Study links Ovary removal to Dementia, Parkinson's

The removal of a woman's ovaries before menopause puts her at significant risk of developing dementia or other mental problems later in life, a team of American scientists found in a long term study.

The latest study, conducted by Dr. Walter Rocca, neurologist and epidemiologist at the Mayo Clinic, and colleagues, stated that women who remove one or both of their ovaries before menopause and do not take estrogen are more at risk to have neurological impairment and even dementia later in life.

To reach their findings that published in the Aug. 29 online edition of Neurology, the medical journal of the American Academy of Neurology, Dr. Rocca, the lead author of the study, and fellow researchers studied 3000 women.

They divided the participating women in two equal groups, one of which was having those women who underwent the removal of one or both ovaries for non-cancer-related reasons, like ovarian cysts, endometriosis, or for the prevention of ovarian cancer, while in the other group were those women who still had both ovaries at the beginning of the study.

After observing the study subjects for 30 years, the researchers found that those women who had one or both ovaries removed before menopause were nearly twice at risk of developing cognitive problems or dementia compared with those who either keep their ovaries or premenopausal women who remove both ovaries but took estrogen until the age of fifty.

They found impairment or dementia in 150 of 1,489 women who'd had ovaries removed, compared to 98 of 1,472 women who hadn't, marking nearly a 50 percent increase in risk.

"This study is one of the first to obtain large-scale data about neurological diseases in women who had their ovaries removed," Rocca said. "Our findings will contribute to a better understanding of the advantages and disadvantages of removing the ovaries in young women."

Besides telling potential effects of removing one or both ovaries before a woman reaches natural menopause, the latest findings also signify how important the estrogen is for a woman.

Ovaries produce estrogen, a steroid, sex hormone that primarily influences the female reproductive system's development, maturation, and function. Removal of ovaries can cause a sudden deficiency of that hormone, which in turn affects the brain, Rocca said.

"When you remove the ovaries in a young woman, you cause an estrogen deficiency. And if you do not compensate that with estrogen given from outside, that woman will be exposed to a known natural state of deprivation of estrogen."

Alzheimer's disease is a neurodegenerative disease characterized by progressive cognitive deterioration together with declining activities of daily living and neuropsychiatric symptoms or behavioral changes. It is the most common type of dementia.

Besides progressive cognitive corrosion, loss of memory, and inhibited daily functioning, the other major symptoms of Alzheimer’s are aphasia, apraxia, agnosia. Impairment is also caused in the frontal and temporal lobes of the brain, fading decision-making and planning abilities.

The disease is characterized by the development of unusual clumps of proteins called amyloid plaques and nerve cell tangles that hinder messages being processed by the brain.

In 2004, Alzheimer’s was the 7th leading cause of death in USA, with 65,829 numbers of deaths. It is the third most costly disease in the U.S., after heart disease and cancer. Currently, nearly 4.5 million Americans have Alzheimer’s.

According to statistics, there are about 24 million people with dementia worldwide, and it has been projected that by 2040, the number of people suffering from AD will have increased to 81 million.

Globally, there are about 60% people in the developing countries affected by Alzheimer’s and by 2040; this proportion will rise to 71%.