Aluminum exposure from intravenous feeding solutions and later bone health: 15 year follow-up of a randomised trial in preterm infants

Background: Aluminum has known neurotoxicity and may impair short-term bone health. In a randomised trial we showed reduced neurodevelopmental scores in preterm infants previously exposed to aluminum from parenteral nutrition solutions. Here, in the same cohort, we test the hypothesis that neonatal aluminum exposure also adversely affects long-term bone health, as indicated by reduced bone mass. Methods: Bone area (BA) and bone mineral content (BMC) of lumbar spine, hip and whole body were measured with Dual X-ray Absorptiometry (DXA) in 13-15yr olds who were born preterm and randomly assigned standard or aluminum-depleted parenteral nutrition (PN) solutions during the neonatal period. Results: 59 subjects (32% of survivors) were followed. Those randomised to standard PN solution had lower lumbar spine BMC; apparently explained by a concomitant decrease in bone size. In non-randomised analyses, subjects exposed to neonatal aluminum intakes above the median (55mcg/kg) had lower hip BMC (by 7.6% (95% CI 0.21 to 2.38; p=0.02)), independent of bone (or body) size. Conclusion: Neonates exposed to parenteral aluminum may have reduced lumbar spine and hip bone mass during adolescence, potential risk factors for later osteoporosis and hip fracture. These findings need confirmation in larger, more detailed studies. Nevertheless, given our previous finding of adverse developmental outcome in these subjects, and the sizeable number of contemporary infants undergoing intensive neonatal care who are still exposed to aluminum via parenteral feeding solutions, the potential adverse long term consequences of early aluminum exposure now deserve renewed attention.