Does Poverty Increase the Death Rate?

Richard Baldwin looks at the evidence for causation running from extreme poverty to early death:

Aging and death on a dollar a day, by Richard Baldwin, Vox EU: There are more than billion people getting by on less than a dollar a day in the world. How much better would they be if their incomes rose to, say, $2 a day? The sensible answer -- sitting in a country with an average income of $160 per day – would seem to be $1 per day better off, but this ignores many intangibles that come with extreme poverty – things that don’t make it into national income accounts. Many, perhaps most, of these intangibles are unmeasurable, but not all. Recent research by Abhijit Banerjee and Esther Duflo has shed some light on one that is very easy to understand and measurable – premature death.

In the world’s poorest countries, poor people die early, as Table 1 illustrates for the case of Indonesia. The numbers are shocking. For the best off in the survey sample – those in households whose daily household expenditure per capita valued at purchasing power parity is between four and six dollars a day – the numbers show that of the over-50s that entered the survey in 1993, 7% were dead four years later and 18% seven years later. For those living in the poorest households, the figures were much higher: 15% and 22% respectively.

Do the poor die young or are the dying poor?

But what causes what? Does ill health reduce people’s ability to work and thus lower incomes, or is it low incomes that lead to ill health and early death? The relationship between poverty and mortality seems intuitively obvious, and their correlation is well documented. However, isolating the causal relationship is a very difficult and complex task.

Part of the elusiveness stems from the two-way nature of the relationships between poverty and disease, and between poverty and death. Poor people may owe their fate to sickness[1] or the early death of a spouse.[2] Conversely, they may be sick and/or die because they are poor.[3]

Third, factors further complicate the analysis. Some authors, often epidemiologists, argue that higher income inequality is associated with increased mortality, at all per capita income levels,[4] while most economists attribute correlations between poverty (or other measures of socioeconomic status) and mortality rate to underlying effects of education (Deaton, 2003).[5]

Theoretical complexity aside, other issues prevent a clear isolation of the relationship between poverty and mortality. First, measurement of variables and the choice of levels of aggregation influence results; second, data availability restricts the degrees of freedom available to researchers.

Missing aged poor people

The Banerjee-Duflo study begins with the puzzling finding that, in nine out of fifteen developing countries in their study, they observe 20% to 35% more old people in a cohort corresponding to slightly better-off old individuals (i.e., defined as those spending $2-$4 or $6 to $10 per capita per day) than in the cohort of extremely poor old people (i.e., $1 per capita per day).

One way to establish whether the poor really die more than the non-poor is to use a panel data set – a longitudinal study – to track the mortality of those identified as poor in the first period. The necessary data exist for Udaipur (India), Indonesia and Vietnam.

The results indicate that mortality is higher for poorer people in all age cohorts, and in all three countries analysed. More interestingly, the largest difference in mortality rates across incomes is consistently found in cohorts of old people. For example, in 1992-93, an Indonesian or Vietnamese aged 50 year-old or more faced a 15% probability of dying within 5 years if he lived in an extremely poor rural household compared to just a 3% to 5% chance if he lived in a rural household with a daily per capita expenditure of $6 to $10.

Mere correlation?

The above results do not constitute evidence of a relationship between adult mortality and income groups, but Banerjee and Duflo perform two additional regressions that yield insights on the direction of causality.

The impression that the correlation is not completely driven by the ‘dying are likely to be poor’ force is strengthened by the fact that when they look at older women in households where there are prime age adults, they continue to find the same pattern. In Vietnam, for example, for women above 50 who live with prime-age adults, the five-year mortality rate goes from 12% among the poor to 7.7%among those with daily per-capita household expenditures of between $6 and $10. Since older women in households with prime-age adults are very unlikely to be engaged in any market work, it is unlikely their household’s poverty is due to their poor health. This makes it less likely that the causation runs from poor health to poverty, though to the extent that poor health is inherited, it could of course be the case that unhealthy old people live with unhealthy younger adults, and this is the reason why the household is poor.

Hence, on balance, Banerjee and Duflo are, in their cautious words, “tempted to interpret the evidence accumulated in our paper as revealing, at least in part, that poverty does kill.”

References

Banerjee Abhijit V. and Esther Duflo (2007). “Aging and death under a dollar a day.” NBER Working Paper 13683.

Deaton, Angus. 2003. “Health, Income, and Inequality.” NBER Reporter: Research Summary Spring 2003.

Elwan, Ann. "Poverty and Disability: A Survey of the Literature." Background Papers prepared for the World Development Report 2000/2001 on Poverty and Development.

Lynch JW, Kaplan GA, Shema SJ. Cumulative impact of sustained economic hardship on physical, cognitive, psychological, and social functioning. New England Journal of Medicine. 1997;337:1889-1895.

Lynch JW, Kaplan GA, Cohen RD, Tuomilehto J, Salonen JT. Do cardiovascular risk factors explain the relation between socioeconomic status, risk of all-cause mortality, cardiovascular mortality and acute myocardial infarction? American Journal of Epidemiology. 1996;144:934-942.

Lynch, J.W, George A. Kaplan, Elsie R. Pamuk, Richard D. Cohen, Katherine E. Heck, Jennifer L. Balfour, and Irene H. Yen. Income Inequality and Mortality in
Metropolitan Areas of the United States. American Journal of Public Health. July 1998, Vol. 88, No. 7.

Sorlie PD, Backlund E, Keller JB. US mortality by economic, demographic, and social characteristics: the National Longitudinal Mortality Study. American Journal of Public Health. 1995;85:949-956.

Wagstaff, Adam (2002), “Poverty and Health Sector Inequalities,” Bulletin of the World Health Organization, 80 (2).

