What causes diabetes? Behind the different causes of Type 1 and Type 2.

Diabetes affects 37 million people in the U.S. The Centers for Disease Control and Prevention estimates another 96 million people – or 1 in 3 adults – have prediabetes, a condition where blood sugar levels are higher than normal but not high enough to be diagnosed with Type 2.

Most people know of Type 1 and Type 2 diabetes, but not all know how their causes differ. We asked Dr. Rodica Busui, the president of Medicine and Science at the American Diabetes Association. Here’s what you need to know.

Diabetes is a chronic health condition. With Type 1 diabetes, your body can’t produce enough insulin and with Type 2 diabetes, it doesn’t use it properly.

But even beyond the two types, the effects and treatment associated with diabetes are different from person to person. It can also have serious complications if left untreated. This is why educating the public about diabetes is so crucial, says Busui.

“It can affect every single part of one body, and that’s important to understand – it cannot be taken lightly,” Busui says.

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Type 1 diabetes is an autoimmune disease where beta cells, a hormone located in the pancreas that creates insulin, are destroyed, Busui says. This destruction may happen quickly or over some time until a “critical mass” of beta cells is lost and the individual cannot survive without insulin from external sources. This is why many Type 1 diabetics undergo regular insulin injections.

“It’s like your own body creates antibodies against your own structures, in this case, the beta cells,” Busui says.

Type 1 diabetes is more commonly diagnosed in children, though it can occur at any age. Busui says she’s diagnosed patients in their mid-60s with Type 1.

Anyone can get Type 1 diabetes, Busui says. Type 1 symptoms, which include increased thirst and hunger, frequent urination, fatigue, blurry vision, slow-healing cuts and bruises and weight loss, often come on quicker than Type 2 diabetes.

Type 2 diabetes is the more common form of diabetes. In Type 2, beta cell dysfunction has multiple, complex causes, including weight gain, lifestyle changes and lack of exercise. Family history, ethnicity and age can also play a role.

These changes cause your body to stop using the insulin it makes properly. This is called insulin resistance – it’s harder for your body to bring blood glucose levels down.

“The more we are insulin resistant … the more insulin is needed to take the same amount of glucose from the blood inside the cell to produce energy,” Busui says. “And because of that, the beta cells have to work overtime constantly, working nonstop. Eventually, they get exhausted and they cannot produce as much insulin.”

This can cause changes in the brain and warp your sense of satiety, or how full you are. Busui says this causes a “vicious cycle,” for those who dealing with obesity and diabetes.

Doctors are diagnosing more children with Type 2 diabetes than ever, an impact of the obesity epidemic in the U.S. and food insecurity, where many children don’t have access to fresh, healthy food. Children can also develop complications from Type 2 diabetes, Busui says.

Not everyone who has Type 2 diabetes needs insulin from an external source – many Type 2 diabetics’ bodies can still produce insulin. This is why early diagnosis is key and can help patients make lifestyle changes or start on medication to prevent further complications. But because Type 2 diabetes symptoms are much more subtle than Type 1, they may not be taken seriously enough to seek care.

“If people ignore (high blood glucose levels) saying ‘Well, I don’t have a pain, I don’t want to do anything,’ then there is a progressive decrease,” Busui says. “The higher blood glucose then generates some changes in the body metabolism that will lead to all these toxic radicals that actually have an additional effect on the beta cells to make them less and less functional.”

Consumption of sugary drinks is associated with a higher risk of Type 2 diabetes, studies show. But there are other risk factors including family history, age and ethnicity. Sugar-sweetened beverages are the largest source of added sugar in American diets.

The American Diabetes Association recommends avoiding sugar-sweetened beverages and switching to water. The Dietary Guidelines for Americans advise no more than 10% of daily caloric intake be from added sugar.

Diabetes is one of the leading causes of death and disability in the country, but Busui says she has a “glass half full” outlook on where diabetes care and research are today. Part of that is providing greater education and access to care, especially for high-risk, historically underserved populations.

“It’s truly remarkable how much progress we have made in discovering effective strategies, medications, technologies,” Busui says.

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