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While there is strong evidence that maternal smallpox infection can cause foetal loss, it is not clear whether smallpox infections were a demographically important cause of stillbirths historically. In this paper, we use parish-level data from the Swedish Tabellverket data set for 1780–1839 to test the effect of smallpox on stillbirths quantitatively, analysing periods before and after the introduction of vaccination in 1802. We find that smallpox infection was not a major cause of stillbirths before 1820, because most women contracted smallpox as children and were therefore not susceptible during pregnancy. We do find a small, statistically significant effect of smallpox on stillbirths from 1820 to 1839, when waning immunity from vaccination put a greater share of pregnant women at risk of contracting smallpox. However, the reduced prevalence of smallpox in this period limited its impact on stillbirths. Thus, smallpox was not an important driver of historical stillbirth trends.

The Demographic Data Base (DDB) at the Centre for Demographic and Ageing Research (CEDAR) at Umeå University has since the 1970s been building longitudinal population databases and disseminating data for research. The databases were built to serve as national research infrastructures, useful for addressing an indefinite number of research questions within a broad range of scientific fields, and open to all academic researchers who wanted to use the data. A countless number of customised datasets have been prepared and distributed to researchers in Sweden and abroad and to date, the research has resulted in more than a thousand published scientific reports, books, and articles within a broad range of academic fields. While there has long been a clear predominance of research within the humanities and social sciences, it has always been used for research in other fields as well, for example medicine. In this article, we first give a brief presentation of the DDB and its history, characteristics, and development from the 1970s to the present. It includes an overview of the research based on the DDB databases, with a focus on the databases POPUM and POPLINK with individual-level data. A number of major traits of the research from 1973 to now have been outlined, showing the breadth of the research and highlighting some major contributions, with a focus on work that would have been very difficult to perform without data from the DDB.

Our study aims to find how disability affected human health in historical time through an examination of individuals' mortality risks and death causes. Swedish parish registers digitized by the Demographic Data Base (DDB) enable us to account for a relatively high number of persons reported to have disabilities, and to compare them with a group of non-disabled cases. The findings concern a 19th-century population of 35,610 individuals in the Sundsvall region, Sweden, and show that disability increased the premature mortality risk substantially. Disability seems to have jeopardized men’s survival in particular, and perhaps due to gendered expectations concerning the type of work men and women became less able to perform when disabled. Our study of death causes indicates that their deaths were less characterized by infectious diseases than among the non-disabled group, as a possible consequence of lower exposure to infections due to the way in which disability could impede opportunities for interaction with peers in the community. In all, our mortality findings suggest that disability was associated with poor living conditions and limited possibilities to participate in work and social life, which further tend to have accumulated across life and resulted in ill health indicated by premature death.

The Demographic Data Base (DDB) at the Centre for Demographic and Ageing Research (CEDAR) at Umeå University has since the 1970s been building longitudinal population databases and disseminating data for research. The databases were built to serve as national research infrastructures, useful for addressing an indefinite number of research questions within a broad range of scientific fields, and open to all academic researchers who wanted to use the data. A countless number of customised datasets have been prepared and distributed to researchers in Sweden and abroad and to date, the research has resulted in more than a thousand published scientific reports, books, and articles within a broad range of academic fields. While there has long been a clear predominance of research within the humanities and social sciences, it has always been used for research in other fields as well, for example medicine. In this article, we first give a brief presentation of the DDB and its history, characteristics, and development from the 1970s to the present. It includes an overview of the research based on the DDB databases, with a focus on the databases POPUM and POPLINK with individual-level data. A number of major traits of the research from 1973 to now have been outlined, showing the breadth of the research and highlighting some major contributions, with a focus on work that would have been very difficult to perform without data from the DDB.

