An analysis done over 34 years from studies shows that poor nutrition has largely contributed to a difference in height and weight for school-going children.
The study showed that there was a difference of 20 cm between countries with the highest people and those with the shortest people under 19 years of age, from the countries that participated in the study.
For the Body Mass Index (BMI), the difference between countries with the highest and lowest unit was about nine to 10 kg per square meter, which is equivalent to about 25 kg.
The analysis, which looked at more than 2,000 studies and about 65 million children in 200 countries and territories between 1985 and 2019, showed that the Netherlands had the tallest boys of about 183.8 cm and that the shortest boy last year of East Timor was about 160.1 cm.
Again, the tallest girls from the Netherlands were about 170.4 cm tall, while the short girls from Guatemala were about 150.9 cm.
In general, countries in Northwest and Central Europe had the highest 19-year-olds. The countries that came to the Netherlands were Montenegro, Estonia and Bosnia and Herzegovina for boys. And for girls, Montenegro, Denmark and Iceland had the highest people. “The difference of 20 cm or higher between countries with the highest and shortest average height, represents about eight years of growth gap for girls and about six years for boys,” the researchers said.
Genetic factors
’19-year-old girls in four countries (Guatemala, Bangladesh, Nepal and Timor-Leste), for example, had the same average height as those of 11-year-old Dutch girls, and those in another 53 countries – such as Burundi, India, Indonesia, Laos, Pakistan, Peru, the Philippines and Yemen – had the same average length as those of 12-year-old Dutch girls.
“Similarly, 19-year-old boys in 11 countries in Asia, Latin America and sub-Saharan Africa had the same average height as those of 13-year-old Dutch boys,” the study added.
An improvement in height was recorded in emerging economies such as China (largest gain for boys and third largest for girls) and South Korea (third largest for boys and second largest for girls).
For BMI, countries on the Pacific island of Oceania had the highest BMI of about 28 kg per square meter. ‘BMI for late adolescence was also high for boys and girls in countries in the Middle East and North Africa such as Kuwait and Bahrain; in Caribbean islands such as the Bahamas; in Chile, the USA and New Zealand; and for girls in South Africa, “the study said.
The lowest average BMI among boys was about 21 kg per square meter and was recorded in East and Central Africa (Ethiopia and Chad), Southeast Asia (India, Bangladesh) and Southeast Asia (Timor-Leste).
The researchers acknowledge that there are various factors that may contribute to the difference in height and BMI of children and adolescents, and the genetic aspect may be one of them. However, they say that genetics contribute very little to the difference, especially for the BMI.
“Genetics play a small role in height and BMI at the population level relative to nutrition and environment is also supported by the finding that the height of migrating descendants within a few generations typically converges to the height of their new country,” the study explained.
Beginning of puberty
The researchers also highlighted other factors that contributed to the variation in height and BMI. “Exposure and intergenerational experiences during pregnancy, age of puberty that may be affected by diet, physical activity, occurrence and treatment of infections, which are themselves affected by water and sanitation, and whether episodes of infections are effectively treated in a timely manner,” the study said.
“Ultimately, all of these pathways are affected by food and nutrition,” the researchers concluded. “Future studies should also evaluate the socioeconomic and geographic patterns of height and BMI at these ages, as has been done for children younger than five years and adults.”