Weightwise, preterm babies will catch up
One in 10 babies are born preterm today, increasing their risk of obesity, high blood pressure, diabetes and cardiovascular disease throughout the course of their life. To date, most research conducted on the link between preterm birth and later body size has focused on the impact of a baby’s birth weight rather than the gestational age (GA) – how far along the pregnancy was. A new study supported by the EU-funded LIFECYCLE and EUCAN-Connect projects now provides new insight into how GA at birth is associated with body size from infancy through adolescence. For their research, the scientists investigated the data of 253 810 mother-child pairs in 16 cohort studies from 11 countries in Europe, North America and Australasia. Their analysis focuses on the following key stages of growth: early infancy (up to 6 months), late infancy (6.01 months to 2 years), early childhood (2.01 to 5 years), mid-childhood (5.01 to 9 years), late childhood (9.01 to 14 years) and adolescence (14.01 to 19 years).
Deeper insight into GA and body size
“Our study extends previous research by examining the association between GA and overweight in adolescence and across key stages of growth development throughout childhood,” report the authors in their paper published in the journal ‘PLOS Medicine’. “Moreover, our study design and large sample size enables an examination of odds of overweight in preterm adolescents and provides insights about this association across a wide range of GA.” GA was categorised as follows: 28 to 33 weeks (very preterm), 34 to 36 weeks (late preterm), 37 to 38 weeks (early term), 39 to 41 weeks (full term), and 42 to 43 weeks (post-term). “This distinction between degrees of preterm births is important as shorter gestational duration is associated with increased risk of mortality, disability, and morbidity across the life span,” the authors note. The research team found that preterm infants (born before 37 weeks of gestation) have a lower BMI and a lower risk of being overweight until 2 years of age than babies born at term. However, this difference lessens as the infants get older. “GA may be important for body size in infancy, but the strength of association attenuates consistently with age. By adolescence, preterm individuals have on average a similar mean BMI to peers born at term,” the study authors state. This suggests that, despite leaving the safety of their mother’s womb earlier than desired, preterm babies on average reach the same body size as term babies before adulthood. The data also indicates that children born very preterm – between 28 and 31 weeks GA – may have a higher risk of becoming overweight in adulthood than their term counterparts. However, the study’s authors advise to interpret this last finding with caution, as it is based on data from only four cohorts that reached the age of adolescence. This research included data from pregnancy and birth cohort studies from the LIFECYCLE (Early-life stressors and LifeCycle health) and EUCAN-Connect (A federated FAIR platform enabling large-scale analysis of high-value cohort data connecting Europe and Canada in personalized health) projects. The cohorts were eligible for inclusion if they had information on GA and at least one measurement of BMI between infancy and adolescence. For more information, please see: LIFECYCLE project website EUCAN-Connect project website
Keywords
LIFECYCLE, EUCAN-Connect, baby, preterm, gestational age, body mass index, BMI, infancy, adolescence, birth