Women and Parkinson’s

It is estimated that 145,000 people are living with Parkinson’s in the UK, 10 million worldwide. If you ask people what Parkinson’s is and who it affects, the image of an older man with a tremor might spring to mind. As many of you will already know, this isn’t an inclusive picture.

Let’s start with the preconceptions about age and Parkinson’s. Parkinson’s can affect anybody. People are more likely to develop Parkinson’s as they get older, many will be over 60, but there are a significant number of people living with young onset Parkinson’s. This is anyone who is diagnosed before the age of 50. Estimates of the number of people who experience symptoms before the age of 50 range from between 5 and 20% of people living with Parkinson’s. This is particularly important when looking at unmet needs for women, as there may be unique considerations related to menstruation and pregnancy.

And, the reason some people may still associate Parkinson’s as a condition that mainly impacts men is because the data so far suggests that women have a lower risk of Parkinson’s. A global study found that men are 1.4 times more likely to be diagnosed with Parkinson’s than women. Of every 100 people diagnosed with Parkinson’s, 42 are women.

This might raise a few questions. Why are women not more represented in research? Why are women less likely to get Parkinson’s and why might this vary in different parts of the world? How might the condition affect women differently? And does this mean women have different needs to men?

 A recent paper entitled, ‘Unmet needs of women living with Parkinson’s: Gaps and controversies’, did an excellent job of starting to address some of these questions. This paper is also a pioneering example of researchers and the Parkinson’s community coming together, with 3 of the 6 all-female authors having the condition, to amplify voices to encourage change in care and research.

So what do we know about Parkinson’s in women?

Hormones with protective properties

If there are differences between men and women, perhaps sex-specific factors, such as different levels of hormones, might play a role in the causes and development of the condition.

Indeed, research has suggested that oestrogen, a female reproductive hormone, may help protect brain cells. While most of this research has been carried out in test tubes or in animal models, a few studies have also tried to look at groups of women with varying levels of oestrogen to unpick how this influences Parkinson’s risk.

The results of the protective effects of oestrogen in people so far are not clear cut. Additionally, studies into the use of hormone replacement therapy, which includes oestrogen, on Parkinson’s risk have also provided conflicting results. All this means more research is needed to understand how hormonal differences might be playing a role in the changes that are happening within cells in Parkinson’s.

It is interesting to note that data suggests the risk of developing Parkinson’s in women may not be the same across the globe, especially when comparing east to west. More research is needed to better understand these differences, suggesting other factors, beyond hormones, must be at play. Perhaps other genetic or environmental factors also need to be considered.

Understanding the role of hormones in Parkinson’s could help uncover ways to protect precious brain cells, understanding that would benefit the whole Parkinson’s community. But this will take time, while there is a pressing need to help women manage their specific symptoms, especially those with young onset Parkinson’s.

It has been reported that the menstrual cycle is linked to the severity of symptoms. Before the start of the menstrual period, when there is a dip in oestrogen, many women experience PMS (premenstrual syndrome) but women with Parkinson’s may also see their symptoms worsen.

A link between oestrogen and worsening symptoms has also been observed for some during pregnancy, post-partum and in the years leading up to the menopause. Yet, there is no defined strategy or advice for how to better manage symptoms during these hormonal stages of a woman’s life. More research could help understand this and develop strategies to adjust treatments in response to natural hormone fluctuations in a safe and beneficial way.

A difference in Parkinson’s symptoms

It’s not only fluctuations in symptoms that may differ in women, there is evidence that women may experience different types of Parkinson’s symptoms compared to men. For instance, women:

• are more likely to have tremor as one of their more dominant symptoms 
• experience higher levels of dyskinesia and have restless legs 
• are less likely to experience changes in thinking and memory 
• have more anxiety, depression and fatigue compared to men with Parkinson’s.

Understanding why this is the case, has yet to be determined. Researchers have suggested that it could be due to different causes of the condition. Theories include potential differences between sexes in the body’s genetic blueprint or response to environmental factors that might contribute to Parkinson’s.

Another possible difference is how medication is absorbed and used by the body. There are differences in body weight and metabolism in women compared to men, which can play a role. It has been previously observed in a group of women taking Parkinson’s drugs, containing the active compound levodopa, that they had higher levels in their blood compared to men taking the same dose. 

This might mean that women are more at risk of side effects of their Parkinson’s medication, fitting in with the observation that dyskinesia is experienced more in women. It is evident that gender needs to be taken into account when looking at dosing of medication, the use of slow release medications, and when investigating new drugs in clinical trials.

Diagnosis, treatment and research

We know that diagnosis for Parkinson’s is not easy for anyone and can be a bumpy road for many, where up to 25% of people are initially misdiagnosed. But the figures suggest that women are more likely to experience a delay in getting an accurate diagnosis compared to men. It is unclear whether this is due to differences in the early signs of the condition or differences in how women disclose symptoms or worries at medical appointments.

More research is also needed to understand why women are less likely to get deep brain stimulation, the main surgical method used to help manage symptoms of Parkinson’s. Could this be down to gender differences when it comes to risk? There is evidence that women are less likely to sign up for trialling new drug-based treatments in clinical trials, but the reasons why are unclear. Or could it be down to differing symptoms, such as the severity of dyskinesia, getting in the way of this being offered as a treatment option?

Biological, sociological and psychological factors all need to be taken into account to help understand the complexities of differences between men and women with Parkinson’s. Part of this is to establish why, more generally, health inequalities exist between men and women. We should also be mindful that there will be nuances when looking at the needs of women from underrepresented communities. Perhaps it’s time to follow the lead of cancer management and therapeutics towards a more personalised approach to care, treatment and research for Parkinson’s, which means addressing sex and gender.

What’s next?

We met with Richelle Flanagan, one of the authors of this recent paper, a person with Parkinson's and founder of the Women's Parkinson's project, to get an insight into what's next and what women can do now to advocate for themselves. 

Richelle said:

"It’s so powerful listening to the stories and experiences of women with Parkinson’s, sometimes the bias is just astounding. But I hope that this work gains momentum and women can see they are not alone.

"I would encourage people to visit the Women’s Parkinson’s Project website and sign up to the newsletter to stay up to date and connect with others.

"I also think it is vitally important for women to track their symptoms, especially around menstruation, pregnancy or leading up to the menopause. I know women use spreadsheets, notebooks, diaries, whatever works for the individual. However, this is an area I am particularly interested in as I have tried over 20 apps to track my symptoms around the menstrual cycle and found none that meet my needs. I recently won a hackathon to further develop and fund an app called My Moves Matter that I hope will meet this unmet need in the near future.

"More research to understand sex and gender differences in Parkinson’s is vital because a better understanding of Parkinson’s for some is a better understanding of Parkinson’s for all."