PubMed and the Cochrane Library database were searched with the terms: “type 1 diabetes”, “insulin-dependent diabetes mellitus”, “juvenile diabetes”, “insulin” and “insulin analogues”, “blood glucose monitoring”, “glycosylated haemoglobin” or “haemoglobin A1c”, “glycaemic index”, “diabetes-related complications”, “diabetic nephropathy”, “retinopathy”, “neuropathy”; and “macrovascular complications of diabetes”. Most recent papers, systematic review articles, meta-analyses and
SeminarType 1 diabetes
Section snippets
Pathogenesis
Type 1 diabetes is a condition in which pancreatic β-cell destruction usually leads to absolute insulin deficiency.3, 4, 5, 6 Two forms are identified: type 1A results from a cell-mediated autoimmune attack on β cells,4, 5, 6 whereas type 1B is far less frequent, has no known cause, and occurs mostly in individuals of Asian or African descent, who have varying degrees of insulin deficiency between sporadic episodes of ketoacidosis.7
In the 1980s Eisenbarth8 proposed the current model for the
Epidemiology and presentation
Past descriptions depict type 1 diabetes as a disease of childhood and early adulthood, with a sudden, severe presentation—ie, most people being younger than 20 years of age at diagnosis and presenting in diabetic ketoacidosis. More recent data suggest that only about 50–60% of those with type 1 diabetes are younger than 16–18 years at presentation and that such disease occurs at a low incidence level throughout adulthood. Furthermore, studies of the natural history of type 1 diabetes in
Management
Intensive approaches to management are based on three sentinel observations highlighted by the extensively documented cohort of type 1 diabetes subjects enrolled in the Diabetes Control and Complications Trial (DCCT) and followed in the Epidemiology of Diabetes Interventions and Complications (DCCT/EDIC) study.57, 58, 59, 60, 61, 62 First, the DCCT provided unquestionable evidence of a very close, curvilinear relation between the degree of glycaemic control (measured by haemoglobin A1c (HbA1c)
Hypoglycaemia
Hypoglycaemia is a major obstacle to glycaemic control for many patients (panel 1). Causes include inadequate caloric intake, excessive insulin dosage, and inadequate preparation for physical activity. Often the cause cannot be determined.
Three issues are important: first, fear of hypoglycaemia often interferes with an individual's ability to achieve near-normal glycaemic concentrations.101 This fear might be based on previous experiences with hypoglycaemia, or it may be part of wider anxiety
Complications and comorbid conditions
Long-term diabetes-related complications are divided into microvascular and macrovascular disorders, which account for most of the increased morbidity and mortality associated with the disease (panel 3).
Psychosocial concomitants
Research has focused attention on the psychosocial concomitants of type 1 diabetes particularly in children and teenagers, but also in adults. For example, children from single parent families and low socioeconomic status are more likely to present in diabetic ketoacidosis at disease onset, have more episodes of diabetic ketoacidosis during the course of their diabetes, attend clinic less frequently, and are less likely to maintain good glycaemic control than those from two-parent and well-off
Challenges
Some of the challenges facing researchers and health-care professionals are as follows. First, we need to perfect the prediction model for type 1 diabetes in both high risk and general populations, and to develop effective and safe interventions that reverse the condition either in its preclinical or early clinical phase. The multicentre prevention trials (eg, European Nicotinamide Diabetes Intervention Trial of nicotinamide, and Diabetes Prevention Trial Type 1 of insulin), although
Conclusions
Type 1 diabetes has transformed from a disease with certain death in the era before the discovery of insulin to one with substantial risk of long-term morbidity and mortality.143 For example, a report from the US Centers for Disease Control recently estimated that a 10-year-old boy or girl developing diabetes in the year 2000 would lose, on average, 18·7 and 19·0 life-years, respectively, compared with their non-diabetic peers.2 Advances in treatment have resulted in improved outcomes, which
Search strategy and selection criteria
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