Definition and Overview

Diabetes mellitus type 2 is a progressive metabolic disorder characterised by insulin resistance, reduced insulin sensitivity, and pancreatic cell dysfunction. The pancreas is the part of the endocrine system responsible for releasing insulin into the bloodstream. Insulin is a hormone that most cells need to take glucose from the blood for energy.

There are two scenarios that can lead to the development of diabetes mellitus type 2. First, if the pancreas fails to produce enough insulin the body needs to maintain normal glucose level. Second, if the cells become resistant or unable to properly respond to insulin. When either of these scenarios occurs, the sugar is not broken down and the body is unable to use it. It then builds up in the bloodstream, increasing the risk of serious complications including heart and blood vessel disease, nerve damage, hearing impairment, and skin conditions. It can also cause serious damage to the foot, eyes, and kidney.

Diabetes mellitus type 2, which is also previously known as adult-onset diabetes, is far more common than type 1 diabetes. Its development is associated with genetics and lifestyle factors. People considered at most risk are those who have a family history of the disease, sedentary lifestyle, and are obese or overweight. There is currently no cure for it but a combination of lifestyle modifications and medications can help effectively manage its symptoms and prevent complications.

Causes of Condition

What causes the pancreas to stop producing enough insulin or the body to become resistant to the said hormone is not fully understood. It is also unknown why some people with risk factors develop the condition while others do not. What researchers are certain of, however, is that the following can increase one’s risk of diabetes mellitus type 2:

  • Age - The risk of diabetes mellitus type 2 increases after age 45

  • Family history of diabetes

  • High blood pressure

  • History of gestational diabetes

  • Low levels of good cholesterol or high levels of triglycerides

  • Obesity or being overweight

  • Polycystic ovarian syndrome or PCOS

  • Race - For unknown reasons, the disorder is more common in Hispanics, African-American, Native Americans, and Asian-Americans than other races.

  • Sedentary lifestyle or inactivity

Key Symptoms

Most people with type 2 diabetes do not present any symptoms and many of them remain undiagnosed until complications occur. However, some experience the following:

  • Blurred vision

  • Feeling tired and lethargic

  • Frequent infections

  • Frequent urination and increased thirst

  • Leg cramps

  • Mood swings

  • Nausea

  • Sores or cuts that are slow to heal

  • Velvety, dark skin in the armpit and neck

  • Unintentional weight loss

Unless the disorder is well controlled, it is more likely to lead to serious complications that produce more noticeable and serious signs and symptoms, such as:

  • Nerve damage or diabetic neuropathy - This complication affects approximately 70% of people with diabetes. High blood glucose levels can cause serious damage to peripheral nerves throughout the body, resulting in numbness, pain, tingling, and loss of feeling in the legs, hands, arms, and feet.

  • Erectile dysfunction (ED) - Many men with type 2 diabetes suffer from ED. The inability to maintain an erection is caused by damage to the nerves and blood vessels that control erection.

  • Heart disease and stroke

  • Kidney disease

  • High blood pressure

  • Eye damage, which can result in total blindness

  • Eating disorders

  • Anxiety and depression

  • Hearing impairment

  • Alzheimer’s disease - Studies suggest that diabetes can cause reduced or blocked blood flow to the brain, which can lead to Alzheimer’s disease and vascular dementia.

  • Gum disease - Diabetes generally causes a dry mouth, which increases the risk of dental infections, gum disease, cavities, and mouth ulcers.

Who to See and Types of Treatments Available

People showing signs of diabetes and those who have risk factors may consult a general practitioner for assessment and diagnosis. The disorder can be diagnosed with urine and blood tests. The tests results could be:

  • Normal - The blood sugar level is within normal range and the person does not have diabetes.

  • Pre-diabetes - The blood glucose level is slightly elevated, indicating that the person is at risk of developing diabetes.

  • Abnormal - The blood sugar level is considerably high, confirming a diabetes diagnosis. Additional tests are then carried out to determine if the patient has type 1 or 2 diabetes. This is crucial because each type requires a different form of treatment.

As previously mentioned, there is no cure for type 2 diabetes. However, it can be managed by eating healthy and with regular exercise. Some patients also require medications and insulin therapy to normalise their blood sugar levels.

  • Healthy diet - A diet consisting of fruits, vegetables, and whole grains is highly recommended. Patients may opt to work together with a dietitian or nutritionist who can put together a meal plan that fits their health goals as well as their lifestyle and preferences.

  • Physical activity - Physical activity is known to lower blood sugar levels. Doctors recommend at least 30 minutes of exercise, five to seven days a week. Combining different types of exercises, such as aerobics, yoga, and weightlifting, among others, is known to provide optimum results.

  • Medications - In cases where a healthy diet and regular exercise is not enough to keep diabetes under control, doctors prescribe medications, such as metformin and sulfonylureas, which help the body to either use insulin more effectively or secrete more insulin.

  • Insulin therapy - Many diabetes type 2 patients will eventually need insulin therapy as their pancreas’ ability to produce insulin declines progressively. This therapy involves injecting short-acting insulin before each meal and long-acting insulin at bedtime. Several studies have confirmed that this therapy reduces the risk of eye damage (by more than 75%), nerve damage (by 60%), and kidney disease (by 50%). There is also an option to use an insulin pump, a device placed under the skin in the abdomen. It works by continuously pumping short-acting insulin to maintain the patient’s normal blood glucose level.


  • Diabetes mellitus (DM). Merck Manual Professional Version.

  • “Diagnosis of Diabetes and Prediabetes”. National Institute of Diabetes and Digestive and Kidney Diseases.

  • Maruthur, NM; Tseng, E; Hutfless, S; Wilson, LM; Suarez-Cuervo, C; Berger, Z; Chu, Y; Iyoha, E; Segal, JB; Bolen, S (19 April 2016). “Diabetes Medications as Monotherapy or Metformin-Based Combination Therapy for Type 2 Diabetes: A Systematic Review and Meta-analysis”. Annals of Internal Medicine. 164: 740–51. PMID 27088241. doi:10.7326/M15-2650.

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