Health care spending for children is rising faster than for the under-65 population as a whole, a new study finds.

The report from the Health Care Cost Institute, a nonprofit backed by large health insurers, found the average child (newborn to age 18) in an employer-sponsored health plan accumulated $2,574 in health care bills during 2013 — an 18 percent increase compared with 2010.

Over the same time period, per capita spending for all employer plan members up to age 64 grew by a more modest 12 percent to $4,864, according to a study being released Wednesday.

The results fit with a trend of more children being treated for diabetes, depression and other health ­problems, said Stephen Parente, a health care finance expert at the ­University of Minnesota.

"This is a trend that's been going on for a while now," said Parente, who also is a board member for the research institute.

The Health Care Cost Institute publishes research on claims data from four of the nation's largest health insurers — Aetna, Humana, Kaiser Permanente and Minnetonka-based UnitedHealth Group.

The new report looked at claims data for an average of about 10.2 ­million children per year with employer-sponsored coverage. It tabulates spending in terms of what insurance companies pay, as well as out-of-pocket costs for health plan members, such as deductibles.

The report found spending for children grew by 5.7 percent per year between 2010 and 2013, compared with 3.9 percent annually for all health plan members up to age 64.

Spending increases in a given year are driven by higher prices, increased use of services or a combination of the two, said Amanda Frost, senior researcher with the institute.

In 2013, increased spending on kids was driven largely by higher prices, Frost said, whereas increased use was the driver in 2011. She said increases in 2012 were driven by more of a balanced mix of the two factors.

Between 2012 and 2013, per capita spending on health care for children increased by 4.6 percent, despite declines in the use of prescriptions and ­emergency rooms.

Use of inpatient hospitals by children grew a little between 2012 and 2013, but rising prices were the bigger driver for overall spending in the category. Frost said the average price for a child's inpatient admission increased by $744 between 2012 and 2013, growing to $14,685.

"The average price per service increased for every ­service category between 2012 and 2013," the report states. "The largest dollar increase in an average price per service was in inpatient admissions."

The report looked at spending by different age groups, and found babies (age 3 and under) had the fastest average annual growth rate at 6 percent per year. Health care spending also was higher per baby in 2013 at $4,813.

"Only spending for middle-age adults (ages 45-54) and pre-Medicare adults (ages 55-64) was higher than spending for babies in that year," the report states. "Additionally, per capita spending for teenagers ($2,746) was higher than that for young adults ($2,676)."

Annual spending figures do not include premium costs for health insurance. Claims for labor and delivery costs typically are tied to a mother's admission.

Is more spending on health care for kids a good thing?

"Many people often quickly jump to the conclusion that more spending — when we have such high spending — is a bad thing," Frost said. "But I think that we really have to keep in mind that we're talking about spending on actual children.

"If more spending means better health outcomes for these children, then I think it's a very good thing," she said. "But we're not really in the business of making those judgments."

Christopher Snowbeck • 612-673-4744

Twitter: @chrissnowbeck