The vast majority of the world’s sexual minority population — an estimated 83 percent of those who identify as lesbian, gay or bisexual — keep their orientation hidden from all or most of the people in their lives, according to a new study by the Yale School of Public Health that could have major implications for global public health.Concealing one’s sexual orientation can lead to significant mental and physical health issues, increased healthcare costs and a dampening of the public visibility necessary for advancing equal rights, said John Pachankis, Ph.D., associate professor at the Yale School of Public Health. He co-authored the study with Richard Bränström, an associate professor at the Karolinska Institutet in Sweden and research affiliate at Yale. Published in the journal PLOS ONE, the study is believed to be the first attempt to quantify the size of the “global closet” in order to gauge its public health impact.“Given rapidly increasing acceptance of sexual minorities in some countries, it might be easy to assume that most sexual minorities are out in 2019, but actually, most sexual minority people in the world today are probably not out,” said Pachankis. Concealment is associated with depression and anxiety, substance abuse and susceptibility to infectious disease. “Concealment takes its toll through the stress of hiding and also because it can keep sexual minorities away from each other and from adequate public health attention. But in many places around the world, concealment and its stressors are safer than the alternative,” he said. The study found that concealment is highest in certain African and Middle Eastern countries and lowest in Western Europe, North America, Australia and New Zealand. Distinct differences, however, were found even within specific regions as a function of varying social and political factors. In Eastern Europe, for example, the study found that four-fifths of sexual minorities reported concealing their sexual orientation, while in nearby Northern and Western Europe, only about one-third reported doing so.The researchers quantified the size of the global closet by first gathering figures from one of the world’s largest data samples of sexual minorities — the European Union Lesbian, Gay, Bisexual and Transgender survey. The 2012 survey of more than 85,000 sexual minorities in 28 European countries identifies the proportion of those keeping their sexuality a secret from all or most of the people in their lives. Concealment takes its toll through the stress of hiding and also because it can keep sexual minorities away from each other and from adequate public health attention.John PachankisPachankis and Bränström then extrapolated the degree of sexual concealment in all world countries as a function of the estimate they derived from the European Union data and an objective index of ‘structural stigma’ for all 197 countries around the globe. The index scored countries based on six distinct forms of legal and policy discrimination and protections: unequal age of consent for same-sex sexual activity, asylum provisions for sexual minorities, protections against bias-motivated violence, legal protections against discrimination, same-sex partnership recognitions and freedom of assembly. This information then served as the basis of a statistical model from which to predict the degree of sexual concealment in all world countries.In a second analysis, the researchers found that eliminating structural stigma at the country level would dramatically reduce the size of the global closet—from 83% globally to about 16%.While eliminating stigma is the most direct route to achieving health equality and improving public health outcomes, the researchers suggest that implementing targeted public health interventions can, in the interim, help sexual minority individuals living under the burden of the closet. The researchers hope their study encourages countries, especially those without adequate health monitoring of sexual minority populations, to reassess the size and health needs of their sexual minority populations.In many countries, free and open sexual expression can be perilous. Out sexual minorities still face, for example, imprisonment, blackmail and sexual assault. In some countries, sexual minorities often have no legal recourse for discrimination and can be subjected to harmful ‘conversion therapies.’ In a large independent survey of Chinese sexual minorities, less than 15% report being fully out, a percentage that is consistent with the estimate derived by the model created by Pachankis and Bränström. Of course, even in the most tolerant countries, out sexual minorities sacrifice the numerous benefits and social capital of presumed heterosexuality, the researchers said.Same-sex marriage is currently legal in 28 countries, while 43 provide protections against hate crimes based on sexual orientation. Same-sex sexual activity is criminalized in 72 countries, including eight countries where it is punishable by death, the authors said.