Obesity: A Global and European Burden
Although obesity was only introduced in the 1950s into the International Classification
of Diseases (currently ICD-10 code E66, though EASO thinks that this categorization
requires revision and is committed to propose novel criteria for ICD-11), it had already
reached epidemic proportions by the end of the century, becoming one of the leading
causes of death and disability worldwide. According to the World Health Organization
(WHO) the prevalence of obesity has tripled since the 1980s in many countries of the
WHO European Region, with overweight and obesity affecting 50% of the population in
the majority of European countries [1]. In 2008, 1.5 billion adults, 20 years and
older, were overweight with an estimated 500 million adults worldwide being obese
(over 200 million men and nearly 300 million women); approximately 65% of the world's
population inhabit countries where overweight and obesity kill more people than underweight
[2,3]. The figures of affected individuals rage on unabated, and more than 40 million
children under the age of 5 years were overweight in 2010 [3]. Noteworthy, severe
obesity (i.e., a BMI > 35 kg/m2) is a rapidly growing segment of the obesity epidemic
in which the detrimental effects are particularly evident and harsh. Moreover, obesity
not only disproportionately affects the disadvantaged segments of the population,
but these groups experience the most important increases in obesity prevalence. Thus,
the WHO has declared obesity as the largest global chronic health problem in adults,
which is emerging as a more serious world health problem than malnutrition. In fact,
obesity has become a truly global problem that has led to coin the term ‘globesity’
to describe the escalating global pandemia affecting both developed and developing
countries [2]. In this sense, it has been estimated that 60% of the world's population,
i.e., 3.3 billion people, could be overweight (2.2 billion) or obese (1.1 billion)
by 2030 if recent trends continue [4]. In spite of these preoccupying facts, obesity
is frequently not even thought of as a frequent, serious, complex and chronic disease
and is often even dismissed or neglected as a clinical entity.
The Health Risks of Obesity
Regrettably, the consequences of obesity are more far-reaching than mere aesthetic
problems and heavily impact both directly and indirectly on a broad range of aspects
of health, expanding from single individuals up to whole nations. The WHO highlights
that obesity is responsible for 10-13% of deaths in different parts of the world [1].
Although a BMI above 30 kg/m2 has been shown to increase the risk of death from heart
disease, stroke, and some cancers, the questions about the strength of the relationship
between high BMI and all-cause mortality as well as the optimal BMI in relation to
mortality are still discussed [5,6]. A recent meta-analysis looking at all-cause mortality
spanning nearly 3 million people (and comprising 270,000 deaths) provided clear evidence
that, relative to normal weight, both all grades of obesity (i.e., a BMI > 30 kg/m2)
and grade 2 and 3 obesity (i.e., a BMI 35-40 kg/m2 and > 40 kg/m2, respectively) were
associated with significantly higher all-cause mortality [6]. However, grade 1 obesity
(i.e., a BMI 30-35 kg/m2) overall was not associated with higher mortality, and overweight
(i.e., a BMI 25-30 kg/m2) was reportedly associated with significantly lower all-cause
mortality. These latter findings were not in line with those of a prior systematic
analysis comprising 1.46 million white adults and over 160,000 deaths [5], including
pooled data from 19 prospective studies adjusted for age, study, physical activity,
alcohol consumption, education, and marital status, in which, overall for men and
women combined, for every 5-unit increase in BMI, a 31% increase in risk of death
was observed, with all-cause mortality being generally lowest with a BMI of 20.0-24.9
kg/m2. Among others, the controversies between both extensive studies may well be
the result of methodological challenges of applying different BMI categories for the
normal-weight comparison as well as the limitations of the BMI in reflecting real
body fat content and distribution [7]. Whatever discussions are arising from these
data, the evidence altogether emphasizes the deleterious health consequences of severe
obesity (i.e., BMI > 35 kg/m2) which is indeed associated with increased all-cause
mortality.
While a more precise BMI cut-off value or a better indicator of unhealthy body composition
is identified, it is worth considering that the Global Burden of Disease Study 2010
(GBD), a multi-investigator collaboration for global comparative descriptive epidemiology,
concluded that in the time period from 1990 to 2010 the GBD continued to shift away
from communicable to non-communicable diseases (NCDs) and from premature death to
disability-adjusted life years (DALYs) [8]. Dietary risk factors and physical inactivity
collectively accounted for 10% of global DALYs in 2010 [9]. Not surprisingly, the
comparison of risk factors during those decades showed that several dietary risks
factors had moved up the rankings with the most prominent one being diets low in fruits
[10]. Excess weight drastically augments a person's risk of developing a number of
NCDs, like cardiovascular disease, diabetes and cancer, at the same time as causing
diverse psycho-social problems and various physical disabilities. The WHO emphasizes
that 44% of the diabetes burden, 23% of the ischaemic heart disease burden and around
7-41% of certain cancer burdens are attributable to overweight and obesity [3]. In
the majority of European countries, overweight and obesity are responsible for about
80% of cases of type 2 diabetes, 35% of ischaemic heart disease and 55% of hypertensive
disease among adults [11]. Moreover, the risk of developing more than one of these
co-morbidities also increases when body weight is elevated. Noteworthy, excess body
weight also puts patients at a higher risk of hypertension, dyslipidaemia, stroke,
sleep apnoea, and other serious co-morbidities. In addition, a range of debilitating
conditions such as osteoarthritis, respiratory difficulties, gallbladder disease,
infertility, and psycho-social problems, which lead to reduced life expectancy, quality
of life and disability, are extremely costly in terms of both absence from work and
use of health resources [1,12,13]. Importantly, while until now life expectancy rates
had continuously increased in the USA despite the obesity epidemic, a recent study
shows that particularly among uneducated females life expectancy has actually decreased,
with obesity likely representing one of the underlying reasons [14].
Time for Action versus Complacency
Although overweight and obesity are considered the 5th leading risk for global deaths
according to the WHO [3], clear opportunities for diagnosis and, consequently, treatment
are being missed [15]. Since obesity truly is a ‘gateway’ to so many other disease
areas, it will block, if appropriately managed and prevented, a major supply route
to ill health [16]. Obesity should be viewed as one of the main targets for current
efforts to combat the increasing NCDs epidemic [17]. As a harbinger of a multitude
of disabling and fatal diseases, obesity represents one of the most relevant public
health challenges of the 21st century, threatening to reverse many of the health gains
achieved so far. We already lost the battle of halting the epidemic in the past century
[18]. In order to curb this situation, obesity should be a top priority, with increased
commitment for concerted, coordinated and specific actions. It is clearly imperative
that obesity is targeted as an area for immediate action and priority. A comprehensive
and pro-active strategy to deal with the challenges posed by the obesity epidemic
in a sustainable way is urgently needed. Encouraging the instauration and implementation
of programmes for early competent diagnosis, treatment and prevention is mandatory.
Obesity is a serious, chronic disease that will only worsen without thoughtful and
evidence-based interventions that address both individual citizens and the environmental
context they live in. It is clearly imperative that obesity is targeted as an area
for immediate action and priority for research, innovation and action at European
level.
Disclosure Statement
The authors declared no conflict of interest.