Tag Archives: life expectancy

Life expectancy update, disparity edition

The good news is that U.S. life expectancy is at a record high, 78.8 as of 2012.

What about life disparity — the inequality in life expectancy? With the economic crisis and rise in income inequality, it would be great to know. However, the National Center for Health Statistics hasn’t released detailed life tables with data more recent than 2008, so I can’t yet update the data for the analysis I did last year, so here it is reposted instead:

Life Expectancy, Life Disparity

Reposted from July 23, 2013

In 2008 the life expectancy at birth in the U.S. was 78.1. That means that if a group children born in 2008 lived every year of their lives exposed to the risks of death observed in 2008, their average lifespan would be 78.1 years. But those who made it to age 60 would live an average of 22.7 more years, for a total of 82.7. And those who live to age 99 would live an average of 2.4 more years, for an average of 101.4.

So “life expectancy” as commonly used is not a prediction of how long today’s babies will live — since we hope the future is better than living 2008 over and over — and it’s not a prediction of how long your elderly loved ones will live.

Life disparity

Life expectancy — for any age — is a measure of central tendency: the average number of years of life remaining. And so there is a dispersion around that mean. That dispersion is inequality. A very nice article in the open-access journal BMJ Open, by James Vaupel, Zhen Zhang and Alyson A van Raalte, describes the measure of life disparity. It’s complicated, but a neat tool.

Life disparity is the average number of years people are expected to live when they die. For example, in the U.S. in 2008 an infant who died on the first day of life died 78.1 years early. And a 78-year-old who died, counterintuitively, died 10 years early (since the life expectancy at 78 is 10). To understand what this measure means, consider that if everyone died at exactly 78.1 years of age, life expectancy would be unchanged but life disparity would be 0. On the other hand, the greatest life disparity would occur if all early occurred at age 0.

Life disparity and life expectancy usually go together. That’s because reducing early deaths has the biggest effect on both measures. Here is the cool figure from that paper:

The association between life disparity in a specific year and life expectancy in that year for males in 40 countries and regions, 1840–2009. The black triangle represents the USA in 2007; the USA had a male life expectancy 3.78 years lower than the international record in 2007 and a life disparity 2.8 years greater. The brown points denote years after 1950, the orange points 1900–1949 and the yellow points 1840–1900. The light blue triangles represent countries with the lowest life disparity but with a life expectancy below the international record in the specific year; the dark blue triangles indicate the life expectancy leaders in a given year, with life disparities greater than the most egalitarian country in that year. The black point at (0,0) marks countries with the lowest life disparity and the highest life expectancy. During the 170 years from 1840 to 2009, 89 holders of record life expectancy also enjoyed the lowest life disparity.

The association between life disparity in a specific year and life expectancy in that year for males in 40 countries and regions, 1840–2009. The black triangle represents the USA in 2007; the USA had a male life expectancy 3.78 years lower than the international record in 2007 and a life disparity 2.8 years greater. The brown points denote years after 1950, the orange points 1900–1949 and the yellow points 1840–1900. The light blue triangles represent countries with the lowest life disparity but with a life expectancy below the international record in the specific year; the dark blue triangles indicate the life expectancy leaders in a given year, with life disparities greater than the most egalitarian country in that year. The black point at (0,0) marks countries with the lowest life disparity and the highest life expectancy. During the 170 years from 1840 to 2009, 89 holders of record life expectancy also enjoyed the lowest life disparity.

Countries at the bottom left (0,0) have both the world’s highest life expectancy and the lowest life disparity in the world for that year, which occurred 89 times over 170 years. Countries below the diagonal have relatively low life disparity given their life expectancy; those above the diagonal (like the U.S.) have higher-than-expected life disparity for their level of life expectancy. In our case that reflects the fact that we do a pretty good job keeping old people alive, but let too many young people die.

U.S. improvement

The good news is that life expectancy is increasing in the U.S. (and most other places), and that the inequality between Blacks and Whites is getting smaller, as reported by the National Center for Health Statistics. That is, the Black-White inequality in average expectation of life at birth has shrunk.

The mixed news is that life disparity is much higher for Blacks than Whites — but that gap is falling as well. Here are those numbers for 1998 and 2008 (I did the life disparity calculations from this and this, and will happily share the spreadsheet). Click to enlarge:

expectancydisparity

So Black deaths are more dispersed than White deaths: 14 and 13 for males and females, compared with 12 and 11. For comparison, the Swedish female life disparity is 9. What does a higher disparity mean? Generally, a larger share of early deaths. That’s why the race gap in life expectancy at birth is greater than the race gap in life expectancy at older ages — average 65-year-old Whites and Blacks have more similar life expectancies than do infants.

