Average life expectancies in developed countries are predicted to increase through 2030, and female life expectancy in some countries may break the 90-year barrier, according to a study published online February 21 in the Lancet.
The United States, however, emerges as a relative poor performer compared to other high-income countries, given its already shorter life expectancy at birth and smaller projected gains.
Unlike most current mortality and life expectancy projections that rely on a single model, the current projections are derived from an ensemble of forecasting models "to more completely capture the uncertainty about future trends," write Vasilis Kontis, PhD, of the Department of Epidemiology and Biostatistics in the School of Public Health, Imperial College London, United Kingdom, and colleagues.
The researchers used a Bayesian model averaging approach to combine projections from 21 models for age-specific mortality and life expectancy at birth in 35 industrialized countries using high-quality vital statistics data.
"Taking model uncertainty into account, we project that life expectancy will increase in all of these 35 countries with a probability of at least 65% for women and 85% for men, although the increase will vary across countries," the authors write.
The model projects life expectancy at birth for women and men by country. It shows that South Korean women have the longest projected life expectancy in 2030, at higher than 86.7 years (90% probability), which is the same as the highest worldwide life expectancy in 2012.
Further, the model indicates a 57% probability that the life expectancy at birth for South Korean women will be higher than 90 years in 2030, "a level that was considered virtually unattainable at the turn of the 21st century by some researchers," the authors write.
They note that the trend is a continuation of the "massive gains" in the life expectancy of South Korean women since 1985. "The probability that South Korean women will have the highest female life expectancy in 2030 is 45%, with a 27% probability of being in second place."
Whereas earlier gains in life expectancy in South Korea were attributable to declining infection-related mortality for children and adults, "more recent gains have been largely due to postponement of death from chronic diseases," the authors explain. Broad-based improvements in socioeconomic status, social capital, nutrition, access to healthcare, and new medical technologies are contributing factors, they write.
Following top-ranked South Korea, female life expectancy in France, Japan, and Spain have overlapping distributions, making them similarly likely to occupy any of the next three positions in rank, the authors write. Countries with emerging economies, such as Slovenia, have made large projected gains in female longevity, as has Portugal. The probability that Slovenia and Portugal will be in the top ten countries for female life expectancy at birth in 2030 is 71% and 63%, respectively.
For men, South Korea, Australia, and Switzerland occupy the top three ranks, with overlapping distributions of projected life expectancy. "There is at least 95% probability that men's life expectancy at birth in these three countries will surpass 80 years in 2030, and 27% that it would surpass 85 years," the authors write.
Men in South Korea, Denmark, Ireland, and a few western European nations, as well men in some central European countries with emerging economies, such as Hungary and Slovenia, are also projected to demonstrate large gains in longevity, according to the authors.
The data also indicate that the life expectancy gap between men and women will continue to narrow. "In 2010, women had a higher life expectancy than men by 3.9 (New Zealand) to 8.5 (Poland) years," the authors write. "We project that the female advantage will shrink by 2030 in every country analysed here except Mexico, where a slightly larger life expectancy gain is projected for women than for men, and in Chile, France, and Greece where male and female life expectancies will increase by about the same."
United States Shows Smaller Gains
Of the countries included in the analysis, the smallest gains in life expectancy for both men and women were projected for the United States, Japan, Sweden, Greece, Macedonia, and Serbia.
For women in the United States, projections for 2030 place them near the 30th rank for life expectancy at birth, at 83.3 years; men are near the 25th position, at 79.5 years.
The United States is "notable among poor-performing countries," the authors write. In the United States, "life expectancy at birth is already lower than most other high-income countries, and is projected to fall further behind such that its 2030 life expectancy at birth might be similar to the Czech Republic for men, and Croatia and Mexico for women."
Compared with other high-income countries, the United States has the highest rates of child and maternal mortality and homicide. It also has the highest average body mass index and was the first to demonstrate a halt or reversal in adult height increases, "which is associated with higher longevity," the authors write. "The USA is also the only country in the OECD [Organization for Economic Cooperation and Development] without universal health coverage, and has the largest share of unmet healthcare needs due to financial costs."
The poor recent and projected performance in life expectancy for the United States "is at least partly due to high and inequitable mortality from chronic diseases and violence, and insufficient and inequitable health care," the authors state.
The projections for life expectancy at birth in the current study are broadly similar UN predictions and "raise crucial issues about which responses are appropriate to tackle such worsening disparity in terms of health policy and provision of health services," Ailiana Santosa, MD, of the Center for Demographic and Ageing Research at Umea University in Sweden, writes in an accompanying commentary.
"Identifying the best model of forecasting life expectancy will help assess appropriate health prevention strategies in different populations," she states.
Forecasting life expectancy "can help governments and health services to make the right investments in health, such as averting deaths due to infectious diseases and reducing maternal and child mortality," Dr Santosa writes. "Achieving universal health coverage is worthy, plausible, and needs to be continued."
The UK Medical Research Council and the US Environmental Protection Agency funded the research. The authors of the study and Dr Santosa have disclosed no relevant financial relationships.
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Cite this: Life Expectancy Nears 90 Years in Some Countries, but US Falls Short - Medscape - Feb 22, 2017.