CHAPTER 1
INTRODUCTION
1.1 BACKGROUND
Metabolic Syndrome (MetS) is a cluster of multiple metabolic abnormalities that increase the risk of cardiovascular morbidity and mortality.
The cluster includes various combinations of elevated blood pressure (BP), atherogenic dyslipidemia, obesity, abnormal glucose tolerance and insulin resistance as well as other abnormalities such as pro-inflammatory and prothrombotic states.
The term "metabolic syndrome" dates back to at least the late 1950s, but came into common usage in the late 1970s to describe various associations of risk factors with diabetes that had been noted as early as the 1920s.
Scientists such as Dr. Jean Vague, Avogaro, Gaetano Crepaldi, Stefania Maggi, Gerald Reaven, Haller and Singer all contributed to the development of the term, ‘metabolic syndrome’.
The presence of metabolic syndrome is associated with an approximate doubling of the risk of cardiovascular disease and mortality, and also a 5-fold risk of developing type 2 diabetes mellitus (T2DM). 2,5 The central abnormality for the MetS is central obesity, which in itself increases the risk of insulin resistance. 6,7
Metabolic syndrome has been described as a global time bomb, with a quarter of the world’s adults estimated to be having the condition. Reports from studies show a high prevalence of metabolic syndrome globally, mirroring the rising prevalence of its components, a sequel to urbanization, industrialization and changes in lifestyle.
The third revised edition of the Adult Treatment Panel (ATP III) placed major emphasis on therapeutic lifestyle changes as an essential strategy for clinical management of people at risk of cardiovascular disease (CVD) and metabolic syndrome. Changing dietary and exercise behavior may lead to a healthier
waistline measurement and body mass index (BMI), improved values for high density lipoprotein (HDL) and triglyceride, lower the blood pressure and lower the blood glucose too.
Metabolic syndrome has been established as a public health concern in the United States of America (USA). Thirty-four percent of adults in the USA met the criteria for metabolic syndrome, with men and women over 60 years of age even more likely to have metabolic syndrome. People with MetS have an increased risk of developing health problems such as heart diseases, diabetes and stroke. Owing to its high prevalence and significant health consequences, it is important to understand the risk factors for metabolic syndrome. 5,6,10,11, The worldwide prevalence of metabolic syndrome varies from 13.6% to 46%, depending on the diagnostic criteria used and the population in question. The prevalence of metabolic syndrome in Nigeria has been documented in recent studies as ranging between 12.1% and 54.3% and highest in people with diabetes mellitus. The prevalence of MetS has been found to be affected by factors such as age, ethnicity, sex and occupation. Previous studies have reported differences between sex, with some reporting a higher incidence of MetS in men and some reporting the opposite.
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The pathogenesis of metabolic syndrome can proceed from any of its components, be it abdominal obesity, insulin resistance, hypertension or dyslipidemia 9,13,14
The risk factors for metabolic syndrome are classified into two broad groups; the modifiable factors such as hyperlipidemia, hypertension, smoking, type 2 diabetes, obesity, sedentary life-style, stress/type A personality, alcohol and unsaturated fatty acid diets, and the non- modifiable factors which include increasing age, male gender, family history and genetic abnormalities. Physical inactivity, often defined as the lack of moderate-to-vigorous physical activity and also known as sedentary behavior, had been shown to be an important risk factor for metabolic syndrome. 10,15,16
Sedentary refers to activities that do not increase energy expenditure substantially above the resting level and includes activities such as sleeping, sitting, lying down, watching television, and other forms of screen-based entertainment.
The number of metabolic equivalents (METs) corresponding to each activity were obtained using the compendium of physical
The ancient scholars believed that there was some form of relationship between physical activity and the overall health of an individual. For many centuries, learned scholars have associated `sedentary living’ with reduced longevity and impaired health. Hippocrates wrote extensively about the benefits of exercise for a variety of ailments, including both physical and mental illnesses.
Claudius Galenus (Galen), whose writings dominated European medicine for centuries, believed that some form of exercise could be used to treat virtually every disease.
For the past half century, epidemiologists and physiologists have validated the perceptions of the ancient scholars by demonstrating that individuals who perform moderate-to-vigorous physical activity on a regular basis manifest a plethora of physiologic benefits and reduced risk of chronic diseases and premature mortality.
Scientists have also reported that sedentary behavior is associated with a variety of health risks, such as obesity, hypertension, diabetes mellitus and some form of cancers. It was also associated with reduced longevity and impaired health.
Sedentary behavior was rated as one of the three major threats to modern health, alongside cigarette smoking and poor nutrition.
The amount of time spent being sedentary is an important risk factor associated with several aspects of ill health, including overweight and obesity and associated metabolic diseases.
Twenty percent of deaths of people 35 years and older were attributed to lack of physical activity.
Similarly, overall physical inactivity was estimated to have caused 1.9 million deaths and 19 million disability adjusted life year globally. There is, however, lack of a clear and universal definition of sedentary lifestyle.
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It
is worthy of note that physical inactivity caused over 5.3 million deaths that occurred worldwide in 2008.
In the 17th century, the occupational physician, Bernadino Ramazzini noted a close relationship between sedentary behavior and deleterious health consequences.
Researchers have relied on self-reported tools to collect information about sedentary life-styles.
In recent years, there has been a growing interest in the relationship between sedentary behavior and overall health outcomes.
