Gov. Paul LePage’s vetoes of the Affordable Care Act’s federal subsidies for Medicaid expansion have already cost Maine thousands of jobs and hundreds of millions of dollars. Yet partisan critics of Obamacare continue to argue that expanded Medicaid coverage will have no effect on health and may actually harm the poor.

Over 40 years of research has documented that the uninsured have fewer doctor visits and fail to receive basic preventive services like blood pressure screening, pap tests, cholesterol testing and influenza vaccinations. As a result, the uninsured are diagnosed at more advanced stages of cancer, especially for cancers detectable by screening. The uninsured are much more likely to have undiagnosed high blood pressure and high cholesterol, more severe strokes and poorer control of diabetes.

A recent study of preventable leg amputations describes an uninsured 53-year-old woman with undiagnosed diabetes who was regularly drinking six-packs of ginger ale. She reported that she “felt like a junkie just looking for something just to quench my thirst.” She suffered a diabetic coma, woke up in the hospital with infected toes and required a leg amputation. Another study of unconscious patients hospitalized after severe motor vehicle crashes found that the uninsured received less care and had a 40 percent higher mortality rate than insured patients, even after controlling for type of vehicle, injury, auto insurance, income, neighborhood and hospital characteristics.

So do Obamacare critics deny the value of Medicaid coverage? Most of the uninsured are young and healthy, they might argue. They cycle in and out of employer-based insurance, and when major health declines do occur, previously uninsured individuals then qualify for disability and Medicaid.

But a study of expanding Medicaid for the uninsured in Oregon shows clearly that gaining insurance had a significant positive effect on the health of the newly insured — and that those newly covered had gone a long time without care they needed.

In 2008, Oregon conducted a lottery to fill 10,000 additional Medicaid slots for low-income, uninsured residents. Researchers compared health and financial outcomes of Medicaid lottery winners with lottery losers over the next two years. Individuals who won the lottery had a greater chance of having a physician visit, getting blood cholesterol or blood sugar tests, receiving a diagnosis of diabetes and, thus, obtaining diabetes medications. There was a 30 percent reduction in depression among insurance lottery winners, a 25 percent lower rate of unpaid bills sent to collection agencies, and catastrophic medical expenditures were reduced by more than 80 percent.

Critics of Obamacare focused on the Oregon results showing that, two years after receiving coverage, blood pressure, cholesterol and diabetes were not significantly different among those who won the Medicaid lottery. They dismissed as “perceptions” the fact that many more of the lottery winners reported their health as the same or better than the previous year, despite the fact that such questions are highly predictive of future health. Critics also decried the increase in emergency room visits for lottery winners.

Yet increased use of health care is typical of the initial transition to insured care. Older uninsured patients who transition to Medicare at age 65 receive an expensive “backlog” of tests and treatments but also experience disproportionately greater gains in health than their continuously insured peers, while their use of health care ultimately stabilizes.

So what is the best evidence of the value of health insurance and, by extension, expanding Medicaid coverage? Studies following older middle-age adults into old age demonstrate that individuals who were uninsured died at younger ages when compared with those of the same age and original health status who were privately insured. The one-third greater mortality of older adults who lacked health insurance was roughly equivalent to the risk of smoking. The lack of health insurance in older middle age would rank as the third leading cause of death behind heart disease and cancer.

A study published in the New England Journal of Medicine in 2012 compared states providing expanded Medicaid coverage to low-income childless adults with neighboring states that did not expand Medicaid. The study found that states that expanded Medicaid coverage decreased uninsurance by 15 percent and had a 6 percent greater decline in deaths of adults aged 20-64 over the next five years. The study concluded that only 176 additional adults would have to be covered by Medicaid to prevent one death per year.

An evaluation of the 2006 insurance expansion in Massachusetts under then-Gov. Mitt Romney found that residents ages 20-64 had a 3 percent lower death rate than similar counties around the country that hadn’t expanded coverage. The greatest dents were made in helping low-income residents and preventing causes of death that were most amenable to medical treatment.

Expanding Medicaid in Maine is not just about economics. It’s about preventing death and suffering for the state’s most vulnerable residents.

Joe Feinglass is a research professor of medicine at the Northwestern University Feinberg School of Medicine in Chicago, Illinois. He is a member of the national Scholars Strategy Network, which brings together scholars across the country to address public challenges and their policy implications. Members’ columns appear in the BDN every other week.