Causes and Risk Factors of Type 2 Diabetes

Table of Contents
View All
Table of Contents

Type 2 diabetes is a common condition with numerous risk factors. The disease is marked by an increase in blood sugar (glucose) levels and heightened resistance to the hormone insulin, which shuttles glucose into the cells. Without adequate insulin sensitivity, too much glucose stays in the bloodstream, which may lead to dangerous complications. Causes of type 2 diabetes may range from lifestyle factors such as obesity and lack of exercise to being diagnosed with gestational diabetes during pregnancy.

African American businessman eating donut at desk
JGI/Jamie Grill / Getty Images

Common Causes

Type 2 diabetes is generally considered to be a lifestyle disease, meaning that the likelihood of developing the condition increases based on several lifestyle factors, but family history and genetics also play a major role. Potential causes include the following:

  • Poor diet: A diet rich in processed foods and refined carbohydrates is often linked with type 2 diabetes. Fiber, fruit, and vegetables are protective against the disease.
  • Low activity level: As exercise can help muscles use glucose from the bloodstream, a sedentary lifestyle is a risk factor for diabetes.
  • Increased age: Although it can set in at any age, type 2 diabetes tends to be diagnosed in adults over age 45.
  • Elevated cardiovascular blood markers: High lipid biomarkers such as triglycerides and cholesterol are strongly associated with the disease.
  • Obesity: A body mass index over 25 is correlated with type 2 diabetes.
  • History of metabolic syndrome: Defined as a constellation of different biomarkers and measurements such as high cholesterol and triglycerides, high waist-to-hip ratio, high blood pressure, etc., having metabolic syndrome is very strongly linked with the prevalence of high blood sugar as seen in diabetes.
  • History of gestational diabetes: Gestational diabetes affects between 2% and 10% of pregnant women in the United States, according to the Centers for Disease Control and Prevention (CDC). Being diagnosed with gestational diabetes during pregnancy makes women three to 10 times as likely to develop type 2 diabetes five to 10 years after they give birth. Their babies are also at risk for developing diabetes later in life.


It appears that people who have family members who have been diagnosed with type 2 diabetes are at a greater risk for developing it themselves. Additionally, those of African-American, Hispanic, Pacific-Island, or Native-American descent also have a higher-than-normal rate of type 2 diabetes, thanks to their genotypes. Studies show more than 120 gene variants have been identified as linked to causing type 2 diabetes.

However, having a genetic disposition towards type 2 is not a guarantee of diagnosis. Lifestyle plays an important part in determining who gets diabetes—a concept called epigenetics—in which genes may be turned on or off depending on your nutrient load, weight, age, sex, and other lifestyle markers.


High blood pressure and high cholesterol (total cholesterol and LDL cholesterol markers) are the hallmark risk factors for many diseases and conditions, including type 2 diabetes. Not only do these blood markers signify possible damage to your heart vessels but they are two key components in metabolic syndrome, a cluster of symptoms including obesity, a high waist-to-hip ratio (which signifies an increased level of metabolically active visceral fat surrounding your organs), and high blood pressure. Having metabolic syndrome increases your risk of heart disease, stroke, and diabetes.

Lifestyle Risk Factors

Aside from genetics and family history, the most important risk factors for type 2 diabetes are lifestyle-based.


The number one risk factor for type 2 diabetes is obesity which according to the CDC affects 42.4% of adults in the U.S. (about 141 million people) and 19.3% of children (14.4 million children and teens). Excess weight increases the risk of insulin resistance because fat interferes with the body's ability to use insulin effectively.

Insulin helps transport glucose from the bloodstream with the help of glucose transporters.

Obesity may be related to genes and family history, but may also be tied to diet and activity level, diseases, and medications.

People with type 2 diabetes who are obese can better manage their blood sugar by losing just 5% to 10% of body weight. For those with prediabetes such a modest weight loss will lower the risk of developing diabetes by 58%.

