Men and women have grown taller over the last century, with South Korean women shooting up by more than 20cm (7.9in) on average, and Iranian men gaining 16.5 cm (6.5in). A comprehensive global study looked at the average height of 18-year old men and women in 200 countries between 1914 and 2014.
The results reveal that while Swedes were the tallest people in the world in 1914, Dutch men have risen from 12th place to claim top spot with an average height of 182.5cm (5ft 11.9 inches).
Latvian women, meanwhile, rose from 28th place in 1914 to become the tallest in the world a century later, with an average height of 169.8cm (5ft 6.9in).
With an increase in height seen across the century in every country around the world, the British have also gained a few inches. Both men and women have added around 11cm (4.3 in) to their height since 1914, with the average man now 177.5cm (5ft 9.8in) tall and the average woman boasting a height of 164.4cm (5ft 4.7in).
James Bentham, a co-author of the research from Imperial College, London, says that the global trend is likely to be down primarily to improvements in nutrition, hygiene and healthcare. “An individual’s genetics has a big influence on [their] height … but once you average over whole populations genetics plays a less key [role],” he added. “Most populations would grow to roughly similar heights if they were all in the same conditions.”
A little extra height brings a number of advantages says Elio Riboli, co-author of the paper and director of the School of Public Health at Imperial College, London. “The good news is that being taller is associated with longer life expectancy,” he said. “This is largely due to a lower risk of dying of cardiovascular disease among taller people.” But, Riboli warns, while taller people have been found, on average, to have larger salaries and higher levels of education, there are downsides, with greater height potentially associated with an increased risk of some cancers.
The research was published in the journal eLife by the NCD Risk Factor Collaboration, a network of nearly 800 health scientists worldwide. The scientists drew on almost 1500 sources, including government health studies and military data, to model changes in the height of 18-year-olds across 200 countries over 100 years from 1914.
The results show that men are taller than women around the world, while for both sexes European countries now scoop the top 10 positions for height, with Dutch men and Latvian women the tallest for their sex. That, says Bentham, could be down to the introduction of a welfare state in many European countries.
By contrast, men from Timor-Leste are the shortest, with a height of 159.8cm (5ft 3in), while the title for shortest women remains with the female population of Guatemala, who have an average height of 149.4cm (4ft 10.8in).
But while height has increased around the world since the eve of the first world war, the researchers found that the degree of change varied greatly between countries.
While South Korean women have shot up by just over 20cm (7.9 in) since 1914, men in South Africa have grown by just 1.4 cm (0.55 in) over the century. American men, meanwhile, have plateaued in height since the 1960s, resulting in a drop from third place in 1914 to 37th place in 2014. That, the authors suggest, could be down to worsening levels of nutrition and greater inequalities.
The trend in many countries of north and sub-Saharan Africa is also cause for concern says Riboli. While the research shows that height increased in countries such as Uganda and Niger during the early 20th century, the trend has reversed in recent years, with height decreasing among 18-year-olds.
“One reason for these decrease in heights in Africa is the economic situation in the 1980s,” said Alexander Moradi of the University of Sussex, who was not involved in the study. The nutritional and health crises that followed the policy of structural adjustment, he says, led to many children and teenagers failing to reach their full potential in terms of height. “I think one thing that one should keep in mind in these studies is that height is a useful indicator of how nutrition and health is developing and that these are closely related to the overall economic development [of a country], ” he added.
Bentham believes the global trend of increasing height has important ramifications. “How tall we are now is strongly influenced by the environment we grew up in. In turn, our height affects both our life expectancy and our health as adults,” he said. “If we give children the best possible start in life now, they will be healthier and more productive for decades to come.”
Tall story? Men and women have grown taller over last century, study shows
