Life expectancy is increasing in nearly every country in the world – a testament to modern medicine, public health policies and socioeconomic development. Nowhere is this more evident than in East Asia, where a recent study estimated that South Korean women will likely be the first to reach an expected life span of 90 years.
However, a new study conducted in China has found that while the number of “oldest-old” – age 80 and up – are increasing, they’re not necessarily healthier.
The study, published in the Lancet last Thursday, found that rates of mortality among the oldest-old going down, but so are their physical and cognitive abilities compared to their counterparts from 10 years ago. According to the authors, it is the largest study of its kind and the first to assess this issue in a low- or middle-income country.
Among those 80 to 89 years old, mortality decreased from 10.3 percent in 1998 to 9.6 percent in 2008. For 90- to 99-year-olds, mortality decreased from 24.1 percent to 23.4 percent. Those 100 to 105 years old saw a mortality drop from 40.7 percent to 38 percent.
However, when tested for physical and cognitive function, all age groups saw a decline from 1998 to 2008. The physical activities used to test the participants were basic – whether they could stand up from a chair, pick up a book off the floor and turn a full circle – and researchers assessed cognition using an examination.
Despite these worse results, the newer group of oldest-old reported that they had less trouble performing daily activities, such as eating, dressing, bathing, using the toilet and continence. Although further research is needed to confirm the reasons why, the authors noted that these improvements may be attributed to better tools and amenities to aid the elderly in daily activities.
“Even though people had some more things wrong with them, they weren’t expressing that as much in terms of disabilities,” Kenneth Rockwood, professor of geriatric medicine and neurology at Dalhousie University, said in an interview with Humanosphere. “So yes, they’re a bit slower, but they were less disabled.”
According to the authors, there are two theories at play: Improvements in medicine, lifestyle, socioeconomic status, standards of living and mechanisms to cope with chronic disease have allowed people to live better and longer, delaying deterioration as they age. This is the “benefits of success” theory.
On the other hand, these same improvements have allowed “frail individuals” to survive life-threatening illnesses, but as a result, they live with health problems that hinder physical and cognitive function. This is the “costs of success” theory.
“The findings of our study provide a clear warning message to societies with aging populations – although lifespans are increasing, other elements of health are both improving and deteriorating leading to a variety of health and social needs in the oldest-old population,” Yi Zeng, lead author of the report and professor at Duke University and Peking University, said in a press release. “This combination poses an enormous challenge for health systems, social care and families around the world.”
According to the World Health Organization, the proportion of the world’s population older than 60 years will almost double between 2015 and 2050, from 12 percent to 22 percent. By 2050, 80 percent of the older population will be in low- and middle-income countries.
Already, countries like Japan and South Korea are calculating the economic cost of caring for a rapidly aging population. According to estimates by the Asia Pacific Risk Center, $20 trillion could be drained from Asia’s economy within the next 15 years just to keep up with the increased health care costs.
However, Rockwood warned that health care needs to make urgent adjustments as well, because “the problems of old age come as a package. When people have one thing wrong, they tend to have more things wrong, too.”
According to him, researchers no longer have the “luxury” of examining stand-alone illnesses in young people, while inferring the findings in old people.
“It won’t just be expressed with only its consequences,” Rockwood said. “It will be expressed through the other consequences of the other illnesses that people have.”
Clinical care professionals must also become more aware of the other conditions their patients are experiencing, perhaps calling for more general skill, rather than specialized care.
To reduce the dimensionality of research – with every person experiencing a different cocktail of illnesses – techniques will need to be employed to consider the person as whole. For example, how an illness is expressed by itself in one person can be compared to how the illness is expressed alongside 10 other illnesses in another person.
“The numbers will work for you,” he said.
Of course, illness isn’t the only thing that determines how a person ages. Researchers are increasingly finding that late life health reflects a person’s accumulation of life conditions and events. For example, early childhood conditions like nutrition and environment are linked to life expectancy as are factors such as education, socioeconomic status and social policies.
“The population that was old in China at the end of the 20th century had been through enormous social changes, including in government and social organization, income levels, and food security,” Rockwood wrote in a comment on the study. “Later changes – such as migration to rapidly growing urban areas, the one-child policy, and variable access to health care – each would have affected the health of China’s oldest-old.”
As life spans increase globally, these are all factors that researchers, health-care professionals and policymakers will have to take into account in order to support the old and the oldest-old.
“This is a really complicated problem,” Rockwood acknowledged, “and we’re going to have to get to grips with it.”