Social determinants of health and mortality
Research on social determinants of health and mortality by members of the Population Research Unit.
The association between income and mortality

Mortality disparity between socioeconomic groups has increased in Finland over the last decades and according to our studies the increasing disparity is particularly pronounced between income groups. The characteristics of this changing association between income and mortality are not known. We include the temporal aspect in exploring the association between income and mortality as it provides insight to mechanisms behind the income-mortality relationship. Considering the history of the individual is beneficial as the income changes over the life course and childhood living conditions are possibly related to underlying mechanisms. The research seeks to understand the causes of the mortality trends of income groups, clarify the association between income and mortality, and the changes in the association since the late 1980s by using nationally representative and internationally unique data which combine information from various administrative registers.

Key words: income, mortality, socioeconomic disparity, mortality trends

Researcher: Lasse Tarkiainen

Key publications:

Tarkiainen, L., Martikainen, P., & Laaksonen, M. (2012). The changing relationship between income and mortality in Finland, 1988-2007. Journal of Epidemiology & Community Health, 67(1), 21-27.

Tarkiainen, L., Martikainen, P., Laaksonen, M., & Valkonen, T. (2012). Trends in life expectancy by income from 1988 to 2007: decomposition by age and cause of death. Journal of epidemiology and community health, 66(7), 573-578.

Automation of work and the career paths and mental health of workers

The effects of automation on the future of labor is a subject of broad debate in academia. Recent development shows that technological progress is allowing automation to spread across many new sectors and occupations and the expectations of machines replacing manpower range from idealistic scenarios, with the fruits of automation benefiting all of mankind, to concerns about them falling in the hands of the few.

This project assesses how developments in automation technologies have affected mental health and employment outcomes of workers in Finland. We use different meters for such technologies, namely the prevalence of industrial robots in given industries and estimated occupation-level automation probabilities to explain these outcomes. We are also interested in what kind of individual socioeconomic- and demographic characteristics moderate these outcomes.  

Additionally, we plan to evaluate how changing task-contents within occupations are associated with health outcomes of workers in the 21st century. The most important change promoting the change of task-contents is likely technological development, which can have implications on job safety, job requirements and possibly job stress or insecurity.

Researcher: Juha Luukkonen

The CODATwins project

There is large variation in social macro environment over birth cohorts and between countries. At the beginning of the 20th century, the standard of living in European countries was at the level of low income societies nowadays. Environment has changed more obesogenic during the last decades, and there is large variation in the prevalence of obesity between countries also reflecting differences in environment. The CODATwins project was established in 2013 to analyze how these macro environmental factors modify the influence of genetic and environmental factors on key physiological, behavioral and social traits in humans by collecting an international database of twin cohorts. The target of CODATwins project was collect together all twin cohorts in the world having information on height and weight. Further, information was collected on smoking and education. The genetic twin study design allows to analyze how genetic, environmental factors shared by co-twins and environment unique to each twin individual affect differences between humans in these traits. Currently, CODATwins is the largest twin cohort in the world having information on half million twin individuals from 53 independent twin projects representing 24 countries. Until the end of 2020, we have published 19 international peer-reviewed articles covering themes such as how macro environment and parental education modifies the heritability of height and body mass index from birth to old age; how the heritability of education has changed over birth cohorts and vary between societies; the effect of intrauterine conditions on height, weight and education; and several studies on the special features of twin pregnancies. Currently, the ongoing studies focus on the genetic regulation of growth and factors affecting individual differences in education.   

Researchers: Karri Silventoinen, Weilong Li

Key publications:

Silventoinen K et al. Genetic and environmental effects on body mass index from infancy to the onset of adulthood: an individual-based pooled analysis of 45 twin cohorts participating in the COllaborative project of Development of Anthropometrical measures in Twins (CODATwins) study. American Journal of Clinical Nutrition 2016, 104, 371-379.

Jelenkovic A et al. Genetic and environmental influences on adult human height across birth cohorts from 1886 to 1994. eLife 2016, 5, e20320.

Silventoinen K et al. Differences in genetic and environmental variation in adult body mass index by sex, age, time period and region: an individual-based pooled analysis of 40 twin cohorts. American Journal of Clinical Nutrition 2017, 106, 457-466.

Jelenkovic A et al. Association between birth weight and later body mass index: An individual based pooled analysis of 27 twin cohorts participating in the CODATwins project. International Journal of Epidemiology 2017, 46, 1488-1498.

Yokoyama Y et al. Genetic and environmental factors affecting birth size variation: a pooled individual-based analysis of secular trends and global geographical differences using 26 twin cohorts. International Journal of Epidemiology 2018, 47, 1195-1206.

Jelenkovic A et al. Association between birth weight and educational attainment: an individual-based pooled analysis of nine twin cohorts. Journal of Epidemiology and Community Health 2018, 72, 832-837.

Silventoinen K et al. Parental education and genetics of body mass index from infancy to old age: a pooled analysis of 29 twin cohorts. Obesity 2019, 27, 855-865.

