ESPE Abstracts

Background and aim: How gestational age and size at birth are related to the timing of puberty and the adult height of an individual is not well known. Children born small, either preterm or small for gestational age (SGA), are known to be shorter than their peers during childhood. Both adult height and pubertal timing depends on both genetical and environmental factors, have changed over time with broad individual variations. Previous studies have shown conflicting results regarding the associations between characteristics at birth and the pubertal timing. The aim of this study was to investigate associations of gestational age and birth size with the timing of puberty and adult height in a population-based study.

Material and Methods: A study population of individuals from both GrowUp1974 and GrowUp1990 Gothenburg was used. 6781 individuals (3370 girls) were included, born between 25 and 45 weeks of gestation (302 preterm and 107 post term, less than 20 individuals were born before 32 weeks of gestation). Medical birth records registering gestational age, birth weight/length, parental heights and longitudinal growth data from well-baby clinics and school health records were collected. Pubertal timing was defined by age at peak height velocity, PHV. Reaching target height was defined as a height of ±1 SDS from mid-parental height. Statistical analyses were conducted using linear regression models.

Results: Gestational age had no association with adult height nor pubertal timing. Neither birth length nor birth weight was found to be significantly associated with pubertal timing. 50% of children born SGA based on birth length did not reach target height. Birth length and birth weight had 25% and 21% (P< 0.001) explanation, respectively, of the variation for adult height when corrected for mid-parental height. Without correction was the explanation for the variation of adult height by birth-length and weight 13% and 7.5% respectively (P< 0.001).

Conclusions: This study suggests that gestational age is not associated with adult height or pubertal timing. However, the study population mainly consisted of individuals born term, including moderately premature born babies. The larger the birth size, the taller the adult height, with the main influence being birth length. No significant association between birth size and timing of puberty was seen, however, may non-linear correlations be present. Future studies including larger numbers of premature born individuals and more sophisticated analyses of growth may give more detailed answers.