European men have grown four inches taller than their fathers just a century ago, sprouting to new heights as infant mortality plummeted amid improved prevention of infectious diseases.

The average height for European men jumped by 11 centimeters from the mid-nineteenth century to 1980, researchers from the United Kingdom say. Moreover, this increase in height — unprecedented in human history — continued during the interim between the World Wars and the Great Depression, a time of economic hardship greatly affecting nutrition.

Timothy J. Hatton, an economics professor at the University of Essex and at Australian National University in Canberra, analyzed group data for men born from the 1870s to 1980 across 15 European countries. "Increases in human stature are a key indicator of improvements in the average health of populations,” he said. “The evidence suggests that the improving disease environment, as reflected in the fall in infant mortality, is the single most important factor driving the increase in height.”

The link between infant mortality and height has already been established by previous research, Hatton added.

Following the Great Potato Famine that hit Ireland and other parts of Europe in the 19th century, infant mortality remained high from not only nutrition but also infectious disease. On average, 178 infants per 1,000 died in Europe between 1871 and 1875, but by 1911 to 1915, the rate had fallen to 120 per 1,000. As the trend continued, 41 of every 1,000 infants died in the first half of the 1950s before hitting a low point of 14 per 1,000 in last half of the 1970s.

The rate of progress experienced a “distinct quickening,” as researchers put it, during the years following World War II that led to the Great Depression. Throughout northern and central European countries, including Britain and Ireland, the Netherlands, Austria, Belgium, and Germany, men grew noticeably taller.

The phenomenon intrigued scientists given that developments in modern medicine and the national delivery of health care services had yet to come. Rather, European men benefited from larger per capita incomes and improvements to sanitation, housing, and education. Smaller family sizes, too, have been linked to greater average heights.

Yet, Hatton acknowledges that improvements in nutrition, hygiene, and medicine remain hard to capture at the aggregate level, reaching back across time and through countries with markedly different systems. Much of the reason for this growth, he says, remains a mystery.

Source: Hatton TJ. How Have Europeans Grown So Tall? Oxford Economic Papers. 2013.