SUMMARY Serum 25-hydroxycholecalciferol levels were measured longitudinally in a series of breast-feeding mothers and their healthy, term infants for up to 6 months after birth. Although levels both in mothers and infants were lower at 6 weeks' postpartum than at delivery and in cord blood, there was little change thereafter with unsupplemented breast feeding.

Objective To investigate the effects of infant feeding mode on childhood cognition and language as the differential effects of infant feeding on development remain understudied. Methods Breastfed [BF, 174], cow's milk‐based formula‐fed [MF, 169], or soy protein‐based formula‐fed [SF, 161] children were longitudinally tested from age 3 to 60 months for neurodevelopment. Data were analyzed using mixed models while adjusting for multiple covariates. Sex differences were also assessed. Results Standard scores were within established norms for all groups. There were no differences in mental development to age 24 months, yet BF children had significantly higher motor development scores at age 3 months than SF children (99.1 versus. 97.2). BF children had significantly higher composite intelligence scores at 48 months than MF and SF children (113.4 versus. 109.6 and 108.4, respectively) and higher verbal intelligence scores than SF children at 48 (105.6 versus. 100.7) and 60 months (109.8 versus. 105.9). Greater total language scores at ages 36 and 48 months were found in BF children compared with children fed MF or SF ( p < .001), with differences between sexes for auditory comprehension. Higher total language scores at age 60 months were found between BF and SF (105.0 versus. 100.1). Conclusion Breastfeeding was associated with small, statistically significant, differences between children ages 3 and 5 years in verbal intelligence, expressive communication, and auditory comprehension with the latter having potential sexual dimorphic effects. Yet, these differences remain small and may not be of clinical relevance. Overall, MF and SF did not significantly differ.

Neonatal primary hyperparathyroidism is a life threatening disorder that is associated with severe hypercalcaemia, hypotonia, bone demineralization, fractures and respiratory distress. Treatment consists of total parathyroidectomy and without this affected infants will usually die by the age of three months. We report a patient with neonatal primary hyperparathyroidism who survived without fractures or parathyroidectomy to an age of nine months, and in whom the hypercalcaemia became masked by vitamin D deficiency. At surgery, four-gland hyperplasia was demonstrated and total parathyroidectomy followed by oral calcitriol treatment has restored well-being and normocalcaemia. An absence of skeletal complications, a survival beyond three months of age without parathyroidectomy and the masking of the hypercalcaemia by vitamin D deficiency represents a unique combination of metabolic abnormalities in a patient with neonatal primary hyperparathyroidism.