Increased prevalence of insulin-treated diabetes mellitus in Funen County, Denmark

To determine the prevalence of insulin-treated diabetes mellitus in Funen County, Denmark as of 1 July 1987 and compare the findings with those of a similar study from 1973.

The population was identified by insulin prescriptions collected during a 1 year period. The identity of the prescription holders, the diagnosis and the date of diagnosis were verified from medical records and public registers.

The estimated degree of ascertainment of the material is 0.95-0.97. The prevalence rates (per 1000 of the population) of insulin-treated diabetes mellitus as of 1 July 1987 are: 4.74 (95% Cl 4.66-4.82) for all cases, 2.08 (95% Cl 2.01-2.15) for the group with onset of diabetes before age 30 years and 2.66 (95% Cl 2.59-2.73) for the group with onset after age 30 years. These figures correspond to increases of 39, 26 and 51% (P < 0.001) on data collected in 1973.

There was a significant increase in the prevalence of insulin-treated diabetes mellitus in Funen County, Denmark from 1973 to 1987. Analysis of the data shows that an important factor for this increase is a liability to start insulin treatment of type 2 (non-insulin-dependent) diabetes mellitus at an earlier stage than previously. Also, the data suggest that improved prognosis for diabetic patients as well as an increasing incidence of diabetes mellitus are factors involved in the increase.