Causes and Risk Factors of Type 2 Diabetes

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Type 2 diabetes is a highly prevalent 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 high blood pressure and family history to being diagnosed with gestational diabetes during pregnancy.

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 30 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 about 4% of pregnant women, as hormones from the placenta may sometimes make the mother insulin resistant. 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 lack of exercise. 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. The Centers for Disease Control and Prevention (CDC) states that the prevalence of obese adults in the U.S. is 39.8 percent. That's equivalent to 93.3 million people. Greater weight means a higher risk of insulin resistance because fat interferes with the body's ability to use insulin effectively. According to the CDC, the prevalence of overweight kids is 18.5 percent, affecting 13 million children and teens. The number of children being diagnosed with type 2 diabetes has also risen. Obesity may be related to genes and family history, but may also be tied to diet and activity level, diseases, and medications. In people who are obese and diagnosed with type 2 diabetes, experts state that losing just five to 10 percent of your body weight can help you better manage your blood sugar and may lead to the reversal of your symptoms if you have prediabetes.

Sedentary Lifestyle

The first guideline in the 2018 Physical Activity Guidelines released by the CDC states to move more and sit less. Studies have shown time and again that a sedentary lifestyle is harming our health and is strongly correlated to our growing obesity epidemic. 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. It's a win-win.

Eating Habits

More than 90 percent of people who have been diagnosed 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. The good news is that transitioning to a healthier diet full of complex carbohydrates (think sweet potatoes, brown rice, lentils), plenty of fiber-rich vegetables and fruit (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.

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