Timely Parkinson's Diagnosis and Specialist Treatment Keeps Eluding Women

Parkinson's disease (PD) is a gradually developing neurodegenerative illness caused by dopamine deficiency that currently affects close to 1 million Americans, impairing the brain's capacity to regulate the body's motor functions. With almost 60,000 new cases reported each year and an estimated 1.2 million US citizens affected by 2030, medical experts have undertaken extensive efforts to identify the characteristics and precise causes of PD.

When narrowing down PD's effects only on genders, studies have uncovered that men are 1.5 times more likely to develop Parkinson's than women. Due to this evident disparity, researchers have begun investigating the specific aspects influencing Parkinson's differing expression in both genders. 

Women Typically Receive Diagnoses Later than Men

While facing lower risks of developing Parkinson’s compared to men, more than 400,000 US women are currently struggling with the affliction. The difference in incidence rates between the genders is estimated based on the total number of fatalities.  However, this fails as a precise indicator since it doesn't track new diagnoses based on gender, and the cause of death isn't accurately reported in all cases.  

Sadly, there is a regrettable lack of women-focused Parkinson's research in the current clinical literature. Despite these limitations, the available studies provide evidence of several variables that can affect how Parkinson's manifests in women. 

A study from 2019 suggests that the female hormone estrogen, which plays a significant role in neuroprotection, may increase dopamine levels, reduce oxidation, and mitigate inflammation-related damage. A 2020 study indicates that women with a more extended period of fertility and later age of menopause have a significantly lower risk of being diagnosed with Parkinson's. 

Recent research suggests that women seem more likely to manifest Parkinson's symptoms at an earlier age than men and are more likely to develop a less severe form of the condition with reduced signs. Although still inconclusive, women with Parkinson's report depression and other psychological symptoms more frequently than men stricken with the affliction. 

Levodopa is usually prescribed as the primary treatment for managing Parkinson's symptoms regardless of gender. However, women's lower average body weight, the medicine's dosage more adapted to men’s body mass, and the differing age of the condition's onset seem to make levodopa a less effective female-focused solution, requiring physicians to adjust their prescriptions per individual case. Concurrently, due to the regular misdiagnosis of Parkinson's symptoms, women are less likely to benefit from deep brain stimulation, even though they report better outcomes on average.  

In terms of overall care quality, women face distinct disadvantages and have a higher probability of attending appointments by themselves, resorting to home care, or residing in a nursing facility. Given their innate nurturing instincts and higher tendency to take care of others, women usually downplay the severity of their symptoms. This can lead to receiving diagnoses and specialist referrals later on, thus incurring higher levels of psychological distress, considering the lack of social support options for women compared to men. 

Environmental Risks Affect Genders Differently 

Besides the common genetic and biological factors, particular environmental risks are suspected to affect Parkinson's development in women and men to varying degrees. Despite the underlying mechanisms remaining unclear, traumatic head injuries, most common in male-oriented activities, are associated with a higher risk of developing Parkinson's.  

A more obvious yet frequently overlooked environmental risk affecting Parkinson's expression is prolonged exposure to hazardous substances in industrial occupations. In the US, industrial toxins associated with PD, such as trichloroethylene (TCE) and polychlorinated biphenyls (PCBs), are either banned or heavily regulated.

Conversely, other toxic substances used intensively in industries like agriculture face no regulation whatsoever, even though clinical research suggests a high correlation with neurologic conditions like Parkinson's. The toxic herbicide paraquat is one such chemical hazard banned in more than 60 countries worldwide due to its association with PD. Paraquat is heavily utilized in US agricultural practices but requires training and licensing to apply it on crops safely. 

Despite issuing measures to handle the pesticide with caution, the EPA downplays paraquat's connection to Parkinson's, even reapproving it for agricultural use until 2035. In 2018, California used 1.3 million pounds of paraquat, meaning roughly 30% of the total 4.2 million pounds applied in the US that year. Coincidentally, California reported the highest number of Parkinson's diagnoses in 2018, with 85,100 confirmed cases. Even more concerning, the states with the following highest reported cases of Parkinson's in that period, namely Florida (64,000), Texas (52,500), New York (48,000), and Pennsylvania (35,400), regularly used large quantities of paraquat.  

The US agricultural sector's overreliance on toxic herbicides like paraquat represents a severe health hazard for the nearly 3 million farmworkers and associated farming communities across the country. Men face a higher risk of direct exposure to paraquat's toxicity during the mixing, application, and clean-up processes. By comparison, women face a higher indirect exposure risk during planting and crop harvesting. Individuals in agricultural communities face additional exposure risks due to farmworkers unintentionally carrying the substance indoors as residue on their footwear, clothing, hair, or skin. 

Increasing Awareness and Improving Outcomes for Women Diagnosed with Parkinson's

Since men are more likely to be diagnosed with the condition, an erroneous perception has developed around PD as a largely male-centered risk. This mistaken belief could partly explain why women face a 61% longer wait time than men to be correctly diagnosed and receive specialist treatment referrals. 

PD affects individuals indiscriminately, regardless of age, ethnicity, or gender. Despite this, research seems to indicate that women with early or moderate symptoms report more pain than men and are more likely to experience anxiety, depression, and disturbed sleeping patterns before reporting any motor dysfunctions. Women who haven't yet reached menopause are especially recommended to track their hormone cycles and the progression of their 
Parkinson's symptoms. 

Healthcare providers should consider gender differentials and adjust their treatment accordingly for women's reduced weight and particular drug metabolism. At the same time, physicians should be provided with the proper guidance and resources to precisely identify, diagnose, and treat female-specific Parkinson's symptoms. Concurrently, the EPA can reduce Parkinson's-related risks by efficiently regulating toxic herbicides that are highly correlated with the condition. 

Considering the plethora of biological differences and social barriers affecting women and men in differing ways, a more extensive public awareness of gender-specific factors and institutional involvement are required to improve the condition of women struggling with Parkinson's. Seeing how women are severely underrepresented in Parkinson's epidemiologic research, more efforts are needed to better understand their specific risk factors, enabling the development of timely and more suitable treatment and care options for women's particular needs.

About the Author
Miguel Leyva serves as a Case Manager with Atraxia Law, assisting individuals injured by toxic substances to gather and organize the required information that supports their paraquat exposure and Parkinson's claim against the manufacturing companies.

​