Physical Activity, Menstrual History, and Bone Microarchitecture in Female Athletes with Multiple Bone Stress Injuries

Bone stress injuries (BSI) occur in up to 20% of runners and military recruits and those with a history of BSI have a fivefold higher risk for a subsequent BSI. Yet, little is known about prior training, menstrual status, and bone structure in runners who experience multiple BSI. Purpose To determine differences in health and physical activity history, bone density, microarchitecture, and strength among female athletes with a history of multiple BSI, athletes with <= 1 BSI, and nonathletes. Methods We enrolled 101 women (age, 18-32 yr) for this cross-sectional study: nonathlete controls (n = 17) and athletes with a history of >= 3 BSIs (n = 21) or <= 1 BSI (n = 63). We collected subjects' health and training history and measured bone microarchitecture of the distal tibia via high-resolution peripheral quantitative computed tomography (HR-pQCT) and areal bone mineral density of the hip and spine by dual-energy X-ray absorptiometry. Results Groups did not differ according to age, body mass index, age at menarche, areal bone mineral density, or tibial bone microarchitecture. Women with multiple BSI had a higher prevalence of primary and secondary amenorrhea (P < 0.01) compared with other groups. Total hours of physical activity in middle school were similar across groups; however, women with multiple BSI performed more total hours of physical activity in high school (P = 0.05), more hours of uniaxial loading in both middle school and high school (P = 0.004, P = 0.02), and a smaller proportion of multiaxial loading activity compared with other groups. Conclusions These observations suggest that participation in sports with multiaxial loading and maintaining normal menstrual status during adolescence and young adulthood may reduce the risk of multiple bone stress injuries.