Several clinical studies have demonstrated that Parkinson’s disease (PD) is less common in women than in men. PD occurs in men 50 percent more than in women. Women are also less likely to be married and working full-time than men with PD.1,2
Parkinson's in women is less common
Researchers are not sure why men get PD more often than women. Some scientists believe that estrogen protects women. Others believe that men experience more minor head trauma and are exposed to more toxins at work. Finally, some believe genes on the sex chromosomes play a role.1
Age of onset of Parkinson’s disease in women
One large study found no difference between the age that women and men begin experiencing PD symptoms. It also found no difference in how long it took to get a diagnosis.3 However, some earlier studies found women develop PD about 2 years later than men and took longer to be diagnosed.4
Symptoms of Parkinson’s disease in women
In general, women with PD have similar motor and non-motor symptoms as men with PD. More women experience tremor and painful early morning muscle contractions than men. Other symptoms include:2,5
- Tremor of the hands, arms, legs, or face
- Rigidity of the limbs and trunk
- Slowness of movement
- Gradual loss of spontaneous movement (bradykinesia)
- Impaired balance
- Lack of coordination
- Depression
- Sleep disturbances
- Impaired memory or thinking
- Difficulties with urination or constipation
Although PD symptoms are highly individual, some studies have found small differences in how symptoms appear in women versus men.
One study from the Netherlands found that women experienced more tremor (67 percent) than men (48 percent).6 Some small studies suggest that women score better on tests for motor abilities and mental processes than men. Women are also more likely to have depression and to report problems with daily living, cardiovascular disease, and fatigue. Men experience higher rates of sleep disorders than women.3
The role of estrogen in Parkinson’s disease
PD affects multiple areas of the body and brain. One of the areas most clearly affected is the substantia nigra pars compacta. There is great damage and death of nerve cells (neurons) in the substantia nigra. These cells make dopamine, a chemical messenger (neurotransmitter) that carries the signal for the muscles to produce smooth, purposeful movements. Damage to the substania nigra causes the movements common to PD, such as tremor, rigidity, and loss of spontaneous movement.2
Estrogen has been shown to have multiple effects on dopamine, including the amount of dopamine absorbed into the nerve cells.7 Plus, estrogen appears to have a protective effect on the neurons that produce dopamine.8 Estrogen’s effects on dopamine change based on menstrual cycles, menopause, and hormone replacement therapies.
Researchers are interested in the possible use of estrogen to slow the progression of PD. However, the complexities of estrogen pose challenges in designing clinical studies.7 In addition, not all studies show that estrogen has a protective effect.3 However, larger scale, placebo-controlled studies are needed.
Treatment of Parkinson’s disease in women
Earlier studies found several gender differences in how men and women respond to treatment for PD. These findings led to levodopa, the standard drug used to treat PD, being prescribed in lower doses for women than for men. These studies also found women had a higher rate of levodopa-induced dyskinesia (involuntary movements) than men.7
However, a study conducted in 2015 found no differences in how levodopa works in women versus men.3Deep brain stimulation can improve motor symptoms and quality of life for women. However, women are less likely to receive this treatment than men.5