Since people who lack health insurance are unable to obtain timely medical care, they have a 40% higher risk of death in any given year than those with health insurance, according to a study published in the American Journal of Public Health. The study estimated that in 2005 in the United States, there were 45,000 deaths associated with lack of health insurance. A 2008 systematic review found consistent evidence that health insurance increased utilization of services and improved health.
Health insurance in the United States is any program that helps pay for medical expenses, whether through privately purchased insurance, social insurance, or a social welfare program funded by the government. Synonyms for this usage include "health coverage", "health care coverage", and "health benefits". In a more technical sense, the term "health insurance" is used to describe any form of insurance providing protection against the costs of medical services. This usage includes private insurance and social insurance programs such as Medicare, which pools resources and spreads the financial risk associated with major medical expenses across the entire population to protect everyone, as well as social welfare programs like Medicaid and the Children's Health Insurance Program, which both provide assistance to people who cannot afford health coverage.