The U.S. government spent an estimated $5.4 billion last year at the state and federal level to incarcerate adults convicted of sex crimes against children under age 18, according to a new study led by a Johns Hopkins Bloomberg School of Health researcher. The study calculated annual spending on incarcerated adults convicted of sex crimes against children under age 18 in U.S. federal and state prisons and sex offender civil commitment facilities. The findings, published online March 23 in the journal Sexual Abuse, highlight the cost of what is considered a preventable public health problem.