A Cochrane review included 6 studies with a total of 164 subjects. 3 studies compared physical activity to minimal dietary and behavioural advice or no advice. 3 studies compared combined dietary, exercise and behavioural interventions to minimal intervention. Intervention provided benefits when compared to minimal treatment for total testosterone (MD -0.27 nmol/L, 95% CI -0.46 to -0.09; 5 trials, n=144), hirsutism by the Ferriman-Gallwey score (MD -1.19, 95% CI -2.35 to -0.03; 4 trials, n=132), weight (MD -3.47 kg, 95% CI -4.94 to -2.00; 2 trials, n=108), waist to hip ratio (MD -0.04, 95% CI -0.07 to -0.00; 3 trials, n=113), fasting insulin (MD -2.02 µU/mL, 95% CI -3.28 to -0.77; 5 trials, n=144) and oral glucose tolerance test insulin (standardised mean difference -1.32, 95% CI -1.73 to -0.92; 3 trials, n=121), and per cent weight change (MD -7.00%, 95% CI -10.1 to -3.90, P < 0.00001). There was no evidence of effect for body mass index, free androgen index, glucose, or lipids. No data were available for fertility or menstrual regularity, for quality of life, patient satisfaction, or acne.
Comment: The quality of evidence is downgraded by risk of bias (inadequate or unclear allocation concealment or selective reporting in half of the studies and inadequate intention-to-treat adherence in all trials), by imprecise results (limited study size), and by indirectness (short follow-up).