Number of potential participants enrolled per month. Rate of screen fails. Study procedure completion rate. Acceptability as determined by participant report. Change in serum estradiol levels (pg/mL). Change in serum procollagen type I intact N-terminal propeptide (P1NP) levels (mcg/L). Change in serum C-terminal telopeptide of type I collagen (CTX-1) levels (pg/mL). Change in lumbar spine bone mineral density assessed by dual-energy x-ray absorptiometry (DXA). Change in quality of life as assessed by Cystic Fibrosis Respiratory Symptom Diary - Chronic Respiratory Infection Symptom Score (CFRSD-CRISS) questionnaire