American Journal of Public Health research highlights:

Note: Hyperlinks to the studies will go live following the embargo lift on Dec. 20, 2016, at 4 p.m. EST.

Social networks increase spread of violence among adolescents

Newswise — Researchers tested the hypothesis that violence among US adolescents spreads like a contagious disease through social networks. They examined responses from a nationally representative sample of 90, 118 U.S. students 12 to 18 years old who were involved in the National Longitudinal Study of Adolescent Health. Violence was assessed by having participants report the number of times in the preceding 12 months they had been involved in a serious physical fight, had hurt someone badly and had pulled a weapon on someone.

Results showed that participants were 48 percent more likely to have been involved in a serious fight, 183 percent more likely to have hurt someone badly and 140 percent more likely to have pulled a weapon on someone if a friend had engaged in the same behavior. The influence spread up to four degrees of separation (i.e., friend of friend of friend of friend) for serious fights, two degrees for hurting someone badly and three degrees for pulling a weapon on someone. Researchers concluded that adolescents were more likely to engage in violent behavior if their friends did the same, and contagion of violence extended beyond immediate friends to friends of friends.

[“The Contagious Spread of Violence Among US Adolescents Through Social Networks.” Contact: Brad J. Bushman, PhD, School of Communication, The Ohio State University, Columbus, Ohio.]

0.53 percent of U.S. adults identify as transgender

Researchers estimated the proportion of U.S. adults who identify as transgender and compared the demographics of transgender and non-transgender populations. They analyzed data from states and territories in the 2014 Behavioral Risk Factor Surveillance System that asked about transgender status. The proportion of adults identified as transgender was calculated from affirmative and negative responses. They also explored differences between male-to-female and non-transgender females and female-to-male and non-transgender males.

Results showed that transgender individuals made up 0.53 percent of the population and were more likely to be non-white and living below the poverty line; as likely to be married, living in a rural area and employed; and less likely to attend college compared with non-transgender individuals. Researchers concluded that the transgender population is a racially diverse population present across U.S. communities, and that inequalities in education and socioeconomic status have negative health implications for the transgender population.

[“Transgender Demographics: A Household Probability Sample of US Adults, 2014.” Contact: Halley P. Crissman, MD, MPH, University of Michigan, Ann Arbor, Michigan.]

Sexual minorities overrepresented in prisons and jails, experience higher rates of mistreatment

Researchers set out to report characteristics of sexual minority U.S. inmates. Data from the National Inmate Survey, 2011–2012, was used to estimate differences between sexual minority and heterosexual inmates.

Results showed that sexual minorities — those who self-identify as lesbian, gay or bisexual or report a same-sex sexual experience before arrival at the facility — were disproportionately incarcerated. About 9.3 percent of men in prison, 6.2 percent of men in jail, 42.1 percent of women in prison and 35.7 percent of women in jail were sexual minorities. The incarceration rate of self-identified lesbian, gay or bisexual persons was more than three times that of the U.S. adult population. Compared with straight inmates, sexual minorities were more likely to have been sexually victimized as children, to have been sexually victimized while incarcerated, to have experienced solitary confinement and other sanctions and to report current psychological distress. Researchers concluded that there is disproportionate incarceration, mistreatment, harsh punishment and sexual victimization of sexual minority inmates.

[“Incarceration Rates and Traits of Sexual Minorities in the United States: National Inmate Survey, 2011–2012.” Contact: Ilan H. Meyer, PhD, Williams Institute, UCLA School of Law, Los Angeles, California.]

Child maltreatment investigations more common across lifespan

Researchers estimated the lifetime prevalence of official investigations for child maltreatment among children in the U.S. Using data from the National Child Abuse and Neglect Data System Child Files (2003–2014) and Census, they estimated the cumulative prevalence of reported childhood maltreatment. They also extended previous work, which explored confirmed rates of maltreatment, and added new estimations of maltreatment by subtype, age and ethnicity.

Results showed that 37.4 percent of all children experience a child protective services investigation by age 18. African American children had a higher rate of maltreatment investigations, while Asians/Pacific Islanders had the lowest rate. Researchers concluded that child maltreatment investigations are more common than is generally recognized when viewed across the lifespan. The data suggest a critical need for increased preventative and treatment resources in the area of child maltreatment.

[“Lifetime Prevalence of Investigating Child Maltreatment Among U.S. Children.” Contact: Brett Drake, PhD, MSW, Brown School of Social Work and Public Health, Washington University, St. Louis, Missouri.]

Find a full list of AJPH research papers to be published online on Dec. 20, 2016, at 4 p.m. EST below:• The Contagious Spread of Violence Among US Adolescents Through Social Networks• Transgender Demographics: A Household Probability Sample of US Adults, 2014• Incarceration Rates and Traits of Sexual Minorities in the United States: National Inmate Survey, 2011–2012• Lifetime Prevalence of Investigating Child Maltreatment Among U.S. Children• Effect of Medicaid Expansion on Workforce Participation for People With Disabilities• Anabolic Steroid Misuse Among US Adolescent Boys: Disparities by Sexual Orientation and Race/Ethnicity• Racial/Ethnic Disparities in the Use of Lethal Force by US Police, 2010–2014• Trends in Walking and Cycling Safety: Recent Evidence From High-Income Countries, With a Focus on the United States and Germany• The Association of a Large-Scale Television Campaign With Exclusive Breastfeeding Prevalence in Vietnam• Impact of a Text-Messaging Program on Adolescent Reproductive Health: A Cluster–Randomized Trial in Ghana• Human Trafficking of Minors and Childhood Adversity in Florida• The Progress of US Hospitals in Addressing Community Health Needs• Familial Factors, Victimization, and Psychological Health Among Sexual Minority Adolescents in Sweden• Incidence of Mental Health Diagnoses in Veterans of Operations Iraqi Freedom, Enduring Freedom, and New Dawn, 2001–2014• Incarceration Rates and Traits of Sexual Minorities in the United States: National Inmate Survey, 2011–2012• US Traffic Fatalities, 1985–2014, and Their Relationship to Medical Marijuana Laws

The articles above will be published online Dec. 20, 2016, at 4 p.m. EST by the AJPH under “First Look.” “First Look” articles have undergone peer review, copyediting and approval by authors but have not yet been printed to paper or posted online by issue. AJPH is published by the American Public Health Association, and is available at

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