The prevalence of obesity in both the developed and developing world have
increased, which leads to diverse health outcomes and is placing a heavy
burden on the economy. Abdominal obesity proved to be one of the main
features in predicting metabolic and cardiovascular disease (CVD) risk and
may be the link that unifies the metabolic syndrome (MS) through pro-inflammatory
pathways. While the pathogenesis of the MS and each of its
components are complex and not well understood, abdominal obesity remains
the mechanism that relates to increased lipolysis causing the liver to increase
blood glucose and very low lipoprotein output. This in turns leads to raised
blood glucose, triglycerides, low-density lipoprotein cholesterol (LDL-C), blood
pressure and inflammatory markers (C-reactive protein, interleukin-6 and
tumor necrosis factor-a) and decreased high-density lipoprotein cholesterol
(HDL-C). Prevention of the metabolic syndrome and treatment of its main
characteristics are now considered of utmost importance in order to combat
the increased CVD risk and all-cause mortality. Decreasing sedentary
behaviour through regular physical activity is a key element in successful
treatment of obesity through an increase in energy expenditure, but the ability
to decrease low-grade systemic inflammation may be an even greater
outcome.
Aims
The aims of this study was firstly, to determine by means of a literature review,
how obesity could be related to a state of chronic systemic inflammation
(increased CRP and IL-6). Secondly to determine whether physical activity
could serve as a suitable method to decrease inflammation associated with
obesity and related disorders. Thirdly to determine if abdominal obesity is a
predictor of the metabolic syndrome and CVD and finally, to determine if
measures of obesity can predict risk for the metabolic syndrome and CVD
risk.
Methods
For this review study, a computer-assisted literature search were utilized to
identify research published between 1990 and 2005. the following databases
were utilized for the search: NEXUS, Science Direct, PubMed and Medline.
Keywords related to obesity (abdominal obesity, overweight), metabolic
syndrome (insulin resistance syndrome, dysmetabolic syndrome, syndrome
X), cardiovascular disease (coronary heart disease, coronary artery disease),
cardiovascular risk factors (hypertension, dyslipidemia, diabetes mellitus,
physical activity), inflammatory markers (CRP, IL-6, chronic low-grade
inflammation) and physical activity (fitness, exercise and training) were
included as part of the search, including the references identified by previous
reviewers (not identified as part of the computerized literature search).
Results and conclusions
Several research studies concluded that obesity could be an
inflammatory disorder due to low-grade systemic inflammation. Adipose
tissue is known to be a sectretory organ producing cytokines, acute
phase reactants and other circulating factors. The synthesis of adipose
tissue TNF-a could induce the production of IL-6, CRP and other acute
phase reactants. CRP is a acute phase reactant, synthesized primarily
in hepatocytes and secreted by the liver in response to a variety of
inflammatory cytokines of which IL-6 and TNF-a are mainly involved.
CRP increases rapidly in response to trauma, inflammation and
infection. Thus, enhanced levels of CRP can be used as a marker of
inflammation.
Several studies of large population cohorts provide evidence for an
inverse, independent dose-response relation between plasma CRP
concentration and level of physical activity in both men and women.
Trends for decreased IL-6, TNF-a and CRP concentrations were linear
with increasing amounts of reported exercise in most of the research
studies, physical activity proved effective in lowering measures of
adiposity (BMI, WHR, WC and percentage body fat) and obesity related
inflammatory markers (CRP & IL-6). Thereby indicating a potential anti-inflammatory
effect.
In the studies reviewed in this article abdominal obesity is identified as
a predictor and independent risk factor for CVD in both men and
women. High levels of deep abdominal fat have also been correlated
with components of the metabolic syndrome, glucose intolerance,
hyperinsulinemia, hypertension, diabetes, increases in plasma
triglyceride levels and a decrease in HDL-C levels (dyslipidemia) in
many of the studies. Prospective epidemiological studies have revealed
that abdominal obesity (determined by WC and WHR) conveys an
independent prediction of CVD risk and is more relevant compared to
general obesity (determined by BMI).
