Prehistory of prediabetes
Prediabetes is a somewhat slippery term that has been banished from the literature several times over the course of the past 80 years, only to reappear. Its use remains controversial. As first used in the 1930s it referred to a presumed genetic predisposition to diabetes, as indicated by a family history or the birth of big babies. By the 1960s it was used retrospectively to denote the period preceding an individual's diagnosis of diabetes. The WHO Expert Committee discarded the term in 1980 and introduced the concept of impaired glucose tolerance (IGT), a condition which conferred an increased risk both of diabetes and of vascular disease. No specific glucose-lowering measures were recommended. The 1997 ADA Committee lowered the fasting glucose threshold for diagnosis of diabetes and introduced the concept of impaired fasting glucose (IFG) as an equivalent for IGT, although the two measures correlated poorly. Prediabetes was reintroduced as a clinical diagnosis, and HbA1c was later incorporated as a diagnostic measure. The concept of early intervention to prevent diabetes and vascular disease was widely accepted, but use of a term which appears to confer disease status upon the majority of old people in the population remains controversial, and is largely restricted to the USA.