RESUMO
OBJECTIVES: To synthesize previous findings on the difference in birth telomere length between newborns with and without intrauterine growth restriction (IUGR) or with and without preterm birth. STUDY DESIGN: We systematically searched 3 databases (PubMed, Embase, and Web of Science) for publications that examined the relationships of IUGR or preterm birth with birth telomere length. We conducted meta-analysis to pool the estimated difference in birth telomere length either between IUGR and non-IUGR or between preterm birth and full-term birth. Subgroup analyses were conducted by tissues (newborn blood vs placenta) and techniques used for telomere length measurement (quantitative polymerase chain reaction [qPCR] vs telomere restriction fragment). RESULTS: We included 11 articles on comparing birth telomere length between IUGR (combined n = 227) and non-IUGR (n = 1897) and 7 articles on comparing birth telomere length between preterm birth (n = 182) and full-term birth (n = 1320). We found IUGR was associated with shorter birth telomere length only when birth telomere length was measured in placenta (pooled standardized mean difference [SMD] = -0.85; 95% CI -1.13 to -0.57; IUGR/non-IUGR n = 87/173), but not in newborn blood (pooled SMD = 0.00, 95% CI -0.18 to 0.19; IUGR/non-IUGR n = 148/1733). Birth telomere length was significantly longer in preterm birth than in full-term birth when birth telomere length was measured by qPCR (pooled SMD = 0.40, 95% CI 0.18-0.63; preterm birth/full-term birth n = 137/682) but not by telomere restriction fragment (pooled SMD = 0.05, 95% CI -0.29 to 0.38; preterm birth/full-term birth n = 44/444). CONCLUSIONS: IUGR is associated with shorter placental telomere length and preterm birth is associated with longer birth telomere length measured by qPCR.
Assuntos
Retardo do Crescimento Fetal/genética , Recém-Nascido Pequeno para a Idade Gestacional , Nascimento Prematuro , Telômero/genética , Idade Gestacional , Humanos , Recém-NascidoRESUMO
OBJECTIVE: To evaluate whether large for gestational age (LGA) etiological subgroups have differential growth trajectories during early childhood. STUDY DESIGN: Approximately 10,700 infants and their parents were included in the Early Childhood Longitudinal Study-Birth Cohort in 2001-2002. Research staff collected data in 5 waves when participating children were approximately 9 months and 2, 4, 5, and 6 years of age. We analyzed 2950 LGA and appropriate-for-gestational-age (AGA) children with at least 1 growth outcome at ages 9 months, 2 years, and 4 years. We divided 600 LGA newborns into 8 subgroups by maternal overweight or obesity before pregnancy (OW/OB), diabetes mellitus (DM), and excessive gestational weight gain (ExGWG). We used mixed effect regression models to compare trajectories of height (length)-for-age or body mass index (BMI) z scores across LGA subgroups and the AGA reference group. RESULTS: Relative to the reference group, the LGA subgroup with maternal OW/OB and DM but normal gestational weight gain had "continuous high rising" BMI z-score trajectory from 9 months to 4 years and the greatest mean z score at 4 years (2.14 [95% CI, 1.29, 2.98]). The LGA subgroup free of maternal OW/OB, DM, or ExGWG had a similar BMI z-score trajectory ("stable low") from 9 months to 4 years and a similar 4-years mean z score (0.97 [95% CI, 0.75, 1.18] vs 0.72 [95% CI, 0.67, 0.78]) relative to the AGA reference group. CONCLUSIONS: The LGA subgroup with co-occurrence of maternal OW/OB and DM had the greatest 4-year BMI, whereas the LGA subgroup free of maternal OW/OB, DM, or ExGWG were tall but lean ("a healthy phenotype").