Two current cases of sustained life expectancy decline, and one possible future one

Co-blogger Scott Peterson recently linked to a study suggesting that in the United States--and by implication, other high-income countries and/or countries with high rates of obesity--the expected sustained increase in life expectancy might not happen, indeed, might be reversed.

“Over the next few decades, life expectancy for the average American could decline by as much as 5 years unless aggressive efforts are made to slow rising rates of obesity, according to a team of scientists supported in part by the National Institute on Aging (NIA), a component of the National Institutes of Health (NIH)…The U.S. could be facing its first sustained drop in life expectancy in the modern era, the researchers say, but this decline is not inevitable if Americans — particularly younger ones — trim their waistlines or if other improvements outweigh the impact of obesity…

The new analysis, by S. Jay Olshansky, PhD, of the University of Illinois at Chicago, Leonard Hayflick, Ph.D., of the University of California, San Francisco, Robert N. Butler, M.D., of the International Longevity Center in New York, and others* suggests that the methods used to establish life expectancy projections, which have long been based on historic trends, need to be reassessed. This reevaluation is particularly important, they say, as obesity rates surge in today’s children and young adults.

“Forecasting life expectancy by extrapolating from the past is like forecasting the weather on the basis of its history,” Olshansky and his colleagues write. “Looking out the window, we see a threatening storm — obesity —that will, if unchecked, have a negative effect on life expectancy.”

Unlike historic life expectancy forecasts, which rely on past mortality trends, the Olshansky group bases their projection on an analysis of body mass indexes and other factors that could potentially affect the health and well-being of the current generation of children and young adults, some of whom began having weight problems very early in life. The authors say that unless steps are taken to curb excessive weight gain, younger Americans will likely face a greater risk of mortality throughout life than previous generations.”

The idea surprises me, but it shouldn't have. I've heard enough about the metabolic syndrome, strongly associated with obesity along with high blood glucose levels, high blood pressure, and so on, to know that its health consequences can be severe, particularly insofar as diabetes and heart disease is concerned. Three of the four risk factors leading to the metabolic syndrome--not genetics, but yes weight, aging, and a sedentary lifestyle--are becoming increasingly common in our increasingly overfed, aging, and physically inactive world. Can medical technology compensate for this? It's open to question.

Long-standing health issues leading to sustained stagnation or declines in life expectancy reminds me of what happened in the Soviet Union, where--contrary many popular reports--life expectancy decline began as early as the 1960s.

During the 1960s, though, life expectancy in the United States rose rapidly, while life expect-ancy in the Russian republic faltered and began to decline. The gap between East and West in life expectancy, like the gap in economic performance, grew steadily wider.

This trend was already apparent by the early 1980s. In a 1982 Population Bulletin published by PRB, Murray Feshbach, former chief of the U.S. Census Bureau's research unit on the USSR's population, noted "the mortality rise of the last decade and a half" and cautioned that "[I]f the health sector is neglected, the adverse mortality trend which has resulted in a major reduction in the life expectancy of Soviet males may persist."

The story within the story came in the late 1980s, when then-President Mikhail Gorbachev instituted a vigorous antialcohol campaign as part of a wider effort to rescue Russian society, and the Soviet state, from self-destruction. The draconian, unpopular, and probably unsustainable campaign produced a sharp but temporary improvement in mortality rates. The collapse of the public health campaign, the collapse of the Gorbachev government, and the breakup of the Soviet Union nearly coincided in 1988 and 1989. The progress quickly made since the mid-1980s was just as quickly lost, and the long-term decline continued until the mid-1990s.

Cause-of-death data are difficult to use for comparisons over long periods or across countries with very different medical and statistical systems, but several independent analyses have come to the same conclusion: The decline in life expectancy and the gap between levels in Russia and the rest of Europe can be attributed mainly to abnormally high rates of cardiovascular disease and injury, for both of which abuse of alcohol was a major risk factor.

But limiting the comparison to the last 10 or 12 years is misleading. Comparing the unusually good years of 1986 and 1987, when the antialcohol campaign was most effective, with the lowest points of the mid-1990s exaggerates the speed of decline. Any other choice of start and end dates would produce a more characteristic picture of steady, long-term decline.

Sharply rising infant mortality from the early 1970s on certainly didn't help. According to Eberstadt in 1988, with the exception of Georgia and Armenia, life expectancy was significantly below Western levels as a result of lifestyle risks, with life expectancy in developed Russia being on part with underdeveloped Uzbekistan's.

Arguably, the HIV/AIDS epidemic in southern Africa is similar in its determination by long-term trends, with the sustained catastrophic drop in life expectancy even in wealthy South Africa produced by a combination of overlapping sexual networks and an apartheid-era migration system that helped break down community and family structures.

Average life expectancy declined from 62 years in 1990 to 50 years in 2007; it is projected to fall even further by 2011, to 48 years for men and 51 for women, according to the Institute's annual South Africa Survey.

The authors note that among 37 developed and developing countries, South Africa is one of only six where life expectancy fell between 1990 and 2007, with only Zimbabwe showing a steeper decline.

Of South Africa's nine provinces, those with the highest HIV prevalence rates also had the lowest life expectancy - KwaZulu-Natal at 43 years, followed by Free State and Mpumalanga, both at 47 years. The leading causes of death were tuberculosis (TB), influenza and pneumonia, all common opportunistic infections associated with HIV/AIDS.

Seventy percent of people diagnosed with TB in South Africa were co-infected with HIV, and "it is thus reasonable to assume that at least 70 percent of observed mortality from tuberculosis, and by extension a comparable percentage of deaths from influenza/pneumonia, also has HIV and AIDS as an underlying cause." Nearly half of all deaths in 2008 were thought to be HIV/AIDS related - up from a third in 2001.

Gail Eddy, a researcher at the Institute, commented that although neither the public health system nor the government's antiretroviral (ARV) treatment programme were reaching all those in need, particularly in rural areas, a slight decrease in mortality rates in the last two years may be the result of ARVs gradually becoming more widely available.

The HIV/AIDS epidemic contributed to a 43 percent reduction in population growth between 2001 and 2008; a fall in birth rates also played a role.

Thoughts?