PCOS and weight gain
There is anecdotal evidence that women with PCOS have a predisposition to weight gain and difficulties with weight management. There is some preliminary evidence to support this.
Hormones involved in the regulation of appetite have been examined in a small number of research projects in PCOS. Cholecystokinin (CCK) is released from the small intestine after eating and inhibits gastric emptying, increases satiety and reduces meal size and energy intake in humans. Ghrelin is released from the stomach before eating and stimulates hunger and food intake. Compared to weight-matched controls, overweight women with PCOS have greater post-prandial hunger and reduced post-prandial CCK and ghrelin levels. This suggests that the regulation of appetite by CCK and ghrelin is impaired in women with PCOS. However, a recent study showed no differences in post-prandial appetite hormones (CCK and peptide YY) and no differences in food intake between women with and without PCOS. Overall, this suggests that some women with PCOS may have abnormalities in appetite regulation, need more increased emphasis on appropriate intensive long-term weight loss or weight maintenance strategies and greater follow up and support. Dietary strategies which optimise appetite and satiety may also aid in achieving and sustaining a reduced weight.
Where the presentation of PCOS is worsened by IR and weight gain, these represent important intervention targets in the community. Targeting weight gain and treating excess weight is therefore an important treatment aim and can improve both the reproductive and metabolic symptoms of PCOS. This can be used prior to commencement of pharmacological therapy or in conjunction with pharmacological therapy if reproductive features do not improve sufficiently.
A large number of studies in women above their healthy weight with PCOS demonstrate that weight loss is achievable in PCOS and reduces insulin resistance. Improvements in hyperandrogenism, measured as decreases in free androgen index, free or total testosterone and increases in SHBG, are also consistently displayed. Hirsutism has been reported to both be improved or not altered following modest weight loss. Moderate weight loss also improves menstrual regularity in a proportion of women with PCOS with this symptom improvement related to reduction in insulin resistance.
A weight loss of 5-10 kg over 2-8 months was found to improve menstrual regularity in 60 per cent and to reduce pregnancy complications (miscarriage rates from 75 per cent pre-treatment to 18 per cent post-treatment) in overweight women with and without PCOS. There is as yet limited additional data on the effect of weight loss on reducing reproductive outcomes or pregnancy complications in PCOS although modest weight loss reduces the risk of developing gestational diabetes in the general population. Weight loss also improves psychological health (self-esteem, anxiety, mean depression scores and scores on general health questionnaire) in PCOS.
Weight loss also reduces a variety of risk factors for DM2 and CVD in PCOS (glucose tolerance, dyslipidaemia, inflammatory markers, blood pressure) with the long-term potential to reduce risk for DM2 and CVD. A similar modest weight loss (5.6 kg over three years) through lifestyle intervention (a low-fat diet, 150 minutes exercise per week and behaviour management strategies) reduced the risk of developing DM2 and the metabolic syndrome by 58 per cent and 41 per cent respectively in overweight individuals with impaired glucose tolerance. As both DM2 and the metabolic syndrome are more common in PCOS than the general population, lifestyle modification strategies therefore also seem appropriate in regards to their reduction of long-term metabolic risks.
An important point is that a modest amount of weight loss (5-10 per cent) is sufficient to improve both the clinical reproductive presentation and to reduce metabolic risk despite subjects remaining clinically above their healthy weight (BMI > 25 kg/m2). This indicates that achievable, realistic short-term goals can be set (5-10 per cent initial body weight or 5-10 kg weight loss and maintenance).