Endocrine Abstracts

Type 2 diabetes is likely to be caused by defects in several genes and their interactions with lifestyle and environmental factors. During the recent years there has been a true increase in the incidence and prevalence of type 2 diabetes. With increasing prevalence of obesity worldwide the epidemic of Type 2 diabetes has emerged. In addition to general obesity, other major modifiable risk factors for Type 2 diabetes are central obesity, lack of physical activity, smoking, low fibre in the diet, and saturated fat in the diet. The Finnish Diabetes Prevention Study has recently shown that Type 2 diabetes can be prevented by changes in the lifestyles of high-risk subjects. Among 522 middle-aged overweight subjects with impaired glucose tolerance (N Engl J Med 2001;344: 1343-50) the risk of diabetes was reduced by 58 percent (p<0.001) in the intervention group. Preliminary results from the Diabetes Prevention Program (DPP) from the United States report similar findings. This trial compared diet and exercise to treatment with metformin in 3 234 subjects with impaired glucose tolerance. Participants randomly assigned to intensive lifestyle intervention reduced their risk of getting Type 2 diabetes also by 58 percent, and metformin reduced the risk by 31 percent. Unpublished data from the STOP-NIDDM trial shows that acarbose is beneficial in the prevention of Type 2 diabetes since it reduced the risk of Type 2 diabetes by 25 percent. Lifestyle and environmental factors have interactions also with genetic factors. For example, the common polymorphism in the PPAR gamma gene (Pro12Ala) has an interaction with diet and changes in body weight. Furthermore, high insulin sensitivity induced by physical exercise and normal weight can counterbalance the primary defect in insulin secretion caused by genetic factors.