(HealthDay News) – High intake of vitamin D is associated with a reduced risk of stress fractures in adolescent girls, particularly for those who engage in high-impact activity, according to a study published online March 5 in the Archives of Pediatrics & Adolescent Medicine.

To investigate the association between calcium, vitamin D, and/or dairy intake and stress fractures, Kendrin R. Sonneville, ScD, RD, of the Children’s Hospital Boston, and associates conducted a prospective study of 6,712 adolescent girls aged 9–15 who completed a food frequency questionnaire every 12–24 months between 1996 and 2001.

During seven years of follow-up, the researchers found that 3.9% of participants developed a stress fracture, predominantly from high-impact sports. Intake of dairy and calcium was not associated with stress fracture risk, while there was an inverse correlation between vitamin D intake and stress fracture risk. For the highest versus the lowest quintile of vitamin D intake, the multivariable hazard ratio of stress fracture was 0.49 (Ptrend=0.07). For girls participating in at least one hour per day of high-impact activity, higher vitamin D intake was associated with a significantly reduced risk of stress fracture (Ptrend=0.04).

“Vitamin D intake is associated with lower stress fracture risk among adolescent girls who engage in high levels of high-impact activity,” the authors write. “Neither calcium intake nor dairy intake was prospectively associated with stress fracture risk.”

One author disclosed financial ties to the pharmaceutical industry and one author disclosed ties to the medical device industry.

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