Lean diabetes mellitus: An emerging entity in the era of obesity

Table 1 Clinical differences between type 1, type 2, ketosis resistant diabetes of the young and lean type 2 variant diabetes

Clinical features	Type 1 diabetes	Type 2 diabetes	KRDY	Lean type 2 variant
Age of diagnosis	Can occur at any age, usually < 25	Usually > 25 yr, but increasing prevalence in adolescents	< 30 yr	Average age around 40 with male preponderance
Weight	Usually lean	Overweight and obesity	BMI < 18	BMI 18-25
Autoantibodies	Present	Absent	Variable	Absent
Family history of diabetes	5% to 10%	75% to 90%	Unknown	Around 50%
Insulin sensitivity	Normal	Decreased	Normal	Normal, in females might be decreased
Insulin dependent at diagnosis	Yes	No	40% at diagnosis	35% at diagnosis
Risk of ketoacidosis	High	Low	Low	Low

KRDY: Ketosis resistant diabetes of the young; BMI: Body mass index.