Metabolic of developing type II diabetes and cardiovascular disease

Metabolic syndrome (MetSyn) is defined as the co-occurrence of multiple disorders including insulin resistance, obesity, hypertension, dyslipidemia, and raised fasting glucose which increases the risk of developing type II diabetes and cardiovascular disease (1). It is a health crisis that create a increase burden on health care system as the prevalence is escalating globally (2). Previous studies indicate that the prevalence rate of this syndrome varies a lot depends on population characteristics such as age, gender and ethnicity. MetSyn is believed to be caused by an interaction between environmental and genetic factors (3) and this etiology could also be suggested by the prevalence difference across ethnicities. There are studies reporting the frequencies of MetSyn stratified by different ethnic groups within country or a specific geographic area (4,5,6,7,8), however, a review on a worldwide basis has not yet been conducted. Therefore, a global examination on the ethnic disparities in population prevalence of MetSyn is worthy as the generated data may provide useful information on future study.   Objective:The current meta-analysis is designed to summarize, through published literature, the ethic variation in prevalence or incidence of Metabolic syndrome.Methods:Search strategyAn Ovid literature search will be run in Medline and Embase aims for epidemiological studies presenting the prevalence or incidence of MetSyn. The key terms that will be used are listed below:1. Metabolic syndrome/2. MetSyn3. 1 or 2 4. Epidemiology*5. Prevalence6. Incidence7. 4 or 5 or 6 8. 3 and 7 9. limit 8 to (comment or editorial or letter)10. 8 not 9The electronic databases will be searched from the earliest available years through present with no restriction on language of publication.Inclusion and exclusion criteria The eligibility will be determined by two researchers independently, a third viewer will be needed for decision making if a disagreement arise. Firstly, the title and abstract of all the articles will be screened. After that, a full text examination will be carried out for those articles that was previously considered to be potentially relevant. The studies will be included if the following requirements are satisfied:1. It is population-based, studies conducted in a specific population will be excluded.2. The sample size of the study is larger or equal to 5003. The study subjects are apparently healthy with age of 18 and order4. The study should contain sufficient information of which criteria was used to diagnose MetSyn and the crude prevalence or incidence rate of this health condition.5. The study should mention at least one ethnic group. And if it contains more than one group, the data reported should be stratified by different ethnicity. Study with no mention of the ethnic information will be excluded. If more than one study based on a single population have been found, the study with the most recent information will be included.Data extractionFor each selected article, the characteristics of the study and the participants as well as the outcome information will be recorded:1. First author 2. Publication year 3. Study design4. Study region 5. Study period6. Sample size 7. Criteria used for diagnosis 8. Sex ratio of the sample population9. Age structure of the sample population10. Ethnicity structure of the sample population11. Number of MetSyn cases12. Crude prevalence or incidence rate of MetSyn for each ethnic group13. Age-specific and sex-specific prevalence or incidence rate of MetSyn for each ethnic groupThe above data will be checked by a second viewer after collection.Quality Assessment For each selected article, its quality will be assessed using the Newcastle-Ottawa Scale (NOS) for observational study.Statistical analysisThe overall crude prevalence or incidence rate of MetSyn for each ethnic group will be calculated from all eligible studies. A random effects model will be used to estimate the prevalence or incidence rate and its 95% confidence interval. Cochran’s Q test and I2 statistic will be used to assess heterogeneity. Meta-regression and sub- group analysis by age, sex and other factors will also be carried out. Ethnic classification will be defined refers to Office of Management and Budget (OMB) DIRECTIVE NO. 15. And all these analyses will be performed using R