When Did the Health Gradient Emerge? Social Class and Adult Mortality in Southern Sweden, 1813-2015.

Across today's developed world, there is a clear mortality gradient by socioeconomic status for all ages. It is often taken for granted that this gradient was as strong-or even stronger-in the past when social transfers were rudimentary and health care systems were less developed. Some studies based on cross-sectional data have supported this view, but others based on longitudinal data found that this was not the case. If there was no gradient in the past, when did it emerge? To answer this question, we examine social class differences in adult mortality for men and women in southern Sweden over a 200-year period, using unique individual-level register data. We find a systematic class gradient in adult mortality emerging at ages 30-59 only after 1950 for women and after 1970 for men, and in subsequent periods also observable for ages 60-89. Given that the mortality gradient emerged when Sweden transitioned into a modern welfare state with substantial social transfers and a universal health care system, this finding points to lifestyle and psychosocial factors as likely determinants.

The Long-Lasting Influenza: The Impact of Fetal Stress During the 1918 Influenza Pandemic on Socioeconomic Attainment and Health in Sweden, 1968-2012.

The 1918 influenza pandemic had not only a massive instant death toll but also lasting effects on its survivors. Several studies have shown that children born in 1919, and thus exposed to the H1N1 virus in utero, experienced worse health and socioeconomic outcomes in older ages than surrounding birth cohorts. This study combines several sources of contemporary statistics with full-population individual-level data for Sweden during 1968-2012 to examine the influence of fetal exposure to the Spanish flu on health, adulthood income, and occupational attainment. For both men and women, fetal exposure resulted in higher morbidity in ages 54-87, as measured by hospitalization. For males, exposure during the second trimester also affected mortality in cancer and heart disease. Overall, the effects on all-cause mortality were modest, with about three months shorter remaining life expectancy for the cohorts exposed during the second trimester. For socioeconomic outcomes, results fail to provide consistent evidence supporting any long-term consequences of fetal exposure. We conclude that although the immediate health effects of exposure to the 1918 pandemic were huge, the long-term effects were modest in size.

The long-term economic effects of polio: Evidence from the introduction of the polio vaccine to Sweden in 1957.

This study explores the impact an exogenous improvement in childhood health has on later-life outcomes. Using extensive and detailed register data from the Swedish Interdisciplinary Panel covering up to 2011, we follow individuals exposed to the introduction of the first vaccine against polio in Sweden (birth cohorts 1937-1966) until adulthood in order to quantify the causal effect of polio vaccination on long-term economic outcomes. The results show that, contrary to what has been found in the literature for other health-related interventions, including other vaccines, exposure to the vaccine against polio did not seem to have any long-term effects on the studied adult economic outcomes. Upon closer inspection of how the disease affects children, this might be explained by the fact that no scarring effects from exposure to high incidence of polio were found on adult income, educational achievement, or hospitalizations, which seems to suggest that those who contracted the illness but suffered only the milder symptoms of the disease made a full recovery and had no lifelong sequels as a consequence of the condition. The absence of scarring effects is hypothesized to be related to the pathology and epidemiology of the disease itself, which infects many, but scars only those who suffer the most recognizable paralytic symptoms.

Social Class and Excess Mortality in Sweden During the 1918 Influenza Pandemic.

Consensus is lacking in the literature about the role of socioeconomic factors on influenza-associated deaths during the 1918 pandemic. Although some scholars have found that social factors were important, others have not. In this study, we analyzed differences in excess mortality by social class in Sweden during the 1918 pandemic. We analyzed individual-level mortality of the entire population aged 30-59 years by combining information from death records with census data on occupation. Social class was measured by an occupation-based class scheme. Excess mortality during the pandemic was measured as the number of deaths relative to the number occurring in the same month the year before. Social class differences in numbers of deaths were modeled using a complementary log-log model that was adjusted for potential confounding at the family, the residential (urban/rural), and the county levels. We found notable class differences in excess mortality but no perfect class gradient. Class differences were somewhat larger for men than for women.

Smoking and early retirement due to chronic disability.

