Japan has long been the world leader in longevity, but some experts are now suggesting that the island nation may soon face a drop in the rankings.
More from TODAY.com
Jenna Wolfe: Bestie babymoons aren't a thing yet, but they should be
- Duchess Kate to give birth in same hospital as Princess Diana
- Principal: Retirement flash mob 'meant everything'
- Best-selling author Vince Flynn dies at 47
- Singer, yodeler Slim Whitman dies at 90
- Jenna Wolfe: Bestie babymoons aren't a thing yet, but they should be
The decline could be fueled in part by the country's significant suicide rate, rising body mass index and relatively high rates of smoking, according to Dr. Christopher J.L. Murray, director Institute for Health Metrics and Evaluation at the University of Washington in Seattle.
"In an era of economic stagnation, political turmoil, aging populations, and inadequate tobacco control, Japan does not seem to be effective in addressing its new set of health challenges," Murray wrote.
"Without concerted action, Japan, like the USA, is likely to continue dropping in the global mortality league tables," he added.
Murray's comments are published in the medical journal the Lancet this week in an issue devoted to exploring the reasons for Japan's health successes.
Although Japan's decline, relative to the longevity of other nations, will not be as severe as the relative decline of the U.S., "it is a cautionary tale that success in the past does not guarantee top performance in the future," Murray wrote.
Murray's prediction relies on, among other sources, a research paper in the same issue entitled "What has made the population of Japan healthy?"
In that article, researchers from the University of Tokyo found that while Japan has achieved a record life expectancy of 86 years for women, "Japan now needs to tackle major health challenges that are emanating from a rapidly aging population, causes that are not amenable to health technologies, and the effects of increasing social disparities to sustain the improvement in population health."
Japan's record-breaking longevity
Murray said that the success of Japanese health care emerged after World War II, with declining infant mortality and reduction of infectious diseases.
That was followed by a period from 1975 to 1995, during which mortality dropped in many nations, as well as Japan.
But in recent years, he said, "Japan has fallen behind Sweden, Italy, and Australia for men, and behind Sweden for women. If recent trends continue, other nations are likely to achieve lower rates of adult mortality than Japan."
Part of Japan's health success has been attributed to universal health coverage, accomplished at a relatively low price: the country spends 8.5 percent of its GDP on health care, while the U.S. spends 16.4 percent, and Germany spends 10.7 percent, Murray said.
But that adds another potential reason for the fall, Murray said.
"Although Japan has a universal health care system, the quality of the care delivered might be low," Murray said, citing the example of coverage for high cholesterol treatments that is much lower than in other high-income countries.
To further increase the country's longevity by reducing its adult mortality, Japan may need to revamp its health care system, he said.
The oldest nation on Earth
But longer life is not the only change that has come to Japan in recent decades. A declining birth rate and long lifespan have helped make Japan the oldest nation on earth, with a median age above 40.
"The aging population, smoking, metabolic syndrome and suicide are all major challenges facing the public health system in Japan," said D. Craig Willcox, a professor of public health at Okinawa International University and at the University of Hawaii, who co-led the long-term Okinawa Centenarian Study.Story: Accomplishing amazing athletic feats — in their 80s and 90s
But the nation faces the need for cultural change as well, said Willcox, who was not involved with Murray's article.
"Losing status among nations may upset the national pride," Willcox said. But "the more important issue is reforming Japanese society to make it more age-friendly, and doing away with age discrimination," he said.
Willcox said he questioned whether it made sense for most Japanese companies and institutions to have mandatory retirement age of 65 years, when 40 percent of the population will be beyond that age in a few decades. He noted that this retirement age doesn't apply to everyone in the country.
Health as a social responsibility
Willcox said he believes, however, that some of the central ideas responsible for the success of Japanese health care may help in the United States. Universal health coverage plays an important role, along with some other ideas.
"In Japan, people are taught to think of their health as not only a personal issue, but also a social responsibility," he said. For example, towns in which not enough people get health screenings may pay more in taxes. "If you don't get your health exam, the whole town could suffer, and everyone could end up paying more taxes!"
Additionally, Willcox said, the government has adapted its language in discussing health conditions such as cardiovascular disease and some age-related cancers, calling them "lifestyle-related diseases" instead of "age-associated diseases," and the public has taken to the change.
"You can see the subtle shift from something that just 'comes along with age' or something you can prevent through your lifestyle," he said. "As a specialist in public health, I thought that was a brilliant move."