Type: Descriptive Essays
Sample donated: Lynn Lawrence
Last updated: April 21, 2019
1 Introduction/Background of StudyNon-Communicablediseases (NCDs) are diseases of long duration and generally slow progression.The four main types of NCDs include cardiovascular diseases, cancer, chronicrespiratory diseases and diabetes. NCDs are by far the leading cause of deathin the world, representing 70% of all annual deaths that kill 40 million peopleeach year (WHO, 2017).In Malaysia, NCDs has contributed to an estimated 73% of total deathswith cardiovascular diseases as the biggest contributor. An estimated 35% ofdeaths occur in individuals aged less than 60 years old. According to the SecondBurden of Disease Study for Malaysia, published by the Institute for Public Health in 2012,hypertension, diabetes, high cholesterol andhigh Body Mass Index (BMI) are ranked as the biggest contributors to both Disability-AdjustedLife Years (DALY) and deaths.
Previous data from National Health & Morbidity Survey (NHMS) showedan increasing trend for all NCDs risk factors. An analysis of NHMS 2011 showedthat at least 63% of adults aged 18 years and above had at least one NCDs riskfactor (either overweight/obesity, high blood cholesterol, high blood pressureor high blood sugar) (Institute for Public Health, 2015). This increasing trend is due to rapid ageing of the Malaysianpopulation, accompanied by changing lifestyles, nutritional transition (to highcalorie, low nutrition food), and declining physical activity (Atun, Berman, Hsiao, Myers, & Wei,2016).Metabolic Syndrome or insulin resistance syndrome is characterized by aconstellation of cardiovascular risk factors including abdominal obesity, high cholesterol,high blood pressure and raised plasma glucose.
It is approximated that around20-25 % of the world’s adult population have metabolic syndrome and they aretwice as likely to die from and three times as prone to have myocardialinfarction (MI) or stroke in contrast to individuals without the syndrome (S. G. Alberti, Zimmet, Shaw, & ScottM. Grundy, 2006). In Malaysia, metabolic syndrome is common where the prevalence ofmetabolic syndrome in adult Malaysian is reported as high as 37.
1% (Dr. Lim, C.H.,2016).Metabolic syndrome is associated with a pro-inflammatory state, and therole of visceral fat is thought to be central to this.
Visceral fat leads toalteration of the normal physiological balance of adipokines, insulinresistance, endothelial dysfunction and a pro-atherogenic state (Ritchie & Connell, 2007).Visceral adipose tissue (VAT) is closely related with adverse cardio metabolicrisk profile and is also known to be a strong predictive factor for severemetabolic complications in adults. Consequently, the prevalence of themetabolic syndrome is worrisome of the future increase of cardiovasculardisease. To our knowledge, the association of visceral fat quantity with cardiovascularrisk factors has never been investigated among Malaysian population with metabolicsyndrome. Therefore, we sought to understand this condition in order to providebetter management to treatment plan for the patient. Figure 1: Cardiovascular disease is the leading cause of death amongNCDs in Malaysia Source: World Health Organization – NoncommunicableDiseases (NCD) Country Profiles , 2014 2 Literature Review2.1 Visceral FatVisceral fat which is also known as extra subcutaneousfat or deep fat is stored within the abdominal cavity (Visceral Fat, 2018). Itis deposited around the vital body organs such as heart and abdominal organs dueto the extra intake of carbohydrate-rich foods, fewer exercises, and othermetabolic imbalances.
The keydifference between the visceral fat and the subcutaneous fat is thesite of deposition. Visceral fatis deposited around the vital organs whereas subcutaneous fat is depositedunder the skin (Samanthi, 2017).Figure 2: White adipose distribution in thebody. White adipose falls under two major classifications: visceral, orsurrounding organs, and subcutaneous, under the skin. Source: Cook, A. and Cowan, C., Adipose (March 31, 2009)Excess visceral fat is a central factor in thepathogenesis of metabolic syndrome. It is the strongest risk for cardio metabolicdiseases compared to epicardial and subcutaneous fat (Sato et al.
