Expanding the number of young adults with health insurance appears to have improved their health and saved them money, according to a new study that is among the first to measure the effect of the healthcare law that President Obama signed four years ago.
Starting in 2010, the Affordable Care Act allowed adults under age 26 to remain on their parents' health plans, the first coverage expansion to take effect under the law.
Previous surveys have indicated that this provision, which remains among the law's most popular, allowed millions of young adults to get health insurance over the last several years.
The new study, published in the Journal of the American Medical Assn., suggests the coverage expansion also measurably increased the number of young adults who reported that they are in excellent physical and mental health.
Researchers also found a significant drop in how much young people were paying out of pocket for their medical care after the law went into effect.
"The health insurance that people are gaining seems to be doing what it is supposed to do," said Dr. Kao-Ping Chua, a pediatrician at Boston's Children's Hospital and the lead author of the study.
The question of whether giving people insurance makes them healthier, in addition to protecting them against financial risk, has remained controversial as debate over the federal health law rages. The new research from Harvard University adds to growing evidence about the positive effects of insurance.
Last month, a study of Massachusetts' trail-blazing 2006 health law found a decline in mortality rates after the state began guaranteeing health insurance. That study's lead author, Dr. Benjamin Sommers, also co-authored the new paper.
In the study of young adults, researchers used survey data from the federal Agency for Healthcare Research and Quality to compare the experiences of young adults, ages 19 to 25, who were eligible for coverage under the law, to those 26 to 34, who were not. The study covered the eight years before passage of the health law and one year after.
Insurance coverage increased markedly among the young adults, while declining slightly among the older group.
At the same time, young adults' annual out-of-pocket medical expenses, including copays and deductibles, declined from an average of $546.11 in the period before the health law to $490 in 2011.
By contrast, annual out-of-pocket medical costs for the older group increased from an average of $626.66 to $644.82.
Younger adults also reported feeling better, with nearly 31% reporting themselves in excellent physical health after passage of the law, compared to nearly 27% giving that rating before.
The older group experienced a decline in self-reported health, with 21% reporting excellent physical health after passage of the law, compared 23% before.
How insurance may have contributed to the apparent health improvements remains unclear. The researchers did not detect any meaningful increase in the use of healthcare services among young adults after 2010. Their use of primary care remained constant, while it declined among the older group in 2011.
Chua speculated that the additional protections from having health coverage may contribute to a greater sense of security and health, a phenomenon that other research on coverage expansions has detected.
Tracking the young adult population over more years after they gained coverage may further explain the health impacts of insurance.
Additional research will also be needed to assess the health impact of the broader insurance expansion that began this year under the Affordable Care Act.
Unlike the young adults who joined their parents' health plans, many of which were employer-provided plans, millions of the newly insured this year signed up for government Medicaid plans or for individual health plans, many of which have high deductibles.
At the same time, the law's critics argue that even if increased coverage improves health, it may not be worth the cost.
Chua said the latest research cannot settle that question.