We designed a retrospective cohort study for exploring the impact of municipality-level income inequality, based on the Gini 1986, 2004 indices, on all-cause old-age mortality among the older Swedish population during 2005-2009. We controlled for the confounding effects of individual and regional correlates and the lag effects of inequality by using multilevel logistic regression. The effects of income inequality were not consistent across age cohorts and, among the youngest cohorts, were negligible. This study reiterates that individual-level economics rather than the immediate or lagged effects of income inequality matter more for old-age mortality, even after controlling for individual and regional factors.

Research benefits a great deal when different kinds of registers can be combined. Record linkage is an important tool for connecting sources to create longitudinal databases of individual data. In ...

Background and aims: Little is known about health impacts of climate in pre-industrial societies. We used historical data to investigate the association of temperature and precipitation with total and age-specific mortality in Skellefteå, northern Sweden, between 1749 and 1859. Methods: We retrieved digitized aggregated population data of the Skellefteå parish, and monthly temperature and precipitation measures. A generalized linear model was established for year to year variability in deaths by annual and seasonal average temperature and cumulative precipitation using a negative binomial function, accounting for long-term trends in population size. The final full model included temperature and precipitation of all four seasons simultaneously. Relative risks (RR) with 95% confidence intervals (CI) were calculated for total, sex- and age-specific mortality. Results: In the full model, only autumn precipitation proved statistically significant (RR 1.02, CI 1.00–1.03, per 1cm increase of autumn precipitation), while winter temperature (RR 0.98, CI 0.95–1.00, per 1 °C increase in temperature) and spring precipitation (RR 0.98, CI 0.97–1.00 per 1 cm increase in precipitation) approached significance. Similar effects were observed for men and women. The impact of climate variability on mortality was strongest in children aged 3–9, and partly also in older children. Infants, on the other hand, appeared to be less affected by unfavourable climate conditions. Conclusions: In this pre-industrial rural region in northern Sweden, higher levels of rain during the autumn increased the annual number of deaths. Harvest quality might be one critical factor in the causal pathway, affecting nutritional status and susceptibility to infectious diseases. Autumn rain probably also contributed to the spread of air-borne diseases in crowded living conditions. Children beyond infancy appeared most vulnerable to climate impacts.

Climate change is projected to increase the frequency of extreme weather events. Short-term effects of extreme hot and cold weather and their effects on mortality have been thoroughly documented, as have epidemiologic and demographic changes throughout the 20th century. We investigated whether sensitivity to episodes of extreme heat and cold has changed in Stockholm, Sweden, from the beginning of the 20th century until the present.We collected daily mortality and temperature data for the period 1901-2009 for present-day Stockholm County, Sweden. Heat extremes were defined as days for which the 2-day moving average of mean temperature was above the 98th percentile; cold extremes were defined as days for which the 26-day moving average was below the 2nd percentile. The relationship between extreme hot/cold temperatures and all-cause mortality, stratified by decade, sex, and age, was investigated through time series modeling, adjusting for time trends.Total daily mortality was higher during heat extremes in all decades, with a declining trend over time in the relative risk associated with heat extremes, leveling off during the last three decades. The relative risk of mortality was higher during cold extremes for the entire period, with a more dispersed pattern across decades. Unlike for heat extremes, there was no decline in the mortality with cold extremes over time.Although the relative risk of mortality during extreme temperature events appears to have fallen, such events still pose a threat to public health.

Background: While there is ample evidence for health risks associated with heat and other extreme weather events today, little is known about the impact of weather patterns on population health in preindustrial societies. Objective: To investigate the impact of weather patterns on population health in Sweden before and during industrialization. Methods: We obtained records of monthly mortality and of monthly mean temperatures and precipitation for Skellefteå parish, northern Sweden, for the period 1800-1950. The associations between monthly total mortality, as well as monthly mortality due to infectious and cardiovascular diseases, and monthly mean temperature and cumulative precipitation were modelled using a time series approach for three separate periods, 1800−1859, 1860-1909, and 1910-1950. Results: We found higher temperatures and higher amounts of precipitation to be associated with lower mortality both in the medium term (same month and two-months lag) and in the long run (lag of six months up to a year). Similar patterns were found for mortality due to infectious and cardiovascular diseases. Furthermore, the effect of temperature and precipitation decreased over time. Conclusions: Higher temperature and precipitation amounts were associated with reduced death counts with a lag of up to 12 months. The decreased effect over time may be due to improvements in nutritional status, decreased infant deaths, and other changes in society that occurred in the course of the demographic and epidemiological transition. Contribution: The study contributes to a better understanding of the complex relationship between weather and mortality and, in particular, historical weather-related mortality.

