Oral contraceptives reduce diabetes risk in women with PCOS

Women with polycystic ovary syndrome face twice the risk of developing type 2 diabetes or prediabetes as those without the disorder.

Dave Yasvinski 3 minute read October 19, 2021
illustration of different women

Taking birth control may lower risk of diabetes by 25 per cent. GETTY

Women with polycystic ovary syndrome face twice the risk of developing type 2 diabetes or prediabetes as those without the disorder, according to a new study that found this risk can be reduced by over 25 per cent by taking oral contraceptives.

The research, published in the journal Diabetes Care, stressed the need to develop effective new treatments for PCOS, a condition that affects roughly 10 per cent of women — including as many as 1.4 million Canadians — worldwide. In addition to raising the risk of diabetes, PCOS is connected to a number of other concerning conditions, including endometrial cancer, cardiovascular disease and non-alcohol related fatty liver disease (NAFLD).

“We knew from previous, smaller studies, that women with PCOS have an increased risk of type 2 diabetes,” said Wiebke Arlt, co-senior author of the study and director of the University of Birmingham’s Institute of Metabolism and Systems Research. “However, what is important about our research is that we have been able to provide new evidence from a very large population-based study to show for the very first time that we have a potential treatment option — combined oral contraceptives — to prevent this very serious health risk.”

Women with PCOS suffer from irregular periods, or no periods at all, which can lead to a range of fertility issues. Many also experience hirsutism, or unwanted hair growth, on their face or body, in addition to oily skin and acne. These symptoms are caused by the presence high levels of hormones known as androgens, which are also believed to be responsible for the weight gain and diabetes risk associated with the disorder.

Affected women are generally less responsive to insulin, meaning their bodies have difficulty absorbing the glucose in their blood. This can result in a vicious cycle where elevated levels of glucose lead to the production of more insulin, which leads to the production of insulin-increasing androgens. In addition to determining the diabetes risk presented by PCOS, researchers examined the ability of oral contraceptives to reduce the likelihood of further complications.

“We hypothesise that the pill reduces the risk of diabetes by dampening the action of androgens,” said Michael O’Reilly, joint first author of the study and a clinical associate professor at RCSI University of Medicine and Health Sciences. “How does this work? The pill contains oestrogens which increase a protein in the blood called sex hormone-binding globin (SHBG). SHBG binds androgens and, thereby, renders them inactive. Thus, if the pill is taken, SHBG increases. This decreases the amount of unbound, active androgens, lowering their impact on insulin and diabetes risk.”

To determine the risk of PCOS resulting in a type 2 diabetes diagnosis, researchers pored over the health data of 64,051 women living with the disorder in the UK and matched them with 123,545 women who did not have PCOS. They found that those with PCOS had double the risk of developing type 2 diabetes or prediabetes compared to those without and that hirsutism was a significant risk factor for diabetes among women with PCOS.

A further nested study of 4,814 women with PCOS determined that oral contraceptives reduced the risk of developing type 2 diabetes or prediabetes by 26 per cent. Researchers are planning another round of research to advance knowledge of the disorder and call attention to the need for changes to global healthcare policy.

“Importantly, our data highlight that normal weight women with PCOS were also at increased risk of type 2 diabetes and prediabetes,” said Krish Nirantharakumar, co-senior author of the study and a professor in Health Data Science and Public Health at the University of Birmingham’s Institute of Applied Health Research. “This parallels our previous finding of increased NAFLD risk in normal weight women with PCOS, further challenging the notion that PCOS-related metabolic complications are only relevant in the context of obesity. These data suggest that, rather than obesity in isolation, PCOS-specific factors, including androgen excess, underpin the increased metabolic risk.”

Dave Yasvinski is a writer with Healthing.ca