Researchers here present an interesting view of the variance in the burden of age-related disease exhibited by populations around the world. Unsurprisingly, the impact of age falls most heavily on those living in the poorest and least developed regions. Modern medicine and the other comforts of technology, for all that they do not directly target the causes of aging, do manage to have a sizable influence on the pace at which aging and age-related disease progresses over a lifetime. The largest gaps are mostly likely due to a combination of sanitation, particulate exposure from fires, and control of pathogens - akin to the difference between today and the 19th century. But the underlying reasons for the differences between wealthier nations, such as Japan versus countries of Western Europe, tend to be harder to pin down.
A 30-year gap separates countries with the highest and lowest ages at which people experience the health problems of a 65-year-old. Researchers found 76-year-olds in Japan and 46-year-olds in Papua New Guinea have the same level of age-related health problems as an "average" person aged 65. These negative effects include impaired functions and loss of physical, mental, and cognitive abilities resulting from the 92 conditions analyzed, five of which are communicable and 81 non-communicable, along with six injuries.
The study is the first of its kin. Where traditional metrics of aging examine increased longevity, this study explores both chronological age and the pace at which aging contributes to health deterioration. The study uses estimates from the Global Burden of Disease study (GBD). Researchers measured "age-related disease burden" by aggregating all disability-adjusted life years (DALYs), a measurement of loss of healthy life, related to the 92 diseases. The findings cover 1990 to 2017 in 195 countries and territories. For example, in 2017, people in Papua New Guinea had the world's highest rate of age-related health problems with more than 500 DALYs per 1,000 adults, four times that of people in Switzerland with just over 100 DALYs per 1,000 adults. The rate in the United States was 161.5 DALYs per 1,000, giving it a ranking of 53rd, between Algeria at 52nd with 161.0 DALYs per 1,000 and Iran at 54th with 164.8 DALYs per 1,000.
Using global average 65-year-olds as a reference group, researchers also estimated the ages at which the population in each country experienced the same related burden rate. They found wide variation in how well or poorly people age. Ranked first, Japanese 76-year-olds experience the same aging burden as 46-year-olds in Papua New Guinea, which ranked last across 195 countries and territories. At 68.5 years, the United States ranked 54th, between Iran (69.0 years) and Antigua and Barbuda (68.4 years).