Early-Life Disease Exposure and Its Heterogeneous Effects on Mortality Throughout Life: Sweden, 1905-2016.

Exposure to infectious diseases in early life has been linked to increased mortality risk in later life in high-disease settings, such as eighteenth- and nineteenth-century Europe. Less is known about the long-term effects of early-life disease exposure in milder disease environments. This study estimates heterogeneous effects from disease exposure in infancy on later-life mortality in twentieth-century Sweden, by socioeconomic status at birth and sex. Using historical population data for southern Sweden, we study 11,515 individuals who were born in 1905-1929 from age 1 until age 85. We measure exposure to disease using the local post-early neonatal mortality rate in the first 12 months after birth and apply flexible parametric survival models. For females, we find a negative effect on life expectancy (scarring) at ages 1-85 following high disease exposure in infancy, particularly for those born to unskilled workers. For males, we find no negative effect on later-life survival, likely because stronger mortality selection in infancy outweighs scarring. Thus, even as the incidence of infectious diseases declined at the start of the twentieth century, early-life disease exposure generated long-lasting negative but heterogeneous population health effects.

Disease exposure in infancy affects women's reproductive outcomes and offspring health in southern Sweden 1905-2000.

Ample evidence demonstrates that early-life adversity negatively affects morbidity and survival in late life. We show that disease exposure in infancy also has a continuous impact on reproduction and health across the female life course and even affects early-life health of the next generation. Using Swedish administrative data, obstetric records, and local infant mortality rates as a measure of disease exposure, we follow women's reproductive careers and offspring health 1905-2000, examining a comprehensive set of outcomes. Women exposed to disease in infancy give birth to a lower proportion of boys, consistent with notions that male fetuses are more vulnerable to adverse conditions and are more often miscarried. Sons of exposed mothers are also more likely to be born preterm and have higher birthweight suggesting in utero out-selection. Exposed women have a greater risk of miscarriage and of male stillbirth, but their overall likelihood of giving birth is not affected.

Is increased size at birth associated with longevity on the population level? - A historical and comparative analysis of regions in Sweden.

Increased population longevity could be influenced by early life factors. Some areas have long-lived populations, also in a historical perspective. We aimed to study these factors in Halland, an area with the highest life expectancy in Sweden. We collected archival data on gestational age and birth characteristics from 995 live singleton full-term births at the Halmstad Hospital, Halland, from the period 1936 to 1938 and compared these to 3364 births from three hospitals in nearby Scania for the period 1935-1945. In addition, data were obtained on maternal and offspring characteristics from the national Swedish Medical Birth Register during 1973-2013. The results show that when controlling for background maternal and offspring characteristics, mean birth weight (BW) and mean birth length were higher in Halland than in Scania, but the proportion of low birth weight (LBW) and small for gestational age (SGA) was lower. However, mean BW for Halland did not differ from the rest of Sweden in recent years 2004-2013. We also conducted a mortality follow-up for children born in Scania, which showed that LBW, being born SGA, or short birth length reduced survival. In conclusion, the high mean life expectancy in Halland compared to the rest of Sweden could have been associated with beneficial early life factors influencing birth size in the past. In more recent decades the mean BW of Halland is not different from the national mean. Thus, longevity could be expected to become more equal to the national mean in the future.

Inequality and demographic response to short-term economic stress in North Orkney, Scotland, 1855-1910: Sector differences.

We examine economic inequality and social differences in infant and child mortality, and fertility responses to food price changes in North Orkney, 1855-1910, using linked vital records. This small population featured a diverse occupational structure, limited land resources, and geographic isolation from mainland Scotland. Segments of Orkney's non-agricultural working population were living so close to the margin of subsistence in normal years that an increase in food prices in bad years cost the lives of their children. Delayed childbearing, in addition to increased labour intensity, occupational diversification, and poor relief, failed to mitigate the negative effects of unfavourable prices in this group. While previous studies for Western Europe show a strong social gradient in mortality responses to food prices, and for Eastern Asia a strong household gradient, this study shows a strong sectoral gradient, indicating low standards of living for the non-agricultural working population well into the twentieth century.

Early life effects across the life course: the impact of individually defined exogenous measures of disease exposure on mortality by sex in 19th- and 20th-century Southern Sweden.

Using micro-level longitudinal data from Southern Sweden for 1813 to 1968, this work evaluates the effect of exposure to disease in early life on mortality over the entire life course and separately by sex. The local rates of post-early neonatal mortality are considered indicators of early life disease exposure, and these rates are calculated specifically for each person based on birth date. The loss in median remaining life among exposed individuals who survived to age 1 is 1.1 years for females and 2.1 years for males. Exposed individuals show a cross-over from lower to higher relative mortality as they age. This change occurs in adulthood for males and in old age for females. During adulthood, exposed males present higher rates of death than exposed females. These results are new to the literature and shed light on the importance of adopting a full life course approach and capturing sex differences when evaluating the long-term impacts of early life exposures.

Migrants and the diffusion of low marital fertility in Belgium.

Although the diffusion of fertility behavior between different social strata in historical communities has received considerable attention in recent studies, the relationship between the diffusion of fertility behavior and the diffusion of people (migration) during the nineteenth century remains largely underexplored. Evidence from population registers compiled in the Historical Database of the Liège Region, covering the period of 1812 to 1900, reveals that migrant couples in Sart, Belgium, from 1850 to 1874 and from 1875 to 1899 had a reduced risk of conception. The incorporation of geographical mobility, as well as the migrant status of both husbands and wives, into this fertility research sheds light not only on the spread of ideas and behaviors but also on the possible reasons why the ideas and behaviors of immigrants might have been similar to, or different from, those of a native-born population.