Epidemiology of diabetes

Diabetes is a chronic disorder of glucose metabolism, associated with microvascular (retinopathy, nephropathy, neuropathy) and macrovascular (angiopathy with increased risk of ischaemic heart disease and stroke) complications, as well as premature mortality. There are two main aetiological types of diabetes. Type 1 diabetes classically occurs in children and young adults, and is related to an absolute insulin deficiency because of pancreatic β-cell loss, and requires insulin therapy for survival. Type 2 diabetes accounts for 85–90% of all diabetes, is associated with obesity, physical inactivity, diet, certain ethnic groups, and classically occurs in older adults (aged > 40 years), but recently there has been an increasing trend towards type 2 diagnosis in children and adolescents, owing to the increasing overweight and obesity epidemic worldwide. There is convincing evidence for the rising prevalence of diabetes worldwide, putting an increasing clinical, social and financial burden on individuals, carers and health service providers. This contribution describes the prevalence and incidence of type 1 and type 2 diabetes focusing on variation by individual, place, and time. It also examines the epidemiologically based aetiological factors for diabetes, and the potential for prevention and screening.