CHAPTER ONE
INTRODUCTION
1.1 Background to the study
The English word
“obesity” derives, from the Latin word obesus
meaning ‘fat’ or plump. The first English use of the word was made in 1651 in
Noah Bigg’s medical book
‘metaeotechnia medicinae praxeos’ (Mckeigne, 1996). Clinical evidence of obesity can be dated as
far back as Greece Roman times but little scientific progress was made towards
understanding the condition until the 20th century (James, 2005).
Also, the discovery that fat is stored in ‘cells’ the basic unit of biology,
led to the idea that obesity could be caused by the presence of too many fat
cells (hyperplasia)
(WHO, 1990).
Obesity in children is a complex disorder. Childhood obesity predisposes them to insulin resistance and type 2 diabetes, hypertension, hyperlipidemia, liver and renal disease, and reproductive dysfunction. This condition also increases the risk of adult-onset obesity and cardiovascular disease.The body mass index (BMI) has not been consistently used or validated in children younger than 2 years, because weight varies in a continuous rather than a stepwise fashion, the use of these arbitrary criteria is problematic and may be misleading. Nevertheless, children and adolescents defined as overweight or obese according to published criteria are highly likely to maintain this ponderal status as adults. Metabolism, lifestyle, and eating habits, are believed to play a role in the development of obesity.
In Nigeria, like in most
developing countries of Africa, the emphasis has been on under nutrition and
food security rather than overweight, since obesity is viewed as a disease of
affluence, but recent studies has proved otherwise (Power, Lake & Cole, 1999).
Obesity is negatively affecting adults.
Recent studies have shown that there are approximately 550 million obese people
with a BMI of 30.0 and over 2 billion overweight people with a BMI of 25 and
over in the world. (American
Obesity Association (AOA), 2005) Overall, about 3 million
deaths are attributed to overweight/obesity world-wide. The World Health
Organization (WHO) in their recent national survey for chronic, non-
communicable disease risk factors, identified that between 8% and 10% of
Nigerian people are obese (WHO,
2002).
Children and teenagers are becoming
obese at an alarming rate (Whitaker, Wright, & Pepe 1999). The prevalence
of childhood obesity in the world has risen dramatically in the past several
decades with 25-30 percent of children being affected; it is not confined to
the industrialized countries, as high rates are already evident in developing
countries (Moran, 1999). All children
gain weight as they grow older but extra pound more than what is needed to
support their growth and development can lead to childhood obesity. Childhood
obesity is a serious medical condition that affects children and adolescents.
It occurs when a child is well above the normal weight for his or her age and
height. Childhood obesity is
particularly troubling and can be dangerous to ones health. The treatment of obesity in adults give
disappointing results because, rebound weight gain within months is present in
the vast majority of adults who loose weight, but behavioral interventions in
children population may yield greater weight loss and better maintenance than
in adults (Epstein, 1998). Moran(1999) have recommended that making
steady changes in eating and physical activity habits overtime, will bring
about weight loss, better feeling and overall health improvement.
1.2 Statement
of the Problem
The
prevalence of childhood obesity has highly increased in several traditional
populations. This is not only of social concern, it is also of public health
concern, (Garrow, 1991). Obesity is considered a disease and one of the key
risk factors for many chronic non-communicable diseases, such as type 2
diabetes mellitus, high blood pressure, heart disease and some cancers. The most
important long term consequence is their persistence into adulthood, with all
the associated health risks (Anderson & Musaiger, 2006). The rapid increase
in childhood obesity predicts the future health consequences.
The Centre for Disease Control and Prevention
(2003), reported that social and psychological problems are the most
significant consequences of obesity in children. Furthermore, obese children may
have psychological problems because the extra weight often place kids on the
path to health problems such as diabetes, high blood pressure and high
cholesterol that were once confined to adults.
