Systematic Review or Meta-analysis Diabetes in people with an intellectual disability: a systematic review of prevalence, incidence and impact K. McVilly 1 , J. McGillivray 1 , A. Curtis 1 , J. Lehmann 3 , L. Morrish 1 and J. Speight 1,2,4 1 Deakin University, School of Psychology and Centre for Mental Health and Wellbeing Research, Burwood, Victoria, 2 The Australian Centre for Behavioural Research in Diabetes, Diabetes Australia, Melbourne, Victoria, 3 EdHealth Australia, Malvern, South Australia, Australia and 4 AHP Research, Hornchurch, UK Accepted 9 May 2014 Abstract Aims To establish the prevalence and incidence of Type 1 and Type 2 diabetes in people with an intellectual and developmental disability and determine their impact on health and well-being and to appraise the evidence available to inform good practice in diabetes management for people with intellectual and developmental disabilities. Methods We conducted separate searches of multiple databases (EMBASE, CINAHL, MEDLINE, PsycINFO, SCOPUS, Web of Science, PUBMED and Cochrane Library) to find relevant articles. Results A total of 13 studies were identified: 13 addressed the prevalence of diabetes in people with intellectual and developmental disability, three addressed the impact of diabetes on their health and well-being and three addressed the management of diabetes. The prevalence of diabetes in people with intellectual and developmental disability remains uncertain, and the incidence of diabetes in this group of people is unknown. There is some evidence to support the assertion that people with intellectual and developmental disability might be at greater risk of diabetes than the general population. Overall, the quality of the evidence on which to base prevention and management strategies is variable. Conclusions There is a paucity of research focusing on the prevalence, incidence and impact of diabetes among people with intellectual and developmental disability. Further research is needed to inform policy and practice in this area and, in particular, work is needed to develop methodologies, evaluation tools, educational resources and diabetes care support services appropriate to the needs of people with intellectual and developmental disability. Diabet. Med. 31, 897–904 (2014) Introduction People with intellectual and developmental disability (IDD) comprise 1–3% of the population [1,2], with higher rates in communities characterised by poverty [3–5]. People with IDD are high-frequency users of health services, presenting with multiple comorbidities [3,6,7] and earlier manifestation compared with people without IDD, and this is confounded by a combination of genetic, personal and socio-economic factors [4,5]. People with IDD are at higher risk of Type 2 diabetes, which is attributed to obesity, reduced physical activity, elevated blood pressure and poor nutrition [8–10]. Identifying the prevalence of Type 1 diabetes in people with IDD is difficult, as they are sometimes excluded from studies for logistical reasons (e.g. communication difficulties) or their co-existing disability is not recognised or recorded; however, where co-existing IDD has been recognized, a greater prevalence has been observed in people with autism [6,14] and those with Down’s syndrome [9,10] than in the general population. The prevalence of Type 1 diabetes in people with Down’s syndrome in Denmark was identified as being four times that of all children born in Denmark in 1981–2000 [11]. In Scotland, the prevalence of Type 1 diabetes in people with Down’s syndrome is estimated at 10.6%, or 10 times greater than in the general population [12]. This higher prevalence of Type 1 diabetes among people with Down’s syndrome should be a matter of concern, given that diabetes can account for 3% of deaths annually in the general population [15]. Furthermore, diabetes-related morbidity and mortality has been identified as a particular concern for people with IDD, including those with autism [7,8]. Optimum diabetes management requires considerable self-care involving a number of practical tasks, e.g. choosing appropriate foods and portion sizes, monitoring and inter- preting blood glucose levels, being physically active and taking medication [16]. People with IDD experience chal- lenges with such tasks [1], and can be overwhelmed by them Correspondence to: Keith McVilly. E-mail: Keith.McVilly@deakin.edu.au ª 2014 The Authors. Diabetic Medicine ª 2014 Diabetes UK 897 DIABETICMedicine DOI: 10.1111/dme.12494