Over the past decades there has been a dramatic rise in the number of people with type II diabetes. Once a fairly rare disease, increasing rates of obesity have driven a climb in the number of cases globally. The number of adults with type II diabetes has more than doubled since 1980, rising from 153 million (1) to 415 million in 2015, and predictions are that it will affect 640 million people by 2040 (2). This has concerning consequences for worldwide heart health. Diabetes is one of the major risk factors for cardiovascular disease, and cardiovascular disease rates will rise in response to the diabetes epidemic (3). Measures taken to prevent or treat diabetes will improve heart health around the globe.
What is diabetes?
Diabetes is a disease where blood glucose levels are too high over a long period of time. Blood glucose is required for energy and is kept at a stable concentration by the action of insulin. Normally after a meal, glucose levels rise and this triggers a rise in insulin. Insulin tells the body to start to take up glucose from the blood and blood sugar falls again. Insulin keeps blood glucose levels from increasing too much. When people have diabetes, blood glucose can no longer be controlled effectively by the action of insulin.
Three types of diabetes
There are three types of diabetes: type I, type II and gestational diabetes. Type I diabetes normally starts in childhood when the cells in the pancreas that make insulin do not function properly. The exact cause is unknown however it is thought that the combination of genetics and an environmental trigger cause the body to destroy the insulin-making cells. This means that the body cannot make enough insulin to reduce blood glucose levels after a meal, and the body also cannot get the nutrients that it needs for normal growth and development. Insulin must be given as a treatment. The prevalence of type I diabetes has remained stable.
Type II diabetes tends to start later in life. For this type of diabetes, the cells in the body do not react to the insulin that is being produced. Cells do not take up glucose as they should, and blood glucose levels remain. Further along the course of the disease, the body’s ability to produce insulin is also reduced. Type II diabetes is far more likely to occur in obese, sedentary adults.
In gestational diabetes, the state of pregnancy means that the body’s cells are less able to take up glucose from the blood. It is thought that this helps the fetus to secure its own supply of glucose by preventing the mother from using it for herself. Gestational diabetes generally resolves after the mother has given birth, however women who have had gestational diabetes are at a higher risk of developing type II diabetes later in life (4).