Sedentary Lifestyle

The first guideline in the 2018 Physical Activity Guidelines released by the CDC is to move more and sit less. Inactivity and being overweight go hand in hand towards a diagnosis of type 2. Muscle cells have more insulin receptors than fat cells, so a person can decrease insulin resistance by exercising. Being more active also lowers blood sugar levels by helping insulin to be more effective.

Eating Habits

More than 90% of people with type 2 diabetes are overweight. An excess of refined, simple carbohydrates and a lack of fiber both contribute to obesity and a diagnosis of diabetes. Transitioning to a diet based on complex carbohydrates (think sweet potatoes, brown rice, lentils), fiber-rich vegetables and fruits (leafy greens, berries), lean proteins (fish, poultry), and healthy fats (olives, avocado, nuts, and seeds) can actually reverse or prevent type 2 diabetes.

Increased Age

The older we get, the greater our risk of type 2 diabetes, as insulin sensitivity decreases with age. Regardless of weight or body mass, elderly people may still be predisposed to having diabetes. Scientists theorize that the pancreas ages right along with us, and doesn't pump insulin as efficiently as it did when we were younger. Also, as our cells age, they become more resistant to insulin, making it harder for glucose to be effectively removed from the bloodstream.

A Word From Verywell

Some risk factors for diabetes such as family history and genetic predisposition may be out of your control, but there's still a lot you can do to help manage your blood sugar and prevent the disease from progressing.

The key is to fully embrace a healthy lifestyle: Work with a nutritionist to make sure you're getting plenty of fiber, healthy fats, and the right nutrients, and find a personal trainer to help you get a fitness regimen that works with your abilities and schedule. And don't forget about getting plenty of sleep and reducing your stress levels, too, as stress may also play a role in keeping blood sugar balanced.

Frequently Asked Questions

  • What is the most common trigger for type 2 diabetes?

    Type 2 diabetes typically starts with insulin resistance, a condition where the muscle, liver, and fat cells are unable to use insulin efficiently. As a result, the body needs more insulin to get glucose into the cells and over time, the pancreas is unable to keep up. Carrying excess weight and leading a sedentary lifestyle can lead to insulin resistance.

  • Can you get type 2 diabetes at any age?

    Yes, you can develop type 2 diabetes at any age. Even children can develop type 2 diabetes. However, it is more common in people over the age of 45. 

  • Why is age a risk factor for diabetes?

    As our bodies age, two things happen that increase the risk of diabetes: an increase in insulin resistance and a decrease in pancreatic islet cell function. The risk of type 2 diabetes increases at age 45. By age 65, roughly one-third of adults are diagnosed with type 2 diabetes. 

Was this page helpful?
11 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. National Institute of Diabetes and Digestive Kidney Diseases. Symptoms & causes of diabetes.

  2. Centers for Disease Control and Prevention. Gestational diabetes.

  3. Prasad RB, Groop L. Genetics of type 2 diabetes-pitfalls and possibilities. Genes (Basel). 2015;6(1):87-123. doi: 10.3390/genes6010087

  4. The Centers for Disease Control and Prevention. Adult obesity facts.

  5. The Centers for Disease Control and Prevention. Childhood obesity facts.

  6. Johns Hopkins Medicine. Diabetes.

  7. American Diabetes Association. Blood sugar and exercise.

  8. American Society for Metabolic and Bariatric Surgery. Type 2 diabetes and obesity: Twin epidemics.

  9. Stanford Medicine Scope Blog. Your aging pancreas and you: Researchers chart diabetes-related changes over time.

  10. National Institute of Diabetes and Digestive Kidney Diseases. Type 2 diabetes.

  11. Kirkman MS, Briscoe VJ, Clark N, et al. Diabetes in older adults. Diabetes Care. 2012;35(12):2650-64. doi:10.2337/dc12-1801

Additional Reading