World Diabetes Day: An overview of types of diabetes

Diabetes is one of the most common chronic illnesses impacting daily lives. Medically, diabetes is classified into two primary types: Type 1 Diabetes Mellitus (T1DM) and Type 2 Diabetes Mellitus (T2DM). In Type 1, there is a severe insulin deficiency in the body, while in Type 2, insulin resistance hinders effective insulin function. Additionally, diabetes has other forms, which are explained below.

Type 1 Diabetes Mellitus

Blood sugar levels in the body are regulated within a range of 80-140 mg/dl with the help of insulin and other hormones. When sugar levels rise, the pancreas releases more insulin to move glucose into cells, reducing blood sugar. In Type 1 Diabetes, however, insulin production stops, leading to elevated blood sugar levels. Common symptoms of Type 1 diabetes include:

1. Complete insulin deficiency
2. Diagnosis often at a young age
3. Lack of response to oral medications, requiring insulin
4. Risk of diabetic ketoacidosis (DKA), a serious condition from high blood sugar
5. An autoimmune disorder where the body attacks its own cells, with antibodies like anti-GAD and anti-insulin commonly present

Type 2 Diabetes Mellitus

Type 2 diabetes stems from insulin resistance. Here, the insulin produced by the body does not work effectively, leading to a need for more insulin. Initially, Type 2 diabetics respond to oral medications, but later may require insulin. Key characteristics include:

1. Insulin resistance
2. Typically diagnosed at an older age
3. Associated with obesity, family history, and lifestyle issues

Pancreatic Diabetes

Since the pancreas produces insulin, any long-term illness affecting it, such as chronic pancreatitis, may cause diabetes. This form is called “Fibro-Calcific Pancreatic Diabetes.”

MODY (Maturity-Onset Diabetes of the Young)

In MODY, diabetes is often diagnosed at a young age. It can be mistaken for Type 1 diabetes but differs significantly. Patients with MODY usually respond to oral diabetes medications and often have a strong family history spanning three generations, with over 50% of family members affected. Studies show that MODY is hereditary.

LADA (Latent Autoimmune Diabetes in Adults)

Patients with LADA initially resemble Type 2 diabetics but show Type 1-like symptoms within the first five years, eventually needing insulin.

Secondary Diabetes

Certain hormonal imbalances, such as Cushing’s Syndrome (excess steroids) or Acromegaly (excess growth hormone), or thyroid disorders, can lead to secondary diabetes. Sometimes, medications like steroids prescribed for other conditions can elevate blood sugar, resulting in diabetes. Once the primary condition is treated or steroid dosage is reduced, blood sugar levels usually improve.

Gestational Diabetes

During pregnancy, blood sugar levels may increase, posing risks to both mother and child. Guidelines recommend keeping fasting blood sugar below 95 mg/dl and post-meal sugar under 140 mg/dl. Mild cases can often be managed through diet and exercise. If blood sugar goals are unmet, Metformin or insulin may be required. Generally, gestational diabetes resolves post-delivery, though there is a future risk of recurrence, making yearly screening advisable.

Translated version of Kannada article by Dr. Srinath P. Shetty, Endocrinologist, KMC Hospital, Dr. B.R. Ambedkar Circle, Mangaluru