Bone mineral density of olympic-level female winter sport athletes.

Purpose: To compare areal bone mineral density (aBMD) of female winter sport athletes to healthy controls of similar age and body mass index (BMI).
Methods: Areal BMD (g x cm(-2)) of the whole body, lumbar spine (L2-L4), and right proximal femur were assessed by dual energy x-ray absorptiometry in athletes (N = 40; age: 26.1 +/- 5.7 yr; ht: 165.6 +/- 0.1 cm; wt: 63.0 +/- 6.5 kg; BMI: 23.0 +/- 1.9 kg x m(-2)) involved in speed skating (N = 9), snowboarding (N = 13), freestyle skiing (N = 3), biathlon (N = 8), bobsleigh, skeleton, luge (N = 7), and controls (N = 21; age: 26.0 +/- 5.1 yr; ht: 165.8 +/- 0.1 cm; wt: 62.8 +/- 5.9 kg; BMI: 22.9 +/- 1.3 kg x m(-2)).
Results: Using independent t-tests, athletes had lower fat mass, percent body fat, and higher lean mass than controls (P < 0.001). Areal BMD was higher in athletes than controls for all skeletal sites (P </= 0.007). With lean tissue mass as a covariate (ANCOVA), differences in aBMD remained significant for most skeletal sites (P </= 0.016). Menstrual history, mean daily calcium intake, and oral contraceptive use were not associated with aBMD in the athletic group.
Conclusion: Results show that female winter sport athletes have greater aBMD compared with controls of similar age and BMI. Most aBMD differences remained significant after adjusting for lean tissue mass, and athletes with a history of oligo- and/or amenorrhea had similar aBMD than their eumenorrheic counterparts. This is the first study to examine aBMD in winter sport athletes. The results support the hypothesis that the loading characteristics of intense winter sport participation have osteogenic potential.