For the first time, a study found that the contraceptive pill can reduce the risk of type 2 diabetes by more than a quarter in women with polycystic ovary syndrome (PCOS). The study also discovered that women with PCOS have twice the risk of developing type 2 diabetes or pre-diabetes (dysglycemia), emphasizing the critical need for treatments to reduce this risk.
A study led by the University of Birmingham found that the contraceptive pill can reduce the risk of type 2 diabetes by more than a quarter in women with polycystic ovary syndrome for the first time (PCOS). In addition to the risk of type 2 diabetes, PCOS, which affects 10% of women worldwide, is linked to a number of other long-term conditions, including endometrial cancer, cardiovascular disease, and non-alcohol related fatty liver disease (NAFLD).
PCOS symptoms include irregular or no periods, which can lead to fertility issues, and many women experience unwanted hair growth (known as hirsutism) on the face or body, hair loss on the scalp, and oily skin or acne. These symptoms are caused by elevated levels of androgens in the blood of women with PCOS.
Women with PCOS frequently struggle with weight gain, and their cells are frequently less responsive to insulin – the hormone that allows the body to absorb glucose (blood sugar) into the cells for energy. This decreased insulin response can result in elevated blood glucose levels and cause the body to produce more insulin, which in turn causes the body to produce more androgens. Androgens raise insulin levels even more, creating a vicious circle.
With one in every ten women living with PCOS, which is a life-long metabolic disorder, it is incredibly important that we find ways to reduce its associated health risks.
Anuradhaa Subramanian
The team of scientists led by the University of Birmingham conducted two studies: one to identify the risk of developing type 2 diabetes and pre-diabetes in women with PCOS, and the other to investigate the impact of combined oral contraceptives, commonly referred to as ‘the pill,’ on the risk of type 2 diabetes and pre-diabetes in women with PCOS. Women with PCOS are frequently given the pill to improve the regularity of their menstrual bleeds.
They conducted a large population-based cohort study to examine the risk of type 2 diabetes and pre-diabetes using UK patient GP records of 64,051 women with PCOS and 123,545 matched control women without PCOS. They discovered that women with PCOS were twice as likely as those without PCOS to develop type 2 diabetes or pre-diabetes. They also discovered that hirsutism (excessive hair growth), a clinical sign of high androgen levels, is a significant risk factor for type 2 diabetes and pre-diabetes in PCOS women.
The researchers, who included experts from the RCSI University of Medicine and Health Sciences, then conducted a nested case-control study on 4,814 women with PCOS to investigate the pill’s impact on type 2 diabetes or pre-diabetes. The researchers discovered that using combined oral contraceptives reduced the risk of developing type 2 diabetes and pre-diabetes in women with PCOS by 26%.
The study’s authors, who published their findings today in Diabetes Care, plan to conduct a clinical trial to further validate their findings in the hope that it will lead to changes in global healthcare policy.
Professor Wiebke Arlt, Director of the University of Birmingham’s Institute of Metabolism and Systems Research and co-senior author, stated: “Previous, smaller studies had shown that women with PCOS are more likely to develop type 2 diabetes. What is significant about our research is that we were able to provide new evidence from a large population-based study to show, for the first time, that we have a potential treatment option – combined oral contraceptives – to prevent this very serious health risk.”
Dr Michael O’Reilly, Health Research Board Emerging Clinician Scientist and Clinical Associate Professor at RCSI University of Medicine and Health Sciences and co-first author, added: “We hypothesize that the pill lowers the risk of diabetes by inhibiting androgen action. What is the procedure for this? The pill contains oestrogens, which raise blood levels of a protein called sex hormone-binding globin (SHBG). SHBG binds androgens, rendering them inactive. As a result, if the pill is taken, SHBG rises. This reduces the amount of unbound, active androgens, which reduces their impact on insulin and diabetes risk.”
“With one in every ten women living with PCOS, which is a life-long metabolic disorder, it is incredibly important that we find ways to reduce its associated health risks,” said co-first author Anuradhaa Subramanian of the University of Birmingham.
Krish Nirantharakumar, Professor of Health Data Science and Public Health at the University of Birmingham’s Institute of Applied Health Research, added as a co-senior author: “Importantly, our findings show that normal-weight women with PCOS are at a higher risk of type 2 diabetes and pre-diabetes. This is consistent with our previous finding of increased NAFLD risk in normal-weight women with PCOS, calling into question the notion that PCOS-related metabolic complications are only relevant in the context of obesity. These findings suggest that, rather than obesity alone, PCOS-specific factors, such as androgen excess, are to blame for the increased metabolic risk.”
