The average Dutchman is now 183cm (6ft) tall, while the average Latvian woman reaches 170cm (5ft 7in).
The research, published in the journal eLife, has tracked growth trends in 187 countries since 1914.
It
finds Iranian men and South Korean women have had the biggest spurts,
increasing their height by an average of more than 16cm (6in) and 20cm
(8in).
In the UK, the sexes have gone up virtually in parallel by
about 11cm (4in). “Mr Average” in Britain is now 178cm (5ft 10in) tall;
Ms Average stands at 164cm (5ft 5in).
This contrasts for example
with men and women in the US, where the height of the nation’s people
started to plateau in the 1960s and 1970s. Over the century, they have
seen increases of just 6cm and 5cm (a couple of inches), respectively.
Indeed,
Americans have tumbled down the rankings. Back in 1914, they had the
third tallest men and fourth tallest women on the planet. Today they are
in 37th and 42nd place.
The height charts are now utterly
dominated by European countries, but the data would suggest that growth
trends in general in the West have largely levelled out.
The smallest men on the planet are to be found in East Timor (160cm; 5ft 3in).
The
world’s smallest women are in Guatemala, a status they also held back
in 1914. According to the survey data, a century ago the average
Guatemalan 18-year-old female was 140cm (4ft 7in). Today she has still
not quite reached 150cm (4ft 11in).
East Asia has seen some of the biggest increases.
People in Japan, China and South Korea are much taller than they were
100 years ago.
“The parts of the world where people haven’t got
particularly taller over this 100 years of analysis are in South Asia
(such as India, Pakistan and Bangladesh) and in sub-Saharan Africa. Here
the increase in height is between 1-6cm in those regions,” explained
co-author James Bentham from Imperial College London.
In fact,
in parts of sub-Saharan Africa, average heights have actually fallen
since the 1970s. Nations like Uganda and Sierra Leone have seen a few
centimetres come off the height of the average man.
Some of the
variation in height across the globe can be explained by genetics, but
the study’s authors say our DNA cannot be the dominant factor.
Lead scientist Majid Ezzati, also from Imperial, told BBC
News: “About a third of the explanation could be genes, but that doesn’t
explain the change over time. Genes don’t change that fast and they
don’t vary that much across the world. So changes over time and
variations across the world are largely environmental. That’s at the
whole population level versus for any individual whose genes clearly
matter a lot.”
Good standards of healthcare, sanitation, and
nutrition were the key drivers, he said. Also important is the mother’s
health and nutrition during pregnancy.
Other research has shown that height is correlated with both positive outcomes and a few negative ones.
Tall
people tend to have a longer life expectancy, with a reduced risk of
heart disease. On the other hand, there is some evidence that they are
at greater risk of certain cancers, such as colorectal, postmenopausal
breast and ovarian cancers.
“One hypothesis is that growth factors may promote mutated cells,” said another Imperial co-author, Elio Riboli.
The eLife paper – A Century of Trends in Adult Human Height – was put together by the NCD Risk Factor Collaboration, a group of 800 or so scientists, in association with the World Health Organization.