Height is often used as a proxy for health, because children who get good nutrition and health care tend to grow taller than their forebears.
Now new research shows that the average height of women in 14 African countries is shrinking. And that spells bad news for the future health of those nations.
Researchers at the Harvard School of Public Health looked at the heights of women ages 25 to 49 in 54 countries who had been measured between 1994 and 2008, and compared that to the heights of women in 1945.
They found that women in 14 African countries lost stature, while women in 21 countries stayed the same. In 19 other nations, including Bangladesh and Kazakhstan, women gained stature. The results were reported in the online journal PLosONE.
The changes in average height were almost always associated with income: Poor women lost height, while more affluent women grew taller. The women in the top 20 percent in income gained height in all countries, and were almost 2 centimeters taller on average than the poorest women in their countries. Women in Guatemala showed the biggest height difference between rich and poor, with an almost 8-centimeter gap.
Even though there's been a big drop in infant mortality in the time covered by this survey, the stagnation and decline in height "suggest little improvement, and perhaps deterioration, in early childhood living conditions," according to the study authors.
That's true not just in Africa.
Through most of American history, Americans have been the tallest people on the planet. Credit that to abundant food and fewer diseases than in the crowded cities of Europe. But Americans' height plateaued in the 1960s; the Dutch are now the tallest population on Earth. And a 2010 study by economist John Komlos found that African-American women in the United States have actually lost height, starting with those born in 1975.
Since a population's height usually predicts health, wealth and life expectancy, a loss of height is troubling, the kind of thing usually seen only in times of famine or war, Komlos says. Copyright 2011 National Public Radio. To see more, visit http://www.npr.org/.