Growth and bone mineralization of young adults weighing less than 1500 g at birth

Abstract

Background: Preterm infants are at risk for suboptimal growth and bone mineralization compared to infants born at term but long-term outcomes into early adulthood are unclear.

Aims: To determine (1) if growth and nutrition in the first year of life significantly predict the outcomes measured at adulthood and (2) whole body and regional bone mineral content (BMC) of young adults who were born preterm and weighing <1500 g.

Study design and subjects: In this descriptive follow-up study, subjects were born preterm and weighing <1500 g (n=25, 17.2+/-1.2 years of age) and originally participated in a 1-year follow-up study of infant growth or subjects born at term (n=25, 17.3+/-1.4 years of age).

Outcome measures: In the preterm group, relationships of growth and nutrition in the first year of life with adult anthropometry and BMC were identified using correlation and regression analysis. Birth groups were compared for measurements of anthropometry and whole body and regional BMC obtained at adulthood using t-tests.

Results: After correcting for the effects of bone area using regression, rate of weight gain had a positive relationship and days to regain birth weight a negative relationship to adult BMC. Young adults, born preterm, were significantly shorter with lower whole body BMC than of those born at term, but BMC was appropriate for size.

Conclusions: Growth early in life predicts subsequent attainment of growth and bone mass. Premature birth results in lower attainment of height achieved by young adult age but bone mass is appropriate for body size.