My long- term goal is to become a proficient independent clinical researcher addressing racial and ethnic differences in vitamin D and calcium nutrition. My career development plan includes a Master of Science in Clinical Research and mentored clinical and social research. I plan to study the vitamin D status of pre- and early adolescent African American and Caucasian children. Epidemiologic and clinical data document a high prevalence of vitamin D insufficiency among adults and adolescents in the US. Little is known about the prevalence, seasonal variation and the metabolic impact of vitamin D insufficiency in preadolescent children. In Phase 1, using a longitudinal study design, we will estimate the prevalence and seasonal variation of vitamin D insufficiency in children 6 to 12 years old and characterize its impact on bone metabolism. A cohort of 140 healthy pre- and early adolescent children (6-12 yrs old, Tanner I or II, African American [n=94] and Caucasian [n=46]) will be studied during summer (June through September) and winter (December through March). Vitamin D status, calcitrophic hormones and markers of bone turnover will be assessed during summer and winter. Other measures include dietary intakes of vitamin D and calcium, sun exposure and body mass index. This study will help establish the prevalence, seasonal variation, metabolic impact of vitamin D insufficiency in young school-age African American and Caucasian children. In phase 2,168 (African American: 84, Caucasian: 84) 8 to 14 year old preadolescent and adolescent children will undergo a randomized-placebo controlled trial (RCT) of vitamin D31000 ID daily vs. placebo for 6 months initiated during fall and winter (October through March). This study will determine the serum 25(OH)D cutoff for the definition of vitamin D insufficiency and document the safety and efficacy of treatment on vitamin D status. To address issues of health disparities we will use the study design to test the hypothesis that parental mistrust in medicine and research is a barrier to recruitment of African American children into clinical research compared to Caucasian children. Parents of children recruited for the vitamin D study will be surveyed. Differences in the trust index between consenting and declining groups of parents will be determined. The results should help develop strategies for overcoming those barriers. Prevention of vitamin D insufficiency in children will improve their bone health (increase the peak bone mass) and reduce their """"""""osteoporosis burden"""""""" during adulthood. Optimizing vitamin D status in African American children may have the potential to reduce the disparities from non-skeletal disorders associated with chronic vitamin D insufficiency such as diabetes and prostate cancer that disproportionately affect African American adults.

Agency
National Institute of Health (NIH)
Institute
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
Type
Mentored Patient-Oriented Research Career Development Award (K23)
Project #
5K23HD052550-05
Application #
8127611
Study Section
Pediatrics Subcommittee (CHHD)
Program Officer
Winer, Karen
Project Start
2007-09-30
Project End
2013-08-31
Budget Start
2011-09-01
Budget End
2013-08-31
Support Year
5
Fiscal Year
2011
Total Cost
$165,534
Indirect Cost
Name
University of Pittsburgh
Department
Pediatrics
Type
Schools of Medicine
DUNS #
004514360
City
Pittsburgh
State
PA
Country
United States
Zip Code
15213
Khalid, Arshad T; Moore, Charity G; Hall, Christopher et al. (2017) Utility of sun-reactive skin typing and melanin index for discerning vitamin D deficiency. Pediatr Res 82:444-451
Rajakumar, Kumaravel; Moore, Charity G; Yabes, Jonathan et al. (2016) Estimations of dietary vitamin D requirements in black and white children. Pediatr Res 80:14-20
Rajakumar, Kumaravel; Moore, Charity G; Yabes, Jonathan et al. (2015) Effect of Vitamin D3 Supplementation in Black and in White Children: A Randomized, Placebo-Controlled Trial. J Clin Endocrinol Metab 100:3183-92
Michel, Hilary; Olabopo, Flora; Wang, Li et al. (2015) Determinants of 25-Hydroxyvitamin D Concentrations in Infants and Toddlers. Curr Nutr Food Sci 11:124-130
Rajakumar, Kumaravel; Holick, Michael F; Moore, Charity G et al. (2014) Impact of seasonal flux on 25-hydroxyvitamin D and bone turnover in pre- and early pubertal youth. Pediatr Int 56:35-42
de las Heras, Javier; Rajakumar, Kumaravel; Lee, SoJung et al. (2013) 25-Hydroxyvitamin D in obese youth across the spectrum of glucose tolerance from normal to prediabetes to type 2 diabetes. Diabetes Care 36:2048-53
Rajakumar, Kumaravel; Reis, Evelyn Cohen; Holick, Michael F (2013) Dosing error with over-the-counter vitamin D supplement: a risk for vitamin D toxicity in infants. Clin Pediatr (Phila) 52:82-5
Rajakumar, Kumaravel; de las Heras, Javier; Lee, SoJung et al. (2012) 25-hydroxyvitamin D concentrations and in vivo insulin sensitivity and ýý-cell function relative to insulin sensitivity in black and white youth. Diabetes Care 35:627-33
Rajakumar, Kumaravel; Holick, Michael F; Jeong, Kwonho et al. (2011) Impact of season and diet on vitamin D status of African American and Caucasian children. Clin Pediatr (Phila) 50:493-502
Rajakumar, Kumaravel; de las Heras, Javier; Chen, Tai C et al. (2011) Vitamin D status, adiposity, and lipids in black American and Caucasian children. J Clin Endocrinol Metab 96:1560-7

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