Elevated incidence of type 2 diabetes in San Antonio, Texas, compared withthat of Mexico City, Mexico

OBJECTIVE - To compare the incidence of type 2 diabetes between low-income Mexican-Americans residing in San Antonio, Texas, and low-income residents in Mexico City, Mexico. RESEARCH DESIGN AND METHODS - Using data from the San Antonio Heart Study a nd the Mexico City Diabetes Study, we compared the incidence of type 2 diab etes in 35-to 64-year-old low-income Mexican-American residents of San Anto nio with similarly aged low-income residents of Mexico City. Because of the different follow-up times in t e two stu ies, t e Poisson regression was u sed to compare the rates of diabetes. Potential risk factors for diabetes w ere also analyzed to determine whether they explained or contributed to a d ifference in incidence. RESULTS - The age- and sex-adjusted incidence of type 2 diabetes was signif icantly Higher in San Antonio (RR 2.01) compared with Mexico City. This dif ference was seen primarily in the oldest age group (55-64 years of age) and remained statistically significant after adjusting for a number of diabete s risk factors, including demographic, anthropometric, and metabolic variab les. Follow-up rates were similar in both cities. CONCLUSIONS - We conclude that there was a higher incidence of type 2 diabe tes in San Antonio than in Mexico City, and that difference occurred primar ily in individuals in the oldest age group. The potential mediating factors we examined did not account for this difference. Other factors, such as ex ercise and diet, which were not available for analysis in this study, in ad dition to a cohort effect, may have contributed to the difference in incide nce of type 2 diabetes in the two cities. In addition, there was no evidenc e of a higher case fatality among diabetic individuals from Mexico City com pared with San Antonio.