Ovaries and Parkinson’s disease

Parkinson’s disease is a progressive disorder that affects the nervous system and the parts of the body controlled by nerves. Tremors are common, but the disorder can also cause stiffness or slowing of movement. It is often accompanied by dementia, sleep disturbances, and bowel and bladder problems. Parkinsonism is a general term for slow movement along with stiffness, tremors, or loss of balance.

Parkinson’s disease occurs almost twice as frequently in men as in women in the general population, suggesting that sex or gender-related factors play a role. In women, the ovaries are the main source of estrogen. Surgical removal of a woman’s ovaries may be recommended for cancer, genetic mutations, and other conditions. When a woman has her ovaries surgically removed before reaching menopause, that source of estrogen and other hormones is lost, so the removal causes sudden endocrine dysfunction.

A team at the Mayo Clinic in the United States studied data from the medical records of 2,750 women who had undergone surgery to remove both ovaries, a procedure called bilateral oophorectomy, and 2,749 who had not. The reasons for surgery were a benign (non-cancerous) condition, such as endometriosis, cyst, or other reason, or cancer prevention.

The study authors found that for every 48 women under the age of 43 at the time of surgery, one more woman had Parkinson’s compared to women of the same age who did not have their ovaries removed.

Artist’s rendering of brain cells deteriorating in the setting of Parkinson’s disease. (Illustration: Amazings/NCYT)

The new research findings confirm a 2008 study that suggested that a lack of estrogen caused by the removal of both ovaries in young women may be associated with an increased risk of Parkinson’s disease and parkinsonism. The results support current guidelines that not both ovaries should be removed to prevent ovarian cancer in women at medium risk, says Walter Rocca, MD, a Mayo Clinic neurologist and epidemiologist and the study’s first author.

Based on the study’s conclusions, for women carrying a high-risk gene variant for ovarian cancer, removal of the ovaries before menopause may be indicated, but women should receive estrogen therapy after surgery until age 50 or 51 years, the approximate age of spontaneous menopause.

“As of today, the use of estrogen therapy for the prevention of dementia or parkinsonism after spontaneous menopause in women 46 to 55 years of age is not recommended,” says Dr. Rocca. “But this study and previous ones suggest that estrogen therapy is important in women whose ovaries were surgically removed before age 46. Women who underwent this surgically induced menopause before age 40 are especially vulnerable.”

The study is titled “Association of Premenopausal Bilateral Oophorectomy With Parkinsonism and Parkinson Disease”. And it has been published in the academic journal JAMA Network Open. (Source: Mayo Clinic)