Bone Mineral Density, Body Composition, and Metabolic Health of Very Low Birth Weight Infants Fed in Hospital Following Current Macronutrient Recommendations during the First 3 Years of Life

Abstract

The present study longitudinally evaluated growth, bone mineral density, body composition, and metabolic health outcome in very low birth weight (VLBW) infants whose in-hospital target nutrient intake was within recent recommendations. From six months to three years, bone mineral density (dual-energy X-ray absorptiometry, DXA), body composition, and metabolic health outcome were compared with a reference group of term infants. The aim was to test whether in-hospital achieved weight gain until 36 weeks of gestation (light or appropriate for term equivalent age; LTEA or ATEA) predicts later growth, bone mineral density (BMD), abdominal obesity, or metabolic health outcomes such as insulin resistance, relative to term infants, during the first three years of life. Target in-hospital energy and protein intake was not achieved. Growth in weight, length and head circumference, mid arm circumference, adiposity, fat free mass (FFM), and bone mineralization in VLBW infants was less than those in term infants and influenced by nutritional status at discharge. Preterm infants had poorer motor and cognitive outcomes. Post-discharge body composition patterns indicate FFM proportional to height but lower fat mass index in LTEA preterm infants than term infants, with no evidence of increased truncal fat in preterm infants. The hypothesis of early BMD catch-up in VLBW infants after discharge was not supported by the present data. The clinical significance of these findings is unclear. The data may suggest a reduced obesity risk but an increased osteoporosis risk. Since postnatal growth restriction may have permanent negative health effects, LTEA VLBW infants would especially appear to benefit from targeted preventive interventions. Further follow-up of the infants is required.