Americans appear to have stopped growing. Europeans, on the other hand, are continuing to grow taller. That's an interesting phenomenon, but probably little more than that. In a journalistic version of the children's game telephone, however, an article in the latest New Yorker on the subject was summarized by <?xml:namespace prefix = st1 ns = "urn:schemas-microsoft-com:office:smarttags" />Britain's Observer newspaper and in the process took the opportunity to sneer at America. <?xml:namespace prefix = u1 /><?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />
Robin McKie, the Observer's science editor, wrote baldly, "America has eight million people with no job, 40 million individuals with no health insurance, 35 million living below the poverty line, and a population that exists mainly on junk food." These were, his audience was to understand, unquestionably the reason for the differential.
Yet the true story is much more complex. The original article goes into great depth about the work of John Komlos, a Professor at the University of Munich. His paper, on which the article is based, raises many questions, and points the reader in the direction of McKie's sneer, but with little evidence to back it up. It is Komlos' theory that, because height and nutrition seem closely correlated through history, the stalling of America's collective height must reveal health problems. Yet it may be that Komlos' desire to find this connection is blinding him to other possibilities.
First, there has to be a question on the reliability of the data. Komlos relies on US height data from the Center for Disease Control's 1988-1994 NHANES III study, which deliberately oversampled populations at risk from common disease—the elderly, minorities and other populations that one might suspect would suffer from poor nutrition. It is unclear to what extent the NHANES data have been corrected to account for this problem. Mexican Americans appear to be 3" shorter on average than non-Hispanic whites, for instance, which drags down the average height somewhat.
Indeed, the data Komlos uses are susceptible to the immediate charge that they ignore the effects of immigration. While the NHANES sample surveyed only native-born Americans, nevertheless a large number of the participants were the children of immigrants. It takes several generations for immigrants to catch up in terms of height with the surrounding population, so immigration may well be dragging down America's average height a little. Yet the effect is probably small.
There is also a question as to the reliability of historical data. Some of it comes from descriptions of runaway slaves and servants in the colonial era, for instance. It is well-known that reports of height are generally at variance with actual heights, normally biased towards taller estimates, so data based on those reports may not be as reliable as we would wish. And more reliable data—such as the height measurements of Union conscripts during the Civil War—do not provide as representative a sample as the NHANES data. For years, the CDC growth charts were based on a sample of "not much more than 10,000 infants and children living in Ohio between 1929 and 1975." So there is a degree of comparing apples and oranges in the research, but again, the problem is unlikely to affect Komlos' main finding—that Americans have stopped growing while Europeans have continued to do so.
So what is happening? Is McKie's sneer that inequality and poor diet are the causes a valid one? Not necessarily. The main reason to be skeptical is that Komlos provides little evidence to support that idea beyond the historical links between poverty, nutrition and height. Indeed, he supplies some evidence the other way.
For instance, if the theory that social inequality causes the stagnation holds any water, then there should be some Americans growing and others probably shrinking. The bell curve of heights should be quite wide. But it isn't. Only 12 percent of American men are over 6' tall. Yet a quarter of American households earn a comfortable $75,000 or more annually (14 percent earn over $100,000). As the New Yorker says, if the inequality theory is correct, "Somewhere in the United States, [Komlos] thinks, there must be a group that's both so privileged and so socially insulated that it's growing taller. He has yet to find one."
Meanwhile, one European country provides significant evidence that neither unemployment nor nutrition is the issue. Germany has a much higher unemployment rate than the USA, with 4.5 million from a population of 80 million out of a job. And the Germans are every bit as obese as Americans. Komlos' own data show that more German males and almost as many German females are obese as their American equivalents. Yet young Germans are almost an inch taller than young Americans.
Much play is made by Komlos of life expectancy. "Ask yourself this," Komlos told The New Yorker, "What is the difference between Western Europe and the U.S. that would work in this direction? It's not income, since Americans, at least on paper, have been wealthier for more than a century. So what is it?"
Life expectancy, of course, depends on many things and there are several potential reasons for the discrepancy. America, for example, has much higher homicide and accidental death rates than European countries. The main victims of these premature deaths are young men, which depresses the life expectancy of Americans. Similarly, America has quite a high infant mortality rate—depressing life expectancy. But as the physician Sydney Smith points out, that may be an artifact of advanced medical care.
Perhaps we should not tie too much to the historic link between health and height. Surveys of ancient skeletons have found that the average German barbarian was much taller than the average Roman legionary, for instance. It may be that the heterogeneous American people have reached an appropriate height for their civilization. Europeans may still be reaching theirs.
In the end, does it really matter much? If height isn't really a useful anthropomorphic indicator of human happiness any more then it doesn't. Measures of "life satisfaction" generally show Americans and Western Europeans about level. America doesn't need to be insecure about its height.