Study: Many healthy infants and toddlers are vitamin D-deficient

August 1, 2008

Vitamin D deficiency may be predicted by breastfeeding without vitamin D supplementation.

To determine the prevalence of vitamin D deficiency in infants and toddlers, investigators studied 365 children from 8 to 24 months of age who received physical exams at a primary care clinic in Boston over two years. Investigators collected clinical and anthropometric data, administered parental nutritional and lifestyle questionnaires, and obtained blood samples to measure 25-hydroxyvitamin D (25OHD) level. A level of 20 ng/mL is considered a marker of vitamin D deficiency.

Of the 365 children, 44 (12.1%) were found to be vitamin D–deficient, with 7 (1.9%) severely deficient (≤8 ng/mL). In addition, 146 children (40%) had vitamin D levels below the accepted optimal threshold (≤30 ng/mL). The prevalence of vitamin D deficiency was the same in infants and toddlers. And for both age groups, serum 25OHD and parathyroid (PTH) levels were inversely correlated.

The prevalence of deficiency did not vary by sex, season, time spent outdoors, sunscreen use, sun sensitivity, or skin pigmentation. So what did predict vitamin D deficiency? Among infants, breastfeeding without vitamin D supplementation markedly increased the odds of vitamin D deficiency compared with exclusive bottle feeding (in this study, only 2% of breastfed infants were receiving vitamin D supplementation). Among toddlers, milk consumption significantly decreased odds of deficiency, whereas body mass index showed an opposite (though marginally significant) effect. Juice consumption had no effect on vitamin D deficiency in toddlers.

Commentary

We may need to be more aggressive about supplementing vitamin D in breastfeeding babies. And some are concerned that with increasing obesity, this fat-soluble vitamin is distributed across a larger volume, making old recommended daily requirements insufficient. Watch for revised recommendations on vitamin D.

DR. BURKE, section editor for Journal Club, is chairman of the department of pediatrics at Saint Agnes Hospital, Baltimore. He is a contributing editor for Contemporary Pediatrics. He has nothing to disclose in regard to affiliations with, or financial interests in, any organization that may have an interest in any part of this article.