Type-2 diabetes
also see: Diabetes
and Type-1 diabetesType 2 diabetes is the most common of the two main types and accounts for between 85 - 95% of all people with diabetes. People develop type 2 diabetes when the body can still make insulin, but the cells in the muscles, liver and fat do not use insulin properly - a condition known as insulin resistance. At first, the pancreas keeps up with the added demand by producing more insulin. In time, however, it loses the ability to secrete enough insulin in response to meals. In most cases this is linked with being overweight, hypertension, elevated cholesterol and with the condition often termed metabolic syndrome. Metabolic syndrome is a combination of medical disorders and is associated with a sedentary lifestyle. Type 2 diabetes therefore usually develops in people over the age of 40. However, recently, more children are being diagnosed with the condition, some as young as seven, probably because of unhealthy diets and spending too much time in front of television or computer.
Genetics
Genetic factors play an important role in type 2 diabetes, but the pattern is complicated, since both impairment of beta cell function and an abnormal response to insulin are involved. Researchers have identified a number of genetic suspects.
There is also a theory that suggests that some cases of type 2 diabetes and obesity are derived from normal genetic actions that were once important for survival. Some experts postulate the existence of a so-called "thrifty" gene, which regulates hormonal fluctuations to accommodate seasonal changes. In certain nomadic populations, hormones are released during seasons when food supplies have traditionally been low, which results in resistance to insulin and efficient fat storage. The process is reversed in seasons when food is readily available. Because modern industrialization has made high-carbohydrate and fatty foods available all year long, the gene no longer serves a useful function and is now harmful because fat, originally stored for famine situations, is not used up. Such a theory could help explain the high incidence of type 2 diabetes and obesity found in Pima tribes and other Native American tribes with nomadic histories and newly introduced Western dietary habits.
