28. No Association Between The Prevalence of Hypovitaminosis D And The Occurrence of Fractures Among Overweight/Obese Adolescents

Abstract

There are conflicting data regarding the association between fracture incidence and serum vitamin D (25OHD) concentrations among adolescents with respect to body mass index (BMI) and age. The current study explored the potential association between a low 25OHD level and fracture among overweight, obese, and morbidly obese adolescents. A case-control study was conducted. We reviewed 1,129 electronic medical records of outpatients aged 12-19 years, who presented to the adolescent clinic of an urban hospital between October 1, 2014 – October 1, 2017 and for whom 25OHD levels were available. Patients were excluded if they had chronic diseases that could affect bone health and/or if they received medications that affected bone and mineral metabolism. Participants were identified as cases if they sustained a low/medium impact fracture 12 months before or after the 25OHD level was measured. Twenty-seven were identified [mean (SD) 3.56 (2.1) months between the fracture and 25OHD measurement], with 26 having their 25OHD level taken <6 months before or after the fracture. Controls were matched by age, race, BMI percentile and the season at which their 25OHD was measured (n=81). 25OHD status was defined as sufficient (>30 ng/mL), insufficient (20-30 ng/mL), and deficient (<20 ng/mL) in accordance with the Endocrine Society Clinical Practice Guidelines. Additionally, data were collected regarding fracture location and mechanism, season, hospitalization, and modality of treatment. Independent sample t-tests were used to evaluate for a difference in the 25OHD levels between the two groups. An alpha of 0.05 was considered statistically significant In total, 108 participants were included in the study. The case participants included 15 males (55.6%) and 12 females (44.4%). The control group was composed of 48 females (59.3%) and 33 males (40.7%). For all participants, the mean age was 15.7 ± 2.4 years. 12% were overweight, 53.7% were obese, and 34.3% were morbidly obese. Most fractures involved the upper extremity (59.3%) and were sustained by a low impact mechanism. The mean 25OHD level was 18.5 ng/mL for case participants and 16.1 ng/mL for control participants (P=0.1), indicating deficiency in both groups. No correlations were found between 25OHD levels and fractures, overall, or in any of the weight groups While extremely low levels of 25OHD were common among the adolescents studied, the occurrence of a fracture did not imply lower 25OHD levels among overweight, obese and morbidly obese adolescents. These data suggest that this costly laboratory testing is not justified with respect to bone health prior to vitamin D supplementation