Diabetes Care, Vol 19, Issue 8 801-806, Copyright © 1996 by American Diabetes Association
Trends in the epidemiology of IDDM during 1970-2020 in Fyn County, Denmark
A Green, AK Sjolie and O Eshoj
Genetic Epidemiology Research Unit, Odense University Hospital, Denmark.
OBJECTIVE: To present an epidemiological model applicable to diabetes based
on which prevalence rates are estimated from assumed rates of incidence and
mortality of diabetes. Furthermore, this study illustrates the model by
analyzing epidemiological data on IDDM in a Danish population during
1970-1990, with predictions of prevalence rates for 1990-2020. RESEARCH
DESIGN AND METHODS: The epidemiological model assumes known prevalence
rates as well as incidence rates and mortality at a given time. Under
assumed rates of incidence and mortality of IDDM and its complications, the
prevalence rate is the dependent variable, estimated as a function of
calendar time. We use epidemiological data on IDDM (operationally defined
as insulin-treated diabetes with onset before age 30 years), blindness, and
nephropathy, as well as mortality, as reported for 1973 and 1987 in Fyn
County, Denmark. RESULTS: During 1970-1990, the prevalence of IDDM
increased steadily because of increasing incidence and decreasing risk of
complications and mortality. The relative prevalence of patients with
nephropathy increased, whereas that of blind patients decreased
considerably. Under specified assumptions regarding the future levels of
incidence of disease, complications, and mortality, it is estimated that
the prevalence rate of IDDM in the year 2020 will be 45-60% higher than the
level in the year 1990. The relative prevalence of patients with
nephropathy will increase further, whereas the relative prevalence of blind
patients will remain constant at a low level. CONCLUSIONS: IDDM will
represent an increasing public health problem in Denmark during the next
decades, with increasing overall prevalence rates and a rising proportion
of patients with nephropathy. The major determinant of this trend is
increasing incidence combined with declining mortality and declining risk
of complications. It is strongly recommended that epidemiological models
like the one presented here be further developed and implemented at
regional levels to provide data for the dimensioning of the current and
future diabetes care systems.