This paper presents the longitudinal database POPLINK, which has been developed at the Demographic Data Base at Umeå University, Sweden. Based on digitized Swedish population registers between c. 1700-1950, the database contains micro-data that covers the agrarian society through industrialization and further on to the Swedish welfare state and contemporary society. It is now possible to study the profound processes of the second demographic transition using individual level data with a proper size population. POPLINK allows for a large array of longitudinal studies, such as social mobility, migration, fertility, mortality, civil status, kinship relations, diseases, disability and causes of death. International standards of occupations (HISCO) and diseases (ICD-10) have been applied, facilitating comparability. POPLINK covers two large regions in Northern Sweden and is built on complete registrations. It is one of the world’s most information-dense historical population databases, covering up to 15 generations and 350,000 individuals described by 300 variables, allowing the ability to monitor populations over time. POPLINK has been built to allow linkage to modern registries, clinical data and medical biobanks, which enables the study of transgenerational effects, heredity and genetic transfers in disease incidence of the population today. DDB serves as an infrastructure for research and is open to researchers of any nationality.

The Rh-negative gene is a well-known cause of perinatal mortality. In this article, we analyze the possible role of Rh disease in perinatal mortality and stillbirths in a particular historical setting: the Skellefteå region in northern Sweden between 1860 and 1900. The data used for the study cover 23,067 children born to 4,943 women. The exact impact is not possible to establish using historical data, but the typical pattern of the disease allows us to make estimations. The expected levels based on knowledge of blood group distribution, the risk of sensitization from Rh incompatability, and the risk of perinatal mortality in births by sensitized mothers are compared with the observed levels. The results show that Rh disease was important for perinatal mortality and clustering of deaths within families.

This introduction surveys the field of family clustering of deaths and discusses the contributions in this special issue. The main focus is on mortality in historical contexts. Clustering of deaths in families has been found both in historical and contemporary populations, and we argue that the 'family approach' to infant and child mortality yields important and interesting insights for our understanding of different mortality patterns and the mortality transition. The articles in this issue, representing different but complementary approaches to the problem of death clustering, demonstrate that we should be aware of the strong family effects on child health, but also that we need to develop adequate methods for the analysis of this complex phenomenon. Here we discuss several explanations for death clustering, such as different biodemographic factors and those focusing on socioeconomic and cultural variables. We also discuss some of the methodological challenges in studying family clustering, and emphasize the need for comparison and the adoption of common measures.

The present article analyses social inequality in mortality in the 19th century Sundsvall region, an area that experienced rapid industrialization after 1850. The purpose of the study is to investigate whether there were social differences in mortality in this context and whether these differences increased during the industrial break-through. The expected advantages for higher social classes could not be confirmed in this environment. Instead, the best survival was found among those belonging to the agricultural sector. We found a strongly gendered pattern, with much higher mortality for and small health differences among men, while the results indicate increasing social inequality in female mortality during industrialization. The spatial pattern of mortality was pronounced and living with a partner had a strong impact on survival, particularly for men. We finally discuss the role of gender and class expectations in relation to lifestyles for the social patterning of mortality.

