But a new study of Massachusetts’ healthcare reform published in the Annals of Internal Medicine provides hope that the expansion of health coverage under Obamacare will, in fact, help people live longer and healthier lives.

For the study, the authors compared the mortality rate of people aged 20 to 64 in the years leading up to Massachusetts’ health reform (2001 to 2005) and after (2007 to 2010). They then compared Massachusetts counties with other, demographically similar counties in the U.S.

Annals of Internal Medicine

The results should embolden advocates of expanded health coverage: “In the first four years after Massachusetts instituted comprehensive health reform in 2006, mortality in the state decreased by 2.9 percent compared with similar populations in states that didn’t expand health coverage,” Harvard’s School of Public Health, whose Benjamin D. Sommers co-authored the study, said in a statement. “They estimated that Massachusetts’ health reform law, which provided near-universal coverage, has prevented approximately 320 deaths per year—one life saved for each 830 people gaining insurance.”

If the Massachusetts results are mirrored across the country, the same 3 percent decline in mortality would mean roughly 17,000 fewer premature deaths per year.

The study also found that the poor were especially likely to benefit from the overhaul, and the causes of death that the law helped prevent were ones that were most easily preventable and treatable.

“Massachusetts counties with lower median incomes and a higher percentage of uninsured adults before the law was passed—areas likely to have experienced the greatest increase in access to care under reform—gained the largest health benefits,” the statement reads. “In addition, the decline in mortality was nearly twice as large for minorities as it was for whites.”

In addition to living longer, Massachusetts residents also reported fewer cost-related barriers to care, more outpatient visits, and improvements in self-reported health after the reform was implemented.

This is consistent with a previous study showing better self-reported health in Massachusetts after the expansion of healthcare. And an earlier New England Journal of Medicine study found that other states that expanded Medicaid saw a 6.1 percent reduction in the death rate among adults younger than 65.

One thing to keep in mind is that expanding health coverage isn’t a panacea for all of our healthcare woes. A study of Oregon’s Medicaid expansion found that enrolling in the program caused people to use emergency rooms more, not less, even for treatable conditions. And while the Oregon residents who gained Medicaid coverage had better rates of diabetes detection, less depression, and less financial strain, they didn’t show any significant improvements in cholesterol or hypertension--two major markers of physical health.