Type 2 Diabetes and Its Risk Factors

Type 2 diabetes is the most common form of diabetes and accounts for 90% of all cases. The number of diabetic patients in IR Iran is estimated to be about 1.5 million. Identification of diabetes risk factors and trying to remove them, can prevent or delay it. The relationship between type 2 diabetes and genetic factors is stronger than the relationship in type 1 diabetes. The concordance of type 2 diabetes in identical twins is 70-90%. Obesity particularly visceral is very common in type 2 diabetes. The risk of diabetes increases with increasing age. Prevalence rates of diabetes are strongly different among different ethnic groups. Women with a history of gestational diabetes have a 50% risk of eventually developing diabetes in the next 20 years of their lives. High blood pressure (=>140/90mm hg) could be an early sign of underlying insulin resistance, related to central adiposity. Risk of diabetes in persons with high blood pressure is twice the normal persons. Low birth weight is often followed by accelerated postnatal growth and this may be important for assessing the risk of diabetes. Impaired glucose tolerance (IGT) test is typically characterized by hyperglycemia and insulin resistance. Persons with IGT without changing their lifestyles develop type 2 diabetes in 10 years. Insulin resistance has been observed in women with polycystic ovary (PCO) syndrom. It is estimated that 35-50% of women with PCO have impaired glucose tolerance test. Stress stimulates the release of various hormons, which may cause elevated blood glucose levels. Smoking is not a well-documented risk factor for type 2 diabetes. In spite of this diabetes and CHD have many common causal factors. Large-scale prospective studies have shown that smoking is associated with the development of type 2 diabetes. However larger scale and long-term studies are needed to clarify the role of smoking as a risk factor of diabetes.