A global study has found that poor child nutrition may have contributed to a 20cm height gap between the world's tallest and shortest nations.
The analysis, led by Imperial College London, has assessed the height and weight of 65 million school-aged children and adolescents in 193 countries across the world.
The research, published in The Lancet, found up to 20cm difference in height, an indicator of health, in 19-year-olds between the shortest and tallest nations - equating to an eight-year growth gap for girls and a six-year growth gap for boys.
It found the average height of a 19-year-old girl in countries with the shortest girls - Bangladesh and Guatemala - is the same as an 11-year-old girl in the Netherlands, the country with the tallest boys and girls.
And the average height of a 19-year-old boy in Timor-Leste and Laos – the countries with the world’s shortest boys – is the same as a 13-year-old boy in the Netherlands.
Figures showed that the UK’s global height ranking has worsened over the past 35 years, with 19-year-old boys falling from 28th (176.3cm) tallest in the world in 1985 to 39th (178.2cm) in 2019.
And the global height ranking for 19-year-old British girls fell from 42nd (162.7cm) in 1985 to 49th (163.9cm) in 2019.
The data also showed that the average Body Mass Index (BMI) – a measure of height to weight ratio – for a 19-year-old boy in the UK is 23.5kg per square metre, with a global BMI ranking of 60th.
Meanwhile, the global ranking for 19-year-old British girls is 50th, with an average BMI of 23.8kg per square metre.
Having low height or excessively low BMI can increase the risk of illness and impair cognitive development.
Conversely, high BMI in childhood and adolescence is linked with a greater risk, and earlier onset of, chronic diseases like type 2 diabetes and high blood pressure.
The team say lack of adequate and healthy nutrition and living environment in the school years could explain the height and weight differences between children.
Professor Majid Ezzati, senior author of the study from Imperial College London’s School of Public Health said: “Children in some countries grow healthily to five years, but fall behind in school years.
“This shows that there is an imbalance between investment in improving nutrition in pre-schoolers, and in school-aged children and adolescents.
“This issue is especially important during the Covid-19 pandemic when schools are closed throughout the world, and many poor families are unable to provide adequate nutrition for their children.”
The nations with the tallest 19-year-olds in 2019 were in north-west and central Europe, including:
the Netherlands (boys 183.8cm, girls 170.4cm)
Montenegro (183.3cm, 170cm)
Denmark (181.9cm, 169.5cm)
Iceland (182.1cm, 168.9cm)
The shortest 19-year-olds in the world were mostly in south and south-east Asia, Latin America and East Africa, including:
Timor-Leste (boys 160.1cm, girls 152.7cm)
Papua New Guinea (163.1cm; 156.9cm)
Guatemala (164.4cm, 150·9cm)
Bangladesh (165.1cm, 152.4cm)
The BMI of 19-year-olds was lowest in south Asian countries such as India (boys 20.1kg per square metre, girls 20.1kg per square metre) and Bangladesh (20.4kg per square metre, 20.6kg per square metre).
The countries with the largest average BMI were the US (25.4kg per square metre, 25.4kg per square metre), New Zealand (25kg per square metre, 24.7kg per square metre) and Pacific islands (nearly 29kg per square metre for both sexes).