Endocrine Abstracts

JOINT322

Background: Infant growth results from a complex interplay of genetic, environmental, and hormonal factors, influencing early development and future health. Large population-based GWAS have identified genetic loci linked to traits such as birth weight, adult height, and BMI, enabling the use of polygenic scores (PGS) to reveal genetic predispositions shaping growth and body composition. Examining these associations in infancy may provide insights into the origins of lifelong growth patterns and health risks, including obesity and cardiometabolic diseases. This study aimed to explore how genetic influences on infant growth develop during the first year of life.

Objective: To investigate the association between PGS for birth weight, adult BMI adult body height and IGF-1 levels with anthropometric measurements as well as IGF-I serum concentrations, as assessed by age-specific standard deviation scores (SDS), in healthy infants.

Methods: We conducted a longitudinal cohort study (COPENHAGEN Minipuberty Study, 2016-2018) involving 210 healthy, term newborns (female, n = 101), with up to six clinical examinations over the first year of life. Publicly available PGS were analyzed alongside with repeated measurement in infants.

Results: PGS for birth weight was significantly associated with birth weight SDS in our cohort (adjusted for gestational age: P < 0. 001). However, the PGS for birth weight was not associated with the child’s weight SDS at one year of age (P = 0. 86). The PGS for adult BMI was associated with weight SDS at one year of age (P = 0. 02) as well as with birth weight SDS (P = 0. 03). The PGS for adult height was associated with height SDS at one year of age (P = 0. 002) as well as with birth length (P = 0. 04). PGS for IGF-I were not associated with IGF-I SDS at 1 month (β=0. 40, 95%CI: -2. 01−2. 81) and 2 months (β=1. 84, 95% CI: -0. 65−4. 32), but reached statistical significance at 6 months (β=3. 80, 95%CI: 1. 29 to 6. 31) and 12 months (β=4. 57, 95%CI: 1. 84−7. 31).

Conclusion: Our findings reveal that genetic influences on growth, particularly those linked to adult height and BMI, begin to manifest during the first year of life, while the impact of birth weight genetics gradually diminishes during infancy. Concerning IGF-I, genetic influences appear to be minimal at birth but gradually strengthen as infancy progresses. These results underscore the dynamic interplay between genetic predispositions, IGF-I, and early growth, emphasizing that genetic contributions to physical development are dynamic and unfold progressively throughout infancy.