What Is The Leading Cause Of Type 2 Diabetes? Understanding The Risk Factors And Disease

Diabetes is a chronic (long-term) health condition that affects how your body absorbs food for energy production. 

Unlike type 1 diabetes which is caused by an autoimmune disorder, type 2 diabetes is mainly caused by unhealthy lifestyle choices such as diets with high sugar content. Over time, the insulin-regulating organs in the body become overwhelmed, causing irregular blood sugar levels.

Type 2 diabetes develops gradually and can easily go undetected. Understanding the causes and risk factors of the disease can help you adopt a healthier lifestyle, reducing the risk of developing the disease or helping to manage the disease. 

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What is type 2 diabetes?

Type 2 diabetes is a condition in which your pancreas does not secrete enough insulin for your body, or your body produces insulin, but the body can't process it. This results in having too much sugar circulating in the bloodstream, which eventually leads to disorders of the immune, circulatory, and nervous systems. 

This type of diabetes is most prevalent among people above the age of 40. However, the condition is also increasingly detected among children, teenagers, and young adults. 

Symptoms of type 2 diabetes

Symptoms of type 2 diabetes can develop slowly over time and can easily go unnoticed, but when they do appear, they can include:

What are the risk factors for type 2 diabetes?

As not all symptoms are easy to recognize, knowing the risk factors associated with type 2 diabetes is important. If you have any of the following risk factors, consult a doctor and get your blood sugar levels tested. Early detection can prevent future health complications.

The risk factors include:

Being overweight or living with obesity 

If your body mass index (BMI) is between 25.0 and 29.9, you are considered overweight, while a 30.0 and above BMI indicates obesity.

Large waistline 

According to the National Library of Medicine,¹ measuring the circumference of your waist will help assess the levels of visceral fat (fat around your internal abdominal organs). If your waist circumference has high-fat levels, you are at a higher risk of type 2 diabetes.


You are at risk if you are caucasian and are older than 40 years of age. The rate of type 2 diabetes increases with age because of insulin resistance. Factors contributing to insulin resistance include reduced physical activities, increased weight, and sarcopenia (decreased muscle mass).

In addition, if you are of  African-Caribbean, Black African, or South Asian descent aged 25 years or older, you are at a high risk of type 2 diabetes. This is because your body has become insulin-resistant from a younger age, primarily attributed to a poor diet, contributing to an accumulation of high amounts of visceral fat.


African-Caribbean, Black African, and South Asian descent (Chinese, Indian, Pakistani, and Bangladeshi) people are at a high risk of type 2 diabetes. According to research findings,² social and environmental factors play a huge part in increasing the chances of younger people from this background of having type 2 diabetes. 

Family history

You are more likely to have type 2 diabetes if someone in your family has a history of type 2 diabetes. It can be a parent, sibling, or relative. This is due to several gene mutations linked with the development of type 2 diabetes among blood relatives. 

Medical history

If you have a history of recurrent high blood pressure, stroke, heart attacks, or gestational diabetes, you are at risk of developing type 2 diabetes later in life.

Mental health conditions

People with certain mental illnesses such as schizophrenia, depression, and bipolar disorder are at risk of developing type 2 diabetes because of some medications used to treat these conditions. Although low risk, antipsychotics increase the chances of becoming diabetic due to issues associated with the medications, such as increased weight gain.

Sedentary lifestyle

With little to no exercise or physical activity and unhealthy food as part of your daily routine, this lifestyle can lead to type 2 diabetes. 

Calorie-rich foods, fats, and cholesterol contribute to the development of type 2 diabetes due to weight gain or obesity. Inadequate exercise can also increase the chances of developing type 2 diabetes. Any form of physical activity aids in regulating blood sugar and helps lower bad cholesterol.

Polycystic ovary syndrome (PCOS)

Polycystic ovary syndrome is a medical condition that affects the ovaries. Usually, ovaries store and release eggs for fertilization. Instead, the eggs develop in a small fluid swelling called a follicle. In PCOS, the follicles grow, but the eggs don’t mature for fertilization, and they become cysts.

Women with PCOS have a higher chance of developing type 2 diabetes, as PCOS is associated with insulin resistance. 

What is the leading cause of type 2 diabetes?

Although type 2 diabetes can be referred to as a lifestyle disease, the leading cause is mainly a result of two interrelated issues:

  • The inability of your pancreas to produce enough insulin to manage the blood sugar levels in your body.

  • Cells in the liver, fat, and muscles develop resistance to insulin due to the abnormal cell interactions with insulin, impairing the cells' ability to regulate sugar levels.

Other causes of type 2 diabetes

Apart from your body being insulin insensitive, other external factors that can cause type 2 diabetes include:

  • Poor diet choices

  • Being overweight or living with obesity

  • Lack of enough physical activities and exercise

  • Genetics- if other people in your family have type 2 diabetes

How common is type 2 diabetes?

