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A reduction in health benefits for children and teens living in the cities

CitiesResearch conducted by a global coalition consisting of more than 1500 researchers and physicians has found that the healthy growth and development of children and adolescents’ that are living in cities has reduced across many parts of the world.

This research included researchers from the South African Medical Research Council’s (SAMRC) Non-Communicable Disease Research Unit, it was led by Imperial College London and was published in Nature. The study analysed trends in child and adolescent height and body mass index (BMI) and found that there are far less health advantages to pursuing life in cities.

The analysis gathered height and weight data from 71 million children and adolescents (aged 5 to 19 years) across urban and rural areas of 200 countries from 1990 to 2020. The data collected in this period of time (1990-2020) showed that school-aged children and adolescents living in cities fared better in height than that of their rural counterparts. However, this has changed, in the 21st century, recent research is discovering that there is no longer a height advantage for city living, this in comparison to living in a rural area. The experience in South Africa is one such example of the overall stagnating or reversing of height gains seen in sub-Saharan Africa. For South African boys, mean height stagnated in urban and rural areas over the last two decades, keeping the urban height advantage around 1.5cm by 2020. BMI increased for both South African boys and girls, but similar to their African peers, this increase happened faster for rural children and adolescents, and the urban-rural BMI difference was essentially closed by 2020.

More on the study:

The study also assessed children’s BMI - as a reflection of the quality of nutrition and healthiness of the environment during childhood and adolescence growth. These are important indicators of health and developmental outcomes throughout life providing insight on whether they have a healthy weight for their height. Researchers found that on average children living in cities had a slightly higher BMI than children in rural areas in 1990. By 2020, BMI averages rose for most countries, while faster for urban children, except sub-Saharan Africa and south Asia, where BMI rose faster in rural areas.

Nevertheless, over the 30-year period, the gap between urban and rural BMI remained small—less than 1.1kg/m² globally (less than 2kg in weight for a child who is 130cm tall or less than 3kg in weight for an adolescent who is 160cm tall).

Dr Anu Mishra, lead author of the study, from Imperial College London’s School of Public Health, said “The results of this large global study challenge the commonly held perceptions about the negative aspects of living in cities around nutrition and health.

“In fact, cities continue to provide considerable health benefits for children and adolescents. Fortunately, in most regions rural areas are catching up to cities thanks to modern sanitation and improvements in nutrition and healthcare.”

While height and BMI has increased around the world since 1990, the researchers found that the degree of change between urban and rural areas varied greatly among different middle and low-income countries, while small urban-rural differences remained stable across high-income countries.

The trend in sub-Saharan Africa is a cause for concern:

Boys living in rural areas have levelled in height or even become shorter over the three decades, this in part because of the nutritional and health crises that followed the policy of structural adjustment in the 1980s.

Professor Andre Pascal Kengne, co-author for the study, from the SAMRC, said: “Rural sub-Saharan Africa is now the global epicentre of poor growth and development for children and adolescents. As the cost of food skyrockets and countries finances get worse due to the COVID-19 pandemic and the war in Ukraine, the rural poor in Africa are at risk of falling further behind.”

Particularly large height gaps between urban and rural boys in 2020 were seen in Rwanda (around 4cm) and in the Democratic Republic of Congo, Ethiopia, and Mozambique—all by 2-3.5cm.

Over time, boys and girls in sub-Saharan Africa also gained weight more rapidly in rural areas than cities, which meant that in some countries they went from being underweight to gaining too much weight for healthy growth.

Professor Majid Ezzati, senior author for the study, from Imperial College London’s School of Public Health added: “The issue is not so much whether children live in cities or urban areas, but where the poor live, and whether governments are tackling growing inequalities with initiatives like supplementary incomes and free school meal programmes.”

He continued by stating, “This is a serious problem at every level, from individual to regional. Faltering growth in school-aged children and adolescents is strongly linked to poor health through life, lost educational attainment and the immense cost of unrealised human potential.”

“Our findings should motivate policies that counter poverty and make nutritious foods affordable to make sure that children and adolescents grow and develop into adults who have healthy and productive lives.”


The paper is titled: ‘Diminishing benefits of urban living for children and adolescents’ health’ by Majid Ezzati et al. is published in the journal Nature.

The full paper will be available via this link when the embargo lifts:

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