Obesity and Diabetes in the Developing World- A Growing challenge
Parvez Hossain, M.D., Bisher Kawar, M.D., and Meguid El Nahas, M.D., Ph.D.
Globally, the prevalence of
chronic, noncommunicable
diseases is increasing at an alarming
rate. About 18 million people
die every year from cardiovascular
disease, for which diabetes and
hypertension are major predisposing
factors. Propelling the upsurge
in cases of diabetes and hypertension
is the growing prevalence of
overweight and obesity — which
have, during the past decade,
joined underweight, malnutrition,
and infectious diseases as major
health problems threatening the
developing world.1 Today, more
than 1.1 billion adults worldwide
are overweight, and 312 million of
them are obese. In addition, at
least 155 million children worldwide
are overweight or obese, according
to the International Obesity
Task Force. This task force
and the World Health Organization
(WHO) have revised the definition
of obesity to adjust for ethnic
differences, and this broader
definition may reflect an even
higher prevalence — with 1.7 billion
people classified as overweight
worldwide.1
In the past 20 years, the rates
of obesity have tripled in developing
countries that have been
adopting a Western lifestyle involving
decreased physical activity
and overconsumption of cheap,
energy-dense food. Such lifestyle
changes are also affecting children
in these countries; the prevalence
of overweight among them ranges
from 10 to 25%, and the prevalence
of obesity ranges from 2 to
10%. The Middle East, Pacific Islands,
Southeast Asia, and China
face the greatest threat. The relationship
between obesity and poverty
is complex: being poor in one
of the world’s poorest countries
(i.e., in countries with a per capita
gross national product [GNP]
of less than $800 per year) is associated
with underweight and
malnutrition, whereas being poor
in a middle-income country (with
a per capita GNP of about $3,000
per year) is associated with an
increased risk of obesity. Some
developing countries face the paradox
of families in which the
children are underweight and the
adults are overweight. This combination
has been attributed by
some people to intrauterine growth
retardation and resulting low birth
weight, which apparently confer
a predisposition to obesity later
in life through the acquisition of
a “thrifty” phenotype that, when
accompanied by rapid childhood
weight gain, is conducive to the
development of insulin resistance
and the metabolic syndrome.
The human and financial
costs of obesity are also mounting:
a higher body-mass index
(the weight in kilograms divided
by the square of height in meters)
has been shown to account for up
to 16% of the global burden of
disease, expressed as a percentage
of disability-adjusted life-years.
In the developed world, 2 to 7%
of total health care costs are attributable
to obesity. In the United
States alone, the combined direct
and indirect costs of obesity
were estimated to be $123 billion
in 2001. In 2004 in the Pacific
Islands, the economic consequences
of noncommunicable
diseases, mainly obesity and diabetes,
amounted to $1.95 million
— almost 60% of the health care
budget of Tonga.2
The growing prevalence of type
2 diabetes, cardiovascular disease,
and some cancers is tied to excess
weight. The burden of these
diseases is particularly high in
the middle-income countries of
Eastern Europe, Latin America,
and Asia, where obesity is the
fifth-most-common cause of the
disease burden — ranking just
below underweight. The high risk
of both diabetes and cardiovascular
disease associated with obesity
in Asians may be due to a predisposition
to abdominal obesity,
which can lead to the metabolic
syndrome and impaired glucose
tolerance.
The increase in the prevalence
of type 2 diabetes is closely linked
to the upsurge in obesity. About
90% of type 2 diabetes is attributable
to excess weight. Furthermore,
approximately 197 million
people worldwide have impaired
glucose tolerance, most commonly
because of obesity and the associated
metabolic syndrome.
This number is expected to increase
to 420 million by 2025.
Population-based surveys of 75
communities in 32 countries show
that diabetes is rare in communities
in developing countries where
a traditional lifestyle has been preserved.
