The connection between diabetes and cancer has been the question for many.
While there are things we can’t control, which influence our risk of disease, such as genetics, environmental factors, etc., there are several things we can do to preserve our health.
Understanding what we can do to help promote the quality of our health and reduce these risks gives us as much influence as possible over our health and wellness outcomes.
What is diabetes?
Diabetes mellitus, or diabetes, is a disease affecting the pancreas and its ability to produce the hormone insulin. More specifically, the beta cells of the pancreas are responsible for producing insulin. Diabetes occurs when:
- the beta cells of the pancreas are destroyed
- when the beta cells don’t produce enough insulin to keep blood sugar levels regulated
- or when the body doesn’t respond to insulin effectively
Insulin helps blood glucose (blood sugar) enter our cells, where it’s used as fuel to support the body’s functions. Without enough insulin, sugar remains in the bloodstream and can become dangerously high.
Sustained high blood sugar can adversely affect health. Our bodies make sugar, and we also obtain it from certain foods we eat, such as carbohydrates.
It harms arteries and blood vessels, crucial for supplying blood to our organs and body systems. It also damages nerves. This can result in a loss of sensation in limbs, which can lead to severe wounds and amputations.
There are different types of diabetes, including type 1, type 2, and gestational diabetes. Type 2 diabetes will be the type referenced concerning cancer risk. Type 1 diabetes is an autoimmune disease and not associated with the same metabolic pathways linked with cancer risk.
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How does diabetes increase the risk of other metabolic conditions & diseases?
Having diabetes increases the risk of certain diseases. This is why preventing and managing diabetes is so important. When blood sugars are well-controlled, the risk of complications is reduced.
Cardiovascular disease (heart disease) and stroke. Having high blood sugar over a prolonged period of time damages the arteries and vessels of the heart. The longer a person has diabetes, the higher the risk of heart disease.
Mortality rates from cardiovascular disease are approximately 1.7 times higher in individuals with diabetes compared to those without. The risk is higher because people with diabetes tend to have higher levels of cholesterol and higher blood pressure (hypertension), which can lead to the hardening and narrowing of blood vessels.
Diabetes is a recognized risk factor for stroke. This is due to the changes in the vascular system supplying blood to the brain.
Metabolic syndrome isn’t a disease in itself but involves a cluster of risk factors that can increase the risk of certain diseases.
Metabolic syndrome is directly associated with an increased risk of diabetes, heart disease, and mortality. Some of the risk factors (a diagnosis requires the presence of at least three symptoms/risk factors) include
- a large waistline
- high triglyceride level
- low HDL (good) cholesterol
- elevated blood pressure
- high glucose levels
Chromic Kidney Disease
Chronic kidney disease (CKD). Diabetes damages the vessels of the kidneys. This can cause them to lose some of their function over time. Diabetic kidney disease is the leading cause of kidney failure in the United States.
Does diabetes increase the risk of cancer?
Type 2 diabetes increases the risk of
- Colon cancer
- Postmenopausal breast cancer
- Pancreatic cancer
- Liver cancer
- Endometrial cancer
- Bladder cancer
- Non-Hodgkins lymphoma
Men with diabetes appear to have a lower risk of prostate cancer..
Diabetes can increase cancer risk in several ways. Physical activity level and diet can play a role in the development of tumors, as well as the metabolic changes that can occur.
Increased levels of insulin and C-peptide (an insulin production marker) have been associated with higher risks of colon, postmenopausal breast, pancreatic, bladder, and endometrial cancers.
Elevated insulin levels occur with insulin resistance, which is one of the causes of type 2 diabetes. Insulin resistance is also present in people with prediabetes or borderline diabetes, as well as gestational diabetes.
Elevated insulin levels stimulate the production of insulin-like growth factor-1 (IGF-1). IGF-1 may increase the rate of cells multiplying and reduce the body’s ability to destroy abnormal cells (apoptosis). This combination can mean that cancerous cells can grow more quickly without being destroyed by the body. Elevated levels of IGF-1 are linked to an increased risk of specific cancers.
High blood glucose levels increase the production of free radicals, which can damage the DNA of our cells.
When cells are damaged, there is a higher chance that new mutated cells might be produced to replace those cells, which causes cancer. However, research is inconclusive as to whether or not elevated blood sugar definitively causes an increased risk for cancer.
In fact, in animal studies, hyperglycemia (high blood sugar) without high insulin levels didn’t lead to increased cancer growth. This may indicate that high insulin levels may play a more significant role in cancer development than high blood sugars alone.
Joint risk factors between diabetes and cancer
Certain risk factors are shared between the risk of developing diabetes and developing cancer.
Some of these risk factors are modifiable, meaning we have some control over them and can change them. Other risk factors are considered non-modifiable, meaning we have no control over them.
The risk of developing cancer increases with age. In developed countries, 78% of new cancer diagnoses occur in people 55 years of age and older. Similarly, type 2 diabetes becomes more prevalent with age. People over the age of 60 have the highest prevalence rate of diabetes compared to other age groups.
