The cross-sectional design prevents the establishment of direct causal relationships between PPARGC1A promoter methylation, mtDNA content, and metabolic risk in women with PCOS. Although the study controlled for BMI, it did not account for other potential confounders such as diet, physical activity, or medication use. The population being investigated included women with PCOS from a specific university hospital, which may not be representative of all women with PCOS. This evidence concerns the gene PPARGC1A and polycystic ovary syndrome.