The Canadian Diabetes Association estimates that at least 2.2 million Canadians have diabetes, with many more cases remaining undiagnosed. By the end of the decade, over three million Canadians could have diabetes. An aging population, a rise in obesity and sedentary lifestyles, and immigration from high-risk groups (people of Hispanic, Asian, South Asian or African descent) are the factors contributing to the increasing number of diagnoses. Moreover, The Aboriginal population is 3-5 times as likely to be diagnosed with type 2 diabetes as compared to the rest of the Canadian population. Children, too, are being increasingly diagnosed; American data suggests that children of high-risk population groups have a 1 in 3 chance of being diagnosed with type 2 diabetes in their lifetime.
Also of great concern are those individuals who have been diagnosed with pre-diabetes, which includes impaired glucose tolerance (IGT) and/or impaired fasting glucose (IFG). These individuals are at high risk for type 2 diabetes and/or cardiovascular disease if lifestyle prevention strategies are not implemented and followed.
Type 1 diabetes accounts for approximately 5% to 10% of all known cases of diabetes. The etiology of type 1 diabetes involves a genetic predisposition and an autoimmune destruction of the pancreatic beta cells that produce insulin. This results in a nearly absolute insulin deficiency, making persons dependent on insulin for life. Although type 1 diabetes can occur at any age, even in the eighth and ninth decade, the majority of individuals who develop this type of diabetes do so before age 30.
Ninety to 95% of cases of diabetes are type 2 diabetes. Both genetic and environmental factors contribute to its development. Obesity, particularly intra-abdominal obesity, sedentary lifestyle, aging and a high-fat, high-calorie diet have been identified as environmental factors.
The key to the prevention of diabetes and its complications is early diagnosis and intervention. Type 2 diabetes is a progressive disease caused by both insulin resistance and insulin deficiency. Insulin resistance (decreased cell sensitivity or responsiveness to insulin) is evidenced by an elevation of postprandial glucose values. As insulin deficiency (beta cell failure) becomes more prominent, fasting glucose levels increase due to an increase in hepatic glucose production, especially in the early morning. Evidence shows that the best way to slow the progression of diabetes and its complications is excellent glucose control.
To achieve and maintain glucose goals as diabetes progresses, therapy needs may change. Treatment begins with aggressive lifestyle interventions including plans for healthy eating and physical activity. However, as beta cell failure continues, for many individuals, insulin and/or other medication(s) need to be combined with nutrition therapy. It is important for people managing diabetes to understand that this is not because the “diet” or glucose-lowering medications fail, but because the beta cells of the pancreas are no longer able to produce the insulin needed to maintain adequate glucose control.
Diabetes is also associated with hypertension and a dyslipidemia characterized by increased triglycerides, decreased high-density lipoprotein (HDL) cholesterol and increased small, dense low-density lipoprotein (LDL) cholesterol. Control of hyperglycemia, hypertension and dyslipidemia has been shown to reduce complications of diabetes such as cardiovascular disease, microvascular complications and neuropathy. Canadian Diabetes Association, Clinical Practice Guidelines are listed in Table 1 (5).