Dietz (1999) reported that, obesity has so many complications. The
glaring rise in childhood obesity forced the World Health Organisation (WHO) to
include childhood obesity on the list of essential health problems worldwide,
and proposed it as the most frequent
cause of preventable deaths, after smoking (WHO, 1998).This rise is attributed
to drastic changes in the lifestyle of the children.
The
dietary habits of the average Nigerian child in the urban communities had
shifted from natural traditional foods to high-calorie foods (fast food and
confectionary) which are relatively cheap and heavily promoted, specifically
for children. Exercise is no longer a regular part of daily activity. Some
children never walked or cycled to school or play any kind of sport. Schools in
the urban areas do not have enough open play ground for the children. This has
promoted in door games such as video games for children in the schools in
recent times. It is not unusual now for children to spend hours in front of a
television or computer.
The
National Institute for Clinical Excellence (2000) observed that 4 out of 10
boys and 6 out of 10 girls scarcely perform a minimum one hour daily physical
activity recommended by the health education authority. The past generation was
hard-working and produced hard-working children who maintained active life
style and such did not have to deal with the issues and complications of
childhood obesity. The growth of economy led children of affluent parents to
have no interest in manual labour. This may have precipitated a society of
children suffering from overweight and obesity. This is supported by several
studies that observed that childhood obesity is increasing. The option available
is a strategy to reduce and prevent it. It was in the light of this study
emanated, to conduct an extensive study on the prevalence of childhood obesity among children residing in
the rural and the urban communities of Enugu South Local Government Area of
Enugu State, Nigeria. The study provided evidence on prevalence of obesity in
the communities and possible means of reducing it.
1.3 Objectives
of the Study
1.3.1 General objective
The
general objective of this study was to assess the prevalence of childhood
overweight and obesity; and influence of exercise in children aged (6-12 years)
living in rural and urban communities of Enugu South local Government Area,
Enugu State, Nigeria.
1.3.2 Specific objectives:
The
specific objectives were to:
1. determine the prevalence of childhood
overweight and obesity in school children in Enugu South Local Government Area using anthropometric
measurements;
2 determine the effect of gender, location and
income of the parents on overweight and obesity in children using
questionnaire.
3. assess the food consumption pattern of a
sub-sample of the subjects using weighed food intake;
4. assess the effect of physical exercise
on a sub-sample of the subjects weight;
and
5. assess
the effect of lifestyle on the subjects’ weights.
1.4 Significance of Study
Childhood obesity is
not just a matter of social concern, but is also a health concern that can lead
to health problems. The result of having obesity at such a young age means that
these children are more susceptible to diseases, the majority of which would be
completely preventable if obesity was avoided or reversed. Parents need to be
willing to work out ways to keep children
free from this disease and this will
begin by creating awareness on the existence of this killer disease among our children and its
resultant consequences.
The
risk of health problems starts when someone is very slightly overweight, and
the likelihood of problems increases as the person becomes more overweight and
obese. Many of these conditions cause long-term suffering for individuals and
families. In addition, the costs for the health care system are extremely
high. This
study therefore aims at unraveling the existence of this disease among children
living in both the urban and rural areas of Enugu State, within the age range
of 6-12 years, by first, carrying out an anthropometric measurement of the
sampled population and calculating
their BMI with the figures gotten.
To
reach this goal of ideal body weight, people can limit energy intake from total
fats and shift fat consumption away from saturated fats to unsaturated fats;
increase consumption of fruit and vegetables, as well as legumes, whole grains
and nuts; and limit their intake of sugars. And to increase calories used,
people can boost their levels of physical activity – to at least 30 minutes of
regular, moderate-intensity activity everyday.
The study could identify the major
causes of obesity in children and ways of addressing the problem. The study
will expose parents to the reality of obesity in children, its prevailing
threats. and how to control and monitor the weight of a younger person. The
result of this study will be of immense relevance to both adults, the children
and virtually everybody who desire to live a healthy happy life. Parents will
learn ideal home made delicacies that will positively affect the lives of these
younger generations.
