Endocrine Abstracts

JOINT3020

Introduction: Persons born small for gestational age (SGA) are more prone to various adverse growth and metabolic outcomes later in life. Previous studies showed worse body composition in adults born SGA compared to those born appropriate for gestational age (AGA). The data on bone mineral density (BMD) in subjects born SGA are inconsistent. We aimed to analyze BMD in adolescents born SGA in relation to body composition and size at birth.

Methods: We investigated 107 children from prospective cohort followed from birth (43 SGA and 64 AGA). Birth weight and/or length in SGA individuals were below 2 standard deviations (SD) of the mean according to sex and gestational age and in AGA - between -2 and +2 SD score (SDS). Children were born at 32-42 weeks of gestation. The anthropometric data were obtained at birth, 5, 12, 24 months and 11-13 years of age. DXA scan and laboratory parameters were assessed in adolescence.

Results: Adolescents born SGA were shorter and leaner than AGA (height SDS: -0. 52±1. 31 vs. 0. 36±1. 01, P < 0. 001; weight SDS: -0. 49±1. 69 vs. 0. 59±1. 57; P = 0. 010; BMI SDS: -0. 20±1. 30 vs. 0. 31±1. 25, P = 0. 048). There were no differences in waist to height ratio, lean and fat mass percent in adolescents born SGA vs. AGA. There were no difference in ionized calcium, phosphate, PTH and vitamin D levels in SGA and AGA adolescents. Additionally, there were no differences in IGF-1 and IGF-BP-3 levels (P = 0. 119 and P = 0. 128, respectively). IGF-1/IGF-BP-3 ratio was lower in adolescent born SGA (0. 11±0. 07 vs. 0. 15±0. 12, P = 0. 027). There was no difference in BMD (g/cm2) and apparent BMD (BMAD, g/cm3) between the groups. BMD Z-score was lower in adolescents born SGA compared to AGA (-0. 22±1. 10 vs. 0. 21±0. 83, P = 0. 035). BMD Z-score in adolescence was directly related to gestational age and birth weight, weight SDS and length (P = 0. 024, P = 0. 011, P = 0. 022 and P= 0. 011, respectively). Analyzing SGA and AGA data separately, significant relations remained only in the SGA group. BMD Z-score in adolescence correlated with height and weight gain during first 2 years of life, but in separated analysis, relations remained only in AGA group.

Conclusion: Adolescents born SGA were leaner and had lower BMD Z-score. In SGA subjects, birth size is more important for further bone mineral accrual than early postnatal growth. Ethics: The study was approved by Lithuanian University of Health Sciences Kaunas regional biomedical research ethics committee (Nr. BE-2-42, 2011. 06. 14). Informed written consent was obtained from all parents prior to the study.