TYPES 1: Diabetes mellitus

The development of type 1 diabetes mellitus is based on a combination of a genetic predisposition and an autoimmune process that results in gradual destruction of the beta cells of the pancreas, leading to absolute insulin deficiency. There is usually a pre-diabetic phase where autoimmunity has already developed but with no clinically apparent insulin dependency. Insulin autoantibodies can be detected in genetically predisposed individuals as early as 6-12 months of age.^[1] 

Possible triggers for the process may include viruses, dietary factors, environmental toxins, and emotional or physical stress. Early cessation of breast-feeding has also been linked to increased risk of developing type 1 diabetes, but the association is unproven and controversial.^[2] 

• Approximately 15% of those with diabetes have type 1 diabetes - usually juvenile-onset, but it may occur at any age. It may be associated with other autoimmune diseases. It is characterised by insulin deficiency.
• There is 30-50% concordance in identical twins and a positive family history in 10% of people with type 1 diabetes. Screening for the diagnosis of diabetes in first-degree relatives of patients with type 1 is therefore reasonable, keeping in mind that the absolute risk is quite low.
• Associated with HLA DR3 and DR4 and islet cell antibodies around the time of diagnosis.
• Patients always need insulin treatment and are prone to ketoacidosis.
• The most at-risk population for type 1 diabetes is Caucasian of northern European ancestry. Incidence is high in Scandinavian people.

 References.

1. Dunger DB, Todd JA; Prevention of type 1 diabetes: what next? Lancet. 2008 Nov 15;372(9651):1710-1. Epub 2008 Sep 22

2. Knip M, Virtanen SM, Akerblom HK; Infant feeding and the risk of type 1 diabetes. Am J Clin Nutr. 2010 May;91(5):1506S-1513S. doi: 10.3945/ajcn.2010.28701C. Epub 2010 Mar 24.