Latent autoimmune diabetes of adults, often also late-onset autoimmune
diabetes of adulthood or aging, slow onset type 1 diabetes or diabetes type
1.5 is a form of diabetes mellitus type 1 that occurs in adults, often with a
slower course of onset. Adults with LADA may initially be diagnosed as having
type 2 diabetes based on their age, particularly if they have risk factors
for type 2 diabetes such as a strong family history or obesity.
The diagnosis is based on the finding of high blood sugar together with the
clinical impression that islet failure rather than insulin resistance is the
main cause; detection of a low C-peptide and raised antibodies against the islets
of Langerhans support the diagnosis. It can only be treated with the usual oral
treatments for type 2 diabetes for a certain period of time, after which
insulin treatment is usually necessary, as well as long-term monitoring for
complications. The concept of LADA was first introduced in 1993.
Signs and symptoms The symptoms of latent autoimmune
diabetes in adults are similar to those of other forms of diabetes: excessive
thirst and drinking, excessive urination, and often blurry vision.
Compared to childhood type 1 diabetes, the symptoms develop comparatively
slowly. Diagnosis
It is estimated that more than 50% of persons diagnosed as having
non-obesity-related type 2 diabetes may actually have LADA. Glutamic acid
decarboxylase autoantibody, islet cell autoantibody, insulinoma-associated
autoantibody, and zinc transporter autoantibody testing should be performed
on all adults who are not obese who are diagnosed with diabetes. Not all people
having LADA are thin or skinny, however—there are overweight individuals
with LADA who are misdiagnosed because of their weight. Moreover, it is now
becoming evident that autoimmune diabetes may be highly underdiagnosed in
many individuals who have diabetes, and that the body mass index levels may have
rather limited use in connections with latent autoimmune diabetes.
= C-peptide= This test measures residual beta cell
function by determining the level of insulin secretion. Persons with LADA
typically have low, although sometimes moderate, levels of C-peptide as the
disease progresses. Patients with insulin resistance or type 2 diabetes
are more likely to, but will not always, have high levels of C-peptide due to an
over production of insulin. = Autoantibody panel=
Glutamic acid decarboxylase autoantibodies, islet cell
autoantibodies, insulinoma-associated autoantibodies, and zinc transporter
autoantibodies. Glutamic acid decarboxylase antibodies are commonly
found in diabetes mellitus type 1. = Islet cell antibodies=
Islet Cell IgG Cytoplasmic Autoantibodies, IFA; Islet Cell
Complement Fixing Autoantibodies, Indirect Fluorescent Antibody; Islet
Cell Autoantibodies Evaluation; Islet Cell Complement Fixing Autoantibodies -
Aids in a differential diagnosis between LADA and type 2 diabetes. Persons with
LADA often test positive for ICA, whereas type 2 diabetics only seldom do.
= Glutamic acid decarboxylase antibodies=
Microplate ELISA: Anti-GAD, Anti-IA2, Anti-GAD/IA2 Pool - In addition to being
useful in making an early diagnosis for type 1 diabetes mellitus, GAD antibodies
tests are used for differential diagnosis between LADA and type 2
diabetes and may also be used for differential diagnosis of gestational
diabetes, risk prediction in immediate family members for type 1, as well as a
tool to monitor prognosis of the clinical progression of type 1 diabetes.
= Insulin antibodies= RIA: Anti-GAD, Anti-IA2, Anti-Insulin;
Insulin Antibodies - These tests are also used in early diagnosis for type 1
diabetes mellitus, and for differential diagnosis between LADA and type 2
diabetes, as well as for differential diagnosis of gestational diabetes, risk
prediction in immediate family members for type 1, and to monitor prognosis of
the clinical progression of type 1 diabetes. Persons with LADA may test
positive for autoantibodies; autoantibodies are not present in
persons with type 2 diabetes. = Classification=
The Expert Committee on the Diagnosis and Classification of Diabetes Mellitus
does not recognize the term LADA; rather, it includes LADA in the
definition of Type 1 autoimmune diabetes: "Type 1 diabetes results from
a cellular-mediated autoimmune destruction of the beta-cells of the
pancreas. In type 1 diabetes, the rate of beta-cell destruction is quite
variable, being rapid in some individuals and slow in others.” The
National Institutes of Health defines LADA as "a condition in which Type 1
diabetes develops in adults". Prevalence
It is estimated that between 6-50% of all persons, depending on population,
diagnosed with type 2 diabetes might actually have LADA. This number accounts
for an estimated 5%-10% of the total diabetes population in the U.S. or, as
many as 3.5 million persons with LADA. = Hypoglycemia=
= Hyperglycemia= Long-term complications
Prognosis Diabetes, including latent autoimmune
diabetes of adults, is a chronic illness that can have devastating complications.
However, it is possible for most persons with diabetes to actively participate in
their daily health care needs and dramatically reduce the risk of diabetic
complications. Patient education, motivation, and state
of mental health all play an important role in how well a person with LADA will
be able to manage their disease. Comparison
LADA is slow-onset Type 1 autoimmune diabetes in adulthood.
Onset: Type 1 diabetes onsets rapidly and at a younger age than does LADA.
Family history: There is often a family history of autoimmune conditions and
Celiac Disease, etc.). Contrary to popular belief, some people with latent
autoimmune diabetes of adults may carry a family history for Type 2 diabetes.
Autoantibodies: Persons with type 1 diabetes and LADA usually test positive
for certain autoantibodies that are not present in type 2 diabetes. Studies have
reported an association of Type 1 diabetes/LADA with high risk genes,
HLA-DR3, HLA-DR4. There are also TCF7L2 genes associated with Type 2 diabetes
with latent autoimmune diabetes of adults.
GAD autoantibodies: Persons with LADA usually test positive for GAD
antibodies, whereas in type 1 diabetes these antibodies are more commonly seen
in adults rather than in children. Insulin resistance: People with LADA
have insulin resistance similar to long-term type 1 diabetes; some studies
showed that people with LADA have less insulin resistance, compared with those
with type 2 diabetes; however, others have not found a difference.
Lifestyle and weight: People with LADA typically have a normal BMI or may be
underweight due to weight loss prior to diagnosis. Some people with LADA,
however, may be overweight to mildly obese. LADA is an autoimmune disease
that cannot be prevented. Prognosis: About 80% of all persons
initially misdiagnosed with type 2, who have GAD autoantibodies, will become
insulin dependent within 3 to 12 years. Those with both GAD and IA2 antibodies,
however, will become insulin dependent sooner. LADA occurs more slowly than
classic rapid-onset Type 1 diabetes, though it progresses towards insulin
dependency. Treatment: The treatment for Type 1
diabetes/LADA is exogenous insulin, to control glucose levels, prevent further
destruction of residual beta cells, reduce the possibility of diabetic
complications, and prevent death from diabetic ketoacidosis. Although LADA may
appear to initially respond to similar treatment as type 2 diabetes, it will
not halt or slow the progression of beta cell destruction, and people with LADA
will eventually become insulin dependent.
History The concept of latent autoimmune
diabetes mellitus was first described in 1993 to describe slow-onset type 1
autoimmune diabetes in adults. This followed the concept that GAD
autoantibodies were a feature of type 1 diabetes and not type 2 diabetes.
References External links
Diabetes Research Centre, Melbourne, Australia LADA information, trials,
resource links.