Date of Award

Spring 4-4-2012

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Nutrition

First Advisor

Vijay Ganji

Second Advisor

Xu Zhang

Third Advisor

Anita Nucci

Abstract

Background: Contribution of dietary sources to vitamin D status is not clearly known. Some studies have shown that dietary intake of certain vitamin D rich foods had a significant positive influence on serum 25-hydroxyvitamin D [25(OH)D] concentrations, whereas other studies have shown no effect. Although sunlight exposure is a major source of circulating serum 25(OH)D, children and adolescents have been advised on the dangers of sun exposure. Diet may therefore be an important contributor of circulating serum 25(OH)D in absence of or reduced sunlight exposure.

Objective: The aim of this study was to determine whether serum 25(OH)D concentrations were associated with any specific dietary patterns in US children and adolescents using assay-adjusted serum 25(OH)D data from National Health and Nutrition Examination Survey (NHANES) 2003-2004 and 2005-2006.

Methods: Data from 2 cycles of the NHANES 2003-2004 and 2005-2006 for individuals aged 2 to ≤19 y, were used to study the association between dietary patterns and serum 25(OH)D. Dietary patterns were established using factor analysis based on food-frequency questionnaire data. Eigenvalues and Scree plot were used to derive 2 major principal factors. They were labeled as High Fat Low Vegetable (HFLV) and Prudent dietary patterns.

Results: Serum 25(OH)D was significantly lower in HFLV dietary pattern group compared to Prudent dietary pattern group (25.1 vs 27.0 ng/mL; P=0.001). The highest serum 25(OH)D concentrations for all subjects were in the low-intake HFLV group or medium and high-intake Prudent groups (P=0.003 and P=0.012, respectively). In multivariate adjusted analysis, children with higher Prudent dietary contribution scores to overall diet showed a significant positive relation with serum 25(OH)D (β=62.01, P=0.016). When data were stratified by sex, a significant positive relation was observed in girls who consumed the Prudent diet (β=86.34, P=0.014) and a significant negative relation was observed in girls who consumed the HFLV diet (β=-84.32, P=0.022).

Conclusion: Overall, serum 25(OH)D concentrations were associated with Prudent dietary pattern but not with HFLV dietary pattern in US children and adolescents. When stratified by sex, the relation between dietary patterns and serum 25(OH)D was confined to only girls. Children consuming HFLV pattern diet may benefit from vitamin D supplementation and sunlight exposure (outdoor activities), and should be encouraged to consume more vitamin D fortified foods.

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