Association Between Composite Dietary Antioxidant Index and Bone Mineral Content in Adolescents

Objectives: Antioxidants play an important role in protecting the body from free radicals and oxidative damage. Prior research in adults has shown that a higher composite dietary antioxidant index (CDAI) may protect against osteoporosis, but this has not been explored in children or adolescents. Therefore, this analysis explored the association between CDAI and bone mineral content (BMC) in children and adolescents. Methods: This is a cross-sectional analysis of the baseline visit of the MetA-Bone Trial in healthy 9-14 year-old children and adolescents. Whole body BMC and spine BMC were assessed under dual-energy x-ray absorptiometry (Hologic DXA). Participants also collected two to three 24-hour dietary recalls, which were averaged. Then, CDAI was constructed based on vitamins A, C, and E, magnesium, selenium, and zinc intakes. For this, the sum of the intakes of these six antioxidants was computed and adjusted for energy intake. Then this value was subtracted to the global mean of the intake of these six antioxidants and divided by the global standard deviation. CDAI was associated with BMC using linear regression and logistic regression by associating quartiles of CDAI and quartiles of BMC. The models for adjusted for additional information collected at baseline, such as age, sex, race/ethnicity, Tanner stage, BMI, and physical activity. Results: A total of 153 children and adolescents had complete data. The mean and standard deviation for age was 12.0±1.5 years, for Tanner stage was 2.8±1.20, and for CDAI was 1.84±0.64. In total, 50.7% were females; 69% were Hispanic, and 41.2% were white. CDAI was not significantly associated with whole body BMC in children (B= -11.8, p= 0.776) or spine BMC (B= 0.203; p= 0.873). Similar results were found after adjusting for age, sex, race/ethnicity, Tanner stage, BMI, and physical activity. Similarly, the logistic regression also showed no association between quartiles of CDAI and whole body or spine BMC. Conclusions: CDAI was not significantly associated with BMC during this stage, which coincides with the age of maximal peak bone mass. Future research should be conducted to explore this association in other age groups or with larger samples. Funding Sources: The MetA-Bone trial is funded by Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health.