Prevalence of Vitamin D Deficiency Among Healthy Adolescents

TLDR

Vitamin D deficiency is common in young adults, elderly, and children worldwide, yet data on healthy US adolescents are scarce. This study aimed to estimate the prevalence of vitamin D deficiency among healthy adolescents seeking primary care. A cross‑sectional clinic‑based sample of 307 Boston adolescents undergoing annual physicals was evaluated for serum 25‑hydroxyvitamin D, parathyroid hormone, anthropometry, diet, and activity to identify risk factors. Twenty‑four percent of participants were deficient (≤15 ng/mL), 4.6% severely so, 42% insufficient (≤20 ng/mL); deficiency correlated inversely with PTH, was lower in winter, and was independently predicted by season, ethnicity, milk/juice intake, BMI, and physical activity, with African American teens showing the highest prevalence.

Abstract

<h3>Background</h3> Although vitamin D deficiency has been documented as a frequent problem in studies of young adults, elderly persons, and children in other countries, there are limited data on the prevalence of this nutritional deficiency among healthy US teenagers. <h3>Objective</h3> To determine the prevalence of vitamin D deficiency in healthy adolescents presenting for primary care. <h3>Design</h3> A cross-sectional clinic-based sample. <h3>Setting</h3> An urban hospital in Boston. <h3>Participants</h3> Three hundred seven adolescents recruited at an annual physical examination to undergo a blood test and nutritional and activity assessments. <h3>Main Outcome Measures</h3> Serum levels of 25-hydroxyvitamin D (25OHD) and parathyroid hormone, anthropometric data, nutritional intake, and weekly physical activity and lifestyle variables that were potential risk factors for hypovitaminosis D. <h3>Results</h3> Seventy-four patients (24.1%) were vitamin D deficient (serum 25OHD level, ≤15 ng/mL [≤37.5 nmol/L]), of whom 14 (4.6%) were severely vitamin D deficient (25OHD level, ≤8 ng/mL [≤20 nmol/L]). By using a broader definition (25OHD level, ≤20 ng/mL [≤50 nmol/L]), 129 patients (42.0%) were vitamin D insufficient. Serum 25OHD levels were inversely correlated with parathyroid hormone levels (<i>r</i>= −0.29), and were 24% lower during winter compared with summer. In a final multivariate model, season, ethnicity, milk and juice consumption, body mass index, and physical activity were significant independent predictors of hypovitaminosis D. <h3>Conclusions</h3> Vitamin D deficiency was present in many US adolescents in this urban clinic-based sample. The prevalence was highest in African American teenagers and during winter, although the problem seems to be common across sex, season, and ethnicity.