Carrin, Guy; James, Chris (January 2005). "Social health insurance: Key factors affecting the transition towards universal coverage" (PDF). International Social Security Review. 58 (1): 45–64. doi:10.1111/j.1468-246x.2005.00209.x. Retrieved 10 March 2013. Initially the health insurance law of 1883 covered blue-collar workers in selected industries, craftspeople and other selected professionals.6 It is estimated that this law brought health insurance coverage up from 5 to 10 per cent of the total population.
Sleep is an essential component to maintaining health. In children, sleep is also vital for growth and development. Ongoing sleep deprivation has been linked to an increased risk for some chronic health problems. In addition, sleep deprivation has been shown to correlate with both increased susceptibility to illness and slower recovery times from illness. In one study, people with chronic insufficient sleep, set as six hours of sleep a night or less, were found to be four times more likely to catch a cold compared to those who reported sleeping for seven hours or more a night. Due to the role of sleep in regulating metabolism, insufficient sleep may also play a role in weight gain or, conversely, in impeding weight loss. Additionally, in 2007, the International Agency for Research on Cancer, which is the cancer research agency for the World Health Organization, declared that "shiftwork that involves circadian disruption is probably carcinogenic to humans," speaking to the dangers of long-term nighttime work due to its intrusion on sleep. In 2015, the National Sleep Foundation released updated recommendations for sleep duration requirements based on age and concluded that "Individuals who habitually sleep outside the normal range may be exhibiting signs or symptoms of serious health problems or, if done volitionally, may be compromising their health and well-being."
Historically, Health maintenance organizations (HMO) tended to use the term "health plan", while commercial insurance companies used the term "health insurance". A health plan can also refer to a subscription-based medical care arrangement offered through HMOs, preferred provider organizations, or point of service plans. These plans are similar to pre-paid dental, pre-paid legal, and pre-paid vision plans. Pre-paid health plans typically pay for a fixed number of services (for instance, $300 in preventive care, a certain number of days of hospice care or care in a skilled nursing facility, a fixed number of home health visits, a fixed number of spinal manipulation charges, etc.). The services offered are usually at the discretion of a utilization review nurse who is often contracted through the managed care entity providing the subscription health plan. This determination may be made either prior to or after hospital admission (concurrent utilization review).
Genetics, or inherited traits from parents, also play a role in determining the health status of individuals and populations. This can encompass both the predisposition to certain diseases and health conditions, as well as the habits and behaviors individuals develop through the lifestyle of their families. For example, genetics may play a role in the manner in which people cope with stress, either mental, emotional or physical. For example, obesity is a significant problem in the United States that contributes to bad mental health and causes stress in the lives of great numbers of people. (One difficulty is the issue raised by the debate over the relative strengths of genetics and other factors; interactions between genetics and environment may be of particular importance.)