,2017). An additional 500 increase in fat volume was associated inhigher incidence of metabolic syndrome. Most associations remained significanteven after additional adjustment for BMI change, waist circumference change, orrespective abdominal adipose tissue volumes (p ? 0.001) (Lee, Pedley,Hoffmann, Massaro, & Fox, 2016).
Obese individuals are at increased risk ofdeveloping cardiovascular disease as a consequence of adipose tissue expansionand subsequent dysfunction. In particular, the expansion of VAT is anindependent risk factor for cardiovascular morbidity and mortality. VATexpansion results in local inflammation, characterized by hypertrophicadipocytes and increased influx of proinflammatory macrophages and cytotoxic Tcells, contributing to elevated plasma levels of interleukin-6 (IL-6) and highsensitive C-reactive protein (hsCRP).
At the same time, expression of theanti-inflammatory adipokine adiponectin is downregulated in adipocytes. Theinflammation leads to metabolic complications that predispose to thedevelopment of CVD, including insulin resistance and development of themetabolic syndrome and type 2 diabetes. In 1012 patients with clinically manifestvascular disease, visceral fat thickness was measured ultrasonographically.
Theresults showed that the average age of patients was 59 ± 10 years and 79% weremales. In total 18% of the patients was obese. Mean VAT thickness and waistcircumference (WC) were higher in males than females. Out of 51% of thepatients had metabolic syndrome, defined by the Adult Treatment Panel (ATP) IIIcriteria, there are 36% had central obesity, 94% were hypertensive, 39% hadhypertriglyceridemia, 29% had low HDL cholesterol levels and 63% had animpaired fasting glucose (Kranendonk etal., 2014).Besides adults, there is statisticallysignificant associations of visceral fat and risk factors for metabolicsyndrome in children and adolescents. Adolescence is a time of emergence forcardio metabolic disease, with metabolic syndrome occurring in 4% of alladolescents and 28% of overweight adolescents.
Adolescent cardio metabolichealth has been shown to predict cardiovascular health in adulthood (Schwartz etal., 2013). Visceral fat was found to be independentlyassociated with blood pressure (BP), blood triglyceride, blood high densitylipoprotein cholesterol (HDL-C) and fasting blood glucose (FBG). Thus,screening tests for BP, cholesterol, fasting glucose and WC should be given inclinics for children and adolescents so that metabolic syndrome can be detectedand its risk factors treated early (Kwon et al.,2011). 2.2 Systems to Measure VisceralFatThere are many methods of measuring bodycomposition including hydrostatic weighing, skin fold thickness (SKF), airdisplacement plethysmography (ADP) and dual-energy x-ray absorptiometry (DEXA).
However, all these methods are more expensive, require specific equipment andtraining. Besides that, they are time consuming to use. Overweight and obesity rates are rising fastenough that practical, inexpensive, valid and reliable methods to track changesin body composition are in high demand. BIA is a method that is easy to use, non-invasive, inexpensive,non-time consuming, reproducible and portable. It provides valid estimation of total bodywater (TBW) and fat free mass (FFM) and thus can estimate percent body fat(%BF) (Peterson,Repovich, Eash, Notrica, & Hill, 2007). BIA is based on the principle of resistanceto the ?ow of electrical current due to differences in water content of fat andlean tissue.
Lean tissue contains large amounts of water and electrolytes andis a good conductor of electrical current. On the other hand, fat tissue isanhydrous and a poor conductor. Therefore, the larger the fat tissue, thehigher the resistance to electrical current and the higher the adiposity (Rutherford,Diemer, & Eric D.
Scott, 2010) .Some researchers recommend that BIA may bea useful measurement tool for clinical and public health settings suggesting itcan be reliable to show percent body fat change over time. In the current study, SKF had the highestcorrelation but it cannot be done alone and require a skilled technician forvalidity and reliability while BIA measures can be done alone. For reliabilitywhen using SKF, the same technician should complete each measurement. If thisis not possible when repeated measurements are required, then BIA might stillbe a better option (Peterson etal., 2007).
