Vitamin D intake and serum vitamin D in ethnically diverse urban schoolchildren

Objective: Low serum vitamin D, which largely affects ethnic minorities, is associated with obesity and other chronic diseases. Little is known about racial/ethnic differences in intake, particularly in children, or if any differences are associated with differences in serum 25-hydroxyvitamin D (25(OH)D). The objective of the present study was to determine whether racial/ethnic differences in dietary vitamin D intake exist and whether they explain differences in 25(OH)D. Design: Vitamin D intakes (Block Kids 2004 FFQ) and 25(OH)D were measured. Race/ethnicity was parent-reported (white (37.9%), Hispanic (32.4%), black (8.3%), Asian (10.3%), multi-racial/other (11.0%)). Multivariable analyses were conducted to examine the associations among dietary vitamin D and race/ethnicity, as well as 25(OH)D, independent of BMI Z-score and other covariates. Setting: Elementary/middle schools in Somerville, MA, USA, during January-April 2010. Subjects: Schoolchildren (n 145) in 4th-8th grade. Results: Only 2.1% met the 2011 RDA (15mg/d (600 IU/d)). Average dietary intake was 3.5 (SD 2.2) mu g/d (140 (SD 89.0) IU/d). No racial/ethnic differences in intake were evident. Most (83.4%) were 25(OH)D deficient (<20 ng/ml; 16.0 (SD 6.5) ng/ml). In ANOVA post hoc analyses, 25(OH)D levels were lower in Hispanics than whites (14.6 (SD 6.1) ng/ml v. 17.9 (SD 4.6) ng/ml; P<0.01). Dietary vitamin D was associated with 25(OH)D overall (P<0.05), but did not explain the racial/ethnic differences in 25(OH)D. Conclusions: Most children in this north-east US sample did not meet dietary recommendations for vitamin D and were vitamin D deficient. Dietary vitamin D did not explain the difference in 25(OH)D between Hispanic and white children. Further research is needed to determine if changes in dietary vitamin D by race/ethnicity can impact 25(OH)D levels.