What question did this study set out to answer?

To assess if %fat Z-score from DXA can effectively predict menstrual status in female athletes, compared to traditional BMI and %EBW metrics.

March 13, 2026

Dual-energy X-ray absorptiometry per cent fat Z-score as a predictor of menstrual status in adolescent and young adult female athletes

Key Points

To assess if %fat Z-score from DXA can effectively predict menstrual status in female athletes, compared to traditional BMI and %EBW metrics.
Analyzed 388 female athletes (ages 15–30) classified as amenorrhoeic, oligomenorrhoeic, or naturally menstruating.
Employed DXA scans to derive %fat Z-scores and compared these with traditional BMI and %EBW thresholds.
Calculated sensitivity and specificity for predicting menstrual statuses using differing fat mass and body weight cut-offs.
%Fat Z-score significantly outperformed traditional BMI and %EBW in differentiating menstrual status groups.
A cut-off of %fat Z-score <−1.0 enhanced sensitivity for predicting amenorrhoea to 68.9% from 29.3% with BMI.
Specificity remained lower for %fat Z-score compared to traditional cut-offs, emphasizing the need for more women-focused metrics.

Abstract

Objective Weight/fat mass gain to support resumption of normal menses can be an important treatment goal for female athletes with amenorrhoea (AMEN) or oligomenorrhoea (OLIGO) related to relative energy deficiency in sport (REDs). However, targets based on body mass index (BMI) or per cent expected body weight (%EBW) may be less applicable in athletes, who typically have greater lean mass compared with the general population. Our aim was to determine if dual-energy X-ray absorptiometry (DXA)-derived %fat Z-score can detect menstrual status in female athletes and if a %fat Z-score cut-off of 20 years) or %EBW (in those ≤20 years) thresholds. Methods 388 female athletes (age 15–30 years, Tier ≥2) with DXA scans were classified as AMEN (n=159), OLIGO (n=84) or naturally menstruating (NM, n=145) using clinical records. We compared %fat Z-score and BMI or %EBW values across menstrual groups and calculated sensitivity and specificity for predicting AMEN and the combined OLIGO and AMEN groups (OLIGO/AMEN) using traditional BMI or %EBW risk cut-offs versus a risk cut-off of <−1.0 for %fat Z-score. Results %fat Z-score was superior to traditional BMI or %EBW thresholds in discriminating between menstrual status groups. Using a %fat Z-score cut-off <−1.0 improved sensitivity (p<0.0001) for predicting AMEN (68.9%) and OLIGO/AMEN (57.7%) compared with the sensitivity of traditional BMI or %EBW cut-offs for AMEN (29.3%) and OLIGO/AMEN (25.9%). However, %fat Z-score <−1.0 did not improve specificity for predicting AMEN (75.4%) nor OLIGO/AMEN (79.9%) compared with the specificity of traditional BMI or %EBW cut-offs for AMEN (83.9%; p=0.0078) and OLIGO/AMEN (85.2%; p=0.14). Conclusions When attempting to resume normal menstruation, achieving a %fat Z-score ≥−1.0, rather than using BMI or %EBW targets, may be a better goal for athletes with REDs-related amenorrhoea or oligomenorrhoea.

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Cite This Study

Keating et al. (Tue,) studied this question.

synapsesocial.com/papers/69b3ac3f02a1e69014ccdcff https://doi.org/https://doi.org/10.1136/bjsports-2025-110243

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