Bone mineral status in adolescent girls: Effects of eating disorders and exercise

Abstract

Purpose: To compare whole-body, lumbar, total spine, and pelvis bone mineral density (BMD), body mass index (BMI), body composition, energy expenditure for physical activity, and dietary intake of adolescents, aged 16-22 years. Methods: Three study groups included 25 girls with histories of eating disorders, 25 girls with no histories of eating disorders who exercised ≤ 7 hours/week, and 15 girls with no history of eating disorders who exercised> 7 hours/week. Bone mineral density was measured by dual-energy x-ray absorptiometry (DEXA), body composition by bioelectric impedance and DEXA, energy expenditure by Personal Activity Computer, nutrient intake by 4-day dietary recalls/records, and BMI by measures of height/weight. General linear models, LSM ± SEM, Student's t-tests, and correlation analyses were used to determine group differences. Results: No significant differences in whole-body, spinal, and pelvis BMD were found among the three groups. Mean body fat (percent) was significantly higher (p = .0001) for the group with histories of eating disorders than other groups. Dietary intakes of adolescents with histories of eating disorders were significantly lower for energy (p = .0001), fat (p = .0001), calcium (p = .0007), vitamin D (p = .0180), and zinc (p = .0057) than those without eating disorder histories who exercised ≤ 7 hours/week. Conclusion: Except for body fat (percent), measures of BMD, energy expenditure, and BMI were not significantly different among groups. Our data suggest that with full recovery from eating disorders, teenage girls can achieve normal bone mass and body composition. Copyright (C) 2000 Society for Adolescent Medicine.