ORIGINAL PAPER Prevalence and risk factors for vitamin D deficiency among healthy infants and young children in Sacramento, California Lisa Liang & Caroline Chantry & Dennis M. Styne & Charles B. Stephensen Received: 25 March 2010 / Accepted: 12 May 2010 / Published online: 8 June 2010 # US Government 2010 Abstract This cross-sectional study assessed vitamin D status of healthy infants and young children undergoing routine care in a medical center pediatric clinic in Sacramento, CA, and evaluated associations of status with markers of vitamin D function. Such data have not recently been reported from similar locations with sunny climates that should minimize risk of deficiency. Exposures included diet, supple- ment use, and sun exposure, and outcomes included plasma 25-hydroxy vitamin D (25[OH]D), parathyroid hormone (PTH), bone-specific alkaline phosphatase, and eight markers of immune activation. The median age of the 173 subjects was 12 months (range, 6–19); 49% were female. The median 25 (OH)D was 85 nmol/l (range, 9–198); five subjects (2.9%) had <27.5 nmol/l, indicative of deficiency; 14 (8.1%) had <50 nmol/l, and 49 (28.3%) had <75 nmol/l. Most subjects (154; 89%) received some vitamin-D-fortified cow’ s milk or formula while 19 (11%) received breast milk as the only milk source. Breastfeeding was associated with risk of vitamin D deficiency (p <0.001). Subjects with 25(OH)D <27.5 nmol/ l had elevated PTH (p =0.007). Only four of 35 breastfed infants (11%) consuming <500 ml/day vitamin-D-fortified formula or milk received vitamin D supplements. Plasma interleukin (IL)-1β was significantly higher (p =0.036) in infants in the highest vs. lowest 25(OH)D decile. In conclusion, this study demonstrates that vitamin D deficien- cy with elevated PTH remains a risk for breastfed subjects not receiving supplemental vitamin D even in a region with a sunny, temperate climate. Strategies to improve supplemen- tation should be sought. Keywords Vitamin D . Infant . Plasma 25-hydroxy vitamin D . Infant feeding Introduction Vitamin D deficiency persists among infants and young children in the USA despite the availability of vitamin D supplements and food fortification. Breastfed infants not receiving vitamin D supplements and individuals with dark skin pigmentation are at greatest risk of deficiency [8–10, 17, 30, 34, 36]. Vitamin D deficiency is a concern because of its known effects on calcium absorption and bone metabolism and its suspected effects on immune function and cancer risk [6, 13, 14, 37]. Although cutaneous vitamin D synthesis is a benefit of sun exposure, excessive sun exposure at an early age correlates with lifetime risk of skin cancer and sun exposure is not recommended for infants by the American Academy of Pediatrics [1]. Fortification of infant formula is mandated at a level of 40–100 IU/100 kcal [29], and products commonly contain >200% of the minimum [15]. Cow’ s L. Liang Graduate Group in Nutritional Biology and Department of Nutrition, University of California, Davis, CA, USA C. Chantry : D. M. Styne Department of Pediatrics, School of Medicine, University of California, Davis, CA, USA C. B. Stephensen (*) Western Human Nutrition Research Center, United States Department of Agriculture (U.S.D.A.), 430 West Health Sciences Drive, University of California, Davis, CA 95616, USA e-mail: charles.stephensen@ars.usda.gov Eur J Pediatr (2010) 169:1337–1344 DOI 10.1007/s00431-010-1226-3