A new study finds a disproportionate number of LGBT people in America's prisons — and many of them are subjected to abuse while there.

In the past few years, bipartisan attention has helped shed light on the overincarceration of nonviolent offenders, and researchers have long known that low-income, black, and Latino people are disproportionately imprisoned. Our study, released this month in the American Journal of Public Health, reveals a startling new fact: The incarceration rate of lesbian, gay, and bisexual people is three times greater than that of American adults generally.

We found that 1,882 per 100,000 lesbian, gay, and bisexual people are incarcerated, compared with 612 per 100,000 U.S. residents aged 18 and older. The nationwide incarceration rate of LGB people was previously unknown, and the large difference is striking.

Data came from the National Inmate Survey (2011-2012) conducted by the Bureau of Justice Statistics in U.S. prisons and jails, as mandated by the Prison Rape Elimination Act. Our new analysis of this data showed that not only are sexual minority persons more likely to be held and to receive longer sentences, they are also more likely to experience harm while inside. Compared with straight inmates, sexual minority inmates are more likely to be sexual victimized behind bars. For example, gay and bisexual men in prison are more than six times as likely to be sexually assaulted by a staff member or inmate than straight men.

The over-incarceration phenomenon is particularly acute among women inmates. Thirty-three percent of women in prison and 26 percent of women in jail identify as lesbian or bisexual — yet only 3.4 percent of women in the general U.S. population are lesbian or bisexual. Gay and bisexual men made up 5.5 percent of men in prison and 3.3 percent of men in jail, compared to 3.6 percent of men who identify as gay or bisexual in the general population. (Our forthcoming research looks at incarcerated transgender persons.)

What’s causing the disproportionate incarceration? Other research shows that prejudice may be to blame. Growing up, sexual minorities are more likely to experience family rejection and community marginalization, which can create pathways to substance abuse, homelessness, and detention. Criminal justice profiling of sexual minorities as more likely to engage in sex work or to commit sex crimes can lead to overpolicing. For women, powerful gender stereotypes are likely at play. To the extent that sexual minority women defy norms and are labeled as aggressive or masculine, individuals or institutions may unfairly find them more deserving of punishment.

The biases continue behind bars. For instance, we found that sexual minority inmates are more likely to experience solitary confinement. While sometimes purportedly done for the inmate’s protection, the institutional segregation of inmates is also used as punishment. In either case, the deprivation is severe. Exclusion from programming, 23-hour lockdown, and a lack of family visits and other human contact harm the mental health of those who endure it. Compounding matters, sexual minority inmates are more likely to have experienced childhood sexual abuse than straight inmates. Perhaps unsurprisingly, then, our research also found greater psychological distress among LGB inmates.

In sum, higher rates of incarceration, longer sentences, widespread sexual victimization, disproportionate isolation, and poor mental health outcomes urgently require a rethinking of current health and criminal justice approaches to this population.

In this particular political moment, we hope Americans will find increased concern for the vulnerable among us. Race, class, and sexual orientation serve to privilege some and disadvantage others. Perhaps nowhere is this truer than when we look closely at who is serving time in our country’s prisons and jails and how we treat marginalized individuals who are more likely to be there.

LARA STEMPLE is the Director of the Health and Human Rights Law Project and ILAN H. MEYER is a scholar at the Williams Institute. They, together with Andrew R. Flores, Adam P. Romero, Bianca D. M. Wilson, and Jody L. Herman are coauthors of Incarceration Rates and Traits of Sexual Minorities in the United States: National Inmate Survey, 2011–2012.