Are gender and sexual identity linked to brain health?

LGBTQ+ people may be more likely to have negative brain health outcomes, including a higher risk of dementia and late-life depression, than people who are cisgender and straight, according to a study published in the September 25, 2024, online issue of Neurology.

These results do not prove that sexual or gender diversity causes neurological diseases, they only show an association.

LGBTQ+ refers to people who are lesbian, gay, bisexual, transgender, and nonbinary, plus other people who are sexually or gender diverse. Sexual diversity refers to individuals whose sexual orientation is different from straight, including lesbian, gay or bisexual people.

Gender diversity refers to individuals whose gender identity does not align with the sex they were assigned at birth, which includes transgender and nonbinary people. Cisgender refers to individuals whose gender identity matches their sex assigned at birth.

“In a world that increasingly recognizes the crucial role of equitable health care, it remains concerning how little is known about the health disparities faced by LGBTQ+ people,” said study author Shufan Huo, MD, Ph.D. at the Yale School of Medicine in New Haven, Connecticut.

“Our study looked at this group, which has been historically underrepresented in neurological research, and found that they had an increased risk of adverse brain health outcomes.”

For the study, researchers evaluated data from 393,041 people with an average age of 51. Of the total group, 353,409 were cisgender and straight people, and 39,632 were LGBTQ+ people.

Researchers evaluated electronic health records and self-reported data to identify a composite score of the following neurological conditions: dementia, late-life depression and stroke. They then evaluated each disease separately and looked at all subgroups of the LGBTQ+ participants.

A total of 21,091 people had a neurological disease. Of those, 11,553 people had late-life depression, 6,605 people had strokes and 2,933 people had dementia.

After adjusting for factors that could affect the risk of these three neurological conditions, such as age, smoking or high blood pressure, researchers found that LGBTQ+ people were 15% more likely to develop negative brain health outcomes in these conditions when compared to people who identified as cisgender and straight.

Researchers also found that LGBTQ+ people had a higher risk of dementia and late-life depression, 14% and 27% respectively, than people who were cisgender and straight.

“Our findings underscore the need for further research focusing on the health care disparities affecting the LGBTQ+ community,” Huo said. “Possible reasons for these disparities could include discrimination, stress, access to health care and policy and legal factors.”

When looking at stroke, researchers found a higher risk only for transgender women, who were 68% more likely to have a stroke than cisgender people.

A limitation of the study was that it did not look at the causes and mechanisms behind the inequities faced by LGBTQ+ people. For example, the study did not look at gender-affirming hormone therapy in transgender people, which could play a role in increased stroke risks in transgender women.