Secular trends in obesity in Mexico City and in San Antonio.

The San Antonio Heart Study--conducted from 1979 to 1996--and the Mexico City Diabetes Study--conducted from 1990 to 1999--both show significant secular increases in obesity as indicated by mean body mass index values and proportions of the populations who were obese or overweight. The increase in obesity accounts for an estimated 28% of the increase in the incidence of diabetes in San Antonio. This increase in the incidence of diabetes occurred across all age groups (25-34, 35-44, 45-54, and 55-64). Thus the generational acceleration of diabetes, expected as a result of the greater tendency for people whose mothers were diabetic when pregnant to become diabetic themselves, may not be as severe as would be expected had the increases in diabetes incidence occurred disproportionately more among women prior to or during their child-bearing years.