ESPE Abstracts

Background: Telomere length at birth is a major determinant of telomere length at later ages, up into senescence. However, the prenatal setting of telomere length is poorly understood. Individuals born large are at lower risk for later-life disorders, such as diabetes, than those born small, a feature of their longer health span being a higher lean mass that provides more muscle strength and is already present in infancy.

Objective and hypotheses: To assess leukocyte telomere length (LTL) in small-, appropriate-, or large-for-gestational-age (SGA, AGA, and LGA) infants. To correlate LTL at birth with body composition at age 12 months. LTL will differ between AGA, SGA, and LGA subgroups.

Method: At birth, we studied LTL (by real-time PCR, using RNAseP as a single copy gene) in 103 SGA, AGA, and LGA infants born after an uneventful, term, singleton pregnancy. All infants were breastfed for ≥4 months. At age 12 months, body composition was assessed by absorptiometry.

Results: Telomere lengths were on average 25% shorter in SGA and 22% longer in LGA than in AGA newborns. Birthweights increased with telomere length. Notably, the infants with highest birthweights did not necessarily have long telomeres, but those with longest telomeres were consistently born LGA, whereas none of those with shortest telomeres was born LGA. Lean mass in late infancy – not fat mass – increased with telomere length at birth.

Conclusion: Newborns with longest telomeres are big at birth and have most lean mass – not most fat – in late infancy.