Latent autoimmune diabetes in adults (LADA) is the name most commonly used for diabetes that has characteristics intermediate between type 1 and type 2. It is often misdiagnosed as type 2, which is more common in adults. The difference is important because LADA involves autoimmune destruction of the pancreatic beta cells, which can potentially be minimized with treatment.
Classic type 1 diabetes progresses to insulin dependence rapidly, within days or weeks, as the insulin-producing beta cells are attacked by the immune system. Patients have characteristic autoantibodies circulating in their bloodstreams. Classic type 2 diabetes is a milder condition in which the body develops insulin resistance. Most type 2 cases can be managed with diet, exercise, and oral medication. Autoantibodies are not found in the blood. This condition progresses very slowly, over a period of years, toward insulin dependence. Many type 2 diabetics will never need insulin injections.
Typically, type 1 diabetes develops in young people of any weight, while type 2 develops in obese adults. Researchers now envision a spectrum of diabetes conditions, with type 1 and type 2 at the ends of the spectrum. LADA progresses to insulin dependence over an intermediate time period of months to years. Some insulin resistance is noted, but the primary mechanism appears to be a slower version of the type 1 autoimmune process. Other names for intermediate type diabetes include slowly progressive type 1 diabetes, latent type 1 diabetes, and double diabetes, and type 1.5 diabetes. This last option illustrates the relationship of LADA to the more classic diabetes types.
LADA is now believed to be more common than classic type 1 diabetes. The relatively long time period of autoimmune beta cell destruction provides an opportunity to preserve some insulin producing capability and minimize the complications of diabetes. Several studies have indicated that early treatment with insulin leads to better metabolic control than conventional treatment with oral medication.
Blood tests for LADA measure autoantibodies and insulin. Obese patients with a body mass index of over 35 can skip the test, according to Reference 1, because diet and exercise will be the primary treatment regardless of the test results. However, testing is important for lean and physically active patients with a type 2 diagnosis, who may benefit from early insulin treatment and immune modulating therapies.
References:
1. American Diabetes Association online article:
http://forecast.diabetes.org/magazine/features/other-diabetes-lada-or-type-15
2. Thunander M et al, “Beta-cell function and metabolic control in latent autoimmune diabetes in adults with early insulin versus conventional treatment: A 3-year follow-up”, European Journal of Endocrinology 2011; 164: 239-45.
3. Naik RG et al, “Latent autoimmune diabetes in adults”, Journal of Clinical Endocrinology & Metabolism 2009; 94: 4635-44.
Linda Fugate is a scientist and writer in Austin, Texas. She has a Ph.D. in Physics and an M.S. in Macromolecular Science and Engineering. Her background includes academic and industrial research in materials science. She currently writes song lyrics and health articles.