Comparison of the Incidence of Insulin-Dependent Diabetes Mellitus in Childhood among Five Baltic Populations during 1983–1988

Abstract

We have carried out a comparison of the incidence of childhood onset insulin-dependent diabetes mellitus (IDDM) between five populations around the Baltic Sea. These were Finland, Estonia, Latvia, Lithuania and Poland. The risk of IDDM is highest in the world in Finland and also very high in Sweden, on the western and northern side of the Baltic Sea. The risk of IDDM in children on the eastern side of the Baltic Sea has not been known before. The data collection period covered the years 1983-1988. A marked variation in incidence was seen within this relatively small geographical area. Among these five populations, the incidence increased with the latitude. Our present results confirmed the very high incidence of IDDM in Finland. The average age-standardized yearly incidence of IDDM/100,000 was in males under 15 years of age 36.9 in Finland, 10.7 in Estonia, 6.4 in Latvia, 6.5 in Lithuania and 6.0 in Poland. In females the incidence was 31.6, 10.0, 6.9, 7.0 and 6.4 in these five populations, respectively. The differential in incidence in Estonia as compared with Latvia, Lithuania and Poland was statistically significant (P = 0.0002). A slight male excess in incidence was found in countries with higher incidence--Finland and Estonia, but in lower incidence countries the sex ratio was opposite (P = 0.019 for the interaction sex-population). During 1983-1988 the incidence increased significantly in Finland but not in other populations although a large year-to-year variation in incidence was observed in each country, particularly in males. We recorded a peak in IDDM incidence in most of these populations around 1986.

The epidemiology of diabetes mellitus in the United Kingdom: The Yorkshire regional childhood diabetes register

“…Several prominent features require explanation. There is great geographical variation in incidence, with as much as a 40-fold variation between countries; Finland and Sardinia have the highest incidence rates (over 30 per 100,000 per year); Japan, Africa and Korea have the lowest (0.3 to 2.5 per 100,000 per year) [7][8][9][10][11][12][13]. The age incidence curve typically shows a peak in early adolescence, and may have a secondary peak earlier in childhood.…”

“…The pattern was similar for all age groups. Peaks in incidence in 1982 or 1983 and 1986 have been identified in several registries in Northern Europe [13,18,42,43,45,46], suggesting that there may be large scale patterns in diabetes incidence.…”

“…One study [48] has linked cyclical variation in diabetes in-cidence to cyclical variation in reported infections with the mumps virus, although other studies have not reported this [49]. Several other registries have published temporal incidence curves showing multiple peaks in incidence [1,13,18,42,43,46], although this is not a universal feature [1]. Clearly short-term variations in incidence are a feature of diabetes epidemiology, a fact which complicates the interpretation of apparent epidemics of the disease.…”

Increasing incidence of childhood-onset Type I diabetes in 3 Baltic countries and Finland 1983–1998

“…Differences, documented in our first comparative paper on the Baltic region, have become more manifest [3]. Despite some earlier contradictory reports on the temporal variation in morbidity in Estonia in 1980 s, the incidence has increased in all 3 Baltic states [1,17].…”

“…Case ascertainment and validation procedures in the diabetes registries in these countries have been previously described in detail [3]. Annual population statistics by sex and age group were available for Estonia, Latvia and Finland for the whole study period.…”