Diabetes & Cancer | Part I

Diabetes, also known as diabetes mellitus, refers to a group of chronic, or long-lasting, health disorders seen in people who have high blood sugar levels over a prolonged period. Blood sugar is also commonly referred to as blood glucose. 

According to the Centers for Disease Control and Prevention (CDC), currently over 30 million Americans – representing over 9 percent of the U.S. population – have diabetes. In 2015 alone, an estimated 1.5 million new cases of diabetes were diagnosed in adults aged 18 or older, with both men and women affected equally.

What’s worse, it is estimated that 84 million U.S. adults – more than 1 in 3 – have a health condition known as prediabetes, and most don’t know it.3 In prediabetes, blood sugar levels are higher than normal, but not high enough to be diagnosed as type 2 diabetes. Prediabetes raises the risk for developing type 2 diabetes, heart disease, and stroke. 

Long-term complications of diabetes, especially when managed poorly, include heart failure, stroke, chronic kidney disease and kidney failure, foot ulcers and gangrene, and blindness. 

Further, diabetes causes more deaths in the U.S. every year than breast cancer and AIDS combined. Further, having diabetes nearly doubles the chance of having a heart attack and raises the risk for developing many other health conditions, including stroke and cancer. 

Symptoms of Diabetes

Typical early symptoms of diabetes include:

• Urinating often, especially at night
• Feeling very thirsty
• Extreme fatigue and tiredness
• Blurry vision
• Very dry skin
• Cuts, bruises, and sores that are slow to heal
• Increased incidence of infection
• Constantly feeling hungry and losing weight, even while eating well (Type 1)
• Tingling, pain, or numbness in the hands and feet (Type 2)

People with type 1 diabetes may also experience nausea, vomiting, and stomach pain. Type 2 diabetes symptoms usually develop over several years and can be present for a long time without being noticed. In fact, sometimes there aren’t any noticeable symptoms at all. 

Gestational diabetes (diabetes during pregnancy) also typically doesn’t have any obvious symptoms. As a rule, expecting mothers should be tested for gestational diabetes between 24 and 28 weeks of pregnancy.

What Causes Diabetes?  

To understand how and why diabetes happens, we first need to understand how the pancreas works. This vital organ helps to maintain blood glucose levels in a healthy range by making the hormones insulin and glucagon. 

Actually, the vast majority of pancreatic cells are invested in the digestion of food. Of the remainder, so-called “alpha” cells make glucagon, which works to raise levels of glucose and fatty acids in the bloodstream. “Beta” cells make insulin, which works to lower the levels of glucose and salt in the bloodstream. Without this ongoing balance of glucagon and insulin production, we become susceptible to multiple health complications, including diabetes.

So how does insulin lower blood glucose levels? 

It does so by allowing cells in our body to absorb and use glucose to make energy for their metabolic activities – in essence, maintaining life. 

When we consume carb-containing foods, our body turns them into glucose which enters our bloodstream. At that point, our pancreas should ideally release insulin, also into our bloodstream, which functions as a “key”. Insulin, like a key, binds to its “lock” –known as the insulin receptor, a protein present on the surface of every cell in our body – and opens it. 

When the key opens the lock, glucose from our bloodstream is allowed to freely enter cells, including in our brain, muscles, and other tissue. These cells use glucose to make ATP, or adenosine triphosphate, which provides the energy to drive hundreds of thousands of biochemical processes in our cells. 

As our cells take in and use glucose, our blood glucose levels naturally drop.

Unfortunately, in diabetes, either insulin is absent (Type 1 diabetes), prevented from doing its job (gestational diabetes), or the key doesn’t fit the lock very well anymore (Type 2 diabetes). As a result, blood glucose is unable to enter our cells, which means they become starved of energy, leading to an overall energy deficiency in the body. 

At the same time, glucose levels begin to build up in the bloodstream. If left untreated, high levels of blood glucose can damage fine blood vessels known as capillaries in our eyes, kidneys, nerves, and heart, leading to both short-term and long-term damage of these organs.

How is Diabetes Diagnosed?

There are multiple ways to test for diabetes, which should be carried out in a diagnostic lab or in your physician’s office. 

