More than 40 percent of Americans making between $20,000 and $40,000 a year went without insurance for at least part of the year last year, according to a study published on Tuesday.
The research by The Commonwealth Fund also found that 20 percent of working adults are paying off medical debt — often $2,000 or more — and 60 percent of uninsured adults with chronic illnesses such as heart disease skip pills to save money.
The Commonwealth Fund researchers called the 40 percent figure a "dramatic and rapid increase from 2001," when 28 percent of people in this moderate income bracket were uninsured.
The group, which does the survey every other year, also found that 67 percent of the 48 million going without insurance were in families where at least one person worked full-time.
"The jump in uninsured among those with modest incomes is alarming, particularly at a time when our economy has been improving," said Commonwealth Fund President Karen Davis, who helped write the study.
"If we don’t act soon to expand coverage to the uninsured, the health of the U.S. population, the productivity of our workforce, and our economy are at risk."
The Fund, a private research group focusing on health care issues, surveyed more than 4,000 people by telephone for the report.
It found that people without health insurance were more likely to go without recommended cancer, cholesterol and blood pressure screenings. For instance, 18 percent of adults aged 50 to 64 who lack insurance had a colon cancer screening in the past five years compared to 56 percent of insured adults.
"For an uninsured person who is unlucky enough to get sick, it is easy to see how quickly they can fall into a downward spiral of debt, forgone care, and poorer health," Sara Collins, Commonwealth Fund senior program officer, said in a statement.
The study found that 21 percent of the adults surveyed between August and January had unpaid medical bills.
More than a third said they either had medical bill problems in the past year or were paying off medical debt. Of these, more than 60 percent were insured.
Several reports on people who lack insurance in the United States have shown that they do not have to regular doctors and often rely on emergency care, which in turn drives up costs.
The Commonwealth survey found that 35 percent of uninsured adults with chronic conditions visited an emergency room in 2005, stayed in the hospital overnight, or both, compared to 16 percent of patients with a chronic condition who were steadily insured.