This study will reassure hope to
those who are already victims of obesity. The Scientists, the Nutritionists,
the Dietitians and all other concerned individuals including the various
government units, will updatetheir
knowledge on the prevalence of childhood obesity in the localities and the most
appropriate means of fighting it. It is also assumed that this study will be
useful in obtaining and disseminating information that will educate everybody
especially parents on how to prevent the
early onset of obesity among children.
CHAPTER TWO
LITERATURE
REVIEW
Outline of the Review
2.1 Definition of Obesity
2.2 Historical Trends
2.3 Mechanism of Obesity
2.4 Classification of Obesity
2.5 Types of Obesity
2.5.1 Juvenile onset Obesity
2.5.2 Adult onset Obesity
2.5.3 Upper body (android) Obesity
2.5.4 Lower body (gynoid) Obesity
2.6 Epidemiology of Obesity
2.7 Cultural and Social Significance
2.8 Obesity Among Children
2.9 Prevalence of Childhood Obesity in Developed
Countries
2.10 Prevalence of Childhood Obesity in Developing
Countries
2.11 Prevalence by Region
2.12 Causes of Childhood Obesity
2.13 Problems of Childhood Obesity
2.14 Summary of Literature review
2.1 Definition
of Obesity
An American Heritage Dictionary
defines Obesity as condition of increased body weight and is caused by an
excessive accumulation of fat. Obesity has been termed the new “epidemic” in
both children and adults. In 1998, the World Health Organization (WHO)
designated obesity as a global epidemic (Anrig, 2003). The combination of increasing
high fat foods in our diets and low physical activity. It is very easy to
become over weight/obesed in today’s society. The cost of obesity in Canada for
example has tripled. Studies have shown that obesity has killed people more
than AIDS. However, insurance companies rarely cover any cost that are associated
with treatment for obesity (Kempster, 2004). Obesity, an accumulation of excess fat in the
adipose tissue, is currently an escalating epidemic that affects many countries
in the world including United States of America (Mccauley, 2002). This
condition is responsible for 300,000 deaths annually. And it is attributed to
changes in lifestyle, dietary habits, physical activity, social and economic
evolvement associated with the occurrence of obesity (Allison & Engel,
1996). Some other major reasons for childhood obesity according to the American
Obesity Association 2005 are:
1. poor eating habits, especially when
children are exposed to other children who promote sedentary behaviours.
2. socio-economic stress and genetics
When
a child has genetically obese background, the chances of becoming obese are
greatly increased.
2.2 Historical Trends
Obesity has been recognized as a
medical disorder since the time of Hippocrates when it was stated that
“Corpulence is not only a disease itself, but the harbinger of others (Haslam and James 2005). For most of human
history, mankind struggled with food security with the onset of the industrial
revolution, it was realized that the military and economic might of nations
were dependent on both the body size and strength of its soldiers and workers.
Height and weight thus both increased through the 19th century in the developed
world. During the 20th century, as populations reached their genetic potential
for height, weight began increasing much more than height, resulting in obesity
(Caballero, 2007). In the 1950’s increasing wealth in the developed world
decreased child mortality and increased body weight but as body weight
increased, heart and kidney disease became more common (Caballero, 2007).
During this same period, insurance companies realized the connection between
weight and life expectancy and increased premiums of the obese (Haslam and
James, 2005).
2.3 Mechanism of Obesity
During growth, fat cells increase
in number and when energy intake exceeds expenditure fat cells increase in
size. When fat cells have reached their maximum size and energy intake
continues to exceed energy expenditure, fat cells increase in number. With fat
loss, the size of the cells shrinks, but not the number. When fat loss occurs,
none of the cells decrease in number instead they only decrease in size.
