Type 2 Diabetes: Causes, Risk Factors, Symptoms, Diagnosis and Treatment

Type 2 diabetes is a disease in which blood glucose — blood sugar — is too high. Glucose, which comes from food, is the body’s main source of energy, and a hormone called insulin helps it get into the cells. In diabetes, the body doesn’t make enough insulin or doesn’t use it well, so glucose stays in the blood instead of reaching the cells. Over time, too much glucose in the blood can cause health problems — but there are steps you can take to manage diabetes and help prevent them.

Causes

Type 2 diabetes may result from a combination of factors: being overweight or having obesity, not being physically active, and genetics and family history.

It usually starts with insulin resistance, when cells don’t respond normally to insulin. At first the body makes extra insulin to compensate, but over time it can’t keep up, and blood glucose rises.

Who is at risk

The risk is higher if you:

• are over 45 — children, teens and younger adults can get type 2 diabetes, but it is more common in middle-aged and older people;
• have prediabetes, meaning blood glucose is higher than normal but not yet high enough to be diabetes;
• had diabetes during pregnancy or gave birth to a baby weighing 9 pounds or more;
• have a family history of diabetes;
• are overweight or have obesity;
• are Black or African American, Hispanic/Latino, American Indian, Asian American or Pacific Islander;
• are not physically active;
• have high blood pressure, heart disease, stroke, polycystic ovary syndrome (PCOS) or depression;
• have low HDL (“good”) cholesterol and high triglycerides; or
• have acanthosis nigricans — dark, thick, velvety skin around the neck or armpits.

Symptoms

Many people with type 2 diabetes have no symptoms. When they appear, they develop slowly over several years and may be too mild to notice:

• increased thirst and urination;
• increased hunger;
• tiredness;
• blurred vision;
• numbness or tingling in the feet or hands;
• sores that don’t heal; and
• unexplained weight loss.

Diagnosis

Blood tests diagnose type 2 diabetes:

• the A1C test, which measures average blood glucose over the past 3 months;
• the fasting plasma glucose test, which measures current blood glucose after at least 8 hours without food or drink other than water; and
• the random plasma glucose test, used when someone has symptoms and the provider doesn’t want to wait for a fast.

Treatment

Treatment means managing blood glucose. Many people do it through a healthy lifestyle — a healthy eating plan and regular physical activity, balanced with any diabetes medicine. Some also need medicine: pills, insulin or other injections, and over time some need more than one type. You will also need to check your blood glucose as often as your provider advises, keep blood pressure and cholesterol near your targets, and get regular screening tests.

Prevention

You can help prevent or delay type 2 diabetes by losing weight if you are overweight, eating fewer calories and being more physically active. Managing conditions that raise your risk may lower it too.

Sources

Based on "Diabetes Type 2," MedlinePlus, National Library of Medicine, with information from the National Institute of Diabetes and Digestive and Kidney Diseases; a work of the United States government in the public domain.