Metabolic bone disease in preterm babies: are we underestimating it?”

The terms metabolic bone disorder(MBD), osteopenia of prematurity, or rickets are used interchangeably to indicate the decrease in bone mineral density status in preterm neonates. Despite, the lack of consensus over the definition of MBD, it is generally accepted that MBD represents a significant decrease in the bone mineral content relative to size or gestational age with associated biochemical and/or radiographic changes.1,2 As a result of different definitions, the reported incidence of MBD varies greatly across the published studies. However, the incidence of MBD is inversely correlated with gestational age and neonatal weight.3 It has been found to occur at a rate of 23% and 60% in neonates whose weight is less than 1500g and 1000g respectively.4,5 This estimation was reported to be even higher in infants who are exclusively breast-fed since 16% and 40 % of formula-fed and breast-fed infants, respectively have been found to experience MBD.6 Regarding the long-term effects of low birth weight and preterm birth, it has been shown that preterm neonates whose birth weight is < 1500 g are more likely to have less bone mineral density at the age of 7years than their peers.7 This was confirmed by another study which indicated that Dual-energy X-ray absorptiometry (DEXA) scan that was performed at around the age of 7years on children who were born at 40weeks of gestation, denoted more bone mass than those who were preterm.8