Koreans with disabilities as a whole are aging very rapidly―much more rapidly than the overall population―with those aged 50-plus making up 71.1 percent of them in 2011. The Elderly Welfare Act stipulates the age of 65 as the threshold at which one becomes "elderly" and thus eligible for elderly welfare service. However, there is an abundance of research evidence suggesting that disabled people are likely to experience aging early, perhaps as much as 20 years earlier than their able-bodied counterparts. Often, on top of their disabilities, they have to cope with secondary conditions which add to their existing functional and health-related problems. The age criteria that researchers apply to people with disabilities differ from one research study to another. Some studies use the age 65 when defining older persons with disabilities. Others, especially those looking at policies concerning the employment of disabled individuals, use the age of 55. Still others employ the age of 50 or even 40 as the criteria for defining an older person with disabilities. Although how old a disabled person has to be to become an older disabled person is a matter social consensus, this study uses the age of 50 as the threshold of "older persons" with disabilities. Apart from the age threshold, it should be noted that the disabled elderly can be divided into those aging with disability and those who have disability with aging. They are two different groups of individuals of different disability characteristics and needs. "People with early-onset disabilities are said to "age with disability," while those with mid- or late-life onsets are said to have "disability with aging."