A large number of any population of people with metabolic syndrome will have an important implication for the health sector. Lifestyle factors (nutrition, environment, stress, smoking, alcohol, drug intake and exercise) have a considerable, but not always well understood impact on a variety of health issues. The prevalence of metabolic syndrome is rising worldwide with urbanization and sedentary lifestyle being important risk factors. 25,26 Cardiovascular diseases (CVD) are of global concern, rather than a first world concern, as evidenced by a 1999 World Health Report, which disclosed that 85% of CVD came from developing low and middle income countries like Nigeria.
The cardiovascular disease risk factors have a tendency to cluster. The presence of such a cluster in an individual has been designated the MetS and predicts the development of type 2 diabetes, cardiovascular disease, cause mortality in non-diabetic individuals and is highly prevalent worldwide. To develop effective primary and secondary prevention strategies for this global health problem, its modifiable determinants such as sedentary behavior need to be thoroughly understood and appropriate measures put in place to reduce their prevalence in the community. 7,28
It is on the basis of these findings on sedentary behavior and the high level risk of developing metabolic syndrome that this present study was conceived to assess their relationship in this location with a view to recommending measures to reduce the burden of metabolic syndrome.
In this study, sedentary behavior is the independent variable while the metabolic syndrome is the dependent (outcome) variable. This is because this study set out to view metabolic syndrome as an outcome of the sedentary behavior seen among adults that presented at the General Out-Patient Clinic of Federal Medical Centre, Owerri.
1.2 STATEMENT OF THE PROBLEM
The World Health Organization (WHO) rated inadequate physical activities as one of the three major threats to modern health alongside cigarette smoking and poor nutrition.
Metabolic syndrome and its risk factors like diabetes, hypertension and obesity are leading causes of mortality and morbidity in low and middle income countries like Nigeria.
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Some researchers believe that metabolic syndrome is the most important medical problem of the early part of the 21st century. Recent studies showed the epidemic proportions this has attained (a prevalence of 20-25% worldwide).
The different components of metabolic syndrome are quite common and usually with fatal outcomes if not well managed. These ailments normally have an insidious onset, often with no obvious physical manifestations until there is organ damage. The organs usually affected are very vital to the body; the eyes, brain, heart, kidneys, nerves and limbs. Thus, the risk factors of this dreaded cluster of ailments need to be identified and steps taken to reduce the incidence. Sedentary life-style is obviously one of the most common modifiable risk factors for metabolic syndrome. With advancements in technology worldwide, manual labor is reducing rapidly, paving the way to mechanized jobs and even the use of robots. Thus, the incidence of sedentary life-style is on the increase especially in the urban areas. Hence, the need to measure its prevalence and its input on MetS. The author intends to use this study to bring sedentary behavior to light and highlight measures to reduce its incidence and consequently, that of metabolic syndrome in his environment.
1.3 RESEARCH QUESTIONS
The research questions for this study are; 1. Does sedentary behavior actually predispose to the development of metabolic syndrome? 2. Is there any direct causal relationship between sedentary behavior and metabolic syndrome?
1.4 HYPOTHESIS
The null hypothesis of this study states that there is no relationship between sedentary behavior and metabolic syndrome among adult patients presenting at Federal Medical Centre, Owerri. The alternate hypothesis of this study is that there is a positive relationship between sedentary behavior and metabolic syndrome.
The sedentary behavior is the independent variable while the metabolic syndrome is the dependent (outcome) variable in this study. This is because this study set out to view metabolic syndrome as an outcome of the sedentary behavior seen among adults that presented at the General Out-Patient Clinic of Federal Medical Centre, Owerri.
1.5 JUSTIFICATION OF THE STUDY
The great interest taken in this study started with the observations at the General Out-Patient Clinic (GOPC), Federal Medical Centre (FMC), Owerri. There seemed to be an increase in the number of cases of hypertension, type 2 diabetes mellitus (DM), obesity and dyslipidemia among the adult patients presenting at the GOPC, FMC Owerri. It became more worrisome when considering the fact that these four entities were all part of a particular syndrome. The increasing prevalence of metabolic syndrome and its association with a decreasing hope for a longer lifespan and good quality of life was a matter of great concern to this author.
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Despite the increasing incidence and interest in metabolic syndrome, few epidemiological studies on the subject had been conducted in the locality. The purpose of this study therefore was to assess the prevalence of metabolic syndrome and its relationship with sedentary life- style in FMC, Owerri.
The study also awakened keen interest in the other risk factors for metabolic syndrome, both the modifiable ones such as hyperlipidemia, hypertension, smoking, type 2 diabetes, obesity, sedentary life-style, stress/type A personality, alcohol and unsaturated fatty acid diets, and the non-modifiable ones that included increasing age, male gender, family history and genetic abnormalities. A logistic regression will enable the author make a conclusion and thus, recommendations. Knowledge derived from the result of this study should help to enlighten the public on the need to control and prevent the modifiable risk factors for metabolic syndrome. 10,15
1.6 AIM AND OBJECTIVES
1.6.1 Aim
To determine the relationship between sedentary life-style and metabolic syndrome among adults presenting at the general out-patient clinic, Federal Medical Centre, Owerri, with a view to recommending measures for a reduction in the incidence and burden associated with the ailments.
1.6.2 Objectives
1. To determine the socio-demographic features of the study population and relate same with the prevalence of metabolic syndrome. 2. To determine the prevalence of metabolic syndrome in the study population. 3. To determine the lifestyle practices of the study participants.
4. To determine the relationship between sedentary lifestyle and metabolic syndrome in the study population.
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