Incidence and risk factors for type 2 diabetes mellitus:: a 10-year prospective study

BACKGROUND The aims of this study were to determine the incidence of diabetes mellitus type 2 and to define the associated risk factors. PATIENTS AND METHOD: A 10-year prospective study was done over 584 people identified by screening of the Lejona (Vizcaya, Spain) adult population in 1985. Data on age, sex, body mass index, family history of diabetes mellitus and blood pressure were collected. Also an oral glucose tolerance test was done following the criteria recommended by the WHO. RESULTS: Age-adjusted cumulative incidence per year was 8 per 1,000 persons. In a multivariate logistic regression analysis, impaired glucose tolerance was the major predictor of worsening to diabetes (relative risk 4.17; 95% confidence interval 1.80-9.63). Age and sex were also statistically significant predictors (p < 0.05), and family history of diabetes was almost significant (p = 0.057). Body mass index was not an independent and significant risk factor in this study. However, the rise in body mass index was larger in those who progressed to diabetes mellitus type 2 than in those who did not. CONCLUSIONS: The incidende of diabetes mellitus type 2 found in Lejona was similar to that reported in other european countries. Subjects having impaired glucose tolerance as well as those with elevated blood glucose levels are at higher risk of worsenning to diabetes mellitus type 2. Body mass index seems to play a precipitating role in the progression to diabetes mellitus type 2.