Data presented are arithmetic mean (SE) changes from baseline at 6, 12, 18 and 24 months; FFM (Panel A), t-scores for TASM/ht2 (Panel B). An asterisk indicates a significant difference in the change from baseline to 24 months within the group (Bonferroni-adjusted P values). In subjects treated with placebo followed by MK-677 in year 2 (Group 3), the change from baseline in FFM was significant (P=0.026), however, the t-score for TASM/ht2 was not significant compared with baseline (t-scores did increase in response to MK-677 in year 2, but had declined in year 1 during placebo). FFM = fat-free mass by DXA, TASM=total appendicular skeletal muscle mass from DXA, TASM divided by height (meters) squared = an index of relative limb muscle mass used to compute a t-score by relating it to gender-concordant young adults