Central obesity is a key feature of the syndrome, being both a sign and a cause, in that the increasing adiposity often reflected in high waist circumference may both result from and contribute to insulin resistance. However, despite the importance of obesity, patients who are of normal weight may also be insulin-resistant and have the syndrome.
Historically the treatment for what was called the "hard pulse disease" consisted in reducing the quantity of blood by bloodletting or the application of leeches. This was advocated by The Yellow Emperor of China, Cornelius Celsus, Galen, and Hippocrates. The therapeutic approach for the treatment of hard pulse disease included changes in lifestyle (staying away from anger and sexual intercourse) and dietary program for patients (avoiding the consumption of wine, meat, and pastries, reducing the volume of food in a meal, maintaining a low-energy diet and the dietary usage of spinach and vinegar).
From another perspective, hypertension may be categorized as either essential or secondary. Primary (essential) hypertension is diagnosed in the absence of an identifiable secondary cause. Approximately 90-95% of adults with hypertension have primary hypertension, whereas secondary hypertension accounts for around 5-10% of the cases.  However, secondary forms of hypertension, such as primary hyperaldosteronism, account for 20% of resistant hypertension (hypertension in which BP is >140/90 mm Hg despite the use of medications from 3 or more drug classes, 1 of which is a thiazide diuretic).
The primary complications of diabetes due to damage in small blood vessels include damage to the eyes, kidneys, and nerves. Damage to the eyes, known as diabetic retinopathy, is caused by damage to the blood vessels in the retina of the eye, and can result in gradual vision loss and eventual blindness. Diabetes also increases the risk of having glaucoma, cataracts, and other eye problems. It is recommended that diabetics visit an eye doctor once a year. Damage to the kidneys, known as diabetic nephropathy, can lead to tissue scarring, urine protein loss, and eventually chronic kidney disease, sometimes requiring dialysis or kidney transplantation. Damage to the nerves of the body, known as diabetic neuropathy, is the most common complication of diabetes. The symptoms can include numbness, tingling, pain, and altered pain sensation, which can lead to damage to the skin. Diabetes-related foot problems (such as diabetic foot ulcers) may occur, and can be difficult to treat, occasionally requiring amputation. Additionally, proximal diabetic neuropathy causes painful muscle atrophy and weakness.
14 November 2018. On World Diabetes Day 2018, WHO joins partners around the world to highlight the impact diabetes has on families and the role of family members in supporting prevention, early diagnosis and good management of diabetes. More than 400 million people live with diabetes worldwide, and the prevalence is predicted to continue rising if current trends prevail. Diabetes is a major cause of premature dying, blindness, kidney failure, heart attack, stroke and lower limb amputation. It was the seventh leading cause of death in 2016.
^ Sacks, F. M.; Svetkey, L. P.; Vollmer, W. M.; Appel, L. J.; Bray, G. A.; Harsha, D.; Obarzanek, E.; Conlin, P. R.; Miller, E. R. (2001-01-04). "Effects on blood pressure of reduced dietary sodium and the Dietary Approaches to Stop Hypertension (DASH) diet. DASH-Sodium Collaborative Research Group". The New England Journal of Medicine. 344 (1): 3–10. doi:10.1056/NEJM200101043440101. ISSN 0028-4793. PMID 11136953.
Dr Jacomien de Villiers qualified as a specialist physician at the University of Pretoria in 1995. She worked at various clinics at the Department of Internal Medicine, Steve Biko Hospital, these include General Internal Medicine, Hypertension, Diabetes and Cardiology. She has run a private practice since 2001, as well as a consultant post at the Endocrine Clinic of Steve Biko Hospital.
The distribution of adipose tissue appears to affect its role in metabolic syndrome. Fat that is visceral or intra-abdominal correlates with inflammation, whereas subcutaneous fat does not. There are a number of potential explanations for this, including experimental observations that omental fat is more resistant to insulin and may result in a higher concentration of toxic free fatty acids in the portal circulation. 
^ Jump up to: a b c d e National High Blood Pressure Education Program Working Group on High Blood Pressure in Children and Adolescents (August 2004). "The fourth report on the diagnosis, evaluation, and treatment of high blood pressure in children and adolescents". Pediatrics. 114 (2 Suppl 4th Report): 555–76. doi:10.1542/peds.114.2.S2.555. PMID 15286277.
In the US, 84.1 million adults—more than 1 in 3—have prediabetes, and 90% of them don’t know they have it. Prediabetes is a serious health condition where blood sugar levels are higher than normal, but not high enough yet to be diagnosed as diabetes. Prediabetes increases your risk for type 2 diabetes, heart disease, and stroke. But through the CDC-led National Diabetes Prevention Program, you can learn practical, real-life changes that can cut your risk for developing type 2 diabetes by as much as 58% (71% if you’re 60 or older).