Long-term study finds widening gap in social isolation between sexual minority and heterosexual adults

A new longitudinal study sheds light on how social isolation tends to evolve from early adulthood into midlife—and how this trajectory may differ by sexual orientation. The research, published in the Journal of Health and Social Behavior, indicates that people who identify as lesbian, gay, bisexual, or mostly heterosexual tend to report higher levels of social isolation than those who identify as completely heterosexual. These differences appear early in adulthood and, in some cases, grow larger over time.

The findings point to a persistent and widening gap in social connectedness that could contribute to health disparities later in life. The study is among the first to track patterns of social isolation across more than two decades, with a focus on both differences between and within sexual minority groups.

Although many studies have documented disparities in mental and physical health by sexual orientation, far fewer have explored how social well-being varies across these groups. Social isolation—defined as the absence of meaningful contact or ties to others—is increasingly recognized as a key predictor of poor health outcomes, including earlier death. Yet little is known about how isolation unfolds over time for people who identify as sexual minorities.

The authors of the new study sought to address this gap by following a large and diverse cohort of U.S. adults over time. They applied theories of minority stress, minority resilience, and life course development to investigate how social isolation trajectories differ by sexual orientation and gender. The research also aimed to clarify how a group often overlooked in past studies—people who identify as “mostly heterosexual”—fit into broader patterns of social isolation.

“I was motivated by the growing awareness that social isolation is a serious public health concern—especially during the pandemic—yet we know little about how it affects people with different sexual identities over time. I wanted to understand whether sexual minority individuals experience more isolation as they move through adulthood. This study helps fill that knowledge gap using long-term national data,” said Zhiyong Lin, an assistant professor of sociology and demography at the University of Texas at San Antonio.

The researchers used data from the National Longitudinal Study of Adolescent to Adult Health, a nationally representative sample of people who were first surveyed in the 1990s during adolescence and followed into adulthood. This analysis focused on participants who provided data across three waves: ages 18–26, 24–32, and 32–42. The final sample included over 13,800 individuals, accounting for more than 30,000 person-year observations.

Social isolation was measured across four domains: intimate relationship status, friendship ties, religious attendance, and volunteering. Participants were considered isolated in a domain if they met criteria such as being unpartnered, falling into the bottom quartile of friendship frequency, attending religious services less than once a month, or not volunteering in the past year. These scores were combined into a standardized index ranging from 0 to 4.

Sexual orientation was assessed using self-identification at each wave. Respondents were grouped into three categories: completely heterosexual, mostly heterosexual, and lesbian/gay/bisexual. The study controlled for parental education, race and ethnicity, and gender.

The researchers applied growth curve modeling to examine how isolation scores changed over time and how those changes varied by sexual orientation. They also conducted separate analyses by gender and explored each isolation domain individually.

Across all models, sexual minority individuals reported higher levels of social isolation than their heterosexual counterparts. At age 29—the average in the sample—both mostly heterosexual and lesbian/gay/bisexual adults reported significantly higher isolation scores. These gaps tended to widen over time, particularly among mostly heterosexual individuals.

Notably, the trajectory for mostly heterosexual adults indicated a faster rate of increase in isolation from early adulthood to early midlife. While they initially resembled heterosexual adults in their isolation levels, they ended up closer to lesbian/gay/bisexual adults by their early 40s.

When broken down by gender, the trends became more nuanced. Among women, lesbian and bisexual participants consistently reported higher isolation than heterosexual women. Mostly heterosexual women also showed elevated isolation, and while their rate of increase over time was not significantly steeper, the gap remained persistent.

Among men, gay and bisexual participants reported the highest isolation levels by early midlife. Interestingly, mostly heterosexual men did not begin with higher isolation, but their scores increased more steeply over time—surpassing those of heterosexual men by their mid-20s.

The findings also revealed which aspects of social isolation were most affected by sexual orientation. Across the board, sexual minority participants were more likely to report being unpartnered and less likely to attend religious services. However, no significant differences emerged in volunteering activity or frequency of friendship ties.

“Our study shows that people who identify as lesbian, gay, bisexual, or mostly heterosexual (primarily attracted to the other sex but with some same-sex attraction) tend to experience more social isolation than their heterosexual peers as they move from early adulthood into midlife,” Lin told PsyPost. “This gap actually widens over time, especially for sexual minority men. These findings highlight the need for more inclusive support systems and policies that help all people stay connected throughout adulthood.”

While past research has often grouped all non-heterosexual individuals together, this study suggests that mostly heterosexual people have distinct experiences. Although they tend to face less overt discrimination than those who identify as gay or bisexual, they may also lack access to the supportive networks that other sexual minority individuals create. As a result, they may be especially vulnerable to social withdrawal as they age.

“One surprising finding was that people who identify as ‘mostly heterosexual’—a group often overlooked in research—also showed high and increasing levels of social isolation over time,” Lin said. “While their isolation levels were lower than those of lesbian, gay, and bisexual individuals in young adulthood, by early midlife, they were nearly the same. This suggests that mostly heterosexual individuals may face unique social challenges, possibly because they don’t fully fit into either heterosexual or LGBTQ+ communities.”

The researchers frame social isolation as a key mechanism through which health disparities may emerge later in life. As isolation increases, individuals may have fewer sources of emotional support, caregiving, or informal help. This can become especially significant as people enter midlife and begin to experience health challenges.

While some theories of minority resilience suggest that chosen families or community involvement may buffer against stress, the findings did not show signs that these strengths fully closed the gap. The isolation trajectories for sexual minority groups remained consistently higher, indicating that resilience may mitigate—but not erase—the effects of marginalization.

Although the study offers robust longitudinal data, it also has some limitations. The researchers used a binary measure of gender, which does not capture the experiences of nonbinary or transgender individuals. The categorization of sexual identity may also miss newer identity labels that have become more common in recent years.

The authors also note that their measure of social isolation, while multidimensional, may not capture all relevant aspects of social connectedness—such as the emotional quality of relationships or the role of online communities.

“One caveat is that social isolation can look different across people’s lives and communities—we measured it through indicators like romantic partnership, friendship, religious attendance, and volunteering,” Lin noted. “So someone might score as more isolated even if they feel well supported in other ways. Also, our study follows a single generation born in the 1970s and early 1980s, so patterns may differ for younger generations growing up in a more accepting society.”

Going forward, Lin plans “to study how social isolation in midlife affects health and aging outcomes later in life, especially among sexual minority populations. I’m also interested in how policy and community support can reduce isolation and promote healthy aging for diverse groups.”

“We hope the findings of this study encourage more attention to social connection as a vital part of health. By identifying who is most at risk and when, we can better design interventions that promote inclusion and well-being across the life course.”

The study, “Sexual Orientation and Social Isolation from Early Adulthood to Early Midlife,” was authored by Zhiyong Lin, Kara Joyner, and Wendy D. Manning.