Its prevalence is particularly striking in societies that have made a rapid transition from a traditional to an affluent lifestyle, a process sometimes referred to as 'Coca-Colonisation'.
The rapid development of diabetes in previously undernourished populations gave birth to the 'thrifty gene' hypothesis, which postulated that genes predisposing to diabetes are helpful when food is in short supply.
Women gained weight more rapidly than men in western societies over the first half of the 20th century, and were more subject to diabetes, but weight gain and overall prevalence of diabetes are now equal.
Type 2 diabetes often runs in families, although it is not always easy to distinguish between the effect of shared genes and shared environment.
The genes most strongly associated with type 2 diabetes are gene increases diabetes susceptibility indirectly by contributing to weight gain.
The current pay-off of genetic research in type 2 diabetes is limited by modest effect sizes (only 5–10% of susceptibility is currently explained), limited knowledge of the underlying biological pathways, and limited predictive ability.
The current terminology was formally adopted in the 1990s.
The causes of type 2 diabetes are unknown, and the term is often used to refer to any form of diabetes of unknown aetiology that does not meet the criteria for type 1 diabetes.
Historically, insulin resistance was thought to cause type 2 diabetes, partly because insulin secretion is maintained or enhanced at diagnosis, and the beta cell mass appeared relatively intact at autopsy.
It was later appreciated that beta cell mass is reduced in type 2 diabetes relative to body mass, and that insulin resistant individuals, e.g.