Can breaking-up sitting time ameliorate the type 2 diabetes and cardiovascular disease risk of women with polycystic ovary syndrome?
Project leader: Professor David Dunstan
This experimental study will explore whether breaking up prolonged sitting is an effective strategy in reducing glucose, insulin and androgen markers in women with polycystic ovary syndrome (PCOS). The study outcomes will help to better understand the potential importance of reducing sedentary behaviour in women with PCOS and provide an additional lifestyle strategy in reducing their risk of future type 2 diabetes and cardiovascular disease (CVD).
The International Diabetes Federation has identified women with polycystic ovary syndrome (PCOS) as a population group with a heightened risk for developing type 2 diabetes. In addition, women who have PCOS are 2 to 4 times more likely to develop CVD compared to non-affected women. This is thought to be due to women with PCOS displaying multiple risk factors for type 2 diabetes and CVD including obesity, insulin resistance, glucose intolerance, dyslipidaemia and hypertension. Given that PCOS affects 1-in-5 healthy weight women and 1-in-3 overweight women in Australia,it is critical to identify effective approaches to the prevention and management of type 2 diabetes and CVD in this large group of younger women, who are highly vulnerable to developing these diseases in later life.
Currently, the first-line of treatment for PCOS is weight management through optimising diet and physical activity. However, attrition rates of up to 45 per cent have been reported for both diet and physical activity based lifestyle-interventions in women with PCOS. Furthermore, lean women with PCOS also display, albeit to a less degree, elevated cardiovascular risk markers (e.g. elevated insulin and glucose) with very limited lifestyle management strategies currently available to improve such risks in this subset of women with PCOS. It is therefore important to identify alternate lifestyle strategies to improve the cardiovascular profile of women with PCOS that may be used in conjunction with other weight management strategies.
Recently, excessive sedentary behaviour — or 'sitting time' — has been independently linked to both type 2 diabetes and CVD, as well as a number of cardiovascular risk factors (e.g. insulin resistance, glucose intolerance, hypertension and dyslipidaemia) in the general population. Furthermore, breaking up prolonged sitting time has shown to be beneficial in improving the pathophysiology of these cardiovascular risk markers in both healthy populationsand adults with type 2 diabetes. Building on these recent findings, there is the potential for reducing and breaking up sitting time to be an effective approach to reducing type 2 diabetes and CVD risk in women with PCOS.
However, little is known about the role of sedentary behaviour in the context of PCOS. Only two studies to date have examined associations of ‘sitting time’ in women with PCOS and have reported mixed findings. For example, Moran and colleagues found women with PCOS had higher levels of self-reported sitting time compared to women without PCOS,whereas, Sedighi et al. reported no differences in sitting time between women with and without PCOS. However, these studies were limited by self-reporting of sitting time and did not examine sitting time in relation to any cardiovascular risk markers. Therefore, additional research is needed to examine whether prolonged sitting is associated with type 2 diabetes and cardiovascular risk factors in women with PCOS, and whether breaking up sitting will have beneficial effects in reducing their risk of future type 2 diabetes and CVD.