Over the years, the diet, health and ecosystem of humans have undergone rapid changes. But have these alterations had a corresponding effect on human physical characteristics like height? According to a new study, they have. A group of researchers have found that in just over a century, the average height of men has gone up by 11 centimetres.
The study, published recently in Oxford Economic Papers, analysed data on average men’s height at around the age of 21 in 15 European countries. Researchers looked up data from the 1870s up to around 1980. They however restricted themselves to men because extensive historical data on women’s heights is hard to come by. The statistics were drawn from a variety of sources. For recent decades, the data on men’s heights was mainly taken from height-by-age surveys, while for earlier years it was based on records of heights of military conscripts and recruits.
The researchers found that the average height of a male rose from 167 cm in 1870 to 178 cm in 1980. According to them, improvement in healthcare is the single most important factor driving the increase in height. Timothy Hatton, the lead author of the study and a professor of economics at University of Essex, wrote in the journal: ‘In little more than a century average height increased by 11 cm—representing a dramatic improvement in health...The evidence suggests that the most important proximate source of increasing height was the improving disease environment as reflected by the fall in infant mortality.’ The researchers claim that the growth of an individual is significantly affected by what happens in the first two years of life. Since the rate of illnesses such as diarrhoea and respiratory diseases before a child turns two—often leading to infant mortality—is not as high as it once was, it has had a corresponding effect on a man’s adult height. Other factors, like an increasing move to smaller families, meaning fewer people to feed, higher income, more sanitary living conditions and better education on health and nutrition, also need to be taken into account.
Strangely, however, the researchers found that the average height of men accelerated in the period spanning the two World Wars and the Great Depression. This was strange because not only was this a period of strife and economic downturn, major breakthroughs in modern medicine and national health services were still to take place. In an interview with The Telegraph, Hatton explains this finding, saying, “One possible reason, alongside the crucial decline in infant mortality, for the rapid growth of average male height in this period was that there was a strong downward trend in fertility at the time, and smaller family sizes have already been linked with increasing height.”