Bone mineral density deficits in individuals born preterm persist through young adulthood: A systematic review and meta-analysis of DXA studies

Individuals born preterm are at increased risk for bone deficits given that the majority of skeletal mineral accrual occurs during the final gestational trimester. It is unclear how preterm birth affects bone density with aging or if individuals born preterm have increased rates of osteoporosis. This systematic review and meta-analysis summarizes the current data on bone mineral content and density measured by dual-energy x-ray absorptiometry (DXA) at any time across the lifespan after preterm birth in generally healthy, appropriate size for gestational age individuals. Three databases, including PubMed, Scopus, and CINAHL, were searched using keywords related to preterm birth and skeletal mineralization. Total body, lumbar spine, and femoral neck were the most frequently reported DXA measurement sites. A total of 39 studies (145 comparisons) were included in the meta-analyses, with bone outcomes measured within days of birth through about 30 years of age, depending on the measurement site. Preterm birth was associated with reduced bone mineral content and density. The largest total body bone deficits were observed in preterm individuals who were less than one year of age, with greater variability observed during childhood and adolescence. Individuals born preterm in the oldest cohort (17–30 years) maintained deficits in bone mineral density as they approached the age of peak bone mass. Importantly, there were no DXA studies of preterm individuals beyond 30 years of age, so it remains unclear how preterm birth affects the skeleton with advanced aging.