Although performance of abdominal BIA in predictingthe metabolic syndrome is weak but it may be used in the follow-up of patientswith obesity and/or metabolic syndrome (Mousa et al.,2013). 2.3 Cardiovascular Disease RiskFactorsCardiovascular disease risk factors aredivided into modifiable and non-modifiable risk factors. Among the modifiablerisk factors include hypertension, dyslipidaemia, diabetes mellitus and cardiometabolic risk. Epidemiological studies have shown that cardiovascularrisk rises as BP levels increases, starting at ?115/75 mmHg. The report on theGlobal Burden of Disease 2015 states that there is about 54% of stroke worldwideand coronary heart disease (CHD) were attributable to hypertension.
It is amajor cause of deaths at about 20% and disability. In the Asia Pacific region,up to 66% of some subtypes of cardiovascular disease can be attributed tohypertension. Reduction in BP has consistently shown a reduction incardiovascular events in both primary and secondary prevention.
There is an association between elevated triglyceride(TC), low density lipoprotein cholesterol (LDL- C) levels and cardiovasculardisease. Randomized controlled trials have shown that by lowering TC and LDL-Clevels, cardiovascular events and cardiovascular mortality can be reduced. More than 70% of patients with type 2 diabetesdied of cardiovascular causes.
Women with diabetes are 44% more likely todevelop CHD than men. They are also 50% more likely to have fatal CHD than men.Cardiovascular risk in individuals who have diabetes of long duration (>10years) is similar as in those with a prior cardiovascular event (MOH, 2017).
2.4 Prevalence of Cardiovascular Disease RiskFactors in Malaysia Cardiovascular disease is the main cause of globalmortality and a major contributor to disease related disability. In Malaysia,cardiovascular has been the leading cause of morbidity and mortality for morethan a decade.The Malaysian adultpopulation (?18 years) has high levels of cardiovascular risk factors. 63.6% ofmen, and 64.5% of women are either overweight or obese. 43.
5% of men, and 52.2%of women have hypercholesterolemia. 30.8% of men, and 29.7% of women havehypertension. 16.7% of men, and 18.3% of women have diabetes mellitus.
Data from NHMS V 2015showed that the prevalence of these cardiovascular risk factors begin toincrease from the age of 30 years. The projected adult population (?18 years ofage) in this country for 2016, stands at 21.5 million, with 11 million men and10.5 million women. Clustering of these fourcardiovascular risk factors is common where 43.2% will had at least 2 of therisk factors stated above.
In the INTERHEART study, these 4 modifiable riskfactors (abnormal lipids, hypertension, diabetes and abdominal obesity)contributed to about 80% of myocardial infarcts (MI) (MOH, 2017). 2.5 Metabolic Syndrome CriteriaMetabolic syndrome is one of a cluster of metabolicrisk factors that include central obesity, hyperglycaemia/ glucose intolerance,hypertension, low HDL cholesterol levels, and high triglyceride levels. The criteria for the definition of metabolicsyndrome are variable, since there are different definitions of metabolicsyndrome, depending on the respective health organizations, such as the WorldHealth Organization (WHO), the National Cholesterol Education Program ExpertPanel (NCEP) and Adult Treatment Panel III (ATP III), the InternationalDiabetes Federation (IDF) and the American Heart Association/National Heart,Lung, and Blood Institute (AHA/NHLBI) (Sulistiowati& Sihombing, 2016).WHO emphasized insulin resistance as the majorunderlying risk factor and required evidence of insulin resistance fordiagnosis. ATP III criteria did not requiredemonstration of insulin resistance. Instead, ATP III made the presence of 3 ofthe following 5 factors the basis for establishing the diagnosis: abdominalobesity (which is highly correlated with insulin resistance), elevatedtriglyceride, reduced high-density lipoprotein cholesterol, elevated bloodpressure, and elevated fasting glucose (impaired fasting glucose or type 2diabetes mellitus).
In the absence of cardiovascular disease or diabetes, themetabolic syndrome is a predictor of these conditions. Once cardiovasculardisease or diabetes develops, the metabolic syndrome is often present. The IDFdropped the WHO requirement for insulin resistance but made abdominal obesitynecessary as 1 of 5 factors required in the diagnosis, with particular emphasison waist measurement as a simple screening tool.