This introduction discusses the contributions in the special issue. The articles present results concerning the practice of birth control, mainly at the family level. They represent different analytical approaches where both interviews, letters, surveys and micro-level data have been used. The European fertility decline has made a fundamental change to the societies in the 20th and 21st centuries. Birth control spreads rapidly. Research in this field requires both qualitative and quantitative studies, where both approaches contribute to different perspectives on the transition. The articles in the issue discuss several themes in relation to birth control, of which three are developed in the introduction. These are gender and fertility, gender and health and finally how to control fertility. The presented results demonstrate the importance of including gender in the analyses of the fertility decline. A gender perspective makes it natural to consider historical persons as agents. It is also necessary to acknowledge that we should not treat the married couple as a single unit. They may have conflicting interests, something that several of the articles illustrate. One aspect we would like to emphasize is how health problems can influence the will to have more children and this affects birth control. This is a theme that in different forms is taken up by several of the authors. Finally, families practiced birth control with several different methods that also changed throughout the married years, thus demonstrating a flexibility that is often overlooked in conventional methods for the analysis of fertility.

This article summarizes aspects of the decline in infant mortality in the five Nordic countries. During the nineteenth century, both the levels of infant mortality and its development differed among the Nordic countries. At an early date, Denmark, Norway and Sweden stood out as the countries with the lowest levels in Europe whereas levels of infant mortality in Iceland and Finland were comparatively high. Within the countries there were large regional differences that often crossed national borders. Artificial feeding characterized most of the areas with the highest infant mortality. Within the different countries the high infant mortality came to be seen as a problem during the eighteenth and nineteenth centuries. The spread of information, midwives as agents of change and high literacy are factors that have been proven important in explaining the subsequent decline.

Illegitimacy, infant feeding practices and infant survival in Sweden, 1750-1950 : A regional analysis

Overfeeding and overeating in families are traditions that are often transferred from generation to generation. Irrespective of these family traditions, food availability might lead to overfeeding, in its turn leading to metabolic adaptations. Apart from selection, could these adaptations to the social environment have transgenerational effects? This study will attempt to answer the following question: Can overeating during a child's slow growth period (SGP), before their prepubertal peak in growth velocity influence descendants' risk of death from cardiovascular disease and diabetes? Data were collected by following three cohorts born in 1890, 1905 and 1920 in Overkalix parish in northern Sweden up until death or 1995. The parents' or grandparents' access to food during their SGP was determined by referring to historical data on harvests and food prices, records of local community meetings and general historical facts. If food was not readily available during the father's slow growth period, then cardiovascular disease mortality of the proband was low. Diabetes mortality increased if the paternal grandfather was exposed to a surfeit of food during his slow growth period. (Odds Ratio 4.1, 95% confidence interval 1.33-12.93, P=0.01). Selection bias seemed to be unlikely. A nutrition-linked mechanism through the male line seems to have influenced the risk for cardiovascular and diabetes mellitus mortality.

Longitudinal databases - sources for analyzing the life course : Characteristics, difficulties and possibilities

Background: This study investigated whether large fluctuations in food availability during grandparents' early development influenced grandchildren's cardiovascular mortality. We reported earlier that changes in availability of food - from good to poor or from poor to good - during intrauterine development was followed by a double risk of sudden death as an adult, and that mortality rate can be associated with ancestors' childhood availability of food. We have now studied transgenerational responses (TGR) to sharp differences of harvest between two consecutive years' for ancestors of 317 people in Overkalix, Sweden. Results: The confidence intervals were very wide but we found a striking TGR. There was no response in cardiovascular mortality in the grandchild from sharp changes of early exposure, experienced by three of the four grandparents (maternal grandparents and paternal grandfathers). If, however, the paternal grandmother up to puberty lived through a sharp change in food supply from one year to next, her sons' daughters had an excess risk for cardiovascular mortality (HR 2.69, 95% confidence interval 1.05-6.92). Selection or learning and imitation are unlikely explanations. X-linked epigenetic inheritance via spermatozoa seemed to be plausible, with the transmission, limited to being through the father, possibly explained by the sex differences in meiosis. Conclusion: The shock of change in food availability seems to give specific transgenerational responses.

Social circumstances often impinge on later generations in a socio-economic manner, giving children an uneven start in life. Overfeeding and overeating might not be an exception. The pathways might ...

