Ancient observations
Historical records dating back 3500 years ago, described a disease that caused extreme thirst, weight loss and frequent urination. The urine attracted ants and was found to be sweet as if mixed with honey. This condition was later named Diabetes Mellitus.
Ayurvedic physicians in 500 BCE observed that the condition was common in obese individuals with unhealthy eating habits. The disease was seen to be less severe in these patients when compared to those of lean body weight.
19th Century developments
French physician Étienne Lancereaux using knowledge gained from autopsies and clinical studies, was the first to classify diabetes into two: diabète maigre (thin diabetes) and diabète gras (fat diabetes). In a paper published in 1880 he suggested that the two conditions were not caused by the same thing. He believed that the origin of thin diabetes was pancreatic, whereas the cause of fat diabetes was non pancreatic. He further observed that those with thin diabetes experienced severe symptoms and had a lower chance of survival. This was in line with earlier observations made by ancient Ayurverdic physicians.
20th Century advances
The discovery of insulin in 1922 marked an important milestone in the treatment of diabetes. Insulin became standard treatment for the disease. Doctors described the recoveries from diabetes as the most dramatic thing they had ever seen.
In 1936 Dr Himsworth published a paper that would form the basis for diabetes classification as we know it today. From his research he found that his patients could be divided into two groups: Insulin sensitive and insulin insensitive.
He noted that onset of disease in the insulin sensitive group was sudden and severe. This group comprised mainly of young people. Older patients were found in the insulin insensitive group, where onset of diabetes was subtle and mild.
In 1965 the World Health Organisation (WHO) published a summary of recommendations on the classification of diabetes. Until then, no systematic classification of the disease existed. The expert committee recommended that diabetes be classified in two ways: Period of life, referring to age when patient was first diagnosed and according to need and response to insulin.
The age classification for diabetes was divided into categories: infantile or child diabetics, young diabetics, adult-onset diabetics, and elderly onset diabetics. Juvenile-type diabetes was defined as diabetes in any age group that requires insulin and is prone to attacks of ketosis. Diabetes requiring more than 200 units of insulin a day was defined as insulin resistant diabetes.
Modern understanding and classification.
Knowledge about diabetes was growing yet there was no clear terminology, diagnostic criteria and classification standards for the disease. This lack of uniformity was making it difficult for researchers to share and compare information. Impact of the disease on different communities could not be measured, therefore making it difficult for health departments to plan or assess prevention strategies .
In April of 1978, the National Diabetes Data Group of the NIH sponsored an international workgroup to address these challenges. In 1979 the work of the group was published. For the first time two major classes of diabetes were recognized. They were insulin dependent diabetes mellitus (IDDM) and insulin non-dependent diabetes mellitus (NIDDM).
Insulin Dependent Diabetes Mellitus (IDDM) was a term used to define diabetes that is insulin dependent and prone to ketosis. This replaced the term juvenile diabetes as the term was deemed inappropriate. Since diabetes could present at any age, age-based classification was done away with.
Non- Insulin Dependent Diabetes Mellitus (NIDDM) was described as diabetes that is not dependent on insulin, non-ketosis prone and is not caused by other diseases or conditions.
Gestational diabetes and diabetes associated with certain conditions and syndrome were recognised as two additional classes of diabetes.
In June of 1997, the American Diabetes Association (ADA) expert panel recommended changes in how diabetes was classified. Two years later WHO adopted these recommendations. The previous classification was based on patients’ dependence on insulin. The new classification focused on the cause of the disease.
The term Type 1 diabetes was adopted to replace IDDM. Type 1 diabetes was defined as diabetes caused by death or loss of beta cell function,caused by abnormal activity of the immune system or other unknown factors, resulting in lack of insulin.
The term Type 2 diabetes replaced NIDDM. Type 2 diabetes was defined as adult-onset diabetes, which may be caused by: changes in how the body responds to insulin, a steady decrease in available insulin or defects in insulin production.
Diabetes has been declared a global crisis .The number of people living with diabetes rose from 200 million in 1990 to 830 million in 2022 and is expected to reach 1.31 billion by 2050. Experts predict that this rise will be driven by increases in Type 2 diabetes. Type 2 diabetes account for 90- 95% of all diabetic cases.