Some 26,100 working age Americans died prematurely in 2010 as a consequence of being uninsured, a new study from liberal think tank Families USA estimates.

Using methodology established by the Institute of Medicine (IOM), Families USA calculated that between 2005 and 2010, the number of uninsured people aged 25-64 who died prematurely rose from 20,350 to 26,100. The total number of deaths due to lack of health coverage over this period was estimated at 134,120.

This rate, which the study notes is likely a conservative estimate, works out to 72 deaths a day, or three every hour.

The year 2010 saw the number of uninsured Americans rise to an all-time high of nearly 50 million. Without insurance, people have little choice but to forgo needed medications and regular care, aggravating manageable or wholly preventable conditions into life threatening ones. Millions of people turn to emergency rooms as a last resort; in many cases, it is too little, too late.

Without insurance, working age adults are five times less likely to have regular medical care than those who are insured. According to a 2009 study published in the Journal of Public Health, more than half of uninsured adults who tried to find a primary care physician said it was “somewhat difficult” or “very difficult.” More than 40 percent of uninsured people seeking primary care at a doctor’s office or clinic said they were not accepted as a patient.

Without access to primary care, the uninsured are four times more likely than the insured to forgo or delay needed screenings like mammograms and colonoscopies. The cost of basic preventive procedures is prohibitively expensive without insurance. For this reason, uninsured patients are more likely to be diagnosed with a disease in an advanced stage.

The uninsured also pay more for care, which Families USA attributes to the fact that they are “unable to negotiate the discounts on hospital and doctor charges that insurance companies do.” As a result, those without insurance are “often charged more than 2.5 times what insured patients are charged for hospital services.” Three out of every five uninsured working-age adults report problems with medical debt.

The IOM calculation for premature deaths from lack of insurance is based on a 2002 research that found, after controlling for numerous factors, that the absence of health coverage increases mortality in working-age adults by an average of 25 percent.

“For several reasons, this methodology underestimates the mortality effects of uninsurance,” the Families USA report states. First, “our mortality estimates ignore the benefits of health insurance for individuals under 25 years of age.” Research by the Johns Hopkins Children’s Center suggests that seriously ill uninsured children who are hospitalized are 60 percent more likely to die than insured children in the same situation. (See “US: Lack of insurance linked to thousands of child deaths”)

Secondly, Families USA cautioned that while the IOM relied on data on the entire working age population, it calculated mortality “within 10-year age bands rather than for all adults aged 25-64. This lowered our mortality estimates by more than 15 percent.”

A 2009 Harvard Medical School study, based on more recent data, found that lack of insurance raises mortality rates by 40 percent, to some 45,000 deaths in a year. Noting that the risk of premature death for the uninsured was 25 percent higher than in 1993, the researchers concluded that at least two factors were to blame: the closure of public hospitals and rise of the multi-billion-dollar private hospital industry, and the widening gap in preventive medical care between those with coverage, and those without.

The care provided to Medicaid recipients at community clinics or county health departments, the Harvard study found, was not an adequate substitute for the quality of care accessible to those with adequate health insurance.

As millions of people have lost their jobs and employer-based insurance since the onset of the economic crisis, health insurance premiums have continued to increase.

The average cost of employer-based health insurance now exceeds $20,000 per year, according to health care actuarial firm Milliman, Inc. This is more than double the already high rates of a decade ago. The year 2012 will be the fifth in a row that health care costs have risen by more than 7 percent. Employers have responded to the increases by continually upping the employee contribution in the form of premiums, higher deductibles and co-pays.

According to the Kaiser Family Foundation, out-of-pocket insurance costs for those without employer-based coverage are even higher. Private insurance is simply unaffordable for most working class families. Behind the rising Medicaid rolls is a wave of desperation and impoverishment.

At the same time, public health budgets have been ransacked at the federal, state, and local levels. Health clinics, preventive care outreach and other vital programs serving the poor have been decimated. Florida, Kentucky, and other states have handed management of their Medicaid programs over to private health maintenance organizations (HMOs) and insurance companies that have begun curtailing doctor reimbursement for many basic procedures and coverage for medications.