Diabetes describes a group of disorders characterized by abnormal glucose metabolism and elevated blood sugar levels. The primary forms of chronic diabetes are type 1 and type 2, which have different causes. Although high blood sugar levels characterize the disease, eating too much sugar is not a direct cause of type 1 or type 2 diabetes.
Genetic Causes of Type 1 Diabetes
An errant attack by the immune system on the insulin-producing cells of your pancreas is the immediate cause of type 1 diabetes. Destruction of these cells causes a profound deficiency or absence of the hormone insulin, which regulates blood sugar levels.
Development of type 1 diabetes is a multiphase process. Your genetic makeup sets the stage because certain genes increase your susceptibility to the disease. A single gene does not determine whether you develop type 1 diabetes. Rather, a group of genes affects the probability of the disease occurring. An article published in the October 2010 issue of "Diabetes Forecast" reports that researchers have identified approximately 50 genes that influence your risk of developing type 1 diabetes.
Environmental Triggers
A genetic predisposition for type 1 diabetes does not necessarily mean you will develop the disease. One or more environmental triggers must activate the autoimmune reaction that ultimately leads to destruction of your insulin-producing cells. Possible triggers might include viruses, your diet during infancy and living in a cold climate. Biomedical researchers continue to search for specific environmental triggers and the mechanisms by which they set in motion the development of type 1 diabetes.
Genetic Causes of Type 2 Diabetes
The metabolic defect with type 2 diabetes differs from that of type 1 disease. There is no immune system attack on your insulin-producing cells, which continue to produce normal or increased amounts of insulin with type 2 diabetes. The hormone, however, is ineffective because your tissues become insensitive to it. This metabolic defect, known as insulin resistance, causes an elevation in your blood sugar level.
Your genetic makeup determines your susceptibility to developing type 2 diabetes. Scientists have identified approximately 38 genes that influence the development of type 2 diabetes, with potentially many more yet to be discovered. A predisposition for type 2 diabetes does not mean you are invariably destined to develop the disease.
Lifestyle Triggers
Excess body weight and lack of physical activity are the primary triggers that move you from a genetic predisposition for type 2 diabetes to development of the disease. The National Institutes of Health reports that 85 percent of people with type 2 diabetes are overweight or obese. Carrying excess weight primarily around your abdomen further increases your level of risk. Although eating a high-sugar diet does not directly cause type 2 diabetes, if your sugar intake causes weight gain, it might indirectly affect your risk of developing the disease.
Inactivity contributes to the development of type 2 diabetes because it promotes insulin resistance. Exercise improves your insulin sensitivity, which might help ward off the development of type 2 diabetes, even if you are genetically predisposed to the disease.
References
- American Diabetes Association: Diabetes Myths
- "Genetic Landscape of Diabetes"; Dr. Laura Dean and Jo McEntyre; 2004
- "Diabetes Forecast"; "Why Me? Understanding the Causes of Diabetes: The Roles of Genes and The Toll of The Environment"; Erika Gebel; October 2010
- American Diabetes Association: Genetics of Diabetes
- National Institutes of Health Weight-Control Information Network: Do You Know the Health Risks of Being Overweight?
- "Harrison's Principles of Internal Medicine (16th Edition)"; Dr. Dennis Kasper et al (editors); 2004
