Duration of obesity and risk of non-insulin-dependent diabetes mellitus.

Although obesity is one of the major risk factors for diabetes mellitus, the association of the duration of obesity with glucose intolerance or insulin dysregulation has not yet been clarified. Thirteen articles were picked up from the MEDLINE database by using the four key-word phrases, "duration of obesity," "duration of overweight," "prolonged obesity," and "prolonged overweight." Although the definition of overweight was similar among the children-based studies (> = 20% or 2 SD over ideal weight), the cutoff point for adults ranged from 25.0 to 30.0 kg/m2 of body mass index. With regard to the definition of the duration of obesity, the articles were roughly divided into two groups, with some researchers bearing the definition on the number of years from the onset of overweight and some calculating using the person-years method. The prevalence or incidence of non-insulin-dependent diabetes mellitus (NIDDM) or impaired glucose tolerance (IGT) are probably associated with the duration of obesity. The effect of prolonged obesity on insulin dysregulation is still unclear.