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In the beginning, there were two types of diabetes: juvenile and adult.

But the names were poorly chosen. First, they can actually refer to different diseases. Second, either one can occur at any age.

That is, type 1 diabetes (T1D) is an autoimmune condition in which the immune system mistakenly kills off the cells in the pancreas that make insulin, nature’s blood sugar regulator. Type 2 diabetes (T2D) is a condition of “insulin resistance” in which the body still makes insulin, but it’s unable to process it properly.

Once upon a time, it was believed that only children develop T1D, and so it was called “juvenile diabetes.” But in more recent years, it’s become clear and increasingly common that adults of all ages get the autoimmune type of diabetes, too.

This has become known as LADA (latent autoimmune diabetes in adults), but the term is a controversial one.

While adults being diagnosed with insulin-dependent diabetes is certainly not a new phenom, and even the LADA debate has been going on for several years, what’s remarkably jaw-dropping is that it wasn’t even until 2021 that an international consensus statement materialized recognizing T1D in adults and urging more acknowledgment of its existence by the diabetes care community.

First, a bit of history. Way back when, there was “diabetes mellitus.” This came from the Greek word “diabetes” meaning siphon, to pass through, and the Latin word mellitus, meaning honeyed or sweet. That eventually changed to Insulin Dependent Diabetes Mellitus (IDDM) and Non-IDDM or (NIDDM). These pretty much came with distinctions of “juvenile diabetes” that required insulin once diagnosed, and “adult diabetes” being seen as the type that did not.

Then in 1979, there was a whole renaming effort by a panel of experts, and the terms were replaced with our modern type 1 and type 2 designations. Gestational diabetes was thrown in to describe a sometimes temporary type of diabetes diagnosed during pregnancy, and the experts thought they had all the bases covered.

But then a problem arose.

Some people who developed the autoimmune T1D, especially as adults, were… different. The disease didn’t follow the “normal” rules most in the medical community had come to know. In particular, adults with this slow-motion T1D could go for many months, sometimes years, before insulin had to be started. So eventually in the mid-1980s, the research community coined the term LADA.

Although many adult onset people with diabetes (PWDs) now self-identify as LADA, it is not an officially recognized diagnosis, and it’s not universally accepted. Leading medical organizations that do not use or recognize the term include the American Diabetes Association (ADA), American Association of Clinical Endocrinologists, American College of Endocrinology, World Health Organization, Centers for Disease Control and Prevention, and National Institutes of Health.

So how is this even a thing? Why is the term still used, and how is it defined?

In fact, the only professional diabetes organization that officially recognizes LADA is the Immunology of Diabetes Society, which proposes a definition that boils down to:

  • diagnosis of autoimmune diabetes in a person age 30 years or older
  • presence of any islet cell antibodies
  • no insulin needed for at least 6 months

But it’s not so simple. For one thing, the hallmark slow onset of LADA is also sometimes seen in people younger than 30 years old. And some patients over 30 years old can go longer without insulin than “typical” type 1s but still end up needing it in less than 6 months.

In short, the lines are fuzzy here. Many experts believe LADA is a different disease from T1D, while others say it’s just another flavor of the same condition; yet others still think the LADA label should be thrown out altogether.

Italian Drs. Paolo Pozzilli and Umberto Di Mario, writing an early commentary on LADA in the journal Diabetes Care, said: “This term has been largely used in the last few years when referring to autoimmune forms of diabetes not requiring insulin initially. Now it is clear that diabetes in these patients is not latent and is not limited to adults.”

Yet other researchers have been calling for a refined definition, or a different one, including ADASP, which stands for “autoimmune diabetes in adults with slowly progressive beta-cell failure.” That’s a mouthful.

In addition to this scientific wrangling over LADA, the term creates a significant problem for clinicians and, more importantly, for patients. Since LADA doesn’t fit neatly into a shoebox, many patients with LADA (or whatever you call it) are misdiagnosed and wrongly treated.

Because this flavor of autoimmune diabetes generally strikes older people, who are sometimes heavier, develops more slowly than traditional T1D, and often responds initially to oral medications, it is frequently mistaken for type 2 diabetes — leading to inappropriate therapy, especially a delayed start of insulin.

That begs the questions: Just how is LADA diagnosed? And what do people on the receiving end of a diabetes diagnosis need to know?

In most cases, when an adult is discovered to have elevated blood sugar, and the person is not in a metabolic crisis, it’s assumed they have T2D, and treatment proceeds accordingly. It is only when treatment begins to fail, generally in 6 months to several years, that a deeper dive is undertaken and the true nature of the diabetes — an autoimmune assault — is discovered.

For some adults, however, the onset of autoimmune diabetes is more dramatic and obvious. It presents just the way T1D does in younger people: with a bout of incessant thirst, frequent urination, rapid weight loss, fatigue, and blurry vision.

Technically, a formal diagnosis of LADA would include insulin antibody tests, but in the absence of any diagnostic criteria for LADA, this is rarely done in the trenches.

