Vitamin D in infants with cystic fibrosis diagnosed by newborn screening.

AIMS

Screening enables early nutritional deficiencies to be detected in those with cystic fibrosis (CF). Although vitamin deficiency is considered unlikely in older subjects with normal vitamin E levels, few studies have determined vitamin D status at diagnosis and its relationship to other fat-soluble vitamins.

METHODS

We reviewed vitamin levels in infants diagnosed with CF by newborn screening over a 5-year period in Melbourne, Australia. Vitamin D levels were determined using the IDS gamma-B 25-OH Vitamin D radio-immunoassay (Immunodiagnostic Systems Limited, Boldon, UK). Vitamins A and E were evaluated by high-performance liquid chromatography. We assessed the association between vitamin D level and sex, month of birth, pancreatic status, and vitamin A and E levels.

RESULTS

Fifty-eight infants were diagnosed at a median age of 1 month (range: 0-3 months). Initial vitamin D levels were assessed between 0.2 and 3.5 months in 30 (vitamin D) and 45 (vitamins A and E) infants. The number of infants deficient with vitamins D, E and A were 11 (37%), 7 (16%) and 27 (60%), respectively. Vitamin D levels were unrelated to sex, vitamin A or E levels, month of birth or pancreatic status, whereas vitamin A and E levels were significantly lower in those who were pancreatic insufficient. With supplementation, vitamin D increased over time.

CONCLUSIONS

Vitamin D deficiency is common in infants newly diagnosed with CF by newborn screening and is unrelated to pancreatic status or predicted low vitamin E levels. Vitamin D deficiency is less common over time following treatment.