• The A1C test – Also known as the hemoglobin A1C, HbA1c, or glycated hemoglobin test, this test measures average blood glucose for the past 2 to 3 months and does not require any fasting.
  Hemoglobin is a protein in red blood cells that carries oxygen to our cells. Glucose attaches to hemoglobin – and the higher the glucose levels, the more glucose will be attached to hemoglobin. The A1C test measures the amount of hemoglobin present in the blood with attached glucose.
  An A1C value of greater than or equal to 6.5 percent is considered to be a positive diagnosis of diabetes. 
• Fasting Plasma Glucose (FPG) – This test checks blood glucose levels after not having anything to eat or drink (except water) for at least 8 hours beforehand. This test is usually done first thing in the morning, before breakfast. A fasting blood glucose value of greater than or equal to 126 milligrams per deciliter (mg/dl) is considered to be a positive diagnosis of diabetes. 
• Oral Glucose Tolerance Test (OGTT) – This test checks blood glucose levels before and 2 hours after the subject consumes a special sweet drink and is an indication of how the body processes glucose.
  Blood glucose levels greater than or equal to 200 mg/dl 2 hours after consuming the special sweet drink is considered to be a positive diagnosis of diabetes

Types of Diabetes

There are three main forms of diabetes: 

1 | Type 1 Diabetes – Represents approximately 5 percent of all diabetes cases and results from the pancreas’ inability to make enough insulin. This form of diabetes was previously referred to as “insulin-dependent diabetes mellitus” (IDDM) or juvenile diabetes, because it was believed that it happens only in children and teenagers. However, it is now clear that type 1 diabetes can happen to anyone at any time.

In Type 1 diabetes, the body’s immune system mistakenly perceives insulin-producing beta cells in the pancreas as foreign and destroys them. For this reason, type 1 diabetes is considered to be an autoimmune disease.

Known risk factors include family history, age, and race. In the US, whites are more likely to develop type 1 diabetes than African Americans and Hispanic and Latino Americans. 

A person with type 1 diabetes typically becomes dependent on insulin injections. However, it’s often not possible to know exactly how much insulin to take, as this depends on how much and what type of food was consumed, activity and exercise levels, emotional state, and general health, among other factors.

A child who urinates frequently, drinks a lot, loses weight, and becomes more and more tired and ill is likely to have developed type 1 diabetes, which can be confirmed with a simple blood test. Also, if a child starts wetting the bed again, diabetes might be responsible. Occasionally such a child may get into diabetic ketoacidosis, which is a medical emergency that requires hospitalization and immediate care with insulin and intravenous fluids.

2 | Type 2 Diabetes – This is the most common form and begins with insulin resistance, a condition in which cells in our body fail to respond properly to insulin. In lay terms, due to overuse, the insulin key doesn’t fit the insulin receptor lock very well (or at all) anymore. At first, the pancreas makes extra insulin to make up for this. However, over time it becomes unable to make enough insulin to keep blood glucose at normal levels.

Type 2 diabetes was previously referred to as “non-insulin-dependent diabetes mellitus” (NIDDM) or “adult-onset diabetes”. The most common cause is a combination of a poor diet and sedentary lifestyle, resulting in excessive body weight.

The risk of developing prediabetes, a health condition preceding and leading up to type 2 diabetes, is higher than normal in people who:

• Are overweight or obese
• Have high blood pressure
• Have abnormal lipid values
• Are 45 years or older
• Have a parent or sibling with type 2 diabetes
• Are physically active less than 3 times a week
• Have ever had gestational diabetes or given birth to a baby weighing more than 9 pounds
• Are African American, Hispanic, American Indian, or Alaskan Native. Some Pacific Islanders and Asian Americans are also at higher risk than normal.
  

Similarly, a person is at a higher-than-normal risk for developing type 2 diabetes if they have prediabetes or fulfill any of the criteria described in the checklist for prediabetes above. Fortunately, both prediabetes and diabetes can be prevented or delayed with simple, proven lifestyle changes such as losing excess weight, eating healthier, and getting regular physical activity. 

However, it is advisable to take any prescribed medications regularly and keep insulin handy. Unfortunately, type 2 diabetes tends to get worse over time – so even if medications are not needed at first, they may become necessary later on.

3 | Gestational Diabetes – This form of diabetes occurs when pregnant women without a previous history of diabetes develop high blood glucose levels, usually around the 24th week of pregnancy. According to a 2014 analysis by the Centers for Disease Control and Prevention (CDC), the prevalence of gestational diabetes is more than 9 percent in pregnant American women. 

How does gestational diabetes happen? Hormones from the mother’s placenta help the baby develop. However, these hormones can also block the actions of the mother’s insulin in her own body, making it difficult for the mother’s body to use glucose and leading to energy starvation and other health problems, as we saw earlier.

