Background: Adults in late middle age who lack health insurance are more likely to die or experience a decline in their overall health. Because most estimates of the uninsured are cross-sectional, the true number of individuals whose health is at risk from being uninsured is unclear.
Methods: We analyzed a nationally representative sample of 6065 US adults 51 to 57 years old who were interviewed in 1992, 1994, 1996, 1998, and 2000 as part of the Health and Retirement Study. Insurance coverage was determined at the time of each interview and classified as private, public, or uninsured. Longitudinal data were used to determine the proportion of individuals who were uninsured at any interview during the 8-year study period.
Results: The proportion of participants who were uninsured at the time of the 1992, 1994, 1996, 1998, and 2000 interviews was 14.3%, 10.8%, 9.7%, 8.8%, and 8.2%, respectively. People frequently transitioned between having insurance and being uninsured. As a result, despite the declining prevalence of being uninsured, the percentage who were uninsured at least once during the 8-year period rose to 23.3% by 2000; few participants (2.6%) were continuously uninsured. Only 60.1% of participants were continuously enrolled in private insurance across all 5 interviews.
Conclusions: The proportion of US adults in late middle age at risk from being uninsured over a 10-year follow-up period was 2 to 3 times higher than cross-sectional estimates. At least one quarter of older adults will be uninsured at some point during the years preceding eligibility for Medicare.