Type 2 diabetes affects nearly 10 percent of the U.S. adult population, about 30 million people. An estimated 7 million of them are not yet diagnosed. Also, another 84 million adults have prediabetes, according to the Centers for Disease Control and Prevention.

With numbers like these, it’s important that everyone knows the early signs of type 2 diabetes.

When you have type 2 diabetes, your body loses its ability to use up glucose in the blood, also known as blood sugar. Long-term, uncontrolled blood sugar levels can lead to nerve damage, kidney damage, vision loss, and heart disease.

The early signs of diabetes are not always noticeable. Also, many people are asymptomatic, and can remain undiagnosed for a long time. If you think you may be experiencing any of these early signs, make an appointment with your doctor.

Also known as polyuria, frequent and/or excessive urination is a sign that your blood sugar levels are high enough to “spill” into your urine. When your kidneys can’t keep up with the amount of glucose, they allow some of it to go into your urine.

This makes you have to urinate often, including during the night.

Extreme thirst is another common, early symptom of diabetes. It’s tied to high blood sugar levels, which cause thirst on their own, and is exacerbated by frequent urination. Often, drinking won’t satisfy the thirst.

Intense hunger, or polyphagia, is also an early warning sign of diabetes. Your body uses the glucose in your blood to feed your cells. When this system is broken, your cells can’t absorb the glucose. As a result, your body is constantly looking for more fuel, causing persistent hunger.

Because you have so much extra glucose circulating that it comes out in your urine, you may also lose weight, even while eating more and more to appease your hunger. Unexplained weight loss can be its own warning sign of diabetes.

You might experience tingling or numbness in your hands, fingers, feet, and toes. This is a sign of nerve damage, or diabetic neuropathy. This condition typically develops slowly. You are likely to experience this after years of living with diabetes, but it can be a first sign for many.

There are several reasons wounds will heal more slowly if you have diabetes. Over time, high blood sugar levels narrow your blood vessels, slowing blood circulation and restricting needed nutrients and oxygen from getting to wounds.

Prolonged, high blood sugar levels also damage your immune system, so your body has a harder time fighting infection.

Blurred vision usually occurs early in unmanaged diabetes. It can be a result of suddenly high blood sugar levels, which affect the tiny blood vessels in the eyes, causing fluid to seep into the lens of the eye. The blurriness will usually resolve. Still, see an eye doctor right away.

With prolonged high blood sugar levels, you become at risk for more serious conditions that can lead to blindness, such as diabetic retinopathy.

Dark, velvety discoloration in the folds of your skin is called acanthosis nigricans. This is another early warning sign of type 2 diabetes. It’s most common in the armpits, neck, and groin regions, and the skin also becomes thickened.

This is caused by an excess of insulin in the blood, which is common in people with type 2 diabetes because insulin resistance is the main precursor to type 2 diabetes.

If you suspect that you may be experiencing any of the early signs of type 2 diabetes, talk to your doctor right away. Early diagnosis and swift treatment can significantly reduce the risk of serious and life-threatening complications.