Gestational diabetes usually goes away after the baby is born but unfortunately increases the mother’s risk for type 2 diabetes later in life. Also, the baby is more likely to become obese as a child or teen and is more likely to develop type 2 diabetes later in life as well. 

Women are at risk for developing gestational diabetes if they:

1. Had gestational diabetes during a previous pregnancy
2. Have given birth to a baby who weighed more than 9 pounds
3. Are overweight
4. Are more than 25 years old
5. Have a family history of type 2 diabetes
6. Have a hormonal disorder known as polycystic ovarian syndrome (PCOS)
7. Are African American, Hispanic, American Indian, Alaskan Native, Native Hawaiian, or Pacific Islander.

The chances of getting gestational diabetes can be reduced by losing weight, eating healthier, and being physically active. 

Diabetes-Related Complications

People with diabetes have difficulty managing their blood glucose levels over the course of their disease and are at risk for various health complications, including – 

• Diabetic Ketoacidosis – This occurs when levels of a type of acid called ketones gets too high in the bloodstream. In the absence of insulin, cells are unable to use blood glucose as fuel for their metabolic activities, so the liver breaks down fat for fuel. If the original diabetic condition is left untreated and blood ketone levels get very high, it can cause diabetic ketoacidosis. Typical symptoms include excessive thirst, frequent urination, nausea and vomiting, abdominal pain, weakness, shortness of breath, fruity-scented breath, and confusion.
• Hypoglycemia – Hypoglycemia is the result of blood glucose levels falling below 70 milligrams per deciliter (mg/dL). This condition is also referred to as an insulin reaction or insulin shock.
  The only sure way to know whether someone is experiencing hypoglycemia is to check their blood glucose levels. Hypoglycemia triggers the release of adrenaline, the “fight-or-flight” hormone. Adrenaline triggers the typical symptoms of hypoglycemia including a thumping heart, sweating, tingling, and anxiety. If blood glucose levels continue to drop, the brain stops functioning properly, leading to blurred vision, difficulty concentrating, confusion, slurred speech, numbness, and drowsiness. If blood glucose levels stay low for too long, it can potentially lead to seizures, coma, and even death. 
• Hyperglycemia – High blood glucose levels, known as hyperglycemia, usually happens as a result of inappropriate food choices, lack of physical activity, illness, non-diabetes medications, or being careless with blood glucose-lowering medications.
  In the long term, persistent hyperglycemia can lead to serious health problems. These symptoms of hyperglycemia develop slowly, but the longer blood glucose levels stay high, the more problematic they become. Exercise, reducing food consumption, eating healthier foods, changing the dose of diabetes and other medications or insulin or their timing and frequency – under the guidance of a competent physician – can all help to lower high blood glucose levels.

Diabetes Increases Risk of Heart Disease and Stroke

Along with its own substantial health risks, having diabetes means that a person is more likely to develop heart disease, with a greater chance of having a heart attack or stroke. Also, people with diabetes are more likely to have certain risk factors that increase the chances of having heart disease or stroke, such as high blood pressure or cholesterol. 

Over time, high blood glucose can damage both blood vessels and the nerves that control the heart and blood vessels. The longer a person has diabetes, the more likely they are to develop heart disease. 

Indeed, people with diabetes tend to develop heart disease at a younger age than people without diabetes. Adults with diabetes are nearly twice as likely to die from heart disease or stroke as people without diabetes.

Diabetes and Cancer: Is There a Link?

Worryingly, population studies suggest that people with diabetes are at much greater risk for many forms of cancer, although the link between these two devastating diseases is not yet fully understood.5 Population or epidemiologic studies reveal links and associations, but do not shed any light on cause and effect.

To explore this association, the American Diabetes Association and the American Cancer Society convened a consensus development conference in December 2009 and a consensus report was created to address the following questions:

• Is there a real link between diabetes and cancer? If so, which types of cancer are influenced by diabetes?
• What risk factors are common to diabetes and cancer?
• What are the possible links between diabetes and cancer risk?
• Do diabetes therapies influence the risk of cancer or cancer prognosis in any way?

In part 2 of this series, we’ll take an in-depth look at the answers to these questions and gain a better understanding of how lifestyle changes – including eating healthier and exercising regularly – can slow progression and perhaps even prevent the onset of diabetes.  

Read Part 2