About Diabetes Mellitus
Diabetes mellitus is a chronic disease that affects the body's ability to use glucose, a simple sugar used as the basic form of energy in most tissues, particularly nervous and muscular. The three most common types of diabetes are type 1, type 2 and gestational, and the general risk factors for diabetes depend upon the type.
Diabetes presents more complications the longer a patient lives with the disease. Careful management of the disease may slow the progression and lower the possibility of complications until later in life. Many patients, especially those which do not intensively manage their blood glucose levels, will experience a number of complications which may include eye disease (retinopathy), kidney disease (nephropathy), nerve disease (neuropathy) and diseases of the cardiovascular system.
Type 1 Diabetes
Type 1 diabetes mellitus (T1DM) is an autoimmune disease where the body's immune system attacks and destroys parts of itself. In the case of T1DM, the immune system attacks the β-cells of the pancreas, the cells responsible for the development and secretion of insulin. Insulin allows glucose to enter cells and lowers the levels of circulating blood glucose. Type 1 diabetics require regular injections of exogenous insulin to maintain appropriate blood sugar levels, along with proper management which includes diet and exercise. However, since T1DM tends to develop during childhood and adolescence, patients may begin experiencing complications as early as middle age.
Risk factors are not entirely exact, but seem to follow certain patterns. The single greatest risk factor is that of genetics. Certain gene types indicate an increased risk of disease development. Also, if another family member has had T1DM, risk increases. Non-Hispanic whites are at a higher risk of T1DM than other races. Oddly, geography is another risk factor; likelihood of disease increases the further from the equator a patient lives. Other risk factors include exposure to certain viruses and low vitamin D levels, however early intake of cow's milk may increase chances of diabetes as well.
Type 2 Diabetes
Type 2 diabetes mellitus (T2DM) occurs when chronically high levels of circulating blood glucose (hyperglycemia) causes chronically high levels of circulating insulin (hyperinsulinemia). Over time this causes the cells to no longer recognize insulin in a process called desensitization. As this happens, the pancreas makes less and less insulin, called insufficiency. The body develops a condition called insulin resistance. Complications of T2DM are numerous, and unfortunately, nearly 75 percent of patients who develop the disease will die of a cardiovascular complication.
Of the risk factors associated with T2DM, several are entirely dependent upon the individual patient's lifestyle. Patients with excessive fat tissue are at the greatest risk of disease; adipose (fat) tissue increases insulin resistance. Sedentary lifestyles increase risk because muscular activity uses glucose for energy and increases cellular insulin sensitivity. Other risk factors with a degree of control is the development of impaired glucose tolerance, or prediabetes, and gestational diabetes during pregnancy. Patients have no control over some risk factors, such as family history, race and age; older patients and black, Hispanic, American Indian and Asian American patients have increased risk.
Gestational diabetes mellitus (GDM) develops in pregnant women as a result of placental hormones which interfere with the actions of insulin. While both the mother's and fetus's blood sugar rise after eating, certain placental hormones impair the insulin reaction in the mother and impaired glucose tolerance occurs. This usually occurs later in the pregnancy and, for most mothers, blood glucose levels return to normal soon after delivery.
Some of the risk factors for GDM are beyond the scope of a patient's control, such as family history, race and age; pregnant mothers who are of a minority race or over 25 years of age are at an increased risk. Lifestyle-associated risk factors are being overweight and inactivity. Other risk factors include having GDM during an earlier pregnancy, previous delivery of a child weighing more than nine pounds and experiencing an unexplained stillbirth.
American Diabetes Association: Genetics of Diabetes
Mayo Clinic: Type 1 Diabetes: Risk Factors
Mayo Clinic: Type 2 Diabetes: Risk Factors
Mayo Clinic: Gestational Diabetes-Risk Factors