Statins are the drugs that are keeping millions of us diabetics alive by helping us control our cholesterol levels and reduce our risk of heart disease. Recent research suggests that statins make even more valuable contributions to good health.
Cholesterol is a vital microscopic ingredient found in the membranes of all human and animal cells. You produce it inside your own body. You also get it from the foods you eat, ie from animal products. Plants do not contain any cholesterol.
High levels of cholesterol in your bloodstream are associated with cardiovascular disease (CVD) which causes heart attacks and strokes.
If you have type 2 diabetes, there is an 85 percent chance you also have problems with the level of the cholesterol in your blood.
Statins are drugs used to inhibit the production of cholesterol inside your body and reduce your risk of CVD.
Cholesterol is vital for survival. It holds the thin membranes (sheet-like coverings) of your body cells together—without cholesterol your body would collapse into a jelly-like heap.
It also has a role in sending signals along your nerves to your cells. In addition, cholesterol is the raw material your body uses to make certain hormones, as well as vitamin D which controls the calcium in your body.
About 75 to 80 percent of your cholesterol is made by synthesising other substances inside your own body. Much of this internal production takes place in your liver. Cholesterol is also made in your intestines, adrenal glands and reproductive organs.
The remaining 20 to 25 percent of your cholesterol comes from the meat, fish and other animal products (such as milk) you eat. You do not get any cholesterol from eating plants.
If you eat too much cholesterol, you body will compensate by reducing the amount of cholesterol you make internally, provided all your systems are working properly. If not, you will end up with too much cholesterol in your bloodstream, which is what happens to the vast majority of diabetics.
Benefits of statins
Taken regularly, statins inhibit the enzyme that plays a central role in the production of cholesterol in the liver, thus reducing the internal production of cholesterol.
If you also avoid or reduce the amount of meat, fish and dairy products you eat, you will be restricting the amount of cholesterol you ingest. Because the statins are inhibiting the production of cholesterol in your liver, this will reduce the overall amount of cholesterol in your bloodstream.
Researchers have found that statins prevent cardiovascular disease in persons who have high levels of cholesterol but no history of heart disease. In both America and Europe, the use of statins is recommended for the primary prevention of CVD.
There is also strong evidence that statins are effective for treating already-existing CVD during its early stages. It is estimated that, by lowering LDL cholesterol by 1.8 mmol/L or 70 mg/dl on average, long-term use of statins reduces cardiac events (such as heart attacks and sudden cardiac deaths) by 60 percent and the risk of stroke by 17 percent.
Evidence suggests that statins are not very good at reducing triglycerides and raising levels of HDL-cholesterol (‘good cholesterol’).
Side effects of statins
Taking statins regularly can cause side-effects in some (but not all) people. The most important adverse side effect is increased concentrations of liver enzymes, which indicate damage to the liver.
In addition, 10 to 15 percent of those who take statins experience muscle pain. For non-diabetics, statins may also increase the risk of diabetes by 9 percent, with higher doses appearing to have a a stronger effect.
Other possible adverse effects include cognitive impairment, damage to the pancreas, and sexual dysfunction.
In the opinion of most patients, the cholesterol-reducing benefits of statins far out-weight their side-effects. This is evidenced by sales of these drugs.
Indeed ten years ago the most popular statin, Lipitor (atorvastatin) from Pfizer, was the best-selling pharmaceutical in history. As patents expire, several branded statins are becoming available as less expensive generic drugs.
Newly discovered benefits of statins
In September 2014, a new study from Denmark found that statins may also help prevent common and very serious complications of diabetes, such as damage to small blood vessels (micro-vascular disease) that give rise to amputations and blindness.
Diabetes damages the small blood vessels in the feet, hands, eyes and kidneys. This gives rise to various medical conditions.
In diabetic neuropathy the nerves in the feet and hands are damaged. Once the feet are badly affected they may need to be amputated.
Retinopathy is damage to the tiny blood vessels in retina in the eyes. It eventually leads to blindness.
Diabetic nephropathy is damage to the tiny blood vessels in the kidneys. This destroys the functioning of the kidneys and eventually necessitates dialysis or a kidney transplant.
Thus the findings of the Danish study, in which data on more than 60,000 people with diabetes was collected from clinical registries in Denmark, was significant.
The patients were over 40 years old and had been diagnosed with diabetes between the beginning of 1996 and the end of 2009.
The researchers compared the outcomes for more than 15,500 patients who used statins with more than 47,000 patients who were not on these drugs. The study was reported in The Lancet Diabetes & Endocrinology.
The results showed that after more than 2.5 years, people who used statins were 34 percent less likely to be diagnosed with diabetic neuropathy and 40 percent less likely to develop retinopathy due to their diabetes.
As regards the risk of kidney disease, however, the study found no different between those who took statins and those who did not.
These results were unexpected. High levels of blood glucose (the scourge of diabetics) are linked to micro-vascular diseases. Statins are suspected of raising blood glucose levels and the purpose of the study was to find out if persons on statins might be at increased risk of developing micro-vascular complications.
To the researchers’ surprise, the results showed that statins decreased, rather than increased, the risk of complications such as diabetic neuropathy and retinopathy, and there was no evidence that the use of statins is associated with an increased risk of micro-vascular diseases.
The scientists did not analyse the causes of their findings. However it has been suggested that statins have anti-inflammatory effects and that these may slow the progression of micro-vascular disease in the eyes, limbs or kidneys.
The extra benefits we seem to be getting from statins is good news for us diabetics who take statins regularly to control our cholesterol.
However, further studies are needed to confirm that statins do indeed provide protection against these micro-vascular diseases and to find out how they do so.