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revious research has suggested that
urbanization is a primary factor in the rise in obesity around the world.
However, a new large-scale study contradicts this, indicating that the increase
in obesity rates is more significant among people in rural areas.
A study looking at global weight
gain trends across the globe found that urban areas are not in the lead.
Past studies have suggested that, at a global level,
urbanization is a key contributor to the soaring rates of obesity.
Researchers have explained this
pattern by hypothesizing that people living in urban areas eat more
unhealthful, highly processed foods and live less physically active lifestyles.
However, a major new study — the
results of which appear in the journal Nature — now turns this idea on its head
by showing that obesity rates across the world have grown more rapidly in rural
areas than in urban areas.
In the study, researchers from the
Imperial College London in the United Kingdom led a global team of more than
1,000 specialists. Together, they analyzed the health data of more than 112
million adults from 200 countries and territories, covering a period of 32
years from 1985 to 2017.
The team sourced these data from
2,009 population-based studies that made their participants' height and weight
measurements available. From these two values, it is possible to calculate a
person's body mass index (BMI), which allows healthcare professionals to
determine whether or not the individual has obesity.
To make sure that their final
results were as reliable and unbiased as possible, the researchers excluded
data that participants had self-reported.
'Commonly
held perceptions overturned'
The investigators' extensive
analysis revealed that women's BMI increased by an average of 2.0 kilograms per
square meter (kg/m2)
over the study period, while men's BMI rose by 2.2 kg/m2 on average.
However, the increases in BMI were
most prominent not in urban areas but in rural ones, according to the
researchers. They note that rural areas in low- and middle-income countries
actually accounted for more than 80% of the BMI increase.
The team explains that the situation
has changed since 1985 when in most countries, people living in urban areas had
higher rates of obesity than those in rural areas.
Between 1985 and 2017, the average
BMI in rural regions worldwide rose by 2.1 kg/m2 for adults of both sexes, whereas in urban areas, the
average BMI of women and men increased by 1.3 kg/m2and 1.6 kg/m2 respectively.
"The results of this massive global study overturn
commonly held perceptions that more people living in cities is the main cause
of the global rise in obesity."
Senior author Prof. Majid Ezzati,
Imperial College London
At the same time, the researchers
note that the income of a country plays a role in the average BMI increase of
its population. In high-income countries, BMIs have grown the most in rural
areas, especially in the case of women.
The authors believe that this might
be because rural populations in high-income countries typically enjoy fewer
benefits than their urban counterparts, having lower incomes, more restricted
access to education, and less access to healthful foods due to high costs.
"Discussions around public
health tend to focus more on the negative aspects of living in cities,"
notes Prof. Ezzati. "In fact, cities provide a wealth of opportunities for
better nutrition, more physical
exercise and recreation, and overall improved health."
"These things are often harder
to find in rural areas," he emphasizes.
Rural
populations face different challenges
Rural communities in low- and
middle-income countries have grown economically compared with the 1980s. The
authors note that the benefits that this has afforded them — such as more
modern agricultural tools and access to better infrastructure and means of
transport — may actually have had a negative effect on health by decreasing
people's levels of physical activity and introducing more unhealthful foods.
"As
countries increase in wealth, the challenge for rural populations changes from
affording enough to eat to affording good-quality food," Prof. Ezzati
emphasizes.
The only countries where this
pattern did not seem to apply were those of sub-Saharan Africa, where women
from urban areas had higher BMI growth rates than women from rural regions.
This finding, the researchers say,
could be because the women living in the cities tend to do less physically
active work — desk work, for instance — and do not engage in the same
physically demanding tasks as their counterparts in rural areas.
All in all, however, the current
findings indicate that researchers and policy-makers may need to reassess their
understanding of the factors that drive unhealthful weight gain across the
world and consider new ways of tailoring approaches to health in different
urban and rural communities.
"This
means that we need to rethink how we tackle this global health problem,"
says the senior author.
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