More than 5 million U.S. children, or almost 7 percent, have had a live-in parent incarcerated, well above a previous estimate on parental imprisonment, a study said on Tuesday.

The analysis by the non-profit Child Trends research group into the effects of a parent's imprisonment on children comes as President Barack Obama has made criminal justice reform a priority late in his second term.

The figure of more than 5 million covers children up to 18 who have ever had a parent who lived with them sent to prison. The numbers were based on a 2011-12 survey by the U.S. Department of Health and Human Services.

A 2007 estimate of children who currently had a parent in prison put the number at 1.7 million, or just over 2 percent. That estimate included non-residential parents, Child Trends said.

The report showed that black, poor and rural children were more likely to have had a residential parent go to jail or prison. Black children were about twice as likely as whites to have had a parent incarcerated.

Other research has shown links between parental imprisonment and childhood health and behavior problems, poor school performance and physical and mental health trouble in adulthood, the Child Trends study said.

The damage can be reduced by improving communication between the child and parent, reducing the stigma of incarceration and making prison visits more child-friendly, it said.

(Reporting by Ian Simpson; Editing by Eric Walsh)