Table 3.

Associations Between Menstrual Dysfunction (MD) and Low Bone Mineral Density (BMD; Z Score <−1.0) by Sport-Specialization Status

Menstrual Statusa	Total			Sport-Specialization Status
				Lowb			Moderatec			Highd
	Low BMD		95% CI	Low BMD		95% CI	Low BMD		95% CI	Low BMD		95% CI
	No. (%)	OR		No. (%)	OR		No. (%)	OR		No. (%)	OR
Eumenorrheic	47 (27.7)	1.00	Referent	22 (13.6)	1.00	Referent	19 (42.1)	1.00	Referent	6 (33.3)	1.00	Referent
MD	17 (58.8)	3.74e	1.2, 11.9e	4 (50.0)	1.92	0.6, 63.6	5 (40.0)	0.92	0.1, 6.8	8 (75.0)	6.00	0.6, 61.8
P value			0.02e			0.16			0.67			0.16

Abbreviations: CI, confidence interval; NA, not applicable; OR, odds ratio.

^aRunners who reported primary amenorrhea, cycles > 35 days apart, or ≥3 consecutive missed menstrual cycles in the past year.

^bLow: Distance running (cross-country [XC], track and field [TF], both) ≤8 mo/y competitive sport participation or training and 1 or more other sport(s) played.

^cModerate: Distance running (XC, TF, both) only ≤8 mo/y competitive sport participation or training or distance running (XC, TF, both) ≥9 mo/y competitive sport participation or training and 1 or more other sport(s) played.

^dHigh: Distance running only (XC, TF, both) for ≥9 mo/y competitive sport participation or training.

^eBoldface indicates statistical significance.