Weir, David, Robert Willis, and Purvi Sevak. 2000. The Economic Consequences of a Husband’s Death: Evidence from the HRS and AHEAD. Paper prepared for presentation at the Second Annual Joint Conference for the Retirement Research Consortium, “The Outlook for Retirement Income,” May 17-18, 2000 in Washington, DC.

Footnotes

1 Elwan (1999), for example, summarizes the literature on disability and poverty.

2 Weir et al (2000) argue that early widowhood continues to be an important determinant of lifetime poverty risk.

3 See for example Lynch et al. (1997); Lynch,et al (1996); and Sorlie, et al (1995). Wagstaff (2002) shows that infant mortality is greater among the poor than in richer households.

4 See for example Lynch et al (1998), or Deaton (2003) for a more recent take on the issue.

5 The idea is that more educated people are “better able to understand and use health information, and are better placed to benefit from the healthcare system.”

Comments

[Gil]

Does poverty increase the Death Rate? Er nope. The Death Rate has always been 100%.

[ndd]

This discussion gets to one of my peeves about general welfare theory. We ought to be able to make an assumption that people always and everywhere prefer to be alive than dead (yes, there are a few people in intractable pain, etc., for whom that probably isn't true, but as a working assumption, it seems much closer to the truth than perfect knowledge or rational behavior).
That assumption leads to the conclusion that the economic arrangement (say, socialized medicine) which produces the most people still alive at the end of period X must be a Pareto optimal scenario. Further, any proposed alternative that means more people die during the period cannot be a Pareto superior alternative. The burden would therefore seem to be any anybody proposing an improvement to a government program that results in more people being alive at the end of any given period, to show that their alternative IN FACT will save more lives (as opposed to, their RW theory shows that in theory there is a better system out in the ether somewhere). Somehow, especially in the case of private medicine, I doubt that can be proven.

[Lafayette]

Poverty CAN kill people ...

... in given circumstances.

I once lived in and around the Alps; where lives a hardy race of poor people, who lived typically long lives. Just walking around any graveyard, looking at the headstones, attests to that fact.

But, it was not poverty that killed them as much as hardiness saved them. Meaning that the thin mountain air generally meant stronger hearts and their work regime allowed overall better health. They were a fit people.

In the same country at a time when poverty was elsewhere common in the large cities, yes, people did die earlier deaths. That too, is a recorded fact (though I no longer have access to actuarial data).

However, look at today's Conditional Death Scenario for the poor. First, they don't have the sorts of incomes to allow them to eat protein foods, which they substitute with carbohydrates. This leads to obesity if over-indulged, which the cause of today's obesity pandemic in America.

Secondly, without access to affordable Health Care, they have no one warning them about the dangers of obesity. Obesity will kill one, either from pulmonary emphysema or heart disease. And, by the time a malady becomes so obvious that the patient must do SOMETHING about it, that something is often too late.

Thirdly, the poor subsist in ... er, poor living conditions. Dampness once lead to high levels of pulmonary disease such as pneumonia or tuberculosis, both deadly. They also live in worse conditions, given the generalized dilapidation of the housing that remains affordable to them, which breeds other maladies by means of either lead-paint ("saturnism", or poisoning of children) once used before the 1960s or insect/animal infections of one sort or another.

So, anyone who thinks that decent housing is just another "handout" to the poor by a profligate Welfare State ... well, we must think they have not an ounce of compassion for their fellow man.

[dale]

And then there is the work by social epidemiologists like Marmot and Wilkinson that point towards the conclusion that inequality- in and of itself, beyond the effects of poverty- leads to shorter lifespans. Our place on the relative status hierarchy within our society influences health and well begin.

[Jay]

NDD:

"That assumption leads to the conclusion..." that freedom is not desireable.

Not to mention that your naive assumption that we are better off with everyone alive completely ignores the risk of overpopulation. But you are not the first nor last human to maximize utility with a myopic view of future returns.

[JRossi]

"The numbers are shocking." Not really. Not to someone who knows about death rates or to someone who has spent time in poor countries. If you really want to be shocked--and want to realize how far we have come in the rich countries--read about preindustrial society death rates in Gregory Clark's book "A Farewell to Alms." Close to 50% before age 15 death rates in urban areas , if I recall correctly.

[Patricia Shannon]

Lafayette says...

Poverty CAN kill people ...

... in given circumstances.

I once lived in and around the Alps; where lives a hardy race of poor people, who lived typically long lives.

What about infant/child mortality? A person who survives to adulthood in that environment must be hardy to start off with.

http://www.infoplease.com/ipa/A0005140.html

Eg., In the U.S. in 1850 for white males
At birth, average age at death was 38.3
For those who lived to be 0, average age at death was 58
For those who lived to be 20, average age at death was 60.1

Note that in this table "life expectancy" at a given age is defined as the number of additional years expected to live after living to that age.

[Noni Mausa]

I would also be interested to read the differences between the causes of death in those different income brackets.

In some cases, I think it might be a race between actual disease, and suicide, either active or passive. Might that be a factor in the death rates of the older and presumably nonworking Vietnamese women discussed in "two additional regressions" above? In a household so desperately poor, would you not expect at least some of these women to regret their burden on the household?

Noni

[Patricia Shannon]

correction:

Eg., In the U.S. in 1850 for white males
At birth, average age at death was 38.3
For those who lived to be 10, average age at death was 58
For those who lived to be 20, average age at death was 60.1
For those who lived to be 60, average age at death was 75.6

[Nirvana]

Some times it is happen that poverty cause more death like African under population and under developed country and south Asian countries.