Background: Recent studies have shown an association between weather and climatic factors with mortality, cardiovascular and infectious diseases. We used historical data to investigate the impact of seasonal temperature and precipitation on total mortality in Uppsala, Sweden, during the first two stages of the demographic transition, 1749-1859. Design: We retrieved mortality and population numbers of the Uppsala Domkyrka parish from digitised parish records and obtained monthly temperature and precipitation measures recorded in Uppsala during that time. Statistical models were established for year-to-year variability in deaths by annual and seasonal temperature and precipitation, adjusting for longer time trends. In a second step, a model was established for three different periods to study changes in the association of climate variability and mortality over time. Relative risks (RR) with 95% confidence intervals (CI) were calculated. Results: Precipitation during spring and autumn was significantly associated with annual mortality (spring RR 0.982, CI 0.965-1.000; autumn RR 1.018, CI 1.004-1.032, respectively, per centimetre increase of precipitation). Higher springtime temperature decreased annual mortality, while higher summer temperature increased the death toll; however, both were only borderline significant ( p =0.07). The significant effect of springtime precipitation for mortality was present only in the first two periods (1749-1785 and 1786-1824). On the contrary, the overall effect of autumn precipitation was mainly due to its relevance during the last period, 1825-1859 (RR 1.024, CI 0.997-1.052). At that time, higher winter precipitation was found to decrease mortality. Conclusions: In urban Uppsala, during the 18th and 19th century, precipitation appeared to be a stronger predictor for mortality than temperature. Higher spring precipitation decreased and higher autumn precipitation increased the number of deaths. However, this association differed before and during the early stages of industrialisation. Further research shall take age-specific differences into account, as well as changes in socio-economic conditions during that time. Keywords: climate variability; mortality; Sweden; pre-industrial period; urban population (Published: 3 April 2013) This paper is part of the thematic cluster Global Health Beyond 2015 . More papers from this cluster can be found at http://www.globalhealthaction.net Citation: Glob Health Action 2013, 6 : 20153 - http://dx.doi.org/10.3402/gha.v6i0.20153

Migration may result in exposure to factors that are both beneficial and harmful for good health. How the act of migration is associated with mortality, or whether the socio-economic condition of migrants prior to migration influences their mortality trajectory, is not well understood. In the present study, a cohort of 413 randomly selected individuals born in the rural community of Överkalix, Sweden, between 1890 and 1935 were followed from birth to either death or old age. Around 50% of the study-population moved away from Överkalix at one time or another. To adjust for a potential bias resulting from self-selection among the migrants, the father's occupational status was used together with parents' and grandparents' longevity. Overall, migration could not be shown to predict mortality when the backgrounds of the migrants were taken into account. Nonetheless, socio-economic background conditions appeared to moderate the association, decreasing the mortality rates for migrants with relatively good pre-migratory socio-economic conditions, while increasing it for migrants with poorer pre-migratory conditions. However, further scrutiny revealed that this effect modification mainly affected the female migrants' mortality. In conclusion, the study suggests that there is no general association between migration and mortality, but that migrants with better socio-economic resources are more likely to improve their mortality trajectories than migrants with poorer resources. Better pre-migratory conditions hence appear to be important for avoiding health-adverse circumstances and gaining access to health beneficial living conditions when moving to foreign environments - especially for women.

Transgenerational effects of maternal nutrition or other environmental 'exposures' are well recognised, but the possibility of exposure in the male influencing development and health in the next generation(s) is rarely considered. However, historical associations of longevity with paternal ancestors' food supply in the slow growth period (SGP) in mid childhood have been reported. Using the Avon Longitudinal Study of Parents and Children (ALSPAC), we identified 166 fathers who reported starting smoking before age 11 years and compared the growth of their offspring with those with a later paternal onset of smoking, after correcting for confounders. We analysed food supply effects on offspring and grandchild mortality risk ratios (RR) using 303 probands and their 1818 parents and grandparents from the 1890, 1905 and 1920 Overkalix cohorts, northern Sweden. After appropriate adjustment, early paternal smoking is associated with greater body mass index (BMI) at 9 years in sons, but not daughters. Sex-specific effects were also shown in the Overkalix data; paternal grandfather's food supply was only linked to the mortality RR of grandsons, while paternal grandmother's food supply was only associated with the granddaughters' mortality RR. These transgenerational effects were observed with exposure during the SGP (both grandparents) or fetal/infant life (grandmothers) but not during either grandparent's puberty. We conclude that sex-specific, male-line transgenerational responses exist in humans and hypothesise that these transmissions are mediated by the sex chromosomes, X and Y. Such responses add an entirely new dimension to the study of gene-environment interactions in development and health.

