Objective: To study the risk factors regarding heredity and environment in familial incident type 2 diabetes mellitus (DM).
Methods: To compare the difference of environmental risk factors between type 2 DM, impaired glucose tolerance (IGT) and normal persons through study on familial information and environmental risk factors in 125 familial incident type 2 DM in-patients and out-patients from 1999 to 2001. Falconer was used to estimate heritability. Penrose was used to study the heredity damagers by polygene analysis.
Results: There was a significant constituent ratio diversity (P < 0.01) in triglyceride, body mass index, waist to hip ratio, hypertension history and physical activities history among 3 groups, while no significant diversity in blood lipids and history of coronary heart disease. 83.42% +/- 5.84% heritability of type 2 DM in 125 familial predigree indicated that dominant major gene might exist in these familiar pedigrees. Analysis of polygene in these groups showed type 2 DM might conform to the model of polygene heredity.
Conclusion: This study suggested that type 2 DM had significant heritability and genetic heterogeneity, which generally appeared to be a disease of multi-factorial inheritance. Environmental risk factors, genetic factors and their interactions were due to type 2 DM.