A popular and key aspect of the Patient Protection and Affordable Care Act that allows young adults up to age 26 to stay on their parents' health coverage has "shielded them, their families and hospitals from the full financial consequences of serious medical emergencies," according to new research.

A new RAND Corporation study found that $147 million in medical care service in hospital emergency departments was newly covered by private insurance during a one-year period. Without the new regulation, those costs would have been paid by young people and their families, or been written off by hospitals as uncompensated care, researchers said.

The study, published in the May 30 edition of the New England Journal of Medicine, estimated that more than 22,000 "nondiscretionary emergency room visits" during 2011 involved young adults who were newly insured under the provision. The change increased health insurance rates by 3 percent among the young adults needing care in emergency departments nationwide during the period.