According to the Centers for Disease Control and Prevention, type 2 diabetes is the most common type of diabetes, with 90–95% of 37 million Americans with diabetes affected by the condition. The disease is considered a social epidemic. Most people with type 2 diabetes receive medical interventions based on behavioral factors, such as diet, symptoms, and physical activity. 

However, it's important to address the influence of social and physical environments that lead to the increased rate of being a type 2 diabetic. Some of the type 2 diabetes health outcome factors include poor living conditions, low income, and employment insecurity. 

Diagnosis and test for type 2 diabetes

Testing your blood sugar levels is a simple way of determining if you have type 2 diabetes or not. Type 2 diabetes is diagnosed by the glycated hemoglobin (HbA1C) test. The blood test reveals your blood sugar levels for the past two to three months. 

The HbA1C results are interpreted as:

  • Normal – below 5.7%

  • Prediabetes – 5.7–6.4% (prediabetes is a condition where the blood sugar levels are high, but not high enough to be type 2 diabetes)

  • Diabetes – 6.5% or higher

The HbA1C test can be affected by changes in your red blood cells or hemoglobin. The changes can result from a recent blood transfusion or recent blood loss. In this case, or if the HbA1C tests are not available, the doctor may use the following tests to diagnose diabetes.

Random blood sugar levels

Blood sugar levels are expressed as millimoles of sugar per liter (mmol/L) or milligrams of sugar per deciliter (mg/dL). With this test, regardless of your last meal, a result of  200 mg/dL (11.1mmol/L) suggests diabetes. 

Fasting blood sugar test

This test requires you to skip a meal overnight, and then a blood sample is taken the next day. The results are interpreted as:

  • Normal - less than 100 mg/dL (5.6mmol/L)

  • Prediabetes - 100–125 mg/dL (5.6 to mmol/L)

  • Diabetes - 126 mg/dL (7 mmol/L) or higher in two separate tests

Oral glucose tolerance test

This test is less common except during pregnancy. You will have an overnight fast to take the test, then have a sugary drink in the doctor's office or pathology collection center. The phlebotomist will periodically check your blood sugar levels over the next two hours. 

The results are interpreted as:

  • Normal - less than 140 mg/dL (7.8 mmol/L)

  • Prediabetes - 140–199 mg/dL (7.8 - 11.0 mmol/L)

  • Diabetes - 200 mg/dL (11.1mmol/L) or higher after two hours


The American Diabetes Association³ recommends routine screening for type 2 diabetes in adults above 45, women who have previously had gestational diabetes, and children who are overweight or obese with a type 2 diabetes history in their family.

How to manage type 2 diabetes

You can manage type 2 diabetes, and if detected early, the condition is avoidable. To manage the disease, you should follow the doctor's advice on medications and include lifestyle changes.


As type 2 diabetes can be classified as a lifestyle disease, adopting a healthy lifestyle can reduce the chances of developing the condition. Apart from frequent exercise and a balanced diet, treatment for those with the disease includes using medication such as:

  • Metformin. This is the first-line treatment for people with type 2 diabetes. It works by lowering your blood glucose levels and improving how your body responds to insulin.

  • Thiazolidinediones. These are taken to make your body more sensitive to insulin.

  • Glucagon-like peptide-1 agonists. This treatment is used to slow digestion and improve blood glucose levels.

  • Sulfonylureas. These are oral medications that help your body produce more insulin.


You can prevent type 2 diabetes using achievable lifestyle changes, especially in your diet and physical activities. However, contrary to popular belief, there is no single perfect or specific diet for type 2 diabetes. The most important thing is to center the diet around:

  • Smaller food portions

  • Fewer calorie and refined grains and sweets intake 

  • Modest servings of fish and low-fat meats, and dairy

  • Foods rich in fiber such as whole grains, fruits, and non-starchy vegetables

As for fitness, incorporate activities such as:

  • Swimming

  • Jogging or running

  • Yoga

  • Dancing

When should I see a doctor?

Even if you are managing type 2 diabetes on your own, it's a good idea to inform your doctor if:

  • You experience hyperglycemia throughout the day or every day at a specific time

  • Drinking or urinating more than usual

  • Feeling overwhelmed or stressed

The lowdown

Type 2 diabetes is a condition that occurs when your blood sugar levels build up in your bloodstream. Lifestyle choices can trigger the disease, but also the likelihood of a positive type 2 diagnosis can be increased by genetics, heritage, and age. 

If you are at a high risk of getting the disease, or you are already living with it, talk with your doctor about developing a treatment and lifestyle plan that is suitable for you. Since the condition is common, many available resources can help you in your journey towards managing or preventing the disease.

Have you considered clinical trials for Type 2 diabetes?

We make it easy for you to participate in a clinical trial for Type 2 diabetes, and get access to the latest treatments not yet widely available - and be a part of finding a cure.

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