Osteopenia of prematurity and associated nutritional factors: case-control study.

Background: Preterm newborn nutrition affects postnatal skeletal growth and bone mineralization, but studies have not yet fully concluded the relationship between nutrition and osteopenia. This study was intended to investigate the impact of nutritional factors on osteopenia in preterm newborns.

Methods: This is a case-control study with babies born with gestational age ≤ 32 weeks in a high-risk maternity hospital, between 2018 and 2019. The population consisted of 115 newborns, being 46 cases (40%) and 69 controls (60%). Disease outcome was based on serum alkaline phosphatase levels > 900UL/l and hypophosphatemia < 4 mg/dl. Gestational data at birth and clinical and nutritional follow-up data during 8 weeks postnatally were assessed. Variables were assessed using regressive logistic models.

Findings: Preterm infants who were fed pasteurized fresh human milk with acidity ≥ 4 ºDornic are 5.36 times more likely to develop osteopenia (p = 0.035). Higher calcium intake, compared to controls, also increased the probability of disease occurrence [OR 1.05 (CI 1.006-1.1); p = 0.025], while the presence of a partner [OR 0.10 (CI 0.02-0.59); p = 0.038] and the shortest time using sedatives [OR 0.89 (CI 0.83-0.98); p = 0.010] were protective factors associated with osteopenia. Extremely low birth weight [OR 5.49 (CI 1.20-25.1); p = 0.028], sepsis [OR 5.71 (CI 1.35-24.2); p = 0.018] and invasive ventilatory support [OR 1.09 (CI 1.03-1.18); p = 0.007] were risk factors.

Conclusions: Acidity and high calcium intake are the main nutritional factors associated with osteopenia of prematurity. Further studies on the use of human milk with lower acidity, recommendation and nutritional supplementation of calcium should be accomplished to guide prevention strategies in newborns at risk for osteopenia during hospital stay.