Vitamin D, Calcium, and Dairy Intakes and Stress Fractures Among Female Adolescents JAMA Pediatrics, 03/15/2012

Sonneville KR et al. – Vitamin D intake is associated with lower stress fracture risk among adolescent girls who engage in high levels of high–impact activity. Neither calcium intake nor dairy intake was prospectively associated with stress fracture risk.

• Prospective cohort study.
• Adolescent girls living throughout the United States.
• A total of 6712 girls aged 9 to 15 years at baseline in the Growing Up Today Study, an ongoing prospective cohort study.
• Dairy, calcium, and vitamin D intakes assessed by food frequency questionnaire every 12 to 24 months between 1996 and 2001.

• During 7 years of follow-up, 3.9% of the girls developed a stress fracture.
• Dairy and calcium intakes were unrelated to risk of developing a stress fracture. However, vitamin D intake was inversely related to stress fracture risk.
• They conducted a stratified analysis to estimate the association between vitamin D intake and stress fracture risk among girls participating in at least 1 h/d of high-impact activity, among whom 90.0% of the stress fractures occurred, and found that higher vitamin D intake predicted significantly lower risk of stress fracture (Ptrend = .04).