The AHA/NHLBI slightly modifiedthe ATP III criteria but did not mandate abdominal obesity as a required riskfactor. The remaining 4 risk factors were identical in definition to those ofthe IDF. Recently, IDF and AHA/NHLBI representatives held discussions toattempt to resolve the remaining differences between definitions of metabolicsyndrome. Both sides agreed thatabdominal obesity should not be a prerequisite for diagnosis but that it is 1of 5 criteria, so that the presence of any 3 of 5 risk factors constitutes adiagnosis of metabolic syndrome. Waist measurement should not be an obligatorycomponent but is recommended to continue to be a useful preliminary screeningtool (K. G.
M. M.Alberti et al., 2009).In a study conducted in Kuala Lumpur, Malaysia, atotal of 1494 Malay employees participated in the study. Metabolic Syndrome wasdiagnosed in 618 (41.
4%) and 571 (38.2%) participants using the modified NCEPand IDF criteria respectively. Participants whowere missed by the IDF criteria were mainly males (76.6%). However, there were noparticipants who were diagnosed by IDF but missed by the modified NCEPcriteria. Metabolic Syndrome was highest among those aged 40- 49 years,followed by those aged 50-59 years. The prevalence among those aged 60 yearsand older was the lowest among all age groups. About 11% of theparticipants diagnosed with Metabolic Syndrome were diabetics while 18% werehypertensive.
The study concluded that modified NCEP ATPIII criteria may be moresuitable in diagnosing Metabolic Syndrome in this cohort.According to the definition provided by the modifiedNCEP ATP III, for a person to be defined as having the metabolic syndrome, theymust have any three of the following five factors: abdominal obesity, hypertriglyceridemia (triglycerides ?1.7 mmol/L); lowHDL cholesterol (HDL cholesterol ?1.03 mmol/L for men and ?1.29 mmol/L forwomen); elevated blood pressure (systolic blood pressure ?130 mmHg and/ordiastolic blood pressure ?85 mmHg or current use of antihypertensive drugs);impaired fasting glucose (fasting plasma glucose ?5.6 mmol/L). The modifiedNCEP ATP III criteria suggested the cut-off points of waist circumferenceshould be ethnic specific where individuals of Asian origin should use thecut-off of 90 cm in men and 80 cm in women.
For NCEP criteria, abdominalobesity is a component of the syndrome but not a prerequisite for its diagnosis(Moy , 2010). 2.6 Prevalence of MetabolicSyndrome in MalaysiaAbdominal obesity showed the highest prevalence ofindividual risk factors for metabolic syndrome based on IDF and Harmonizedcriteria among Malaysian adults at 57.4% It was significantly higher in females(64.2%), increased with age, and was highest in the Indian population (68.
8%). Hypertensionwas more prevalent in males than females (56.5% versus 50.0%), increasedsignificantly with age, and was highest in the Malay population (52.2%).
Elevated TG was most prevalent in the Chinese population (47.4%). It was alsonoted that the prevalence of dyslipidaemia was higher in subjects from urbanareas, while hypertension was more prevalent in those from rural areas (Mohamud etal., 2012)There were four components identified for both menand women i.e. anthropometric measurements, blood pressure, glycaemia anddyslipidaemia. In anthropometric measures, BMI had the highest factor loading ofall 4 measurements. BMI is known to be related to insulin resistance, althoughwaist hip ratio explained more on central obesity.
Women were found to havehigher BMI and hip circumference compared to men. However, other anthropometricparameters, i.e. waist and neck circumference and waist –hip ratio were higherin men.
Men also found to have higher blood pressure reading. There are no significantdifferent of glucose and insulin parameters between both sexes (Azwany,Mohamad, Bebakar, M, & Ismail, 2011) 3 Problem StatementMetabolicsyndrome is not a disease but a cluster of metabolicabnormalities that increased the likelihood of developing cardiovasculardisease. Metabolic syndrome is associated with a pro-inflammatory state, andthe role of visceral fat is thought to be central to this (Ritchie & Connell, 2007).
In Malaysia, cardiovascular disease is the biggest contributor to thetotal death of NCDs at 36% (WHO, 2014). The prevalence of metabolic syndrome inadult Malaysian is reported as high as 37.1% (Dr.
