More, Worse Parkinson’s Pain for Women Than Men, Study Reveals
Women with Parkinson’s disease experience more and worse pain than men with the neurodegenerative condition, according to a new study that highlights sex differences in the prevalence and severity of these symptoms.
Chronic pain, pain related to motor symptom fluctuations, mouth/face (oro-facial) pain, and discoloration/swelling were all more prevalent in women than in men, data showed.
“Female [Parkinson’s disease] patients in this [group] also had more severe pain symptoms,” the researchers wrote.
Additionally, the study found that women had more severe impairments in cognitive function than did men, though the team noted that further research is needed to understand potential links between cognitive dysfunction and the perception of pain.
The study, “Gender Differences in Pain Subtypes among Patients with Parkinson’s Disease,” was published in the Journal of Integrative Neuroscience.
Ample evidence suggests that there are sex differences between how men and women experience Parkinson’s disease symptoms in general and pain specifically. For men — for whom Parkinson’s is more common and has an earlier onset — sexual dysfunction and muscle rigidity are more prevalent than in women.
Previous studies have suggested that women with Parkinson’s experience more pain, and that the type of pain symptoms are different between men and women, but the nature of the relationship remains unclear.
Investigating sex differences in pain
Now, researchers in China aimed to investigate the influence of sex on types of pain in people with Parkinson’s. Included in their study were 108 men and 92 women with a mean age of 64.6 who were recruited at the First Affiliated Hospital of Nanchang University, in Jiangxi province in southeast China, between March 2018 and 2021.
All participants were evaluated for pain using the King’s Parkinson’s disease Pain Scale, known as KPPS. A range of clinical questionnaires also was administered to assess other clinical features of the disease.
Most clinical characteristics were similar between men and women, including age, disease duration, medication doses, and overall disease severity. Patients of both sexes had similar motor symptom severity, anxiety, depression, sleep patterns, and ability to perform daily activities.
Women had lower scores on the Mini-mental State Examination (MMSE) than men, reflecting a greater degree of cognitive impairment.
The KPPS is a 14-point scale that evaluates pain across seven domains: musculoskeletal, chronic, motor fluctuation-related, nocturnal, oro-facial, radicular (pain radiating from the nerves in the spine), and discoloration/swelling.
Women had higher overall KPPS scores than men, indicating that female patients experience pain symptoms to a greater degree. They also had higher subscores within certain domains of the questionnaire.
Chronic pain was worse for women, including pain caused by nerve damage (central pain) and visceral pain (pain in the abdomen or chest). Fluctuation-related pain, or that associated with changes in motor symptoms, also was worse for these patients. Specifically, women had worse pain during “off” periods when motor symptoms are more noticeable, and more dyskinetic pain, or that associated with uncontrollable body movements.
Oro-facial pain was worse for women, who experienced more teeth grinding at night and burning mouth syndrome, characterized by a burning sensation in the mouth with no obvious cause.
Women also experienced worse symptoms in the swelling (edema) domain or area, including burning pain in the limbs and generalized lower abdominal pain.
Restless leg syndrome, a nighttime condition that causes an uncontrollable urge to move one’s legs, occurred more in female patients than in males.
The findings overall show that “pain intensity was higher in female patients, and that females were more likely to develop chronic, fluctuation-related and oro-facial pain, as well as discoloration;edema/swelling,” the researchers wrote, noting that a lack of healthy participants for comparison marks a limitation of the results.
The findings are consistent with previous studies that found women to have more pain than men. The team noted that some studies have suggested that certain genetic variations in women with Parkinson’s might underlie this greater risk of pain symptoms.
A potential link could also exist between the greater cognitive dysfunction observed in female patients and the experience of pain, the researchers hypothesized. Research has suggested that pain is a type of memory, and that different brain regions are activated in women and men during a painful experience.
“However, additional research is required to better understand these gender differences in [Parkinson’s]-related pain and the association between cognitive dysfunction and pain perception,” the researchers wrote.