Diabetes (also called diabetes mellitus) is a metabolic disorder that occurs when the body does not use insulin correctly, which means the sugar in your blood is not converted to energy for your cells and organs the way it should be. Insulin, a hormone made in the pancreas, is what the body uses to pull sugar from the blood and convert it to energy, so when this does not happen, the glucose levels in the blood can escalate, causing diabetes.

There are Three Primary Types of Diabetes:

  • Type 1 diabetes is usually diagnosed in children or young adults. Symptoms can develop quickly, over weeks or even days. There is nothing that you can do to prevent Type 1 diabetes. This type of diabetes is always treated with insulin injections.
  • Type 2 diabetes occurs when not enough insulin is produced by the body for it to function properly, or when the body's cells do not react to insulin. This is called insulin resistance. Type 2 diabetes is often associated with obesity and develops in adulthood.
  • Gestational diabetes develops in some women when they are pregnant. Normally, it goes away when the baby is born, but women who have had gestational diabetes are at higher risk for developing Type 2 diabetes later in life.

Diabetes is Common, and Occurring More Frequently

The Centers for Disease Control estimated in 2017 that 9.4% of the U.S. population has diabetes, a staggering 30 million people (up from 23 million people in 2015). 23% of people who have diabetes (7 million people) are not aware they have it and are not receiving treatment. Type 2 diabetes accounts for 90%-95% of all cases of diabetes. The occurrence of diabetes grows as people age, with 25% of people over the age of 65 having diabetes. Diabetes is slightly more common in men than women, and diabetes is more common in African-Americans and Native Americans than in Caucasians and Hispanics.1

Prediabetes is even more prevalent; with 84 million people age 18+ (34% of U.S. adults) having glucose levels high enough to indicate prediabetes. This is when blood sugar levels are higher than normal, but not high enough for a diabetes diagnosis. People with prediabetes are at a much higher risk for developing Type 2 diabetes, but at this early stage, you can still take action to slow down or halt the progression to full-blown diabetes.

Diabetes Diagnosis:

It is important to diagnose diabetes as early as possible so that treatment can be started. A fasting glucose of 126 mg/dL is the threshold at which diabetes is diagnosed. If your blood glucose levels are not high enough to diagnose diabetes but you have symptoms (see below list), you may need to have an oral glucose tolerance test (OGTT).

There are three blood tests used to diagnose diabetes:

  • An A1c test, also called hemoglobin A1c, HbA1c or a glycohemoglobin test. This test indicates the glucose levels in the blood over the previous 3 months, and is the gold standard for diagnosing diabetes and monitoring treatment.
  • A fasting plasma glucose (FPG) test
  • An oral glucose tolerance test (OGTT). To conduct this test, patients are given a glucose drink and then blood samples are taken every half an hour, for two hours, to see how the body is dealing with the glucose.

Should You Ask For a Diabetes Test?

Medical guidelines recommend diabetes testing for all adults age 40+ who are overweight or obese. If results are normal, the diabetes screening should be repeated every three years. People with risk factors for developing diabetes should start testing at a younger age. Here are those guidelines:

  • Women who have ever been diagnosed with gestational diabetes
  • People with parents or siblings who have diabetes
  • People with high blood pressure
  • People who lead a sedentary lifestyle
  • Adults with a BMI (body mass index) of 25 or higher
  • Women with polycystic ovary syndrome and who are overweight
  • Adults who have prediabetes, impaired glucose tolerance or impaired fasting glycemia

Symptoms of Undiagnosed Diabetes

Most people who have diabetes, especially in the early stages, experience no symptoms and are unaware they even have diabetes. But if you experience any of the symptoms listed below, you should talk to your doctor about a diabetes test.

  • Passing urine more often than usual, especially at night (polyuria)
  • Increased thirst
  • Extreme tiredness
  • Unexplained weight loss
  • Red, swollen, tender gums
  • Slow healing of cuts and wounds
  • Blurred vision

Type 1 Diabetes: Causes and Risk Factors

Researchers have not identified the cause of Type 1 diabetes (also known as juvenile diabetes), but there is a genetic component, and potentially environmental factors can play a role as well. Type 1 diabetes is more common among Caucasian children, and people with a parent or sibling with diabetes are at slightly higher risk. There is no way to prevent Type 1 diabetes.

