Diabetes, whether type 1 or type 2, can contribute to the development of several serious long-term health problems. People with type 1 diabetes mellitus (T1DM) no longer make insulin, a hormone necessary to move glucose, or sugar, from the blood into the body cells to be used or stored as energy. Insulin is necessary to sustain life, so people with T1DM require replacement insulin to manage blood sugar levels. Over time, if blood sugar levels run too high, damage to blood vessels and nerves can occur, and this can cause health problems such as heart and blood vessel disease, kidney disease, nerve damage, eye disease and an increased risk of amputation. However, if blood sugars are kept to near-normal levels, these health problems can be minimized or prevented.
According to an October 2013 review published in “Cardiovascular Diabetology," the risk of cardiovascular disease (CVD) in T1DM is 2 to 3 times higher in men and 3 to 5 times higher in women compared to people without diabetes. CVD, the leading cause of death in adults with T1DM, affects the large blood vessels that transport blood throughout the body, including to the heart, arms, legs and brain. Over time, high blood sugars can contribute to an impaired or blocked blood supply to the heart or brain, increasing the risk of heart attack or stroke. Poor blood flow may also lead to slower healing of wounds and serious infections in the limbs -- which in some cases may require amputation of the affected toes, feet or legs.
High blood sugars contribute to the development of neuropathy, or nerve damage. An article published in the October 2008 issue of “Pharmacology & Therapeutics” reports that more than half of those with longstanding diabetes have some type of neuropathy. Diabetes peripheral neuropathy (DPN) is a common type affecting the nerves of the arms, hands, legs and feet. While DPN can lead to pain that is especially bad at night, this nerve damage often causes a loss of sensation to the feet, creating a situation where infections or sores may go unnoticed. If poor blood flow is also a factor, infections can quickly turn serious, increasing the risk of amputation. Diabetes autonomic neuropathy is another type that can affect nerves that control body functions, causing symptoms such as decreased heart rate, the inability to recognize low blood sugar levels, abnormal sweating, slow digestion, erectile dysfunction and frequent bladder infections.
The kidneys filter the blood and eliminate the blood's waste products through the urine. Over time, high blood sugar levels can damage the tiny blood vessels in the kidneys, affecting how well these filters work and putting people with T1DM at a greater risk of developing chronic kidney disease (CKD). According to a November 2011 article published in the “Clinical Journal of the American Society of Nephrology," 35 percent of adults who have diabetes also have CKD. Diabetic kidney disease develops slowly over time and the early stages have no symptoms. Symptoms may only be present when kidney damage is severe, as a result of waste products building up in the blood. Early detection via urine protein tests is an important step in reducing the progression to kidney failure -- which requires dialysis or kidney transplantation.
Although all forms of diabetic eye disease have the potential to cause severe vision loss and blindness, the most common cause of vision loss is diabetic retinopathy (DR). A study in the April 2005 issue of "JAMA Ophthalmology" reported that approximately 86 percent of adults diagnosed with with T1DM before age 30 had some form of retinopathy, and 42 percent had a vision-threatening form. High blood sugar levels cause damage to the retina. In DR, the tiny blood vessels in the retina leak fluid or blood into the surrounding tissue. Over time, this impairs the supply of blood to the retina and new -- but weaker -- blood vessels grow. These changes can progress to vision loss. Diabetic eye disease also includes the formation of cataracts, which cloud the eye’s lenses, and glaucoma, which results from damage to the eye’s optic nerves.
Available data shows the long-term health problems related to T1DM are all too common. However, over the past few decades, better care and treatment strategies have been in place, which may reduce the percentage of people with T1DM impacted by these complications. The results of a landmark study completed in 1993 -- the Diabetes Control and Complications Trial (DCCT) -- dramatically changed the management of T1DM. The DCCT was the first research trial to confirm that controlling blood sugar to near-normal levels can prevent or reduce the risk of long-term complications in people with T1DM. DCCT data showed that this tight blood sugar control reduced the risk of eye disease by 76 percent, kidney disease by 50 percent and nerve disease by 60 percent. Its follow-up trial, the Epidemiology of Diabetes Interventions and Complications study, outlined that good blood sugar control reduced the risk of cardiovascular disease by 42 percent, and decreased the risk of heart attack, stroke or death from CVD by 57 percent.
Precautions and Next Steps
The long-term complications of diabetes can be prevented or minimized by strict control of blood sugar. This involves diligent self care -- testing blood sugar several times daily, frequent daily insulin injections or insulin delivery by an external insulin pump, and adjusting insulin based on diet and physical activity levels. When attempting to achieve near-normal blood sugar levels, diabetics must take care to avoid the most common risk of intensive control -- frequent and severe low blood sugar levels. Regular communication and follow-up with a diabetes health-care team is important. In addition to a primary care doctor, this team will include specialty physicians such as an endocrinologist or diabetologist, and certified diabetes educators, including nurses, dietitians and pharmacists. Those with T1DM should also contact their doctors with any signs or symptoms related to long-term complications.