By contrast, some Arab,
migrant Asian Indian, Chinese,
and U.S. Hispanic communitieschronic, noncommunicable
diseases is increasing at an alarming
rate. About 18 million people
die every year from cardiovascular
disease, for which diabetes and
hypertension are major predisposing
factors. Propelling the upsurge
in cases of diabetes and hypertension
is the growing prevalence of
overweight and obesity — which
have, during the past decade,
joined underweight, malnutrition,
and infectious diseases as major
health problems threatening the
developing world.1 Today, more
than 1.1 billion adults worldwide
are overweight, and 312 million of
them are obese. In addition, at
least 155 million children worldwide
are overweight or obese, according
to the International Obesity
Task Force. This task force
and the World Health Organization
(WHO) have revised the definition
of obesity to adjust for ethnic
differences, and this broader
definition may reflect an even
higher prevalence — with 1.7 billion
people classified as overweight
worldwide.1
In the past 20 years, the rates
of obesity have tripled in developing
countries that have been
adopting a Western lifestyle involving
decreased physical activity
and overconsumption of cheap,
energy-dense food. Such lifestyle
changes are also affecting children
in these countries; the prevalence
of overweight among them ranges
from 10 to 25%, and the prevalence
of obesity ranges from 2 to
10%. The Middle East, Pacific Islands,
Southeast Asia, and China
face the greatest threat. The relationship
between obesity and poverty
is complex: being poor in one
of the world’s poorest countries
(i.e., in countries with a per capita
gross national product [GNP]
of less than $800 per year) is associated
with underweight and
malnutrition, whereas being poor
in a middle-income country (with
a per capita GNP of about $3,000
per year) is associated with an
increased risk of obesity. Some
developing countries face the paradox
of families in which the
children are underweight and the
adults are overweight. This combination
has been attributed by
some people to intrauterine growth
retardation and resulting low birth
weight, which apparently confer
a predisposition to obesity later
in life through the acquisition of
a “thrifty” phenotype that, when
accompanied by rapid childhood
weight gain, is conducive to the
development of insulin resistance
and the metabolic syndrome.
The human and financial
costs of obesity are also mounting:
a higher body-mass index
(the weight in kilograms divided
by the square of height in meters)
has been shown to account for up
to 16% of the global burden of
disease, expressed as a percentage
of disability-adjusted life-years.
In the developed world, 2 to 7%
of total health care costs are attributable
to obesity. In the United
States alone, the combined direct
and indirect costs of obesity
were estimated to be $123 billion
in 2001. In 2004 in the Pacific
Islands, the economic consequences
of noncommunicable
diseases, mainly obesity and diabetes,
amounted to $1.95 million
— almost 60% of the health care
budget of Tonga.2
The growing prevalence of type
2 diabetes, cardiovascular disease,
and some cancers is tied to excess
weight. The burden of these
diseases is particularly high in
the middle-income countries of
Eastern Europe, Latin America,
and Asia, where obesity is the
fifth-most-common cause of the
disease burden — ranking just
below underweight. The high risk
of both diabetes and cardiovascular
disease associated with obesity
in Asians may be due to a predisposition
to abdominal obesity,
which can lead to the metabolic
syndrome and impaired glucose
tolerance.
The increase in the prevalence
of type 2 diabetes is closely linked
to the upsurge in obesity. About
90% of type 2 diabetes is attributable
to excess weight. Furthermore,
approximately 197 million
people worldwide have impaired
glucose tolerance, most commonly
because of obesity and the associated
metabolic syndrome.
This number is expected to increase
to 420 million by 2025.
Population-based surveys of 75
communities in 32 countries show
that diabetes is rare in communities
in developing countries where
a traditional lifestyle has been preserved.
By contrast, some Arab,
migrant Asian Indian, Chinese,
that have undergone westernization
and urbanization are at higher
risk; in these populations, the
prevalence of diabetes ranges from
14 to 20%. In addition, most of
the population growth in the developing
world is taking place in
urban areas.
Consequently, diabetes is rapidly
emerging as a global health
care problem that threatens to
reach pandemic levels by 2030;
the number of people with diabetes
worldwide is projected to
increase from 171 million in 2000
to 366 million by 2030.3
This increase will be most noticeable
in developing countries,
where the number of people
with diabetes is expected to increase
from 84 million to 228
million.1 According to the WHO,
Southeast Asia and the Western
Pacific region are at the forefront
of the current diabetes epidemic,
with India and China facing
the greatest challenges. In
these countries, the incidence and
prevalence of type 2 diabetes
among children are also increasing
at an alarming rate, with
potentially devastating consequences.
