Tag: Infant Mortality

Cross-Species Comparison of Infant Mortality In Primates

Interesting 2012 paper by Anthony Volk and Jeremy Atkinson compiled data for a cross-species comparisons of infant mortality in primates, including human beings. The paper found that the child mortality rate in Old World monkeys is equivalent to that of human beings in pre-modern cultures as well as contemporary hunter-gatherer groups.

The precise quantitative nature of the Environment of Evolutionary Adaptedness (EEA) is difficult to reconstruct. The EEA represents a multitude of different geographic and temporal environments, of which a large number often need to be surveyed in order to draw sound conclusions. We examine a large number of both hunter–gatherer (N=20) and historical (N=43) infant and child mortality rates to generate a reliable quantitative estimate of their levels in the EEA. Using data drawn from a wide range of geographic locations, cultures, and times, we estimate that approximately 27% of infants failed to survive their first year of life, while approximately 47.5% of children failed to survive to puberty across in the EEA. These rates represent a serious selective pressure faced by humanity that may be underappreciated by many evolutionary psychologists. Additionally, a cross-species comparison found that human child mortality rates are roughly equivalent to Old World monkeys, higher than orangutan or bonobo rates and potentially higher than those of chimpanzees and gorillas. These findings are briefly discussed in relation to life history theory and evolved adaptations designed to lower high childhood mortality.

When Is a Dead Baby Not a Dead Baby? (When It’s Born Outside the United States)

Save The Children has released a report on infant mortality that, among other things, claims the United States has the second highest infant mortality rate among industrialized countries. The problem with this claim, however, is that the United States and other countries can’t quite agree on what counts as a dead baby. As such, infant mortality rates aren’t directly comparable between the United States and other countries.

The problem lies in a fact that, as the Save The Children report notes, most infants who die in the industrialized world die because they are either a) born too early or b) have a very low birth weight (and, of course, the earlier the delivery, the lower the birth weight tends to be).

In the United States, an infant born prematurely and weighing less than 400 grams will receive intensive medical interventions to try to keep it alive. If, as is likely, such expensive interventions fail, the event will be recorded as a) a live birth and b) a death.

In much of the rest of the world — including the industrialized world — such extreme medical interventions would never be attempted. Moreover, this would not be recorded as a live birth or as a subsequent death.

The Save The Children report simply relies on World Health Organization statistics, and the WHO itself recommends that births of less than 1,000 grams not be registered as live births in official records. Most countries follow this definition, whereas the United States doesn’t.

How big of a difference does this make? According to the National Center for Health Statistics, in 2003 infants weighing less than 1,000 grams accounted for 48.7 percent of infant deaths in the United States.

Assuming that rate holds for the 2004 U.S. statistics the Save the Children report covers, that results in a >1,000g infant mortality rate of 3.5 per 1,000 births for the United States. That rate puts the United States barely behind countries like Japan, Finland, and Sweden which clock in at 3 deaths per 1,000 births. Not bad, especially given the largely mono-racial nature of those societies as compared to the United States.

Of course, why should we expect advocacy groups or the media to bother with such arcane statistics when U.S. has second worst newborn death rate in modern world, report says makes such a good headline?