(Whitney and Rolfes, 2002). (There are few fatty acids that occur in food or in
our body and are often incorporated in the form of triglycerides which are
found in highly fatty foods. Triglycerides are composed of three fatty acids
attached to a glycerol molecule, to make triglycerides a series of
condensation, reaction takes place with fatty acids combining with a hydrogen
atom to form a fatty acid, releasing a molecule of water. Triglycerides have
recently become popular since they extend the shelf life of many food products
by protecting them against oxidation.
A disadvantage to triglycerides is
that they make poly-saturated fat more saturated. Therefore, any health
advantage of using poly-saturated fat is lost during the process of
hydrogenation and textures of food are also altered. (Whitney and Rolfes,
2002). Research has revealed that obesity is associated with increased levels
of a hormone called leptin (Moran and Philip 2003). Leptin is secreted from
adipose (fat) tissue and is involved in the regulation of food intake, energy
expenditure and energy balance in humans (Moran and Philip 2003). In children
today, obesity is the major and most common metabolic and nutritional disease,
whereas thirty (30) years ago, it was rarely seen in children. In the past 20
years, there has been an exponential increase in the incidence of obesity among
children. A study done by Tremblay and Williams (2000). showed that there were
a 17% increase in obesity rates among boys and a 15% increase among girls,
since 1981 to 1996. This alarming increase in childhood obesity has been
occurring in all westernized countries and specifically in Canada. While
childhood obesity rates were similar to other countries like Scottand, England
and Spain in early 1980’s. By the 1990’s, Canadian rates rose by leaps and
bounds (Ball and McCarger,
2003).
2.4 Classification of Obesity
Obesity in absolute terms is an
increase of body adipose tissue (fat tissue) mass. In a practical setting, it
is difficult to determine this directly. Therefore obesity is best and
typically assessed by BMI (Body Mass Index) and in terms of its distribution
via, the waist circumference (Sweeting, 2007). In addition, the presence of
obesity needs to be evaluated in the contex of other risk factors such as
medical conditions that could influence the risk of complications (Maynard et al.,
2001).
Body Mass Index (BMI), developed by
Belgian century, is a widely accepted scale to measure obesity (Parson, Power, Logan and Summerbell, 1999). BMI is an
accurate reflection of body fat percentage in the majority of the adult
population, but is less accurate in situations that affect body composition
such as in body builders and pregnancy (Department of Health).
BMI is calculated by dividing the
subjects weight by the square of his/her height, typically expressed either in
metric or US “customary” units.
Metric: BMI = kg/m2
Where
kg is the subject’s weight in kilograms and M is the subject’s height in
meters.
The most commonly definitions,
established by the WHO in 1997 and published in 2000 provide the following
values (WHO, 2000).
A
BMI less than 18.5 is underweight
A
BMI of 18.5 – 24.9 is normal weight
A
BMI of 25.0 – 29.9 is overweight
A
BMI of 30.0 – 34.9 is class I obesity
A
BMI of 35.0 – 39.9 is class II obesity
A
BMI of > 40.0 is class III obesity.
Some modifications to the WHO (2000) definitions have been made by
particular bodies (National Institute for Health and Clinical Excellence). A
BMI of 35.0 or higher in the presence of at least one other significant
commodity is also classified by some bodies as morbid obesity. To interpret
BMI, physicians take into account race, ethnicity, lean mass, age, sex and
other similar factors. Although there is no dispute to accept BMI to measure
obesity, but it is not accurate in judging body fat of a very muscular person,
It is also not correct in measuring waist circumference as it does not take
into account different rations of adipose to lean tissues.
BMI also cannot differentiate between
separate types of adiposity, which on many occasions relates to cardiovascular
danger. There is an alternative way, scientists and physicians believe that men
with over 25 percent body fat and women with over 30 percent body are obsessed
(Willet, 1995). There is however difficulty in precisely measuring excessive
fat of a person’s body. Experts suggest that the underwater weight of a person
could be closer to an accurate answer. But underwater measurement is not
generally possible for all the people. It can be conducted in laboratories
only.