Meanwhile, like everything about LADA, experts argue about the length of time that it simmers below the surface before presenting, with some doctors arguing that it could be as long as 15 years.

LADA is caused by the immune system destroying the insulin-producing beta cells in the pancreas. Unlike T1D though, this destruction is a somewhat slow process. For some patients, oral medications or very tiny amounts of insulin may be effective for a while.

In other words, people with LADA tend to experience a prolonged diabetes “honeymoon phase,” in which there is some residual beta-cell function, and they can achieve normal or nearly normal blood sugar levels by taking only minimal amounts of insulin.

But the end result of LADA and T1D are the same: a total dependence on external insulin. And like other forms of diabetes, it’s now clear that LADA can happen at any age.

How common is it? Recent research suggests that LADA may account for up to 12 percent of all cases of diabetes in adult populations. “Moreover,” the authors write, “4 percent to 14 percent of patients diagnosed with T2D are positive for T1D-associated autoantibodies which are diagnostic for LADA… For this reason, when diagnosing diabetes in adult age, a diagnosis of LADA should be always considered.”

What scientists know is that type 1 (autoimmune) diabetes involves an inherited susceptibility to developing the disease, and if a family member has (or had) type 1, you are at a higher risk. If both parents have (or had) type 1, the likelihood of their child developing type 1 is higher than if just one parent has (or had) it.

But they don’t know exactly how it is passed down. A sweeping nationwide study called TrialNet has been researching that since 2000.

Some patients, doctors, and researchers refer to LADA as type 1.5 diabetes, another nonofficial term for “late” autoimmune diabetes in adults. This is further complicated by the fact that a rare genetic form of diabetes called MODY is also sometimes referred to as type 1.5.

The bottom line is that all adults who require insulin to survive will have the same treatment options and face the same health risks, known as “complications” of diabetes.

The only real difference is the progression of the disease, which has kicked off later for those diagnosed later in life. As diabetes is a progressive disease, all patients generally need to increase their insulin (or other medication) doses over time.

Like all forms of diabetes, a cure for LADA remains elusive, and even the proper course of treatment remains controversial.

Thankfully, the ADA and European Association for the Study of Diabetes (EASD) issued a joint statement in October 2021 that delves into important topics for both T1D and LADA:

  • diagnosis
  • goals and targets
  • schedule of care
  • self-management education and lifestyle
  • glucose monitoring
  • insulin therapy
  • hypoglycemia
  • psychosocial care
  • diabetic ketoacidosis (DKA)
  • pancreas transplant/islet cell transplantation
  • adjunctive therapies
  • special populations (pregnant, older, hospitalized)
  • emergent and future perspectives

“The aim of this report is to highlight the major areas that healthcare professionals should consider when managing adults with [autoimmune] diabetes,” said Dr. Richard Holt, professor of diabetes and endocrinology at the University of Southampton, when introducing the consensus statement at the EASD 2021 conference.

The core treatment is of course insulin, but the timing of the start of insulin is problematic. If started too early, the patient will experience lots of hypoglycemia (severe low blood sugar). If started too late, the risk of complications increases. Unlike other forms of diabetes, there’s no therapeutic guidance or treatment algorithms from professional organizations. Doctors have to wing it.

Meanwhile, researchers are investigating what future therapies might be brought to bear to extend the already lengthy (relatively speaking) insulin-free “honeymoon period” that is the agreed-upon hallmark of so-called LADA.

One company working in this area is Diamyd Medical, which is developing a vaccine to prolong that honeymoon period when insulin is not (or barely) needed. This is still in study phase so it will be some time before it could be used in clinical practice.

“We are aware of the many and rapid advances in the diagnosis and treatment of type 1 diabetes… However, despite these advances, there is also a growing recognition of the psychosocial burden of living with type 1 diabetes,” Holt noted, adding that much more work needs to be done on this front.

Any diagnosis of diabetes signals a major change in lifestyle, and this is no different for those with LADA, which generally hits in young to middle adulthood when people are already set in their ways.

One advantage of being diagnosed in adulthood, rather than childhood, is that the negative health complications have less time to develop. But the sudden adjustment in lifestyle required and the psychosocial impact of being diagnosed with the autoimmune form of diabetes later in life is profound.

Some describe it as an “identity crisis” that can bring confusion, sadness, and anger. Others describe mourning a loss of freedom in a way that those diagnosed with type 1 as children never knew.

Open communication with loved ones, and both in-person and online support from peers also living with diabetes, are key.

There is a lot of research on LADA, but much of it focuses on how blurred the lines are between T1D and LADA. Meanwhile, much of the professional literature focuses on how the label should be defined, and whether the label should even exist.

“(LADA) probably has its own genetics and autoimmunity to it, an overlap with ‘classic’ type 1 and even possibly with type 2… But currently definitions are less important than treatment, which is with insulin, like a ‘classic’ type 1,” says Dr. Anne Peters, director of clinical diabetes programs at the University of Southern California. “So clinically we should care less about the name and more about the whole patient.”

See also, DiabetesMine’s guide to “Newly Diagnosed with Type 1 Diabetes: What to Know.”