A new study finds evidence that there are early warning signs of type 2 diabetes.

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Doctors may be able to find warnings signs for diabetes years before a diagnosis. Getty Images

A study out of Japan, published in The Journal of the Endocrine Society and presented at the European Association for the Study of Diabetes (EASD) Annual Meeting in Berlin, could change how we treat prediabetes — and could potentially help prevent type 2 diabetes.

There are over 422 million people living with diabetes across the world, a number that’s risen by over 300 million since 1980, according to the World Health Organization. In America alone, more than 100 million people have type 2 diabetes or its earlier form, prediabetes.

Dr. Matthew Mintz, a primary care physician and internist based in Maryland, gets even more specific: He said while 30 million Americans have type 2 diabetes, around 80 million are living with prediabetes, the precursor to the full-blown disease.

Additionally, complications from diabetes — including “blindness, kidney failure, heart attack, and stroke” — can lead to death: In 2015, diabetes caused an estimated 1.6 million deaths worldwide.

Despite the number of people affected by the condition, little has been known about exactly when the warning signs of a type 2 diabetes diagnosis appear.

Now this new study, performed in Matsumoto and Tokyo, Japan, may change that.

Between 2005 and 2016, the research team tracked over 27,000 adults who didn’t have diabetes, looking at a few factors commonly associated with type 2 diabetes. These included fasting blood glucose levels, body mass index (BMI), and insulin sensitivity.

Researchers tracked each participant until they received a diagnosis of prediabetes or type 2 diabetes or until the end of the study, whichever came first.

Throughout the 11 years of the study, 4,800 participants were diagnosed with prediabetes, while almost 1,100 developed type 2 diabetes.

Participants who developed prediabetes and type 2 diabetes had similar risk factors early on. And those who ended up developing type 2 diabetes had even more risk factors than those who didn’t develop it, both 5 years and 10 years before the diagnosis.

Not only did those with diabetes show elevated risk factors, the differences in these risk factors between those with diabetes and those without widened over time.

Participants who didn’t develop diabetes maintained a mean fasting glucose level of roughly 94 milligrams per deciliter (mg/dL) throughout the entire study.

In those who developed diabetes, that number steadily increased from a mean of 101.5 mg/dL 10 years before diagnosis to 110 mg/dL just one year before diagnosis.

Those same warning signs were observed in those who developed prediabetes on a smaller level more than a decade before their prediabetes diagnosis.

This study was actually not the first on rising glucose levels as a precursor to prediabetes. Other studies have already shown that abnormal glucose regulation in the body normally increases up to 10 years before a prediabetes diagnosis.

Typically, Mintz said, there are “roughly 10 to 15 years” between a prediabetes diagnosis and a type 2 diagnosis, but that the condition can progress in less than five years.

As the name implies, prediabetes is “the earliest stage of diabetes,” said Mintz.

And the study’s lead researcher, Dr. Hiroyuki Sagesaka, from Aizawa Hospital in Matsumoto, said at the presentation in Berlin, “The vast majority of people with type 2 diabetes go through the stage of prediabetes.”

However, Mintz also noted that “from a disease process standpoint, there isn’t much of a difference” between the two. People with prediabetes have only slightly elevated blood sugar compared to those without the condition, while those levels are drastically higher in those who have type 2 diabetes.

Now, the study’s researchers hypothesize that rising levels of blood glucose can be seen earlier than even 10 years before a person is diagnosed — much earlier.

Sagesaka said, “Our findings suggest that elevated metabolic markers for diabetes are detectable more than 20 years before diagnosis.”

The good news to come out of this study is twofold:

  1. Markers for prediabetes can show up far earlier than diagnosis, which gives patients and their doctors an opportunity to tackle the condition.
  2. Prediabetes doesn’t necessarily progress into type 2 diabetes. In fact, Mintz said, “Prediabetes can even be reversed.”

While this study’s results largely focus on fasting blood glucose levels, other factors shouldn’t be forgotten.

Mintz said, “The main risk factor for type 2 diabetes is obesity. However, not all obese patients get diabetes, and some patients who are only a little bit overweight become diabetic. Thus, there are other factors, specifically genetics.”

He pointed out that a family history of diabetes increases your risk and that certain ethnicities also have an increased risk.

Other factors include age (“about 25 percent of adults over 65 will get diabetes,” Mintz said) and gestational diabetes during pregnancy.

“Years and years of damage to the cells in the pancreas that make insulin can lead to diabetes that can’t be reversed,” Mintz said. It’s crucial for patients to “lose weight, diet, and exercise, and talk to [their] doctor about medications that can prevent prediabetes from turning into diabetes.”

Sagesaka said much of the same in Berlin: “We may need to intervene much earlier than the prediabetes stage” and that a “much earlier intervention trail, either drug or lifestyle-related, is warranted.”

A Japanese study has shown that risk factors for type 2 diabetes can be detected more than 20 years before diagnosis.

It’s crucial to make healthy lifestyle choices, particularly as you gain weight or as you age, in order to avoid a diagnosis of prediabetes, as well as to prevent prediabetes from progressing to type 2 diabetes.