Abdominal fat has been linked to metabolic risk factors like high systolic
blood pressure, atherogenic dyslipidemia, with increased serum TG
and decreased HDL-C, and glucose intolerance. Although magnetic
resonance imaging (MRI) and computerized tomography (CT) have
been used successfully in many studies to measure adipose
compartments of the abdomen (subcutaneous and visceral fat),
anthropometrical measures like WHR and WC have been proven to be
an effective measure in predicting the metabolic syndrome. WC has
also been included in the metabolic syndrome definitions of the WHO,
ATP Ill and new IDF. / The prevalence of obesity in both the developed and developing world have
increased, which leads to diverse health outcomes and is placing a heavy
burden on the economy. Abdominal obesity proved to be one of the main
features in predicting metabolic and cardiovascular disease (CVD) risk and
may be the link that unifies the metabolic syndrome (MS) through pro-inflammatory
pathways. While the pathogenesis of the MS and each of its
components are complex and not well understood, abdominal obesity remains
the mechanism that relates to increased lipolysis causing the liver to increase
blood glucose and very low lipoprotein output. This in turns leads to raised
blood glucose, triglycerides, low-density lipoprotein cholesterol (LDL-C), blood
pressure and inflammatory markers (C-reactive protein, interleukin-6 and
tumor necrosis factor-a) and decreased high-density lipoprotein cholesterol
(HDL-C). Prevention of the metabolic syndrome and treatment of its main
characteristics are now considered of utmost importance in order to combat
the increased CVD risk and all-cause mortality. Decreasing sedentary
behaviour through regular physical activity is a key element in successful
treatment of obesity through an increase in energy expenditure, but the ability
to decrease low-grade systemic inflammation may be an even greater
outcome.
Aims
The aims of this study was firstly, to determine by means of a literature review,
how obesity could be related to a state of chronic systemic inflammation
(increased CRP and IL-6). Secondly to determine whether physical activity
could serve as a suitable method to decrease inflammation associated with
obesity and related disorders. Thirdly to determine if abdominal obesity is a
predictor of the metabolic syndrome and CVD and finally, to determine if
measures of obesity can predict risk for the metabolic syndrome and CVD
risk.
Methods
For this review study, a computer-assisted literature search were utilized to
identify research published between 1990 and 2005. the following databases
were utilized for the search: NEXUS, Science Direct, PubMed and Medline.
Keywords related to obesity (abdominal obesity, overweight), metabolic
syndrome (insulin resistance syndrome, dysmetabolic syndrome, syndrome
X), cardiovascular disease (coronary heart disease, coronary artery disease),
cardiovascular risk factors (hypertension, dyslipidemia, diabetes mellitus,
physical activity), inflammatory markers (CRP, IL-6, chronic low-grade
inflammation) and physical activity (fitness, exercise and training) were
included as part of the search, including the references identified by previous
reviewers (not identified as part of the computerized literature search).
Results and conclusions
Several research studies concluded that obesity could be an
inflammatory disorder due to low-grade systemic inflammation. Adipose
tissue is known to be a sectretory organ producing cytokines, acute
phase reactants and other circulating factors. The synthesis of adipose
tissue TNF-a could induce the production of IL-6, CRP and other acute
phase reactants. CRP is a acute phase reactant, synthesized primarily
in hepatocytes and secreted by the liver in response to a variety of
inflammatory cytokines of which IL-6 and TNF-a are mainly involved.
CRP increases rapidly in response to trauma, inflammation and
infection. Thus, enhanced levels of CRP can be used as a marker of
inflammation.
Several studies of large population cohorts provide evidence for an
inverse, independent dose-response relation between plasma CRP
concentration and level of physical activity in both men and women.
Trends for decreased IL-6, TNF-a and CRP concentrations were linear
with increasing amounts of reported exercise in most of the research
studies, physical activity proved effective in lowering measures of
adiposity (BMI, WHR, WC and percentage body fat) and obesity related
inflammatory markers (CRP & IL-6). Thereby indicating a potential anti-inflammatory
effect.
In the studies reviewed in this article abdominal obesity is identified as
a predictor and independent risk factor for CVD in both men and
women. High levels of deep abdominal fat have also been correlated
with components of the metabolic syndrome, glucose intolerance,
hyperinsulinemia, hypertension, diabetes, increases in plasma
triglyceride levels and a decrease in HDL-C levels (dyslipidemia) in
many of the studies. Prospective epidemiological studies have revealed
that abdominal obesity (determined by WC and WHR) conveys an
independent prediction of CVD risk and is more relevant compared to
general obesity (determined by BMI).
Abdominal fat has been linked to metabolic risk factors like high systolic
blood pressure, atherogenic dyslipidemia, with increased serum TG
and decreased HDL-C, and glucose intolerance. Although magnetic
resonance imaging (MRI) and computerized tomography (CT) have
been used successfully in many studies to measure adipose
compartments of the abdomen (subcutaneous and visceral fat),
anthropometrical measures like WHR and WC have been proven to be
an effective measure in predicting the metabolic syndrome. WC has
also been included in the metabolic syndrome definitions of the WHO,
ATP Ill and new IDF. / Thesis (M.A. (Human Movement Science))--North-West University, Potchefstroom Campus, 2006.
| Identifer | oai:union.ndltd.org:NWUBOLOKA1/oai:dspace.nwu.ac.za:10394/1020 |
| Date | January 2005 |
| Creators | Beneke, Jeanine |
| Publisher | North-West University |
| Source Sets | North-West University |
| Detected Language | English |
| Type | Thesis |
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