Spatial disparities at death Age-, sex- and disease-specific - PDF document

Spatial disparities at death Age-, sex- and disease-specific mortality in the Belgian districts at the beginning of the twentieth century Tina Van Rossem a,b,c , Laura van den Borre a,b , Patrick Deboosere b and Isabelle Devos c a: PhD Fellow Research Foundation – Flanders (FWO) b: Interface Demography, Vrije Universiteit Brussel, Belgium c: History Department, Ghent University, Belgium Working paper, please do not cite without permission of the authors Abstract At the beginning of the twentieth century, average life expectancy at birth was much lower in Flanders, the northern part of Belgium, than in Wallonia, the southern part of the country. In the literature, this excess mortality is mainly attributed to high levels of infant mortality, caused by bad feeding practices and low quality drinking water. In contrast, little is known about the mortality risks at other ages, their determinants and their regional variability. In this article, we reconstruct age-, sex- and disease-specific death rates for the 41 Belgian districts around 1910. We construct maps classified according to a relative scale to visualise the mortality variations. Our spatial analysis shows that after childhood there was no clear-cut Flemish-Walloon divide in total mortality. High death rates for male and female adolescents, adults and elderly were found in both areas. The inclusion of disease-specific mortality data in our analysis is innovative compared to previous studies. For these rates as well, we note large differences between the Northern and Southern districts, even for infants and children. At young ages, respiratory and airborne infectious diseases were important killers together with a lack of viability and neurological diseases. At adolescent and young adult ages, we observe a large contribution of pulmonary tuberculosis and respiratory diseases, while cardiovascular diseases became more important with age. We conclude that the majority of the spatial disparities in total and disease-specific mortality crossed the Flemish-Walloon border as well as provincial borders and that the ranking of the districts varied considerably according to age and sex. The diverging spatial mortality patterns between adolescent and adult men and women suggest, moreover, the importance of sex-specific determinants of health and mortality at these ages. Keywords: mortality, causes of death, spatial variation, Belgium, sex differences 1. Introduction The study of spatial differences in mortality has a long tradition in Belgium. Already in 1826, the famous Belgian government official and statistician Adolphe Quetelet noted ‘la prodigieuse difference’ between city and countryside [Quételet, 1826]. His work on urban health penalties was confirmed by later studies for Wallonia, the southern part of Belgium [Eggerickx and Debuisson, 1990; Eggerickx, 2001; Neven, 2000; Oris, 1998]. Whereas many studies in Belgium and beyond have focused on the urban-rural mortality gap, few have examined other spatial levels. Notable exceptions for Belgium are the study of Grimmeau et al. [2010] on the provincial level and our recent studies on urban health penalties [Devos and Van Rossem, 2015; Van Rossem et al. , 2017]. During the nineteenth century, there was in Belgium a marked health divide between the Flemish and Walloon provinces. Average life expectancy at birth was much lower in Flanders, the northern part of the country, than in Wallonia [Grimmeau et al. , 2010]. Seemingly, the low levels of life expectancy in Flanders were strongly related to high levels of infant mortality, caused by bad feeding practices and low-quality drinking water. The regional variability and the determinants of infant mortality were studied in detail by Masuy-Stroobant [1983] and Debuisson [2001]. However, because the comprehensive measure of life expectancy is extremely sensitive to infant and child mortality, mortality in Flanders could potentially have been lower at other ages. Our research on urban 1

mortality has already demonstrated spatial variation in Belgium between mortality of different age groups. High death rates for infants and children did not per se occur in the same towns and cities where high death rates for adolescents, adults and elderly were noted. Whereas the highest levels of mortality for infants and children were consistently found in Flemish towns and cities, above the age of 10 the ranking of Flemish and Walloon cities was mixed. In other words, high death rates for adolescents, adults and elderly were observed in Flemish as well as Walloon towns and cities [Van Rossem et al. , 2017]. In this article, we aim to deliver more insight into the spatial mortality differences within Belgium at the beginning of the twentieth century. Grimmeau et al. [2010] already indicated that their analyses at the provincial level possibly masked interesting patterns at the district level. We therefore present maps classified according to a relative scale with age-, sex- and disease-specific death rates for the 41 Belgian districts around 1910. According to the analyses of Grimmeau et al. [2010], this period largely marks the end of clearly lower life expectancy levels in Flanders. After the 1920s, this spatial clustering gradually blurred 1 . The advantage of using district data is threefold: (1) There is a larger social and economic homogeneity in districts than in provinces. (2) In contrast to some small municipalities, the level of (disease-specific) deaths in districts is still large enough to derive meaningful statistical results. (3) The collection and digitalization of mortality data for 41 Belgian districts is manageable within a reasonable amount of time. Since Belgium at the time consisted of more than 2,600 municipalities, it would take months to digitalize all the data on population and mortality [Debuisson, 2001]. We use death rates to avoid the disadvantages of the life expectancy measure. The mortality data are derived from the register of vital events Le Mouvement de la Population et de l’Etat Civil 2 , whereas we made use of the population census of 1910 for data on population size and structure 3 . We distinguish in this article six different age groups: infants (<1 year), children (1-9), adolescents (10-19), young adults (20-39), middle-aged adults (40-59) and elderly (60-79). Men and women are studied separately because they experience different genetic and biological risks. As women have two X chromosomes, they appear to be more resistant to infectious diseases than men because of X- linked immunoregulatory genes [Waldron, 1983]. Moreover, in contrast to men, women experience many risks related to childbearing. Besides biological differences, the different work tasks of men and women are important. Furthermore, we include disease-specific mortality data in our study, which is innovative for research on early twentieth-century mortality risks in Belgium. Belgian mortality data at the aggregate level are available from 1886 onwards, but 1910 is the first year for which age-specific cause-of-death data are available in Le Mouvement based on the new detailed international nomenclature introduced in 1903 4 . The cause-of-death data are extremely useful because most diseases are strongly linked to specific determinants. Hence, according to Reid and van den Boomen [2015: 310] “ by using epidemiological insights into the origin and course of the diseases and conditions that eventually caused death, the complex context determining mortality levels can be, to a certain extent, unveiled ”. We distinguish in this article 16 different disease categories. Most of them, such as airborne infectious diseases or enteritis, are strongly related to specific environmental and socio-economic conditions via distinct transmission routes. Although it is not our intention to explain the observed spatial differences in mortality, the maps with cause-specific mortality figures may as such hint at possible determinants. 1 From the 1980s onwards, the pattern is reversed and life expectancies are clearly lower in Wallonia than in Flanders (Grimmeau et al. , 2010). 2 National Archives in Brussels, Statistiques du Mouvement de la Population et de l’Etat Civil, 1909-1910-1911. 3 Statistique de la Belgique, Population. Recensement général du 31 décembre 1910. Bruxelles: Ministère de l’Intérieur. 4 This classification is based on the nomenclature agreed upon during the international conference on the revision of the nosological nomenclatures organised in Paris in 1900 (Velle, 1985). 2