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People who identify as a sexual and/or gender minority may have a higher risk of adverse brain health outcomes compared with people who are both straight and cisgender — the term for identifying as the sex you were assigned at birth, a new study has found.
The large study of more than 393,000 adult participants, published Wednesday in the journal Neurology, found a 15% higher risk of a composite brain health outcome — including dementia, stroke and late-life depression — defined as a depressive episode first diagnosed at or after age 60.
“It is concerning to see the differences in brain health between sexual gender minority (SGM) individuals and cisgender straight people,” said lead study author Dr. Shufan Huo, postdoctoral research fellow in the department of neurology at the Yale University School of Medicine, via email. “At the same time, I am glad that we can raise awareness for this often overlooked group. Medicine has traditionally focused on white, male patients, but nowadays we realize that this approach does not sufficiently address the needs of our diverse population.”
Prior studies on the health of these groups, of which there are few, often have small sample sizes, lack more specific categories of sexuality or gender identity, and overemphasize topics such as HIV, hormone use, substance use disorder and mental health, the authors said.
The latest study “is important because it is the first one of this kind to collect detailed information on sexual orientation and gender identity,” said Dr. Riccardo Manca, research fellow in the department of life sciences at Brunel University London, who wasn’t involved in the study. “Such a degree of diversity in the sample makes it more representative of the LGBTQ+ population.”
The findings could help inform future studies that investigate increased risk of negative outcomes in LGBTQ+ subgroups to understand the specific challenges for each, Huo said.
Studying brain health among diverse populations
To tackle the gap in knowledge, the authors studied participants enrolled in the United States-based All of Us Research Program between May 2017 and June 2022. Participants disclosed whether they identified as a sexual minority — lesbian, gay, bisexual, diverse sexual orientation or non-straight sexual orientation — and/or as a gender minority, defined as gender diverse, transgender or a gender identity different from the sex assigned at birth.
The authors included only dementia, stroke and late-life depression in their list of brain health outcomes since those are some of the most prominent diseases that affect neurological, psychiatric and cognitive aspects of the brain. The conditions are also interrelated and share common risk factors.
Of the 393,041 adults age 51 on average, about 10% belonged to sexual or gender minority groups. Of that subset, 97% identified as a sexual minority and 11% as a gender minority, but these two groups weren’t mutually exclusive.
“Remarkable findings were the differences between the subgroups,” Huo said. “People assigned male at birth (AMAB) had higher rates of late-life depression (compared to the cisgender population), whereas sexual minority people assigned female at birth (AFAB) and gender diverse people had higher rates of dementia.
“Transgender women had higher rates of stroke,” Huo said. “These findings show that each group has distinct risk profiles, for example because of differences in societal stigma.”
Understanding disparities in the LGBTQ+ community
The study’s use of a large database to establish population-level correlations is helpful for highlighting specific disparities, said Dr. Amir Ahuja, director of psychiatry at the Los Angeles LGBT Center, who wasn’t involved in the study.
However, “correlation does not equal causation, and we do not know why these disparities exist,” he added via email. “What this does do is let us focus on this issue in particular, and message to transgender women so that we can get them into preventive care and reduce their risk factors in advance.”
One “major limitation” is the lack of data on key factors such as gender-affirming hormone therapy, Huo said, though not every transgender person chooses this form of treatment.
The average age of the participants was also “very young” in comparison with the age after which dementia risk typically increases, which is 65, Manca said.
“Interestingly, a recent epidemiological study from the UK has shown that dementia risk among non-heterosexual people was higher only in those younger than 55 years of age,” Manca added. “This means that decline in brain functions in the LGBTQ+ community, or at least in some sub-groups within it, may occur earlier than expected in the heterosexual population. However, the reasons behind this effect remain elusive.”
There is no evidence that being a sexual or gender minority alone causes worse brain health, experts said. The increased risks likely stem from a combination of psychosocial and biological factors, Huo said — chronic stress, discrimination and stigma can lead to mental health conditions including depression and anxiety, which in turn can worsen brain health.
Inequities in health care access
The authors did try to control for some substance use and economic disparity but weren’t able to account for all of it. Many people who identify as a sexual or gender minority are low-income and disproportionately housing insecure, which can lead to worse health outcomes, Ahuja said.
Structural inequities in access to health care also likely contribute, experts said.
“We cannot ignore the factors of the health care system itself,” Ahuja said. “Numerous studies, including the (US Trans Survey), consistently show that SGM populations are not always taken seriously by health care providers, and outright discrimination is common. This leads to patients not following up and tests not being done, and problems not being investigated, which can also lead to worse outcomes.”
Proactively establishing healthy habits can help protect brain health, experts said. Those behaviors include staying active, quitting smoking, working with knowledgeable health providers, and managing stress and cardiovascular risk factors. So can maintaining positive and meaningful relationships, which is especially important for LGBTQ+ people who often rely on the support of chosen families, Manca said.
However, experts said, addressing the larger issues of inclusive health care and the reduction of discrimination is essential for long-term improvement in health outcomes and ensuring individuals won’t be left fighting alone.