In today’s Academic Minute, Dr. Timothy Hatton of the University of Essex discusses the factors behind the increase in average height over the past century.
Tim Hatton is a professor of economics at the University of Essex where his research is focused on economic history and applied economics. He has published extensively on the economic history of labor markets, including the issues of unemployment, poverty and the causes and effects of international migration. He earned his Ph.D. at the University of Warwick.
Dr. Timothy Hatton– History and Average Height
We all know that children grow up to be taller than their parents. In a historical study of the heights of men in fifteen European countries I found that those born in the 1970s were 11 centimetres (a little over four inches) taller than those born a century earlier. In northern Europe the most dramatic increases were in the first half of the twentieth century, while in the south, the spurt came somewhat later. Of course, the heights of individuals vary widely because of genetic variation, but by examining average heights we can learn something about the evolution of living conditions during childhood.
My analysis of the data shows that the long-term growth of income, and better nutrition, contributed to the increase in height. But more important still was the reduction in gastrointestinal and respiratory infections, which are known to inhibit growth during childhood. A sensitive indicator of the disease environment is the rate of infant mortality (that is the death rate of those aged less than one). This fell very steeply and it is strongly associated with the timing of increases in height.
So what accounts for this improvement? Public investment in water supply and sewage disposal was important in producing a cleaner environment. So was improvement in housing, as the slums were cleared and overcrowding was reduced. But access to better medical treatments expanded only modestly until after the Second World War. Nevertheless, basic knowledge about nutrition and hygiene spread more and more widely. Improvements in the education of parents (particularly mothers) combined with smaller families meant significant improvements in the nurturing of children. These influences probably contributed more to increases in height and health than was previously believed.