Diabetes mellitus describes a group of metabolic disorders characterised by increased blood glucose concentration. People living with diabetes have a higher risk of morbidity and mortality than the general population. The global prevalence of diabetes in adults has been increasing over recent decades. In 1964, it was estimated that 30 million people had diabetes [15]. Less than 40 years later, the WHO estimated that there were 171 million people living with diabetes [51]. The International Diabetes Federation (IDF) estimated the global prevalence to be 151 million in 2000 [28], 194 million in 2003 [27], 246 million in 2006 [26], 285 million in 2009 [25], 366 million in 2011 [24], and 382 million in 2013 [23].
