Dutch men and Latvian women tallest in world

Johan Van Zyl -- Mon, 08/01/2016 - 08:15

Dutch men and Latvian women tallest in world

Dutch men and Latvian women are the tallest on the planet, according to the largest ever study of height around the world. The research, led by scientists from Imperial College London and using data from most countries in the world, tracked height among young adult men and women between 1914 and 2014.

From the North-West University (NWU) Prof Salome Kruger of the Centre of Excellence for Nutrition, and Prof Alta Schutte of the Hypertension in Africa Research Team contributed to this report as part of this huge international collaborative effort.

Among the findings, published in the journal eLife, the research revealed South Korean women and Iranian men have shown the biggest increases in height over the past 100 years. Iranian men have increased by an average of 16,5 cm, and South Korean women by 20,2 cm.

The height of men and women in the UK has increased by around 11 cm over the past century. By comparison, the height of men and women in the USA has increased by 6 cm and 5 cm, while the height of Chinese men and women has increased by around 11 cm and 10 cm.

The research also revealed once-tall USA had declined from third tallest men and fourth tallest women in the world in 1914 to 37th and 42nd place respectively in 2014. Overall, the top ten tallest nations in 2014 for men and women were dominated by European countries, and featured no English-speaking nation. UK women improved from 57th to 38th place over a century, while men had improved slightly from 36th to 31st place.

The researchers also found that some countries have stopped growing over the past 30 to 40 years, despite showing initial increases in the beginning of the century of study. The USA was one of the first high-income countries to plateau, and other countries that have seen similar patterns include the UK, Finland and Japan. By contrast, Spain and Italy and many countries in Latin America and East Asia are still increasing in height.

Furthermore, some countries, particularly those in sub-Saharan Africa, North Africa and the Middle East have even seen a decline in average height over the past 30 to 40 years. In 1896, the average height of 18-year old South African men ranked 50th in the world, and although average height increased slightly, South Africa ranks 158th 100 years later, showing marginal increases in environmental factors contributing to height – especially when compared to other countries. For South African women, the picture is quite similar, namely ranking 36th in 1896, and sliding down to 125th in 1996.

How tall we grow is strongly influenced by nutrition and environmental factors, although an individual's genetic factors may also play a role. Children and adolescents who are better nourished and live in better environments tend to be taller, and height may even be influenced by a mother's health and nutrition during pregnancy. It has lifelong consequences for health and even education and earnings. Some research suggests people who are taller tend to live longer, gain a better education and even earn more.

Both Prof Kruger and Prof Schutte from the NWU agree that environmental factors, including the diet of South Africans, must become a very high priority. If a particular stage in life can be highlighted, it should be children – from pregnancy to adolescence – that require urgent attention to ensure very good nourishment with a diet containing quality protein, vegetables and fruit. This will have lifelong benefits in terms of health and contributions to society. Short adult height can also be attributed to environmental chronic exposure to pathogens due to poor hygiene and contaminated water causing repeated infections, malabsorption and inflammation. As a consequence, nutrients are lost or used in immune responses rather than for growth.

However, being tall may carry some health risks, as studies have linked height to a greater risk of certain cancers including ovarian and prostate.

Professor Majid Ezzati of the School of Public Health at Imperial who led the research said: "This study gives us a picture of the health of nations over the past century, and reveals the average height of some nations may even be shrinking while others continue to grow taller. This confirms we urgently need to address children’ and adolescents' environment and nutrition on a global scale, and ensure we're giving the world's children the best possible start in life."

He added: "Our study also shows the English-speaking world, especially the USA, is falling behind other high-income nations in Europe and Asia Pacific. Together with the poor performance of these countries in terms of obesity, this emphasises the need for more effective policies towards healthy nutrition throughout life."

The research team, which included almost 800 scientists and was in collaboration with the World Health Organization, used data from a wide range of sources, including military conscription data, health and nutrition population surveys, and epidemiological studies. They used these to generate height information for 18-year-olds in 1914 (who were born in 1896) through to 18-year-olds in 2014 (who were born in 1996).

Among the findings the team found that:

  • Dutch men are the tallest on the planet, with an average height of 182,5 cm. Latvian women are the tallest on the planet, with an average height of 170 cm.
  • The top four tallest countries for men are the Netherlands, Belgium, Estonia and Latvia.
  • The top four tallest countries for women are Latvia, the Netherlands, Estonia and the Czech Republic.
  • Men from East Timor were the smallest in the world in 2014, with an average height of 160 cm. Women from Guatemala were the smallest in 2014 with an average height of 149 cm.
  • The difference between the tallest and shortest countries in the world in 2014 was about 23 cm for men – an increase of 4 cm on the height gap in 1914. The height difference between the world's tallest and shortest countries for women has remained the same across the century, at about 20 cm.
  • The height difference between men and women has on average remained largely unchanged over 100 years – the average height gap was about 11 cm in 1914 and 12 cm in 2014.
  • The average height of young men and women has decreased by as much as 5 cm in the last 40 years in some countries in Sub-Saharan Africa such as Sierra Leone, Uganda and Rwanda.
  • Australian men in 2014 were the only non-European nationality in the top 25 tallest in the world.
  • In East Asia, South Korean and Chinese men and women are now taller than their Japanese counterparts.
  • Adult height plateaued in South Asian countries like Bangladesh and India at around 5‑10  cm shorter than in East Asian countries such as Japan and South Korea.
  • The smallest adult men in 1914 were found in Laos, where the average male height was 153 cm, a similar height to a well-nourished 12-year-old boy living today. In 1914 the smallest women were found in Guatemala, where the average female height was 140 cm, a similar height to a well-nourished 10-year-old girl.