Another alternative is the skin-fold
test which is dependable and can be easily conducted (used to determine the
thickness of sub factor fat layer). The bioelectrical impedance analysis (BIA) is
also acceptable to doctors because of its easy conductibility in medical
clinics. Other types of measurement are computed tomography (CT Scan) and
magnetic resonance imaging (MRI) and dual energy x-ray absorphometry (DXA).
Measurement of risk factors and diseases associated with overweight can be
judged by clinical analysis.
For Asian, overweight is a BMI between
23 and 29.9 kg/m2 and obesity a BMI > 30 kg/m2. The
surgical literature breaks down “class III” obesity into further categories.
A BMI > 40 is severe obesity
A BMI > 40.0 – 49.0 is morbid obesity
A BMI of 50 is super obese
Body
mass index (BMI) calculation and classification in children
The body mass index of children is calculated
using the formula,
Weight (kg)
Height(m2)
The classification is done using WHO (2007)
growth reference (5 – 19years),
BMI for age classification.
Cut offs is as follows; Severe thinness
(< -3SD of the median value of the reference population), thinness (<-2SD of the median value of the
reference population), normal (>-2SD and <2SD of the median value of the
reference population), Overweight
(>+1SD of the median value of the reference population) and Obesity
(>+2SD of the median value of the reference population).
2.5 Types of Obesity
The accumulation of fat in adipose
cells resulting from the excess consumption of calories is different depending
on the time of onset and its storage or distribution, obesity is thus
classified into four namely:
- Juvenile onset obesity
- Adult onset obesity
- Upper body (Android) obesity and
- Lower body (Gynoid) obesity.
2.5.1 Juvenile onset Obesity
This type of obesity develops in infancy
or childhood, and numerous adipose cells develop, each with the ability to grow
larger. This presents a special pattern because the greater number of adipose
cells may increase the body’s resistance to cutting down fat stores.
Adipose cells have a long life span
and apparently need to store some fat. If one adipose cell automatically require
more fat storage, reducing total body fat becomes a tough task (Wardlaw, Hamp,
Disilvestron, 2004).
2.5.2 Adult onset Obesity
This type of obesity sets in at
adulthood, fewer adipose cells are usually present, but these contain an excess
amount of fat. Still as it progress in adulthood, adipose cells can increase in
number. (Wardlaw et al.,
2004).
2.5.3 Upper body (android) Obesity
This is a type of obesity in which
fat is stored primarily in the abdominal area and is defined as a waist
circumference > 40 inches (102cm) in men and > 35 inches (89cm) in women
and is closely associated with a high risk of cardiovascular diseases,
hypertension and type 2 diabetes. (Wardlaw et
al., 2004).
2.5.4 Lower body (gynoid) Obesity
This type of obesity is one in which
fat storage is primarily located in the buttocks and thigh area. This is
usually more common in women than in men, as estrogen and progesterone
(primarily female hormones) encourage lower body fat storage (Wardlaw et al., 2004).
Of all these types of obesity, the
one that is of paramount concern to this study is Juvenile onset obesity
(childhood obesity).
2.6 Epidemiology of Obesity
In Africa, initially obesity was not
regarded as a health problem in view of the fact that the etiology of obesity
revolves around overeating and most Africa nations are poverty stricken and
cannot feed their citizens. This is not to say that obesity does not exist here
for “it is common knowledge that market women in West Africa are fat”. The
story is that urbanization and socio-economic awareness are currently causing a
change in the food availability and food habits of many inhabitants. With a
resultant effect that there is improved nutrition with the attendant risk of
over nutrition and its associated diseases.
The African picture of obesity is
some what different when compared with the European. For instance, there is
relative obesity seen in the African female which is accepted as a mark of
beauty.
Despres, (2001) painted the picture well when he spoke
about premarital fattening and joy in accumulation of fat around the buttocks
(Steatopygia). In Ghana, Larsson,
(2004)
showed that serious obesity is prevalent among the women in Accra.
