Japan, with the world's highest proportion of retirees, can't build nursing homes fast enough. By 2025, one in three citizens will be 65 years or older from 12 percent of the population in 1990, the Organization for Economic Cooperation and Development estimates. A lack of long-term care facilities means seniors increasingly risk living alone in ill-equipped homes or suffering abuse in the care of resentful relatives.

By 2030, the number of seniors living alone will increase 54 percent to 7.2 million household units from 2010 levels, according to the National Institute of Population and Social Security Research in Tokyo. Elderly-care costs will more than double to 19.8 trillion yen ($212 billion) a year by 2026, the health ministry estimates. That threatens to overload the world's second-most indebted nation.

From now through 2030, an estimated 470,000 seniors will die alone in Japan unless more investment is made in caring for them, according to Hiroshi Takahashi, a professor of health sciences at the International University of Health and Welfare in Otawara City.

Japan may be a harbinger of a bigger crisis. Confucian-influenced societies from Vietnam to South Korea are grappling with the conflicting demands of modernization and traditions that venerated the elderly and obligated families to care for them, the Center for Strategic International Studies said in a report in July.

“The family is already under increasing stress from the forces of modernization,” the Washington-based center said. “Over the next few decades, massive age waves are due to engulf the region, slowing economic growth, driving up old-age dependency costs, and heaping large new burdens on governments and families alike.”