Background: There is limited evidence describing the relationship between calcaneal bone mineral density (cBMD) and activity level, menstrual history, or the development of bone stress injury (BSI).
Hypothesis/purpose: The purposes of this study were to: 1) examine the influence of physical activity on cBMD in healthy college students (HCS), 2) determine if there is an association between cBMD, body mass index (BMI), sex, menstrual history, and history of BSI in HCS, and 3) compare the cBMD of HCS to cBMD data collected on intercollegiate athletes (ICA) from a previous study.
Study design: Cross-sectional design.
Methods: This cross-sectional study recruited a convenience sample of HCS at one institution. Subjects provided self-reported injury and menstrual history, completed a physical activity questionnaire, and cBMD and BMI measures were obtained. Descriptive statistics, statistical analyses of relationships (Chi-square and relative risk), logistic regression, and differences (t-tests) were used in the statistical analyses.
Results: One hundred three HCS (82 female, 21 male; age 21.9 ± 1.13) consented to participate. The composite score for work, leisure, and sport activity ranged from 5.6 to 11.1 (7.9 ± 1.1) for HCS subjects. There was no significant correlation between cBMD and physical activity in HCS, however, a significant correlation was found between reported age of onset of menstruation and left and right cBMD (r = -0.22 and r = -0.23; p < 0.05) and history of secondary amenorrhea and history of BSI (r = 0.32; p < 0.05). There was no difference in cBMD between the male ICA and male HCS, but highly significant differences in cBMD between the female ICA and female HCS groups (p < 0.000).
Conclusions: Age of menarche and secondary amenorrhea are significantly associated with cBMD and history of BSI in HCS subjects, respectively. Differences in cBMD among the HCS subjects were not related to activity level. cBMD was significantly lower in female HCS as compared to female ICA. This difference in cBMD between ICA and HCS may be activity related.
Level of evidence: Level 3.
Keywords: amenorrhea; bone density; bone stress injury; menarche; physical activity.