Neurological Disease Study Leads to Precision Medicine Progress

July 13, 2021 - A new study from the University of Arizona Health Sciences could lead to a breakthrough in the development of precision medicine to prevent neurodegenerative diseases.

By studying women on hormone therapy, researchers discovered those women were up to 58 percent less likely to develop neurodegenerative diseases such as Alzheimer's disease. The reduction of risk varied by type, duration, and route of the hormone therapy.

According to the study, women who underwent six or more years of menopausal hormone treatment were 79 percent less likely to develop Alzheimer’s and 77 percent less likely to develop any neurodegenerative disease.

"This is not the first study on the impact of hormone therapies on neurodegenerative disease reduction," Roberta Diaz Brinton, PhD, director of the UArizona Center for Innovation in Brain Science and senior author on the paper said in a press release. "But what is important about this study is that it advances the use of precision hormone therapies in the prevention of neurodegenerative disease, including Alzheimer's."

During the study, Briton and his team of researchers examined the insurance claims of almost 400,000 women aged 45 and old who were in menopause.

The team focused on looking at the effects of individual US Food and Drug Administration-approved hormone therapy medications, including estrogens and progestin, and combination therapies for neurodegenerative diseases.

Additionally, researchers investigated the impacts of the type of hormone therapy, how it was administrated, and the duration of therapy on the risk of developing diseases. Through the research, they discovered that using the nature steroids, estradiol and progesterone, led to more significant risk reduction than using synthetic hormones.

“Oral hormone therapies resulted in a reduced risk for combined neurodegenerative diseases, while hormone therapies administered through the skin reduced the risk of developing dementia. Overall risk was reduced the most in patients 65 years or older,” the press release stated.

Additionally, hormone therapy showed protective effects on Alzheimer’s, Parkinson’s disease, and dementia the longer an individual continues treatment. By pinpointing hormone therapies that appear to reduce the likelihood of developing a neurodegenerative disease, researchers can use precision medicine to prevent diseases including Alzheimer’s, Parkinson’s, and dementia.

“With this study, we are gaining mechanistic knowledge. This reduction in risk for Alzheimer's disease, Parkinson's and dementia means these diseases share a common driver regulated by estrogen, and if there are common drivers, there can be common therapies," said Brinton.

"The key is that hormone therapy is not a treatment, but it's keeping the brain and this whole system functioning, leading to prevention. It's not reversing disease; it's preventing disease by keeping the brain healthy," Brinton continued.

In another paper recently written by Brinton, he and a team of researchers found that the menopausal transition stage has a significant impact on the brain’s structure, connectivity, and energy metabolism, and provides a neurological framework for vulnerability and resilience.

As the population of people 65 and older increases, neurodegenerative diseases tied to aging are a major public health concern. There is currently no cure for Alzheimer’s, which affects more than 5.5 million people in the US.