Trending Science: Research finds men and women have grown taller over the last century
The study, published in the journal ‘eLife’, highlights the impressive growth spurts experienced by people across the world between 1914 and 2014, with South Korean women shooting up by more than 20cm on average and Iranian men gaining 16.5cm. Whilst Swedes were the tallest people in the world on the eve of the First World War, they have now been usurped by Dutch men who have risen from 12th place to claim the top spot and now have an average height of 182.5cm. Latvians now boast the tallest women in the world, rising from 28th place in 1914 to first place in 2014, also knocking Sweden off the top spot, and with an average height of 169.8cm. Belgian men and Dutch women narrowly take the second place positions. East Asia has also seen some of the most impressive height gains, with people in Japan, China and South Korea being much taller now than they were in 1914. From tallest to shortest However, the ten tallest nations worldwide are all found in Europe, including Estonia, Denmark, Serbia and the Czech Republic. The United States had the third-tallest men and fourth-tallest women in the world back in 1914 but has now respectively slipped to 37th and 42nd place. In the UK, British men are the 31st tallest worldwide, with British women being in 38th place. Regardless of the impressive inches gained over the past century, the data however points to slowing growth trends in the Western world. For example, the researchers saw that Americans’ average height started to plateau in the 1960s and 1970s. ‘Our study shows the English-speaking world, especially the US, is falling behind other high-income nations in Europe and Asia Pacific,’ commented Majid Ezzati, a global health researcher at Imperial College, London. ‘Together with the poor performance of these countries in terms of obesity, this emphasises the need for more effective policies towards health nutrition throughout life.’ A little extra height brings a number of health advantages, according to the research team. Being taller is associated with longer life expectancy, largely due to the decreased risk for taller people of developing cardiovascular disease. From a social perspective, taller people have also been found to have larger salaries and higher levels of education. However, there are some downsides to being taller, including an increased risk of some cancers. At the other end of the scale, the smallest men are to be found in one of the world’s youngest nations, Timor-Leste, at 160cm, whilst Guatemala hosts the smallest women in the world. Interestingly, Guatemala also held this status back in 1914. According to the study’s data, the average 18 year-old woman in 1914 Guatemala was 140cm. In 2014, she had still not quite reached 150cm. Worrying trends The regions of the world which recorded the lowest average height gain were South Asia and sub-Saharan Africa. ‘Here, the increase in height is between 1-6cm in those regions,’ explained co-author James Bentham. Worryingly, the data indicates that in some sub-Saharan countries, average heights have actually fallen since the 1970s following a general increase in the earlier half of the twentieth century. Countries such as Uganda, Rwanda, Niger and Sierra Leone have actually seen a few centimetres come off the height of the average man. So what could be the explanation behind the discrepancy amongst the various regions of the world? ‘About a third of the explanation could be genes, but that doesn't explain the change over time,’ stated Ezzati. ‘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.’ One explanation as to why Europe has done so well is because of the introduction of comprehensive welfare states in the twentieth century. In contrast, one can look to the economic readjustments of the 1980s as a possible explanation for the decrease in height in sub-Saharan Africa, due to subsequent health and nutritional crises that did not allow many children and young adults to reach their full potential in terms of height. ‘How tall we are now is strongly influenced by the environment we grew up in,’ commented Bentham, who believes the global trend of increasing height has important consequences. ‘In turn, our height affects both our life expectancy and our health as adults. If we give children the best possible start in life now, they will be healthier and more productive for decades to come.’
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