Prolonged hyperglycemia, or high blood sugar levels over several years in people with diabetes, can affect different organs, such as the heart or blood vessels. This increases the risk of cardiovascular disease, the leading cause of death among people with type 1 diabetes (T1D) over the age of 40.
What is atherosclerosis?
To better understand the risk, let’s look at how atherosclerosis works. Over time, hyperglycemia can weaken arterial walls (the linings of larger blood vessels) and promote the formation of atheroma plaques (fat, blood, fibrous tissue, calcareous deposits). These plaques, mostly made of cholesterol (a sign of atherosclerosis), make the arterial walls thicker, which reduces their diameter and promotes clotting. As a result, blood flow is restricted.
In time, these complications can obstruct the blood supply to certain body parts and keep them from getting enough oxygen to function properly. If the blood vessels become completely blocked (ischemia), complications involving the heart (e.g., stroke, heart failure), the brain (e.g., cerebrovascular accident or CVA) or the lower limbs can arise.
How to reduce the risk of cardiovascular complications
Here are some important strategies for reducing the risk of cardiovascular complications:
- Maintain blood sugar levels within the target range as much as possible.
- Regularly check blood pressure and take medication as needed for prevention or treatment.
- Regularly check blood lipid (fat) levels, including LDL-C (low-density lipoprotein cholesterol) or “bad cholesterol,” which should generally be under 2 mmol/L, and take medication (statin) as needed for prevention or treatment.
- Quit smoking.
- Do physical activity regularly.
- Eat a diversified and balanced diet: avoid foods with trans fat (e.g., commercial pastries, ultra-processed foods), reduce saturated fat (e.g., red meat, fat cheeses, butter), choose foods with “healthy” fats (e.g., fish, nuts and seeds, olive oil) and a high fibre content (e.g., whole-grain products, fruits and vegetables).
Reducing blood lipid levels, especially bad cholesterol (LDL-C), will help reduce the risk of atherosclerosis. The recommended levels of LDL-C are lower for people with T1D than for people without T1D since they are at a higher risk of cardiovascular complications.
A drug that lowers cholesterol levels
Statin is a class of prescription drugs that can lower blood fat and LDL-C levels or prevent the increase of LDL-C levels.
It is currently recommended for people with T1D who are in one of the following situations to take statin.
- People over the age of 40.
- People with a history of cardiovascular complications (all ages).
- People with one of the following complications (all ages): retinopathy (eye damage), nephropathy (kidney damage) or neuropathy (nerve damage).
- People over the age of 30 who have been living with T1D for more than 15 years.
Even though studies have found that statin helps reduce the risk of cardiovascular events by about 21%, close to 40% of adults aged 40 and over who live with T1D don’t use this medication.
Why does it have such a bad reputation?
Over the last few years, there has been much noise in the media about statin’s (in)efficacy and side effects, so much so that it has affected the number of patients who use it as a treatment.
Yet, the efficacy of statin has been well established, especially in preventing cardiovascular disease in at-risk patients. Studies show that it is important for people with a higher risk of cardiovascular disease, including people with T1D, to start treatment as early as possible.
The side effects of statin, especially muscle pain, are also said to be a deterrent for patients. Several observational studies have shown that muscle pain is 20% to 50% more intense in people who take statin than in people who don’t.
Even so, a recent trial concluded that there is no difference in symptoms between participants who received a placebo (a pill that contains no active principle) and those who received statin. The trial involved 60 participants who had previously stopped taking statin due to side effects. They were randomly administered one of three treatment options per month (20 mg of atorvastatin [statin] per day, placebo, or no treatment) alternately over 12 months, so that each option could be observed for a total of 4 months. Participants and healthcare professionals were not aware of which option they were receiving. During the trial, participants who received statin and those who received a placebo reported muscle pain. According to the trial, 90% of symptoms were due to the nocebo effect (i.e., having negative expectations when taking medication). Still, the pain that was experienced should not be ignored. A full assessment should be done to identify the possible causes of symptoms. After this trial, most participants who had stopped taking statin due to side effects resumed treatment.
For most patients, the benefits of statin far outweigh the risks of side effects. According to some studies, statin also reduces the risk of dementia and could have a positive effect in preventing or treating certain types of cancer (e.g., prostate, breast).
The best way to prevent complications
With the right treatment and adequate management of blood sugar levels, it is entirely possible to reduce, or even avoid T1D-related complications. Statin is a treatment option that reduces the risk of cardiovascular disease, and there are treatment options to reduce the risk of kidney-related complications.
A study shows that many people in a group of 351 people living with T1D for more than 50 years did not experience any complications:
- 86.9% did not have any kidney disease.
- 51.5% did not have any cardiovascular disease.
- 42.6% did not have any eye disease.
- 39.4% did not have any nerve damage.
- Sun, Jennifer K et al. “Protection from retinopathy and other complications in patients with type 1 diabetes of extreme duration: the joslin 50-year medalist study.” Diabetes care vol. 34,4 (2011): 968-74. doi:10.2337/dc10-1675
- Fowler, Michael J.. “Microvascular and Macrovascular Complications of Diabetes.” Clinical Diabetes 26 (2008): 77-82.
- Livingstone SJ, et al. Risk of cardiovascular disease and total mortality in adults with type 1 diabetes: Scottish Registry Linkage Study. PLoS Med 2012;9:e1001321.
- Fisher, M. (2016), Statins for people with type 1 diabetes: when should treatment start?. Pract Diab, 33: 10-11. https://doi.org/10.1002/pdi.1990
- Liu, Binliang et al. “The relationship between statins and breast cancer prognosis varies by statin type and exposure time: a meta-analysis.” Breast cancer research and treatment vol. 164,1 (2017): 1-11. doi:10.1007/s10549-017-4246-0
- Kantor, Elizabeth D et al. “Statin use and risk of prostate cancer: Results from the Southern Community Cohort Study.” The Prostate vol. 75,13 (2015): 1384-93. doi:10.1002/pros.23019
- Bebu, Ionut et al. “Risk Factors for First and Subsequent CVD Events in Type 1 Diabetes: The DCCT/EDIC Study.” Diabetes care vol. 43,4 (2020): 867-874. doi:10.2337/dc19-2292
- Eldor, Roy, and Itamar Raz. “American Diabetes Association indications for statins in diabetes: is there evidence?.” Diabetes care vol. 32 Suppl 2,Suppl 2 (2009): S384-91. doi:10.2337/dc09-S345
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