Sneaking Up - How Diabetes Puts Lives at Risk
World Diabetes Day, held each year on 14 November, is truly a global event because diabetes affects people in every country. The International Diabetes Federation aims to raise awareness amidst concern over an escalating diabetes epidemic. The numbers and scale of this epidemic are breathtaking. Less well-known are the mechanisms by which diabetes damages the vascular system and that this process begins many years prior to the diagnosis.
Diabetes is a metabolic disorder that affects blood glucose levels. Glucose is one of the major metabolic fuels, along with fats and protein, and is carried in the blood to every cell in the body where it is used to provide energy. Insulin produced in the pancreas allows the cells to absorb glucose from the blood. If the pancreas cannot make enough insulin - or if the cells stop responding to the insulin that is available - then the cells cannot absorb glucose.
The two distinct causes of diabetes mean it is labeled Type 1 (no insulin) or Type 2 (insulin resistance). If the level of sugar in the blood rises high enough, it will spill into the urine - one reason doctors test a patient’s urine even at routine physicals.
Diabetes increases the risk of heart attack, stroke and peripheral vascular problems. Excess sugar damages the inside of all blood vessels in the body. It makes artery walls prone to furring up with atheroma. The large vessels in the heart form plaques that rupture and cause clots, which block blood supply and lead to heart attacks. Some clots travel through the circulation, blocking smaller vessels in the legs (deep vein thrombosis), the lungs (pulmonary embolism) or the neck and brain (stroke). Diabetes can also lead to blindness as damage to the tiny blood vessels causes them to dilate, burst and leak blood in the eyes.
Around 10% of diabetes is Type 1, which often develops in childhood due to genetic predisposition, but generally diabetes is caused by obesity - typically the result of physical inactivity and an unhealthy diet rich in sugar and fat. Being overweight makes cells more resistant to the effects of insulin, thereby overworking the pancreas as it tries to produce more insulin. Eventually the insulin-producing capacity of the pancreas is exhausted and diabetes may be confirmed. This evolving scenario represents a spectrum of diabetes but it could be several years before it is recognized, by which time the vascular damage that it causes may be advanced.
The long-term consequence of having undetected high blood glucose is significant, as shown in the graphic below.
Over the years, as insulin secretion and sensitivity tail off, excess blood glucose damages the inner lining of the blood vessels. This process, which is called endothelial dysfunction, promotes atherosclerosis – the combination of fat deposits and scar tissue that form plaques that can rupture and trigger a clot (thrombosis) to form, leading to devastating health consequences.
Diagnostic latency means large numbers of people live with undetected Type 2 diabetes for decades while unregulated abnormal glucose metabolism damages their blood vessels. It means “healthy” individuals can find their lives transformed overnight by the need for treatment to lower blood glucose and mitigate vascular risks with drugs such as statins, ACE inhibitors, beta blockers and aspirin.
While this year World Diabetes Day has a positive theme - healthy eating - people who are at high risk of having diabetes could benefit even more from being encouraged to undergo a quick blood glucose check with their doctor.