Table 3 presents the M = 1 GEE estimates for both diabetes outcomes. The covariates of special interest are the fluoride exposures, using the LL of per capita water consumption. In the incidence models (E = 1), adjusting for changes in physical inactivity, obesity, poverty, log population per square mile, mean number of years fluoridated and year, a 1 mg increase in the amount of added fluoride for an average county significantly increased the diabetes incidence by 0.23 per 1,000 (P < 0.001) as compared to a county without such an increase, whereas for natural fluoride the estimate was of equal magnitude and significance, but negative.