Low Bone Mineral Density in Elite Female Athletes With a History of Secondary Amenorrhea in Their Teens.

OBJECTIVE

To determine whether secondary amenorrhea during teenage years influences bone mineral density (BMD) in female athletes in their 20s.

DESIGN

Original research.

SETTING

Japan Institute of Sports Sciences.

PARTICIPANTS

Two hundred ten elite female athletes older than 20 years were included in the study.

MAIN OUTCOME MEASURES: Information on the participants' past (ie, during their teenage years) and current menstrual cycle, training time, history of stress fractures, and blood tests for hormones received was obtained. Bone mineral density of the lumbar spine was evaluated by dual-energy x-ray absorptiometry; low BMD was defined as a Z-score ≤-1. We investigated the correlation factors for low BMD in athletes in their 20s by univariable and multivariable logistic regression analysis.

RESULTS

A total of 39 (18.6%) female athletes had low BMD. Secondary amenorrhea in their teens [odds ratio (OR), 7.11, 95% confidence interval (CI), 2.38-21.24; P < 0.001] and present body mass index (BMI) (OR, 0.56, 95% CI, 0.42-0.73; P < 0.001) were independent correlation factors for low BMD in the multivariable logistic regression analysis. The average Z-score for those with secondary amenorrhea in their teens and 20s, secondary amenorrhea in their 20s only, and regular menstruation was -1.56 ± 1.00, -0.45 ± 1.21, and 0.82 ± 1.11 g/cm, respectively.

CONCLUSIONS

Secondary amenorrhea for at least 1 year during teenage years in female athletes and BMI at present was strongly associated with low BMD in their 20s.