This paper considers the long-term effects of smoking on disability retirement in Sweden. Smoking is known to have damaging effects on health, but there is limited evidence on how the effects of smoking translate into worse labour market outcomes, such as the inability to work. In contrast to the few previous studies on smoking and disability retirement, we use a large population sample with registry information on smoking, which is recorded for all women who give birth in Sweden. Thanks to these comprehensive data, we are able to account for a much broader range of potential confounders. In particular, by the use of sibling and twin fixed effects, we account for unobserved heterogeneity in childhood environment and family characteristics. Given that smoking is often initiated in adolescence, one would suspect such factors to play important roles. Among individuals aged 50-64 in 2011, a simple model suggested smokers to have a 5 percentage point higher probability of receiving (full) disability pension, making them more than twice as likely as non-smokers to receive this. However, in a model with sibling fixed effects, the size of the effect was reduced by more than a third. The results point to the importance of confounders, such as childhood circumstances or behaviours, which were not accounted for by previous studies. We also consider effects on disability due to different health conditions. In relative terms, effects are the largest for circulatory conditions and tumours. Results are largely driven by health problems severe enough to merit hospitalization, and there is no evidence of a role played by financial incentives.

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.

Do conditions in early life affect old-age mortality directly and indirectly? Evidence from 19th-century rural Sweden.

Previous research has shown that the disease load experienced during the birth year, measured as the infant mortality rate, had a significant influence on old-age mortality in nineteenth-century rural Sweden. We know that children born in years with very high rates of infant mortality, due to outbreaks of smallpox or whooping cough, and who still survived to adulthood and married, faced a life length several years shorter than others. We do not know, however, whether this is a direct effect, caused by permanent physical damage leading to fatal outcomes later in life, or an indirect effect, via its influence on accumulation of wealth and obtained socio-economic status. The Scanian Demographic Database, with information on five rural parishes in southern Sweden between 1813 and 1894, contains the data needed to distinguish between the two mechanisms. First, the effects of conditions in childhood on obtained socio-economic status as an adult are analyzed, then the effects of both early-life conditions and socio-economic status at various stages of life on old-age mortality. By including random effects, we take into account possible dependencies in the data due to kinship and marriage. We find that a high disease load during the first year of life had a strong negative impact on a person's ability to acquire wealth, never before shown for a historical setting. This means that it is indeed possible that the effects of disease load in the first year of life indirectly affect mortality in old age through obtained socio-economic status. We find, however, no effects of obtained socio-economic status on old-age mortality. While the result is interesting per se, constituting a debatable issue, it means that the argument that early-life conditions indirectly affect old-age mortality is not supported. Instead, we find support for the conclusion that the effect of the disease load in early-life is direct or, in other words, that physiological damage from severe infections at the start of life leads to higher mortality at older ages. Taking random effects at family level into account did not alter this conclusion.

Deliberate control in a natural fertility population: southern Sweden, 1766-1864.

In this article, we analyze fertility control in a rural population characterized by natural fertility, using survival analysis on a longitudinal data set at the individual level combined with food prices. Landless and semilandless families responded strongly to short-term economic stress stemming from changes in prices. The fertility response, both to moderate and large changes in food prices, was the strongest within six months after prices changed in the fall, which means that the response was deliberate. People foresaw bad times and planned their fertility accordingly. The result highlights the importance of deliberate control of the timing of childbirth before the fertility transition, not in order to achieve a certain family size but, as in this case, to reduce the negative impacts of short-term economic stress.

Airborne infectious diseases during infancy and mortality in later life in southern Sweden, 1766-1894.

BACKGROUND: The importance of early life conditions and current conditions for mortality in later life was assessed using historical data from four rural parishes in southern Sweden. Both demographic and economic data are valid. METHODS: Longitudinal demographic and socioeconomic data for individuals and household socioeconomic data from parish registers were combined with local area data on food costs and disease load using a Cox regression framework to analyse the 55-80 year age group mortality (number of deaths = 1398). RESULTS: In a previous paper, the disease load experienced during the birth year, measured as the infant mortality rate, was strongly associated with old-age mortality, particularly the outcome of airborne infectious diseases. In the present paper, this impact persisted after controlling for variations in food prices during pregnancy and the birth year, and the disease load on mothers during pregnancy. The impact on mortality in later life stems from both the short-term cycles and the long-term decline in infant mortality. An asymmetrical effect and strong threshold effects were found for the cycles. Years with very high infant mortality, dominated by smallpox and whooping cough, had a strong impact, while modest changes had almost no impact at all. The effects of the disease load during the year of birth were particularly strong for children born during the winter and summer. Children severely exposed to airborne infectious diseases during their birth year had a much higher risk of dying of airborne infectious diseases in their old age. CONCLUSIONS: This study suggests that exposure to airborne infectious diseases during the first year of life increases mortality at ages 55-80.