In Yoruba land of Nigeria, a man
gains more respect by his sheer size. Among the higher income group, corpulence
is symbol of prosperity and abundance, so obesity is not only appreciated but
desired Graves, Meyers and Clark (1988).
In Enugu Nigeria, the prevalence of
obesity is higher in women than in men. While obesity in men appears to
decrease with increasing age, than in women, it shows some linear relationship
with age (Okeke, 1988).
2.7 Cultural and Social Significance
Many cultures throughout history
have viewed obesity as a flaw. The obesus or fat character in Greek comedy was
a glutton and figure of mockery. During the Christian times, food was viewed as
a gateway to the sins of sloth and lust (World Health Report 2002). In Western culture, obesity is
once again seen as a sign of a low socio-economic status (Crister 2004). They appear unattractive
and is commonly associated with various negative stereotypes. Obese people are
less likely to be hired for a job, make less money when hired due to inactive
nature, and even when eventually hired, they are less likely to be promoted.
As under nutrition is the major
concern of most people, over nutrition has also become a major problem among
the high income families (Mohammed, 1991). People commonly view weight gain and
fat storage as signs of health and prosperity. In the earlier time of hard
labour and frequent food storage, securing an adequate energy to meet body
energy requirement has the major nutrition concern (Bray 1996).
An Australian study has found that
children are more likely to be obese if they are from low income families and
the risk is increased further if they are from particular racial background. A
study carried out by Associate Professor Dr. Jenny O’Dea in 2002 says her study
of 8,500 children is the first to measure the effect of income, social class
and ethnicity on obesity and the result revealed that about 9% of the children
from low-income families were obese compared to about 4% of children from
high-income families. She says the study also found out that children from
pacific Island, Middle Eastern, Aboriginal or Southern European background have
greater risk of obesity.
“Both low income and being of a
certain ethnic background really confers a higher risk of obesity” she said.
Compared to the Caucasian white children from, Pacific Island-background who were
4 to 4 ½ times more likely to be obese Middle Eastern children were 4 times
more likely, so it really was quite a clear relationship”.
Since the mid-seventies, the
prevalence of overweight/obesity has greatly increased for both children and
adult (Centres for Disease Control and Prevention). The survey further showed
increase in overweight among children and teens. For children aged 2 – 5 years,
the prevalence of obesity increased from 5.0% to 13.9%, aged 6-11 years, from
6.5% to 18.8% and 12 – 19 years, from 5.0% to 17.4%. These increasing rates
raises a concern because of their implications on victims health.
Today, however, as the standard of
living continue to rise, weight gain and obesity are posing a threat to
inhabitants of many countries all over the world (WHO, 1998). According to the
centres for disease control and prevention (CDC) in the United States nearly
31% of the population is obese, up from 13% in 1960, then from 1980 to 2000,
obesity among American adults doubled and the number of obese children and
teenagers nearly tripled. Public health officials are concerned that obesity is
reaching epidemic proportions. Research on this condition has been much
neglected when compared to those of other disease that associated with
affluence like diabetes mellitus and cancer (Garrow, 1988). Obesity is a
chronic medical problem prevalent in developed as well as in developing
countries and affects children as well as adults (Bray, 1996). Obesity is the key risk factor in the
natural history of other chronic and other non-communicable diseases
particularly in developed countries (WHO, 1998). It is not a recent phenomenon
and can be traced to more than 25,000 years ago. The prevalence has never
reached such epidemic proportion as today. It has become the major risk, pose.
(Eckel,
1992).
Over nutrition with
overweight/obesity is mainly found with the healthy people in the developing
countries coupled with few cases from the low socio-economic status group that
become victims through lack of nutrition education and therefore depend on
carbohydrates rich foods that has high caloric values as a result of not being
able to afford other nutritious foods (Blundell and King 1999).
&