Why is life disparity more interesting than life expectancy alone, and how does this help explain Black-White inequality in the U.S.? For one thing, high life disparity indicates either relatively unhealthy or dangerous living conditions at younger ages. So it’s partly a measure of the quality of life. Vaupel et al. add:

Reducing early-life disparities helps people plan their less-uncertain lifetimes. A higher likelihood of surviving to old age makes savings more worthwhile, raises the value of individual and public investments in education and training, and increases the prevalence of long-term relationships. Hence, healthy longevity is a prime driver of a country’s wealth and well-being. While some degree of income inequality might create incentives to work harder, premature deaths bring little benefit and impose major costs. Moreover, equity in the capability to maintain good health is central to any larger concept of societal justice.

I think what they say about differences between countries would apply to differences between groups within a society as well.

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Are White women high school dropouts getting sicker?

My Twitter feed lit up yesterday with this story about how life expectancy is falling for White women who have not finished high school. The story was called, “What’s Killing Poor White Women?“, by Monica Potts.

I have complete sympathy for poor people with health problems and high mortality rates. Things are killing them, and that’s bad. They should have better education, better jobs, better health care and more money.

White women without high school degrees have lost five years of life expectancy. Something must be getting worse. But I don’t quite think so. I could be wrong. But I think that as the category White women without high school degrees shrinks, it is the healthier people who are leaving (or never entering) the group. As a result, the group’s average health is declining.

The first thing to realize is that, according to the Census Bureau [spreadsheet link], 95% of non-Hispanic White women ages 25-29 have completed four years of high school or more. So we’re talking about a very (negatively) select population. And it’s getting more select – it was 92% 20 years ago. (Potts’s story revolves around a woman who died at 38.*)

The article doesn’t give any numbers to show that more people are dying, just that the life expectancy of the group has fallen. If this were a group, like race or gender, whose membership doesn’t change much over time, that would be enough to indicate their health status was getting worse. But an education group isn’t like that. It’s membership changes over time. Neither of the two academic articles Potts cites seem to consider this possibility (here and here).

One take

Here’s a try at it. Since 1996, the Current Population Survey has asked an excellent health status question, asking people to rate their own health as excellent, very good, good, fair, or poor. Let’s treat those whose health is “poor” as the group driving the mortality trend (which seems to fit the narrative in the story).

Here is the scary trend: A sharp rise in the proportion of non-Hispanic White women high school dropouts, ages 20-29, who rate their health as “poor.” (All the figures use three-year averages.)

poorhealthThat looks terrible, and it is, of course. But look at the size of the total group (all health statuses) over the same period:

dropoutsSo, the group has shrunk by about 18%, from about 850,000 to less than 700,000. And here is how the group’s population has changed according to health status, using the two endpoints of the trend, 1996-98 and 2010-12:

drophealthSo, there has been, in effect, no change in the number of non-Hispanic White women high school dropouts ages 20-29 in poor health, for the last decade and a half (the numbers shown are population estimates based on a sample size of only a few hundred women in this category per year, so I discount small shifts). In contrast, there has been a decline of those in good health. Result: the average health of the group has declined, but there are not more sick women.

That’s good news, because in Potts’s telling their problems are very serious, and something should be done about it.

*I (or you) could redo this to include more ages. I used young people because, if they have high mortality rates, they’re going to disappear from the sample at relatively young ages and make the group look healthier.

 

 

 

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Fact pattern: Women’s life expectancy advantage

Women live longer than men in all but a small handful of countries. Is that “natural”?

A future post will deal with this more. But here’s a preview.

It partly depends what you think is a “natural” fertility rate. It’s hard to find societies with really high fertility rates nowadays — hardly any countries have 6 or more children per woman. But where fertility rates are higher, women’s advantage in life expectancy is less (click to enlarge).

femaleadtfr

Why? Some women die in childbirth, but that’s not a huge factor in life expectancy anymore, thankfully. In sub Saharan Africa about 400-600 mothers die for every 100,000 births, about half of 1%, which isn’t going to drive overall life expectancy that much. Still, those places are rough places to be a woman, apparently.

Some distinctly unnatural elements are at work — besides war, murder, accidents and suicide — especially smoking, which has enlarged the female life expectancy advantage in the U.S. and Europe dramatically. The World Health Organization has smoking rates by sex for 133 countries or so. The differences are huge. Only Austria has more women than men smoking. The average prevalence gap is 21 percentage points, and in Indonesia the smoking gap is 64% (67% for men versus 3% for women). In a bunch of Arab countries almost half the men smoke, along with almost no women.

The effect of the smoking gap is not apparent in the recent cross-sectional data, however. It takes a few decades after men take up smoking at higher rates (peak female advantage for the U.S. was in the 1970s). But this could be an important factor in the world’s life expectancy gender gap for decades to come.

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