Parkinson’s Disease in Women

Several clinical studies have demonstrated that Parkinson’s disease (PD) is less common in women than in men. PD occurs in men 50% more than in women. In addition to the differences in incidence, there are some other differences seen in PD in women versus in men.1,2

Why is Parkinson’s disease more common in men than women?

Researchers aren’t yet sure why there is a difference in the rate of PD between men and women. Some suggested explanations are the protective effect of estrogen in women, the higher rate of minor head trauma and exposure to occupational toxins in men, and genetic susceptibility genes on the sex chromosomes.1

Age of onset of Parkinson’s disease in women

Women on average develop the disease 2.1 years later than men. However, some studies that evaluated gender differences in PD have found no differences between men and women for the age of onset.4

Symptoms of Parkinson’s disease in women

In general, women with PD have similar motor and non-motor symptoms as men with PD. However, more women experience tremor than men. Other symptoms include:

Although PD is highly individual, and symptoms vary in their presence and severity between people with PD, there may be some differences in how these symptoms appear in women compared to men with PD.

One study from the Netherlands identified that women more often experienced tremor (67%) than men (48%).3 Data from the study at the University of Kansas suggested that women have better scores for motor abilities than men, based on the scoring of the Unified Parkinson’s Disease Rating Scale. These differences in motor symptoms were significant only in patients who had PD for more than 5 years.4 Women are also more likely to have depression and to report impairments in daily living. Men have a higher incidence of REM sleep behavior disorder than women.

The role of estrogen in Parkinson’s disease

Conflicting results have been obtained on the role of estrogen in PD. PD affects multiple areas of the body and brain, and one of the areas most noticeably affected is the substantia nigra pars compacta in the brain. There is extensive damage and death of nerve cells (neurons) in the substantia nigra that produce dopamine, a chemical messenger (neurotransmitter) that transmits signals for producing smooth, purposeful movement. Damage to the substania nigra causes the motor (movement) symptoms that are characteristic of PD, including tremor, rigidity, and loss of spontaneous movement.5

Estrogen has been shown to have multiple effects on dopamine, including the amount of dopamine absorbed into the nerve cells.6 In addition, estrogen appears to have a protective effect on the neurons that produce dopamine.7 There are differences in estrogen’s effects on dopamine based on cyclic fluctuations, the estrogen-deficient state of menopause, and the various 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 to designing clinical studies.6 Additionally, not all studies show that estrogen has a protective effect. However, larger scale, placebo controlled studies are required for more conclusive evidence on the differences between women and men in the symptoms and treatment of PD.

Treatment of Parkinson’s disease in women

There are several gender differences in response to treatment for PD. Levodopa, the standard medication to treat PD, is metabolized differently in women, so the dosage for women with PD is less than for men. In addition, there is a higher rate of levodopa-induced dyskinesia (involuntary movements that are a side effect with levodopa) in women compared to men.6 Deep brain stimulation in women with PD can improve motor symptoms and quality of life.

Written by: Emily Downward | Last reviewed: March 2017
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