Type 2 Diabetes: Causes and Risk Factors

Diabetes is basically insulin resistance, which means the body isn't using the insulin produced by the pancreas effectively. When this occurs, the pancreas starts making more insulin in a response to higher glucose levels in the blood, but this increased production cannot be sustained. Eventually the pancreas cannot keep up insulin production and diabetes develops. Many medical researchers are studying this complex process, but no definite cause for diabetes has been determined. Obesity and living a sedentary lifestyle are associated with diabetes, but if and how these cause diabetes is still undetermined. People with the highest risk of developing diabetes are:

  • Over age 45 (risk grows as people age)
  • Are overweight with a body-mass index (BMI) of 25 or higher. Calculate your BMI here.
  • Lead a sedentary lifestyle with little or no exercise
  • Have a family history of type 2 diabetes in first-and second-degree relatives, meaning parents, grandparents, or siblings
  • Are Native-American, African-American, Hispanic-American, or Asian/South Pacific Islander
  • Have signs of insulin resistance or conditions related to insulin resistance such as polycystic ovary syndrome, high blood pressure, high cholesterol, or have had a stroke or heart attack

Managing risk factors for diabetes is critical to reducing the likelihood of developing diabetes. Here is what is recommended by experts:

  • Lose weight, if you are overweight or obese. Be sure your BMI (body mass index) is below 25. You can calculate your BMI here.
  • Maintain a waist size under 31.5 inches if you are a woman and under 37 inches if you are a man
  • Get at least 30 minutes of exercise every day
  • Do not smoke
  • Keep your blood pressure and cholesterol levels under control
  • Drink alcohol in moderation

These lifestyle changes can help anyone reduce their risk of developing type 2 diabetes, but are particularly important for those who have an increased risk of developing diabetes.

Diabetes And How It Causes Damage to the Body

There are many ways that diabetes causes significant, lasting damage to the body, making it critically important to seek treatment for diabetes and follow the doctor's instructions diligently when a diabetes diagnosis is received.

  • Excess glucose in the bloodstream causes restricted blood flow, leading to damage to the blood vessels. People who smoke and have diabetes have an even higher risk of damaging their blood vessels.
  • Diabetes causes nerve damage, making it difficult to feel pain, heat, and cold. When this nerve damage happens in the feet, as it often does, there is an increased risk of falling.
  • Blood vessel damage from diabetes leads to high blood pressure
  • Nerve and blood vessel damage can cause poor circulation in the feet (called neuropathy), and wounds heal more slowly, causing ulcers and infections. In the worst case scenario, infections in the feet become so bad that limb amputation is required.
  • People with diabetes have a four times higher risk for stroke.2
  • Damage to the blood vessels substantially increases the risk for cardiovascular disease.
  • Damage to the kidneys can affect their ability to filter waste products from the body, which can, over an extended time, lead to the need for dialysis.
  • Diabetes can cause the blood vessels in the retina to swell and leak, resulting in vision loss. This is called diabetic retinopathy, and it is one of the leading causes of adult blindness in the U.S.3

Treatment for Type 2 Diabetes

Treatment for diabetes is focused on lowering glucose levels in the blood and may include insulin, medications to stimulate insulin production in the pancreas, weight loss, and increased activity. People who have diabetes are required to monitor their blood glucose levels several times a day.4 Recent research also shows that patient education about diabetes, what causes it, and how to manage it, results in better outcomes.5 This could include seeking the help of a nutritionist or physical trainer. The new research also recommends that doctors aggressively manage the risk for heart disease caused by diabetes, especially if glucose targets are not being met consistently. Patients with a BMI of 40+ may also be referred for weight loss surgery, as this has shown to be effective in controlling and sometimes even eradicating diabetes.

Warning Signs of Type 2 Diabetes

Most people with Type 2 diabetes live with it for years without realizing they have it. If you are experiencing any of the symptoms listed here, you should consider getting a glucose screening test for diabetes.

  • Frequent urination
  • Unusual thirst
  • Extreme hunger
  • Unusual weight loss
  • Extreme fatigue
  • Irritability
  • Frequent infections
  • Blurred vision
  • Cuts or bruises that are slow to heal
  • Tingling or numbness in the hands and feet
  • Recurring skin, gum or bladder infections


1 Centers for Disease Control and Prevention. National Diabetes Statistics Report, 2017. Atlanta, GA: Centers for Disease Control and Prevention, U.S. Dept of Health and Human Services; 2017., https://www.niddk.nih.gov/health-information/health-statistics/diabetes-statistics

2 Healthline, The Effects of Diabetes on Your Body, June 28, 2017, www.healthline.com, https://www.healthline.com/health/diabetes/effects-on-body#1

3 American Academy of Opthamology, What Is Diabetic Retinopathy?, December 4, 2018, www.aao.org, https://www.aao.org/eye-health/diseases/what-is-diabetic-retinopathy

4 Mayo Clinic, https://www.mayoclinic.org/diseases-conditions/diabetes/diagnosis-treatment/drc-20371451

5 Management of Hyperglycemia in Type 2 Diabetes, 2018. A Consensus Report by the American Diabetes Association (ADA) and the European Association for the Study of Diabetes (EASD), Diabetes Care, 2018 Dec; 41 (12): 2669-2701, http://care.diabetesjournals.org/content/41/12/2669