PON1 and carotid atherosclerosis: Dursun et al. stated that PCOS reduced serum PON-1 level and this may be related to the probability of increased atherosclerotic heart diseases [9]. However, this is not consistent with the study by San Millan et al., who did not show a significant difference between the PCOS and control groups in the serum PON-1 activities [20]. Xita et al. found no association between PON-1 and PON-2 gene polymorphisms and PCOS but the association between the L55M polymorphism and insulin levels, which may be implicated in the PCOS's IR phenotype [21].