height, weight, IGF-I and IGFBP-3 with some gender differences in healthy children. Influence of income on height and weight show sexual dimorphism, a slight but significant effect is observed only in boys. MPH is the most prominent variable effecting height in healthy children. Higher height and MPH SDSs observed in higher income groups suggest that secular trend in growth still exists, at least in boys, in a country of favorable economic development.Publication Metadata only Upper segment/lower segment ratio and armspan-height difference in healthy Turkish children(WILEY, 2005) BEREKET, ABDULLAH; Turan, S; Bereket, A; Omar, A; Berber, M; Ozen, A; Bekiroglu, NAim: The determination of body proportions is an important part of the clinical evaluation of children with short stature. The upper segment/lower segment ratio (US/LS ratio) and armspan-height difference is commonly used for this purpose. However, reference data are scarce in this respect, and available standards do not include standard deviations for the measurements. We aimed to establish the normal values for upper segment/lower segment ratio and armspan-height difference in Turkish children. Methods: In the present study, height, upper and lower segment, and armspan were measured in 1302 healthy children (3-18 y). The age-related mean and standard deviation curves of the US/LS ratio and armspan-height difference were constructed for each sex. Results: The mean values of the US/LS ratio in boys were decreased from 1.108 at 3 y to 0.984 at 10 y. The nadir of the US/LS ratio (0.922) was reached at age 15 y. In girls, the mean value of the US/LS ratio gradually decreased to less than 1 at 9 y of age (1 y earlier than in boys). The nadir of the US/LS ratio (0.946) was reached at age 13 y in girls (2 y earlier than in boys). Armspan was shorter than height as expected in younger ages, but became slightly longer at around age 12 in girls and boys. Unlike boys, the armspan-height difference did not change much after puberty in girls. Conclusion: US/LS ratio and armspan-height difference are practical parameters and easy to perform in any setting. We hope that these standards will aid clinicians in the evaluation of children with short stature.