Pamela Farley Short of Pennsylvania State University and colleagues culled their findings from data gathered for the U.S. Census Bureau's Survey of Income and Program Participation, which collects information from the same individuals every four months over a four-year period.
The team examined changes in insurance coverage among people ages 4-64 from 2004 to 2007, which is the most recent period for which four-year data are available.
Of the 89 million people uninsured during that period, 12 million were continually uninsured, 11 million gained coverage at some point, 11.5 million lost coverage, 14 million experienced a single gap in coverage and 6 million had a temporary spell of coverage but were otherwise uninsured, Short said. In addition, 23 million people lost health insurance more than once during the four-year period.
"There is clear evidence that people who are uninsured use fewer services than people who have insurance; they postpone prevention and ignore serious problems because they don't feel they can afford the care," Short said in a statement. "As a result, some even die for lack of insurance."
The analysis appeared online in a recent issue of Medical Care Research and Review.