An analysis of infant mortality (based on 133,448 births) in two regions, Sundsvall and Skelleftea, in north-eastern Sweden during the nineteenth century shows that infant mortality was highly clustered with a relatively small number of families accounting for a large proportion of all infant deaths. Using logistic regression, two important factors were found to be associated with high-risk families: (i) a biological component evidenced by an over-representation of women who had experienced stillbirths, and (ii) a social component indicated by an increased risk among women who had remarried. The results strengthen the argument for using the family rather than the single child as the unit of analysis. The clustering of infant deaths points to the need to re-evaluate our interpretations of the causes of infant mortality in the past.

Background: A lively public and academic debate has highlighted the potential health risks of living in regions characterized by inequality. Research provides an ambiguous picture, however, with positive association between income equality and health mainly being found on higher levels of geographical division, such as nations, but rarely at local level. Methods: We examined the association between income inequality (using the Gini coefficient) and all-cause mortality in Swedish municipalities in the 65-74 age group. A multi-level analysis was applied and controlled for by variables including individual income and average income level in the municipality. The analyses were based on individual register data on all residents born between 1932 and 1941, outcomes were measured for the year 2006. Results: Lower individual income and lower average income in the municipality of residence were associated with significantly increased mortality. We found an association between income inequality and mortality with excessive deaths in unequal municipalities after controlling for mean income level and personal income. The results from the analysis of individual data differed substantially from the analysis of aggregate data. Conclusions: Income inequality was significantly associated with mortality in the age group 65-74 at municipality level. The association is small compared to many other variables, but is not negligible. Even in a comparatively equal society like Sweden, the potential effects of income inequality on mortality at the local level warrant consideration. Keywords: income inequality; mortality; Gini index; Sweden; municipality level; old age (Published: 16 January 2013) Citation: Glob Health Action 2013, 6 : 19116 - http://dx.doi.org/10.3402/gha.v6i0.19116

This article reviews the following work:Henrik Karlsson, Vården av de arbetsoförmögna: reumatikervårdens framväxt i den tidiga välfärdsstaten, Örebro studies in history 12 (Örebro: Örebro universitet 2012). 208 s. (Summary in English: The care of those unable to work: the development of care for rheumatics in the early welfare state.)

Maternal access to food during pregnancy affects birth weight and other characteristics of offspring. It has been suggested that fluctuations in food availability during infancy, ranging from plentiful to starvation, may influence cerebro-cardiovascular risk factors for the offspring during adult life. This study was designed to test the correlation between food availability changes during life before birth and adult sudden death from disease. This was a follow-up study of ancient cohorts in the parish of Skelleftea, Sweden, comprising 7,572 individuals born between 1805 and 1849 and still alive at age 40. Food availability variations in the parish during their prenatal life were ascertained from historical sources, the main outcome measures being overall mortality and mortality from sudden death in the age range 40-70 years. The risk of sudden death was almost doubled for those whose mothers were struck by a poor harvest during the early stages of pregnancy, but who experienced a good harvest toward the end. Yet almost the same over-risk was evident for the converse case: plentiful food supply in early pregnancy followed by a poor harvest toward the end. A stable maternal access to food during pregnancy is important for the offspring's risk of sudden death from cerebro- and cardiovascular disease as an adult. Am. J. Hum. Biol. 12:447-453, 2000. Copyright 2000 Wiley-Liss, Inc.