A new global analysis led by Imperial College London, in which the Instituto de Saúde Pública da Universidade do Porto (ISPUP) participated, found a 20 cm height difference between young people in countries with the highest and lowest population. One possible explanation for these differences may be the practice of inadequate nutrition.
The study, published in The Lancet, used data on the weight and height of 65 million children aged five to 19 years old in 193 countries, evaluated between 1985 and 2019. For this analysis, ISPUP contributed with information from the EPIPorto and EPITeen population cohorts.
In this study, height increase was considered to be a positive indicator, that is, an indicator of improved health and food quality, while the increase in body mass index (BMI) was considered to be a negative indicator.
Height differences and their evolution
The researchers compared the height of 19-year-olds, and found a difference of 20 cm between young people in countries with the tallest population (Northwest and Central Europe) and the shortest (South and Southeast Asia, Latin America and East Africa). For instance, the study revealed that the average 19-year-old girl in Bangladesh and Guatemala is the same height as an average 11-year-old girl in the Netherlands.
In the 35 years analyzed, there was an approximation of values in height between regions, with the greatest increase in the average height of individuals occurring in countries such as China, South Korea and in some parts of Southeast Asia.
Differences observed in body mass index
Regarding BMI, 19-year-olds with highest BMI lived in the Pacific Islands, Middle East, United States of America and New Zealand. Those with a lowest BMI, on the other hand, lived in countries in South Asia such as India and Bangladesh.
In man countries, especially in Latin America, the Middle East and North Africa, five year olds were found to have a height and weight in the healthy range, but after this, they didn’t grow much and, proportionally, they increased a lot of weight.
The main explanation may lie in the absence of adequate and healthy nutrition, and in the environment in which these children live, during their school years, since weight gain and height are closely related to the quality of food.
For Andrea Rodriguez Martinez, from Imperial’s School of Public Health, “our findings should motivate policies that increase the availability and reduce the cost of nutritious foods, as this will help children grow taller without gaining excessive weight for their height”.
Joana Araújo, an ISPUP researcher involved in the study, points out that “although these data did not focus specifically on the Portuguese reality, the article shows the importance of context throughout development, reinforcing that an environment that promotes healthy choices, during childhood and adolescence, can enhance the gains achieved during the first years of life, or, on the contrary, contribute to children not being able to reach their maximum development potential”.
ISPUP´s participation
Five ISPUP researchers participated in this investigation by The Lancet, using data from the EPIPorto and EPITeen population cohorts. The EPIPorto cohort has been studying, since 1998, the health determinants of the adult population living in the city of Porto. EPITeen, on the other hand, has been investigating, since 2003, how habits and behaviors acquired in adolescence will be reflected in adult health.
The article entitled Height and body-mass index trajectories of school-aged children and adolescents from 1985 to 2019 in 200 countries and territories: a pooled analysis of 2181 population-based studies with 65 million participants is available online. The international network NCD Risk Factor Collaboration (NCD-RisC), which involves scientists from around the world, participates in the research. The following ISPUP researchers are part of it: Ana Azevedo, Ana Henriques, Elisabete Ramos, Joana Araújo, and Nuno Lunet.
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