The United States health care system relies heavily on private health insurance, which is the primary source of coverage for most Americans. As of 2012 about 61% of Americans had private health insurance according to the Centers for Disease Control and Prevention.[54] The Agency for Healthcare Research and Quality (AHRQ) found that in 2011, private insurance was billed for 12.2 million U.S. inpatient hospital stays and incurred approximately $112.5 billion in aggregate inpatient hospital costs (29% of the total national aggregate costs).[55] Public programs provide the primary source of coverage for most senior citizens and for low-income children and families who meet certain eligibility requirements. The primary public programs are Medicare, a federal social insurance program for seniors and certain disabled individuals; and Medicaid, funded jointly by the federal government and states but administered at the state level, which covers certain very low income children and their families. Together, Medicare and Medicaid accounted for approximately 63 percent of the national inpatient hospital costs in 2011.[55] SCHIP is a federal-state partnership that serves certain children and families who do not qualify for Medicaid but who cannot afford private coverage. Other public programs include military health benefits provided through TRICARE and the Veterans Health Administration and benefits provided through the Indian Health Service. Some states have additional programs for low-income individuals.[56]
The remaining 45% of health care funding comes from insurance premiums paid by the public, for which companies compete on price, though the variation between the various competing insurers is only about 5%.[citation needed] However, insurance companies are free to sell additional policies to provide coverage beyond the national minimum. These policies do not receive funding from the equalization pool, but cover additional treatments, such as dental procedures and physiotherapy, which are not paid for by the mandatory policy.[citation needed]
As far as the compulsory health insurance is concerned, the insurance companies cannot set any conditions relating to age, sex or state of health for coverage. Although the level of premium can vary from one company to another, they must be identical within the same company for all insured persons of the same age group and region, regardless of sex or state of health. This does not apply to complementary insurance, where premiums are risk-based.
As the number of service sector jobs has risen in developed countries, more and more jobs have become sedentary, presenting a different array of health problems than those associated with manufacturing and the primary sector. Contemporary problems, such as the growing rate of obesity and issues relating to stress and overwork in many countries, have further complicated the interaction between work and health.
Health, as defined by the World Health Organization (WHO), is "a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity."[1][2] This definition has been subject to controversy, as it may have limited value for implementation.[3][4][5] Health may be defined as the ability to adapt and manage physical, mental and social challenges throughout life.[6]