Rapid rise in the incidence of type 2 diabetes from 1987 to 1996 - Resultsfrom the San Antonio Heart Study

Background: The prevalence of type 2 diabetes has increased in the early pa rt of the 20th century, particularly in developing countries. There is now evidence that the prevalence also continues to increase in developed countr ies, including the United States. However, it is unknown whether this incre ase is due to a rise in the incidence of diabetes or to decreasing diabetic mortality or both. Methods: Participants in the San Antonio Heart Study, who were nondiabetic at baseline and who returned for a 7- to 8-year follow-up examination, were examined for secular trends in the incidence of type 2 diabetes. Risk fact ors for diabetes, such as obesity, were also examined. Patients were enroll ed in the San Antonio Heart Study from 1979 to 1988 and 7- to 8-year incide nce of diabetes was determined from 1987 to 1996. Results: A significant secular trend in the 7- to 8-year incidence of type 2 diabetes was observed in Mexican Americans (5.7% for participants enrolle d in 1979 to 15.7% for participants enrolled in 1988). In non-Hispanic whit es, the incidence increased from 2.6% for participants enrolled in 1980 to 9.4% for participants enrolled in 1988 (P = .07). After adjusting for age a nd sex, the secular trend remained significant in Mexican Americans and bor derline significant in non-Hispanic whites. This indicates that between 198 7 and 1996 the 7- to 8-year incidence of type 2 diabetes approximately trip led in both ethnic groups. The overall secular trend also remained signific ant after adjusting fur additional risk factors for diabetes, such as obesi ty. A rising secular trend in obesity was also observed. Conclusions: There has been a significant increasing secular trend in the i ncidence of type 2 diabetes in Mexican Americans and a borderline significa nt trend in non-Hispanic whites participating in the San Antonio Heart Stud y. Unlike other cardiovascular risk factors such as lipid levels, cigarette smoking, and blood pressure, which are either declining or under progressi vely better medical management and control, and unlike cardiovascular morta lity, which is also declining, obesity and type 2 diabetes are exhibiting i ncreasing trends. Thus, obesity and diabetes could easily become the preemi nent US public health problem.