Arvo Naukkarinen

Regional Differences in the Incidence of Insulin-dependent Diabetes Mellitus among Children in Finland from 1987 to 1991

The regional pattern of insulin-dependent diabetes mellitus (IDDM) incidence among children in Finland was analysed applying several methods attempting to describe the geographical variation in occurrence of IDDM. From 1987 to 1991 the number of newly diagnosed cases aged 14 years or less at diagnosis was 1728. The incidence, the incidence rate ratio and the Bayes relative risk (RR) for IDDM were calculated by municipality, by functional area (an urban centre with a subordinated surrounding area) and by area with a population of equal size at risk employing the Geographical Information Systems. The association of IDDM incidence with the degree of urbanization was assessed using the population density as a criterion for the degree of urbanization. The overall mean of the IDDM incidence was 35 per 100000 persons per year. Between municipalities the incidence varied from 4 to 245 per 100000 persons per year, whereas a clear regional pattern was seen among the functional areas and the incidence varied from 26 to 43 per 100000 persons per year. The RR for IDDM among the municipalities ranged from 0.82 to 1.34 and from 0.73 to 1.27 among the functional areas. The incidence determined in four zones with the same size of population was the highest in the middle part of the country. There was a strong inverse correlation between population density and the incidence of IDDM and this also applied to the relationship between child population density and incidence.

Finnish Socio-Economic Grid Data, GIS and the Hidden Geography of Unemployment

The use of georeferenced data in geographical research into unemployment reveals internal fluctuations and differences within localities. The observation unit in the present paper is a 1x1 km grid cell. The results obtained here indicate that the rate of unemployment in Finland during 1993-95 was highest in the most sparsely populated cells. The duration of unemployment in 1993 was longest in the centres and suburbs of major cities, and it was also very long in the most sparsely populated cells. In the largest ten cities, the areas with the highest unemployment rate mainly remained the same during 1989-96; more than 60% of the cells with the highest unemployment rates in 1989 also fell within the same quartile in 1996. Restricting the availability of grid-based information would have a contrasting impact on analysis. If data on cells containing five people or fewer had not been available, it would have meant a loss of 42.3% of the total inhabited cells and a 2.4% loss in population. Copyright Royal Dutch Geographical Society 2001.

From subsistence to market economy: Responses of Tibetan pastoralists to new economic realities

In many regions around the world the pastoral economy shifted from subsistence-oriented to a market-oriented production. Pastoral goods acquired monetary value and became a market commodity that entailed changes in the production system and in the attitude towards livestock. On the Tibetan plateau this shift did not follow a linear way. Until the 1950s, most consumption requirements could be satisfied with animal products. Economic exchange relations were essential to provide grain requirements, at least for those households who relied exclusively on animal husbandry. During the Mao era, animal husbandry was carried out in line with state targets and the produce was delivered according to central planning. In the late 1970s the transition towards a market-oriented production began. This paper discusses the recent reactions of pastoralists to the new realities in one specific area on the eastern Tibetan plateau. This shift from pastoral products to market commodities, the commercial network established as well as the market places for pastoral produce, are examined in this paper. These facts show that the pastoralists in question successfully market their produce. The research area, Dzoge county, is located on the eastern border area of the Tibetan plateau, where different ethnic groups live in proximity to each other. Grassland predominates the landscape, used by nomads as pastures for livestock breeding (yak, sheep and horses). Mobile animal husbandry and the marketing of the livestock products are decisive to guarantee the livelihood of the majority of the population.

DETECTION OF OVERALL SPACE–TIME CLUSTERING IN A NON-UNIFORMLY DISTRIBUTED POPULATION

We developed a test statistic based on an approach of Whittemore et al. (1987) to detect space-time clustering for non-infectious diseases. We extended the spatial test of Whittemore et al. by deriving conditional probabilities for Poisson distributed random variables. To combine spatial and time distances we defined a distance matrix D, where dij is the distance between the ith and jth cell in a three-dimensional space-time grid. Spatial and temporal components are controlled by a weight. By altering the weight, both marginal tests and the intermediate test can be reached. Allowing a continuum from a pure spatial to a pure temporal test, the best result will be gained by trying different weights, because the occurrence of a disease might show some temporal and some spatial tendency to cluster. We examined the behaviour of the test statistic by simulating different distributions for cases and the population. The test was applied to the incidence data of insulin-dependent diabetes mellitus in Finland. This test could be used in the analysis of data which are localized according to map co-ordinates, by addresses or postcodes. This information is important when using the Geographical Information System (GIS) technology to compute the pairwise distances needed for the proposed test.

Income differences within municipalities in Finland, 1989–1997

Abstract Differences in income between population groups in Finland have begun to increase since the recession of the early 1990s. These differences are examined here in terms of mean taxable incomes per household in 1989, 1993 and 1997 in 1 × 1 km grid cells, and the results are compared with those obtained using postal districts and municipalities as areal units. In spite of the increase, taxable income differences within municipalities are still relatively small. It is clear, however, that incomes have risen more in areas of increasing population than in areas of declining population. The results also indicate that the smaller the areal unit used, the greater the income differences, and vice versa. Thus the results of analyses based on different areal units cannot necessarily be regarded as comparable.