Endocrine, nutritional and metabolic diseases
Metabolic syndrome, formerly known as Syndrome X, is a condition characterized by clustering of certain factors that increase an individual's susceptibility to cardiovascular diseases, stroke, and diabetes. These factors include abdominal obesity, atherogenic dyslipidemia, hypertension, insulin resistance, and a prothrombotic and proinflammatory state. Diagnosis of the condition is fairly easy, and depends on a waist circumference >102 cm for men and 88 cm for women, triglycerides levels >150mg/dL, blood pressure >130/85 mm Hg, HDL cholesterol <40mg/dL in men and 50 mg/dL in women, and fasting glucose >100mg/dL.
Major risk factors for the condition include increasing age, racial predilection, with Asians and Hispanics showing a greater tendency to develop the disease, obesity, a history of diabetes or other diseases involving the endocrine system. Management primarily involves making lifestyle changes, such as loosing weight, exercising, stopping smoking, and reducing dietary fat intake. For many affected individuals, modifying their lifestyle itself is enough to control the condition. Some others, however, may also require antihypertensive and hypolipidemic medications in addition.
Researchers are still trying to learn what causes the metabolic syndrome. Results indicate that it is a multifactorial condition, involving a variety of genetic and environmental factors. Genes that have been identified to play some sort of role in the development of this condition include the Beta-3-Adrenergic Receptor (ADRB3), Hormone Sensitive Lipase (HPL), Lipoprotein Lipase (LPL), Insulin Receptor Substrate 1 (IRS1), Glycogen Synthase 1 (GYS1), and SH2-Containing Inositol Phosphatase 2 (SHIP2) genes. Products of most of these genes function as key regulators of insulin or play major roles in lipid metabolism.
In addition, alleles of certain important genes have also been seen to be associated with the condition. For instance, the -3G and 553T alleles of APOA5 (Apolipoprotein A-V), 1866T allele of LDLR (Low Density Lipoprotein Receptor), 13989G allele of CYP3A4, and 1014A allele of C1QTNF5 (C1q- and Tumor Necrosis Factor-Related Protein 5) have been shown to be positively associated with susceptibility to Metabolic Syndrome.
Mabry et al. (2010) undertook a literature review study to understand the prevalence of the metabolic syndrome in men and women in the GCC countries. The four high-quality studies that were identified showed the prevalence of this condition in men to range from 21% to 37% (ATPIII) and from 30% to 36% (IDF). Among women, the studies identified a prevalence rate ranging from 32% to 43% (ATPIII) and from 36% to 46% (IDF). Mabry et al. (2010) concluded that the prevalence of this condition in the GCC countries is about 10-15% higher than in most developed countries, and that the prevalence rates for women are generally higher.
Al-Shaibani et al. (2004) screened 609 Kuwaiti subjects between the ages of 30 and 60-years to study the prevalence of Insulin Resistance Syndrome in Kuwait. They found an overall prevalence rate of 33% using the ATPIII criteria.
Al Rashdan and Al Nesef (2010) carried out a nationwide cross-sectional study on a random sample from Kuwait through gathering demographic and clinical data. The prevalence in an adult Kuwaiti population was found to be 80.4% for the overweight, 48% for obesity, and 36% for metabolic syndrome. Overweight and obesity rates were found to be higher in females (82% and 53%, respectively) when compared to males (78% and 39%, respectively). Al Rashdan and Al Nesef (2010) demonstrated that in Kuwait the prevalence of obesity, overweight, and metabolic syndrome was found to be distressingly high and proposed vital and active community-based public health intervention.
Al-Lawati et al. (2003) estimated the prevalence of metabolic syndrome in adults in the Omani population. By two-stage cluster sampling, the study group (1000 individuals from each sex) was randomly selected from a list prepared from a pre-survey census of 16 Enumeration Areas. The age-adjusted prevalence of metabolic syndrome was found to be 21%, with nearly 85% of the population having at least one component of the syndrome. The crude prevalence was 17% (slightly lower due to the young population). Sex-specific prevalence rates were 19.5% and 23% in men and women, respectively. It was found that with increasing age, the rates increased in both sexes from 4.7% and 2.8% in men and women, respectively, in the age group 20-29 years, to 29.8% and 48.7%, respectively, in the age group 60-year and above.
Bener et al. (2009) conducted a cross-sectional survey over a period of 18 months starting in 2007 among Qatari nationals over 20-years of age. A total of 1204 subjects were interviewed and tested. The prevalence of Metabolic Syndrome was 21% and 32% among men and women, respectively using the ATPIII criteria, and 30% and 38% among men and women, respectively, using the IDF criteria. Multivariate logistic regression analysis revealed both age and BMI to be significant contributors to the increased prevalence.
Al-Nozha et al. (2005) reported on the results of the 5-year (1995-2000) National Epidemiological Health Survey to study CAD and its risk factors among Saudis. A total of 17,293 subjects were selected for the study using a two-stage cluster random sampling method. Using the ATPIII definition, 37% men and 42% women were found to be positive for Metabolic Syndrome.
Malik and Razig (2008) collected data from 4,097 Emirati men and women using a stratified, multistage random sampling method. The age-adjusted prevalence of Metabolic Syndrome in this sample population was found to be 40% (men: 35%, women: 43%) using the ATPIII definition, and 40% (men: 30%, women: 38%) using the IDF criteria.
Hajat and Shather (2012) reviewed the date from the population-based screening program 'Weqaya' in Abu Dhabi to investigate the prevalence and predictive value of metabolic syndrome. Of the total of 760 subjects included in the study, 325 (43%) were males with a mean age of 41.9 years. Of these, 149 (20%) were newly diagnosed diabetics, and Metabolic Syndrome was found in 29% vs. 32% of non-diabetics. Both the International Diabetes Foundation (IDF) and Adult Treatment Panel III (ATPIII) criteria were good predictors of CVD risk. However, IDF criteria were found to better predict pre-diabetes or diabetes, while ATPIII was found to be a better predictor of CVD.