Lim, C.H.,2016). Therefore, this study is toexplore the degree to which the quantity of visceral fat is associated withchanges in cardiovascular risk factors such as metabolic syndrome. A healthygroup will be used as the control group for comparison be made to those withexisting metabolic syndrome.4 Study Aim & Justification Thepurpose of this study is to investigate the association of visceral fat quantity with cardiovascular disease risk factors among Malaysian population with metabolic syndrome. The effect ofvisceral fat quantity on metabolic syndrome has never been investigated amongMalaysian population and requires further studies.
5 Significance/Rationalof the studyThe findings of the study will help to combat cardiovascular diseasewhich is the number one killer in Malaysia by serving an evidence-basedplatform. If the results show that metabolic syndrome subgroup has higherquantity of visceral fat as compared to healthy group, then Malaysianpopulation should be caution with their visceral fat quantity and takeprevention measures. This study can helpto provide further knowledge among Malaysian population as well as healthcareprovider to take primary prevention to intervene and overcome cardiovascular disease. 6 Objectives 6.1 MainObjective Tostudy the association of visceral fat quantity with changes in cardiovascular disease riskfactors such as metabolic syndrome in Malaysian population. 6.2 Specific Objectives 1. To measure the quantity of visceral fat usingBioelectrical Impedance Analysis (BIA).
2. To compare the quantity of visceral fatbetween individual with metabolic syndrome and healthy group. 7 Methodology7.1 Study Design and settingThe study will be conducted as cross-sectional studyfrom 1st June 2018 to 31st December 2018 (7 months) in the medicalclinics of Hospital Serdang. A healthy group from the staffs of HospitalSerdang will be used as the control group for comparison be made to those withmetabolic syndrome. 7.2 Patient SelectionThe following are inclusion and exclusion criteria forindividual eligible to be included in this study. 7.
2.1 Inclusion criteria:i. Any individual age 18 andabove with either three of the following criteria: abdominal obesity, raisedtriglycerides, reduced HDL cholesterol, raised blood pressure or raised fastingplasma glucose. 7.2.2 Exclusion criteria:i. Any individual who iscurrently a smokerii.
Any individual who eat/drink2 hours before testingiii. Any individual who drinkalcohol 24 hours before testingiv. Any individual who takecaffeine 24 hours before testingv. Any individual whoparticipate in moderate or vigorous exercise for 24 hours before testingvi. Any individual withchronic kidney disease vii. Pregnant womenviii.
Cancer patient 7.3 Samplingmethod & Sample size calculation Sample size is calculated using Cochran’s formula:n = Wheren = Sample size Z = Statistic for level of confidence (e.g.: 1.
96 for 95% confidenceinterval)P = Expected prevalence (0.5 used for sample size needed)d = precision (margin of error is 0.05) Sample Size = = 384.16 Corrected sample size for finite population:New Sample Size = = = 131.75 ? 132 participants 7.4 Toolsand materials 7.
4.1 Data Collection form A self-structured data collection form (APPENDIX 1) will be used duringthe data collection period to record the details from every subject. Patients’demographic data and risk factors will beobtained.
This study will also evaluate the clinical aspects involving BMI, waist circumference, visceral fat quantity,total cholesterol, fasting blood glucose and blood pressure. Every study population will have to undergothese clinical measurements in order to access the criteria of modified NCEPATP III for metabolic syndrome. 7.4.2 DataAnalysisAll statistical analyses will be performed using Statistical Package forSocial Sciences (SPSS) Version 23.0.
The percentage of metabolic syndrome willbe analysed based on descriptive analyses such as mean of different age group,mean of both genders, mean of different ethnicity, mean of visceral fatquantity. T-test or Mann-Whitney test will be used to measure the effect ofvisceral fat quantity on metabolic syndrome. Chi-square or Fischer’s exact testwill be used to compare between healthy group and metabolic syndrome subgroup.The association between visceral fat quantity and cardiovascular risk factorswill be analysed using Pearson or Spearman’s test. The variable in this studyis the quantity of visceral fat. P value less than 0.
05 is consideredstatistically significant. 8 Ethicalapproval of the studyAll aspects of the study protocol will be reviewed and authorized by NationalMedical Research Register (NMRR) and Clinical Research Centre (CRC) HospitalSerdang.