There were reports in the press yesterday of research which shows, based on statistics from 15 European countries, that the average height of men has increased by 4.3 inches between 1870 and 1980. One such report can be read at How men have gained 4 inches in height in just 100 years ... and corroborated by evidence from Australia as in Today's men are reaching new heights | thetelegraph.com.au.
I recall reading some years ago a newspaper article setting out how similar research showed that at the time of the American Revolution North American men were on average taller than Britons were, by the end of the twentieth century men in the US and the UK were of similar height. The same article also argued that in France at the time of the revolution there class differences were marked out by height - better nourished aristocrats were, not surprisingly, taller on average than the peasants - if that is not too simplistic a phrasing (it probably is, but hopefully you get my point).
Looking on the internet I saw this story Height of Pakistanis has fallen 4 inches over 50 years, say ... which suggests that such trends are not just in one direction.
Such historical resesarch is interesting, and insightful, but runs the risk of so many statistical studies in that it is quoted without reference to other factors, such as the genetic inheritance of individuals, and also the different national patterns - the Dutch are famously taller than other west Europeans.
Thus in Britain it has been suggested for the period of the Industrial Revolution average height decreased because of cramped, or at least different, living conditions combined with poor diet and poor public health. On the other hand there is evidence that many early Industrial workers comsidered themselves better off than they had been as agricultural or home workers. There are many factors to be allowed for.
We know that people in the past were tall, and not just figures from the elite, such as the 6'4" King Edward IV - think of the Potsdam Grenadiers of King Frederick William I, all well over six foot high - and today we often see a reduction in height requirements for the military and police as against what was expected in the nineteenth century. I have also seen statistics based on a medieval cemetary in, if i recall the facts correctly, Gloucester, suggesting at most an average two centimetres difference in height between fourteenth century and twentieth century males.
In other words we should be carefull in using and interpreting these studies and look closely at all the historic evidence.