With the progress of society, development of health care, exaltation of people living level, and prolongation of human life, whether quantities or proportions of aging of populations are increasing.

• 随着社会的进步、卫生事业的发展和人民生活水平的提高,人类寿命逐年延长,老年人口无论是数量还是占总人口的比重都在不断地增加。