With more than 2 million people behind bars, the U.S. has the highest incarceration rate in the world. This mass incarceration has serious implications for not only the inmates, but their children, finds a new University of California-Irvine study. The study found significant health problems, including behavioral issues, in children of incarcerated parents and also that, for some types of health outcomes, parental incarceration can be more detrimental to a child's well-being than divorce or the death of a parent.

"We know that poor people and racial minorities are incarcerated at higher rates than the rest of the population, and incarceration adversely affects the health and development of children who are already experiencing significant challenges," said study author Kristin Turney, an assistant professor of sociology at UC Irvine.

When comparing children with similar demographic, socioeconomic, and familial characteristics, the study found that having a parent in prison or jail was linked to a greater incidence of attention deficit disorder/attention deficit hyperactivity disorder (ADD/ADHD), behavioral or conduct problems, learning disabilities, speech or other language problems, and developmental delays.

"The results suggest that children's health disadvantages are an overlooked and unintended consequence of mass incarceration," Turney said. "In addition, given its unequal distribution across the population, incarceration may have implications for racial and social class inequalities in children's health."

Turney presented the study at the 109th Annual Meeting of the American Sociological Association, and the research will appear in the September edition of the Journal of Health and Social Behavior.

"About 2.6 million U.S. children have a parent in state prison, federal prison, or jail at any given time," said Turney, who noted that "Sesame Street" recently introduced a Muppet named Alex, whose dad is in jail, as a way to address the stigma associated with having an imprisoned parent.

The likelihood of having an incarcerated parent is especially high in certain groups. "Among black children with fathers without a high school diploma, about 50 percent will experience parental incarceration by age 14, compared with 7 percent of white children with similarly educated fathers," Turney said.

Compared to divorce, parental incarceration is more strongly associated with both ADD/ADHD and behavioral problems in children; compared to the death of a parent, parental incarceration is more strongly associated with ADD/ADHD.

"These findings have important implications for health professionals," Turney said. "Physicians serving poor communities where incarceration is common may consider screening children for parental incarceration, as it is a risk factor that, in some cases, is more consequential than other forms of parental absence like divorce."

Turney's study used data from the 2011-2012 National Survey of Children's Health, a population-based and representative sample of 0- to 17-year-olds.