The serious cardiovascular complications
of obesity and diabetes
could overwhelm developing countries
that are already straining
under the burden of communicable
diseases. The risk of cardiovascular
disease is considerably
greater among obese people, and
this group has an incidence of
hypertension that is five times the
incidence among people of normal
weight. Hence, overweight and
obesity are contributing to a global
increase in hypertension: 1 billion
people had hypertension in
2000, and 1.56 billion people are
expected to have this condition
by 2025.4 This increase will have
a disproportionate effect on developing
countries, where the prevalence
of hypertension is already
higher than that in developed
countries and where cardiovascular
disease tends to develop earlier
in affected persons. The effect
of diabetes on complications of
cardiovascular disease is also
more severe among members of
most ethnic minority groups in
Western countries as well as
among the populations of developing
countries, where an increased
waist-to-hip ratio is a
strong predictor of ischemic heart
disease and stroke. The estimated
risk of cardiovascular disease
is higher among South Asians
than among white Westerners or
persons of African origin; this
difference is attributable to earlier
onset and later detection of
diabetes and to higher blood
pressure.
In addition, in 2000, in developing
countries, 2.41 million premature
deaths, primarily from
cardiovascular causes, were attributed
to smoking. This emerging
epidemic of tobacco-related illnesses
is exacerbating mortality
related to obesity, diabetes, and
hypertension.
Obesity, diabetes, and hypertension
also affect the kidneys.
Diabetic nephropathy develops in
about one third of patients with
diabetes, and its incidence is
sharply increasing in the developing
world, with the Asia–Pacific
region being the most severely
affected. According to a survey
published in 2003,5 diabetic nephropathy
was the most common
cause of end-stage renal disease
in 9 of 10 Asian countries, with
an incidence that had increased
from 1.2% of the overall population
with end-stage renal disease
in 1998 to 14.1% in 2000. In
China, the proportion of cases
of end-stage renal disease that
were caused by diabetic nephropathy
increased from 17% in the
1990s to 30% in 2000. In India,
diabetic nephropathy is expected
to develop in 6.6 million of the
30 million patients with diabetes.
These statistics raise the daunting
prospect of an epidemic of
diabetic nephropathy in a developing
world unable to cope with
its repercussions — a world where
end-stage renal disease is a death
sentence.
Furthermore, renal involvement
has a major “multiplier” effect on
the rates of diabetes-related complications
of cardiovascular disease
and related deaths. The WHO
Multinational Study of Vascular
Disease in Diabetes showed that
proteinuria was associated with
an increased risk of death from
chronic kidney disease or cardiovascular
disease, as well as of
death from any cause.
Changes in lifestyle that lead
to weight loss reduce the incidence
of diabetes and hypertension.
But preventing obesity, diabetes,
and hypertension will
require fundamental social and
political changes. Public health
initiatives will be required to
make affordable, healthful foods
available, and initiatives in education
and community planning
will be needed to encourage and
facilitate exercise. In 2003, the
World Health Assembly adopted
the Global Strategy on Diet, Physical
Activity, and Health, which
targets lifestyle modifications that
can combat the increase in noncommunicable
diseases. The WHO
issued objectives for developing
countries regarding school meals
and healthy living. Some countries,
including Brazil, India, and
China, have initiated monitoring
programs related to obesity and
nutrition. Since these programs
are still in their infancy, few
data are available on the cost of
their implementation, and many
such initiatives will encounter
fierce opposition from food manufacturers
and rights-oriented consumer
groups who resent their
effects on civil liberties. The challenge
will be to overcome these
obstacles and implement acceptable
strategies to curb the rising
tides of obesity, diabetes, and hypertension.
Dr. Hossain and Dr. Kawar are research fellows
and Dr. El Nahas is a professor of nephrology
and head of the academic nephrology
unit at the Sheffield Kidney Institute,
University of Sheffield, Sheffield, United
Kingdom.
Haslam DW, James WP. Obesity. Lancet
2005;366:1197-209.
The world health report 2006: working
together for health. Geneva: World Health
Organization, 2006.
Wild S, Roglic G, Green A, Sicree R, King
H. Global prevalence of diabetes: estimates
for the year 2000 and projections for 2030.
Diabetes Care 2004;27:1047-53.
Kearney PM, Whelton M, Reynolds K,
Muntner P, Whelton PK, He J. Global burden
of hypertension: analysis of worldwide data.
Lancet 2005;365:217-23.
Lee G. End-stage renal disease in the
Asian-Pacific region. Semin Nephrol 2003;
23(1):107-14.
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