Very low birth weight survivors have reduced peak bone mass and reduced insulin sensitivity

Context Increasing numbers of very low birth weight (VLBW) infants are surviving into adulthood because of improvements in neonatal intensive care. Adverse events in early life can have long-term effects through reprogramming of metabolic systems. Objective To determine whether young adult VLBW survivors have abnormalities of skeletal development or endocrine function. Design Cross-sectional, observational, case-control study. Participants Thirty-seven VLBW subjects and 27 healthy controls at peak bone mass (mean age 23). Measurements Differences between cases and controls in body size, body composition, bone mass and bone geometry [assessed by dual-energy X-ray absorptiometry (DXA), hip structure analysis and peripheral quantitative computed tomography (pQCT)], bone turnover [urine N-terminal telopeptide of type I collagen (NTX), serum C-terminal telopeptide of type I collagen (CTX)], aminoterminal propeptide of type I procollagen (PINP) and bone alkaline phosphatase), hormones (sex steroids, IGF-1, PTH and 25-OH vitamin D) and insulin sensitivity (HOMA-IR and oral glucose tolerance testing). Results VLBW subjects had lower bone density at the lumbar spine (5.7%) and femoral neck (8.6%), which persisted after correction for bone size by the estimation of volumetric density (bone mineral apparent density). Urine NTX was higher in VLBW subjects than in controls, but there were no significant differences in other bone turnover markers. VLBW survivors had lower insulin sensitivity (mean INS-30 controls = 57.0, VLBW subjects = 94.3, P < 0.01), but there were no differences in whole body fat mass or truncal fat mass between VLBW subjects and controls. Conclusions Young adult VLBW survivors have reduced bone density for their bone size and reduced insulin sensitivity, which may have significant implications for their risk of fracture and diabetes in later life.