The effect of a healthy lifestyle for women with polycystic ovary syndrome

Review question

We reviewed the evidence on the effects of lifestyle interventions on reproductive, anthropometric (body measurement), metabolic and quality of life outcomes in women with polycystic ovary syndrome.

Background

Polycystic ovary syndrome (PCOS) is a very common condition affecting 8% to 13% of women. Being overweight worsens all clinical features of PCOS. These clinical features include reproductive issues such as reduced frequency of ovulation and irregular menstrual cycles, reduced fertility, polycystic ovaries on ultrasound and high levels of male hormones such as testosterone, which can cause unwanted facial or body hair growth and acne. PCOS is also associated with metabolic features, with risk factors for diabetes and cardiovascular disease including high levels of insulin or insulin resistance and abnormal cholesterol levels. PCOS affects quality of life and can worsen anxiety and depression either due to its symptoms or due to the diagnosis of a chronic disease. A healthy lifestyle consists of a healthy diet, regular exercise and achieving and maintaining a healthy weight.

Study characteristics

We found 15 studies that included 498 participants. Ten studies compared physical activity to minimal dietary and behavioural intervention or no intervention. Five studies compared combined dietary, exercise and behavioural intervention to minimal intervention. One study compared behavioural intervention to minimal intervention. The risk of bias in the studies varied and was generally unclear. The evidence is current to March 2018.

Key results

There were no studies that investigated the effect of a healthy lifestyle on live birth, miscarriage or regularity of menstrual cycles. Adopting a healthy lifestyle may result in weight loss or reduction in male hormone levels in some individuals. Diet and exercise may not have an effect on the body's ability to maintain normal blood glucose levels.

Quality of the evidence

The evidence was of low quality. The main limitations in the evidence were inconsistent and imprecise findings, and poor reporting of the methods used in the studies.

Authors' conclusions: 

Lifestyle intervention may improve the free androgen index (FAI), weight and BMI in women with PCOS. We are uncertain of the effect of lifestyle intervention on glucose tolerance. There were no studies that looked at the effect of lifestyle intervention on live birth, miscarriage or menstrual regularity. Most studies in this review were of low quality mainly due to high or unclear risk of bias across most domains and high heterogeneity for the FAI outcome.

Read the full abstract...
Background: 

Polycystic ovary syndrome (PCOS) affects 8% to 13% of reproductive-aged women and is associated with reproductive and metabolic dysfunction. Obesity worsens the presentation of PCOS and weight management (weight loss, maintenance or prevention of excess weight gain) is proposed as an initial treatment strategy, best achieved through lifestyle changes incorporating diet, exercise and behavioural interventions.

Objectives: 

To assess the effectiveness of lifestyle treatment in improving reproductive, anthropometric (weight and body composition), metabolic and quality of life factors in PCOS.

Search strategy: 

We searched the Cochrane Gynaecology and Fertility Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, PsycINFO, CINAHL and AMED (date of last search March 2018). We also searched controlled trials registries, conference abstracts, relevant journals, reference lists of relevant papers and reviews, and grey literature databases, with no language restrictions applied.

Selection criteria: 

Randomised controlled trials (RCTs) comparing lifestyle treatment (diet, exercise, behavioural or combined treatments) to minimal or no treatment in women with PCOS.

Data collection and analysis: 

Two authors independently selected trials, assessed evidence quality and risk of bias, and extracted data. Our primary outcomes were live birth, miscarriage and pregnancy. We used inverse variance and fixed-effect models in the meta-analyses. We reported dichotomous outcomes as an odds ratio and continuous outcomes as a mean difference (MD) or standardised mean difference (SMD).

Main results: 

We included 15 studies with 498 participants. Ten studies compared physical activity to minimal dietary and behavioural intervention or no intervention. Five studies compared combined dietary, exercise and behavioural intervention to minimal intervention. One study compared behavioural intervention to minimal intervention. Risk of bias varied: eight studies had adequate sequence generation, seven had adequate clinician or outcome assessor blinding, seven had adequate allocation concealment, six had complete outcome data and six were free of selective reporting. No studies assessed the fertility primary outcomes of live birth or miscarriage. No studies reported the secondary reproductive outcome of menstrual regularity, as defined in this review.

Lifestyle intervention may improve a secondary (endocrine) reproductive outcome, the free androgen index (FAI) (MD -1.11, 95% confidence interval (CI) -1.96 to -0.26, 6 RCTs, N = 204, I2 = 71%, low-quality evidence). Lifestyle intervention may reduce weight (kg) (MD -1.68 kg, 95% CI -2.66 to -0.70, 9 RCTs, N = 353, I2 = 47%, low-quality evidence). Lifestyle intervention may reduce body mass index (BMI) (kg/m2) (-0.34 kg/m2, 95% CI -0.68 to -0.01, 12 RCTs, N = 434, I2= 0%, low-quality evidence). We are uncertain of the effect of lifestyle intervention on glucose tolerance (glucose outcomes in oral glucose tolerance test) (mmol/L/minute) (SMD -0.02, 95% CI -0.38 to 0.33, 3 RCTs, N = 121, I2 = 0%, low-quality evidence).

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