Certain cancers are sex-specific, such as prostate, endometrial. But, overall, men have a higher risk of developing cancer than women. Men also have a slightly higher age-adjusted risk of developing diabetes than women.
Certain races are at an increased risk of developing cancer and diabetes. African Americans and non-Hispanic whites have a higher prevalence of cancer. African Americans, Hispanics, Native Americans, and Asian Americans have a higher incidence of type 2 diabetes compared to other races.
People with a BMI considered overweight or obese (BMI 25+) are at increased risk of many cancers. Similarly, being at a higher weight is linked with insulin resistance and the development of diabetes. Some studies have found a link between high waist circumference and certain cancers, regardless of BMI. Weight loss may be a protective factor against developing certain diseases and type 2 diabetes.
Diets low in red and processed meats and rich in plant-based foods like fruits, vegetables, legumes, and whole grains are associated with a decreased cancer incidence, as well as a decreased incidence of type 2 diabetes.
Diets rich in foods with high glycemic indexes (meaning they turn to blood sugar rapidly) are also associated with an increased risk of diabetes. However, the link between high glycemic index foods and cancer isn’t established. Still, the American Cancer Society recommends against eating high-sugar foods, as it can contribute to overweight and obesity.
Being physically active, such as getting 30 minutes of moderate-intensity exercise at least five days per week, can reduce the risk of developing type 2 diabetes by up to 36%. Similarly, physical activity can help reduce the risk of certain cancers. Therefore, a sedentary diet is a risk factor for both cancer and type 2 diabetes.
Smoking is a risk factor for both type 2 diabetes and cancer. Smoking accounts for 71% of all trachea, bronchus, and lung cancer deaths, and is associated with several other types of cancers.
Alcohol consumption, even in moderate amounts, is a risk factor for the development of several types of cancer. Excessive alcohol consumption is a risk factor for developing diabetes.
How can you reduce your risk?
Cancer and type 2 diabetes share many risk factors. Maintaining a healthy lifestyle can reduce your risk of both of these diseases.
For those who already have diabetes, these healthy habits can still reduce cancer risk and promote healthy blood sugars. This reduces the likelihood of diabetes complications.
Aim for a balanced diet
Individuals with excess weight, having a body mass index (BMI) of 25 and above, face an elevated risk of developing type 2 diabetes. Moreover, they may be at increased risk of developing certain cancers. You can calculate your BMI here.
Eat a healthy diet
A diet rich in whole grains, fruit, vegetables, lean protein, and low in refined carbohydrates and sugar is an all-around healthy diet. This type of eating, similar to a Mediterranean diet, can reduce disease risk, including cancer.
The American Diabetes Association and the American Heart Association both recommend the Mediterranean diet for its health benefits. Following the Mediterranean diet can also reduce inflammation and insulin resistance, potentially lowering the risk of cancer.
(C-reactive protein (CRP) measures inflammation in the body. High CRP levels are associated with both diabetes and cancer, which confirms the importance of an anti-inflammatory diet such as the Mediterranean diet.)
Smoking is a risk factor for both type 2 diabetes and cancer. Not only that, but smoking increases the risk of heart disease. People with diabetes are already at an increased risk of developing heart disease. Therefore, quitting smoking is a significant step to improve heart health.
Be physically active
Participating in 30 minutes of moderate-intensity exercises, at least five days per week can help improve insulin resistance and decrease inflammation.
Be mindful of alcohol consumption
Excessive alcohol consumption is a risk factor for developing type 2 diabetes and cancer. Excessive alcohol intake can also increase the risk of chronic pancreatitis, which is inflammation of the pancreas.
Chronic inflammation of the pancreas can damage the beta-cell. These are responsible for producing insulin, which can result in diabetes. Chronic pancreatitis and diabetes can heighten the risk of pancreatic cancer, the most lethal among all cancers.
Participate in regular preventative medical care
Visiting with a healthcare provider annually is helpful for early detection, diagnosis, and prevention of diabetes and certain cancers. Prostate and breast exams, as well as routine blood work, can help screen for potentially serious health problems.
Consider treating diabetes with metformin
Metformin (Glucophage) is one of the most commonly used medications to treat type 2 diabetes. It can also be used in some people with prediabetes to lower their risk of developing type 2 diabetes. Studies have found that metformin may stop the growth of cancer cells. Of course, speaking with your healthcare provider about the best diabetes treatment for you is the ultimate priority.
Type 2 diabetes is associated with an increased risk of cancer. Specifically, people with diabetes are more likely than people without diabetes to develop certain cancers.
While there are many risk factors for diabetes and cancer that can’t be controlled, such as age, sex, and race, many risk factors are within our control. These modifiable risk factors that are shared between type 2 diabetes and cancer include weight, diet, physical activity level, smoking status, and alcohol consumption.
Practicing healthy diabetes management such as:
- eating a healthy diet
- maintaining a healthy weight
- being physically active
- abstaining from smoking
- and avoiding excessive alcohol intake can reduce the risk of both diabetes and cancer.
Receiving regular preventative medical care can also reduce the risk of developing type 2 diabetes and certain cancers through proper screening measures.