The cumulative effect of the female athlete triad (Triad) risk factors on the likelihood of low bone mineral density (BMD) in exercising women is unclear.
Purpose: This study aimed to determine the risk of low BMD in exercising women with multiple Triad risk factors.
Methods: We retrospectively examined cross-sectional data from 437 exercising women (mean ± SD age of 18.0 ± 3.5 yr, weighed 57.5 ± 7.1 kg with 24.5% ± 6.1% body fat) obtained at baseline from 4 prospective cohort studies examining Triad risk factors. Questionnaires were completed to obtain information on demographic characteristics, self-reported eating attitudes/behaviors, menstrual function, sport/activity participation, and medication use. Height and body weight were measured. BMD was measured using dual energy x-ray absorptiometry. Low BMD was defined as z-scores of <−1 and ≤−2. Chi-square tests were performed to determine the percentage of women with low BMD who met the criteria for individual (current oligo/amenorrhea, late menarche, low body mass index (BMI), elevated dietary restraint, lean sport/activity participation) or multiple (2, 3, 4, or 5) Triad risk factors.
Results: Late menarche and low BMI were associated with the highest percentage of low BMD (z-score < −1), 55% and 54%, respectively, and low BMD (z-score ≤−2), 14% and 16%, respectively. The percentage of participants with low BMD (z-score < −1 and ≤−2) increased from 10% to 62% and from 2% to 18%, respectively, as women met the criteria for an increasing number of Triad risk factors.
Conclusions: A cumulative number of Triad risk factors were associated with an increased risk of low BMD, suggesting a dose–response association between the number of Triad risk factors and BMD in exercising women. Further research should be conducted to develop a user-friendly algorithm integrating these indicators of risk for low BMD in exercising women (particularly factors associated with low BMI/body weight, menstrual dysfunction, lean sport/activity participation, and elevated dietary restraint).
1The Pennsylvania State University, University Park, PA; 2University of California, Los Angeles, CA; 3California State University, Northridge, CA; 4San Diego State University, San Diego, CA; and 5University of California, San Diego, CA
Address for correspondence: Mary Jane De Souza, Ph.D., Department of Kinesiology, The Pennsylvania State University, 104 Noll Laboratory, University Park, PA 16802; E-mail: firstname.lastname@example.org.
Submitted for publication February 2013.
Accepted for publication June 2013.