After adjusting for baseline HbA1C, changes in HbA1C were related to type 2 diabetes duration (r = 0.40, P<0.002; Figure 2A), changes in fasting serum FFA (r = 0.36, P<0.004; Figure 2B) and, adiponectin (r = −0.26, P<0.03; Figure 2C) levels, and skeletal muscle PGC-1α protein (r = −0.28, P = 0.02; Figure 2D) independent of sex (−0.09% (−0.36%, 0.17%) vs. −0.55% (−0.92%, −0.17%); women vs. men, respectively; P = 0.05) and ethnicity (−0.00% (−0.23%, 0.23%) vs. −0.64% (−1.09%, −0.19%), Caucasian vs. non-Caucasian, respectively; P = 0.02). Here, PPARGC1A is linked to type 2 diabetes mellitus.