The participant was informed of the decrease in caloric intake and was instructed again
to increase her daily energy intake to 2,600 kcal/day (10,878 kJ/day). She was moderately successful, increasing her intake to approximately 2,350 kcal/day (9,832 kJ/day). Consequently, the cycle following the second resumption was ovulatory but characteristic of an inadequate luteal phase, representing the first ovulatory cycle that this participant experienced during the intervention. Estrogen exposure during the 28 days preceding the ovulation-associated menses increased 64.3% compared to the baseline cycle. Furthermore, Selleckchem MEK inhibitor despite its anovulatory nature, the length of the subsequent and final cycle during the study declined sharply with an intermenstrual interval of 21 days. Changes in bone click here health As Table 4 demonstrates, the participant had a low BMD at the lumbar spine at baseline. After the 12-month intervention, no increases in BMD were observed at any skeletal site; however, P1NP, a marker of bone formation, increased by 49.6%. Table 4 Baseline measurements and the 6-month and 12-month percent change for bone marker concentrations and BMD Participant 1 Participant 2 Bone markers P1NP (μg/L) 52.90 36.95 6 month % change 5.6 22.6 12 month % change 49.6 51.6 CTx (ng/ml) 0.65 0.64 6 month % change
−23.1 −29.0 12 month % change 17.7 −36.1 Bone mineral density Lumbar spine Z-score −1.6 −1.4 Lumbar spine BMD (g/cm2) 0.983 1.056 6 month % change 1.7 2.6 12 month % change 0.8 2.0 Femoral neck Z-score 0.5* −0.6 Femoral neck BMD (g/cm2) 1.062 0.994 6 month % change −2.8 −0.3 12 month % change −4.3 1.4 Hip Z-score 0.0* −1.1 Hip BMD (g/cm2) 0.996 0.955 6 month % change −1.3 −0.4 12 month % change −2.0 1.9 *Z-score at month 6. BMD: bone mineral density; CTx: collagen type 1 cross-linked C-telopeptide; P1NP: pro-collagen type 1 amino-terminal propeptide. Participant 2: short-term amenorrhea Characteristics at baseline This participant was a 24-year old graduate
student who participated in approximately 7 hours of exercise each week, consisting of dancing, running, and Reverse transcriptase weight training. She presented with a normal BMI of 19.7 kg/m2 and percent body fat of 22.7%; however, at the start of the intervention, she had not had menses for three months, and her menstrual history revealed multiple extended episodes of amenorrhea (Table 1). Menarche occurred at 13 years of age. At age 16, she experienced an 8-month episode of amenorrhea. After she resumed menses, she had regular cycles until the age of 21 years when she experienced a prolonged episode of amenorrhea for 2.5 years that she associated with low food intake, selleck chemical stress, and excessive exercise. During this time of amenorrhea, she weighed 43 kg but gained about 10 kg to bring her to the weight of 53.8 kg which was measured at the baseline period of this report.