['It has been shown that there is an increase in oxidative stress in polycystic ovary syndrome (PCOS). Statins are considered to have a pleiotropic effect other than their lipid-lowering effect. These effects may be mediated in part by reducing oxidative stress.', 'This randomized, double-blind, placebo-controlled study was conducted to assess the effect of atorvastatin on serum malondialdehyde (MDA) concentrations as a marker of oxidative stress in patients with PCOS. Forty medication-naïve patients with PCOS were randomized to either atorvastatin 20 mg daily or placebo for 3 months. A 3-month extension study for both groups of patients was undertaken with metformin 1500 mg daily after completing initial 3 months of atorvastatin or placebo.', 'There was a significant decrease of MDA concentrations with atorvastatin [mean (sem)] [0.29 (0.04) vs. 0.25 (0.02) μmol/liter; P < 0.01] compared with placebo [0.28 (0.02) vs. 0.29 (0.12) μmol/liter; P = 0.52]. Three months treatment with metformin resulted in further reduction of MDA levels with atorvastatin compared with baseline [0.25 (0.02) baseline vs. 0.23 (0.03) μmol/liter for atorvastatin treated; P = 0.02]. There was also a significant correlation between the reduction in MDA with a reduction in high-sensitivity C-reactive protein (r = 0.71, P < 0.01), an increase in 25-hydroxyvitamin D (25OHD; r = -0.68, P = 0.02), and a reduction in testosterone levels (r = 0.63, P = 0.01). Multiple linear regression analysis revealed Δ25OHD, ΔC-reactive protein, and Δtestosterone were independent predictors of changes in MDA after atorvastatin treatment. No correlation was observed between the reductions in serum MDA concentrations with changes in the lipid parameters.'] Does atorvastatin reduce malondialdehyde concentrations in patients with polycystic ovary syndrome?