Among surprises from a new study on U.S. health spending is the realization: Whether insured or not, young adults spent about the same on out-of-pocket health expenditures throughout the year.

Researchers analyzing federal data from 2009 reported this week in the Journal of Adolescent Health that young Americans covered by health insurance for at least part of the year also incurred greater expense for emergency care than their uninsured counterparts, Kaiser Health News reported. Although much continues to change as the Affordable Care Act (ACA) expands Medicaid coverage throughout “Blue State” America, the study might yet serve as a “baseline” to study future effects of the new federal health care law.

Josephine Lau, an assistant professor of adolescent and young adult medicine at the University of California at San Francisco, called the results surprising. “It could be they had just lost coverage as they were going through changes in their lives,” Lau said.

In 2009, 27 percent of young adults went without health coverage entirely while another 21 percent lacked insurance for at least part of the year. However, the new federal health law requires no co-payments for many preventive health services, a feature Lau says may encourage more young adults to visit doctors as a matter of routine.

However, Larry Levitt, an executive at the Kaiser Family Foundation, warns that not every health plan sold online is equal. “When you give an uninsured person insurance, they have better protection but their out-of-pocket costs may go up because they’re able to use more services,” he said in an online statement.

Still, some things may never change. As women require greater use of medical services, they would continue to pay higher out-of-pocket costs for health care — as much as $700 higher than the annual cost for men. “There’s nothing in the ACA that’s going to make young men not be young men,” said Levitt. “Young men use fewer health services [than young women], but by their 50s and 60s, that reverses.”

When looking at younger Americans, the researchers found that African Americans and Hispanics were less likely than whites to use the medical system at all. They also found that poorer young Americans received less preventive care and relied more on the emergency room.

“Low office-based visit utilization is of concern for young adult health, given their relatively high rates of health problems in the areas of obesity, substance use disorders, mental health problems, unplanned pregnancies, and sexually transmitted infections, many of which can have lasting negative consequences across the life course,” Lau and his colleagues wrote.

Source: Lau, Josephine S., Adams, Sally H., Boscardin, John W., et al. Young Adults' Health Care Utilization and Expenditures Prior to the Affordable Care Act. Journal of Adolescent Heatlh. 2014.