Type 2 Diabetes Causes & Risk Factors

About nine out of 10 people with diabetes have type 2 diabetes. The exact genetic cause of type 2 diabetes isn’t known, but some factors can increase your risk of developing the condition.

What causes type 2 diabetes?

Unlike people with type 1 diabetes, people with type 2 diabetes can make insulin (a hormone that helps cells absorb glucose [sugar] from your blood to use as energy) within their pancreas. But they either don’t make enough insulin or their body doesn’t use insulin as it should:

• Pancreatic dysfunction: Beta cells in the pancreas make insulin. In type 2 diabetes, your beta cells may not work properly, which means your body may not have enough insulin to handle the glucose in your blood (insulin deficiency).
• Insulin resistance: This happens when the body’s cells do not respond as they should to insulin.  When cells resist insulin, glucose can build up in your blood, leading to higher blood sugar levels. 

Who is at risk for type 2 diabetes?

Diabetes tends to run in families, but other factors may increase your risk of developing type 2 diabetes:

• Obesity or being overweight: Excess body weight, especially in your belly, is one of the main risk factors. Fat cells in the belly can release chemicals that raise your chances of becoming insulin resistant.
• Age: The risk of type 2 diabetes increases with age, especially after age 45.
• Physical inactivity: Lack of physical activity and sitting for long periods can increase your risk for type 2 diabetes and other chronic (ongoing) health problems.
• Unhealthy diet: What you eat and drink can increase your risk of getting type 2 diabetes (read more about it below).
• High blood pressure (hypertension): High blood pressure and diabetes often go hand in hand. Managing your blood pressure helps reduce diabetes risk.
• Gestational diabetes: People who had gestational diabetes during pregnancy or had a baby weighing more than 9 pounds are at a greater risk of developing type 2 diabetes later in life.
• Prediabetes: Prediabetes is a condition where your blood sugar level is higher than normal but not high enough to be diabetes. Left untreated, it can lead to type 2 diabetes.
• Polycystic ovary syndrome (PCOS): More than half of people with PCOS develop type 2 diabetes by age 40. 
• Race and ethnicity: Although it’s not clear why, people of certain ethnicities, including African American, Hispanic or Latino and Asian American have a higher chance of developing type 2 diabetes. 
• Sleep apnea: Having obstructive sleep apnea (OSA) puts you at risk of developing diabetes. 
• Certain medications: While important to your health, some medicines can increase the chance of getting type 2 diabetes. These include:
  • Corticosteroids (steroids): Commonly used to treat a variety of immune or inflammatory conditions. They might make your body resist insulin.
  • Antipsychotics: Medicines for mental health issues like schizophrenia. They can lead to weight gain and insulin resistance.
  • Thiazide diuretics: Used to control high blood pressure. They can affect how your body handles sugar.
  • Statins: Medicines used to control cholesterol. Despite the increased risk, statins are often recommended for those with diabetes to help prevent heart disease. 

If you have concerns about the medication you are taking, talk to your health care provider. They can help you come up with the best plan for your situation.

Can what I eat cause type 2 diabetes?

What you eat plays an important role in your health. While it’s not accurate to say that a specific food will cause diabetes, regularly eating these foods can raise your risk: 

• Sugary foods and beverages: Soda and sugary drinks, candy and sweets, pastries, cakes and sugary cereals.
• Heavily processed foods: Fast food, especially fried items, frozen meals high in sodium, packaged snacks with trans fats, instant noodles and processed meats.
• Unhealthy fats: Deep-fried foods, fatty cuts of red meat, processed and fried snacks and margarine.
• Highly refined carbs: Such as white bread, white rice and many cereals.
• Portion sizes: Oversized restaurant meals, buffet-style dining with unlimited servings and super-sized fast-food meals.

It’s important to note that while some risk factors for type 2 diabetes can’t be changed, many others are in your control. A balanced and nutritious diet, exercise and getting to a healthy weight can greatly reduce your risk of developing type 2 diabetes or help manage the condition if you’ve been diagnosed with it.

If you think you may be at risk for type 2 diabetes, talk to your health care provider to check your blood sugar and discuss your health goals.

Next step: Understand the symptoms of type 2 diabetes.