Silventoinen K et al.  Genetic and environmental variation in educational attainment: an individual-based analysis of 28 twin cohorts. Scientific Reports 2020, 10, 12681

ERC Advanced Grant on social inequalities in population health: integrating evidence from longitudinal, family-based and genetically informed data

Social inequalities in health are observed in all societies. These inequalities have grown markedly over the past 30 years, with those in less advantaged social positions currently expected to live 5–10 years less than those in more advantaged positions. The study aims to establish the root causes of these inequalities by (1) assessing the drivers of long-term changes in health inequalities and establishing the contribution of family factors and macro-level social and economic conditions to these changes; (2) examining multigenerational interdependencies of social position and health in up to four generations; (3) estimating the causal effects of social position on health by employing molecular genetic information and assessing whether genetic associations are mediated or modified by social position; (4) evaluating the generalisability of explanations of social inequalities in health through international comparative research. The study will integrate research scattered in multiple disciplines by establishing how family background – both social as experienced through living conditions and social resources in families, and genetic as inherited from biological parents – affects health and social disadvantage within and across generations. The project will go beyond standard observational research through new conceptual insight and by using a unique combination of longitudinal register-based and genetically informed data sources. We will take advantage of natural experiments – educational and alcohol policy reforms and rapid economic changes – to identify pivotal social processes in the production of health inequalities. Our results will be ground-breaking because we will establish how family and genetic factors are intertwined with individual social characteristics and how they manifest in health outcomes in different macro-level social conditions. The power to test causal hypotheses will advance science and help devise policies to reduce health inequalities.

Researchers: Pekka Martikainen, Hanna Remes, Hannu Lahtinen, Sanni Saarinen

Estimating future burden of Type 2 diabetes and life expectancy by income in Finland

Following the trends around the world, Finland is experiencing rapid increases in its burden of diabetes. Additionally, there has been suggested that the increase in diabetes risk would continue to be driven by the predicted rise in the prevalence of obesity in Finland.

Furthermore, socioeconomic status is widely acknowledged to influence the risk of diabetes, the development of complications, all-cause mortality and life expectancy.

Therefore, this study aims to explore the socioeconomic differences of past and future trends of the incidence, prevalence and mortality of type 2 diabetes in Finland and their impact on life expectancy. In addition, we also explore the potential effect of different future obesity trends scenarios on diabetes burden.

We used a multistate life tables’ framework to estimate transition probabilities by sex, age, and income quintile between four health states. We calculated life expectancy at 65 with and without diabetes. To obtain valid projections for T2D prevalence to 2040, we extended the multi-state model. The model simulates transitions of the Finnish population aged 30 or more years through states of illness and mortality. These transitions are governed by one-year probabilities estimated from the life table.

Researchers: Maria Guzman Castillo, Pekka Martikainen, Kaarina Korhonen, Michael Murphy

Excess mortality among the unemployed

Several individual-level observational follow-up studies have shown that, after adjusting for age, mortality is higher among the unemployed than among the employed, and the effects are especially strong with respect to suicide.  The reasons for this association are not fully established. Strong inferences about the causal effects of unemployment on mortality are still not warranted, because the possibility that individuals with a high risk of mortality might be selected for unemployment cannot be fully ruled out. We estimate the effects of unemployment and establishment downsizing on mortality in periods of low (1989) and high (1994) unemployment.  Unemployment was found to be associated with a notably larger increase in the hazard of mortality during economic boom than in the recession. By showing that, in the context of either a high level of unemployment or rapid downsizing, the effects of unemployment on mortality are modest these studies provides strong evidence of unaccounted confounding. Also, high relative suicide mortality among the unemployed during times of economic boom suggests that selective processes may be responsible for some of the employment status differences in suicide. However, long-term unemployment seems to have causal effects on suicide, which, especially among men, partly stem from low income. Altogether, individual-level studies may overestimate the causal effects of unemployment on mortality.

Key words: unemployment, mortality, suicide, selection, causal effects, economic boom, recession

Researchers: Netta Mäki and Pekka Martikainen

Key publications:

Mäki, N., & Martikainen, P. (2012). A register-based study on excess suicide mortality among unemployed men and women during different levels of unemployment in Finland. Journal of Epidemiology & Community Health, 66(4), 302-307.

Martikainen P., Mäki N., & Jäntti M. (2007). The Effects of Unemployment on Mortality following Workplace Downsizing and Workplace Closure: A Register-based Follow-up Study of Finnish Men and Women during Economic Boom and Recession. American Journal of Epidemiology, 165(9), 1070–75.

Life-course determinants of youth self-harm

Previous research has time and again shown that childhood family circumstances, such as adverse childhood experiences (ACEs) and low parental socioeconomic status (SES) increase the risk of self-harm during adolescence and young adulthood. Moreover, it is well established that individual correlates of self-harm, including e.g. psychiatric disorders, behavioral problems and school performance are related to these same childhood factors. To make matters even more complex, family circumstances, individual risk factors of self-harm and self-harming behavior itself form an interplay with multidirectional associations and complicated interactions. The purpose of this research project is to disentangle these associations. The project focuses on the interactions between ACEs and childhood SES, the mediating factors in the association between childhood SES and self-harm, treatment-seeking differences by childhood SES and the impact of self-harm on family members. The study uses register-based data on all Finnish children aged 0-14 in 2000. The results so far suggest that adverse childhood experiences may exacerbate the risk of self-harm in low-income families and that most of the effect of childhood SES on self-harm is mediated through adolescent mental health, behavioral problems and school performance. Ongoing analyses show indications of treatment-seeking differences by parental SES as well as increases in mental ill health of the family members of self-harming youth.

Keywords: adverse childhood experiences, childhood socioeconomic status, self-harm, adolescence, mental health, behavioral problems, school performance, socioeconomic disparities, treatment-seeking

Researcher: Joonas Pitkänen

Longitudinal birth cohort and family-based studies of morbidity, mortality and social disadvantage (BIRTHFAM)

In the BIRTHFAM consortium (Population Research Unit & Institute for Molecular Medicine Finland) funded by the Academy of Finland we aim to gain a fuller understanding of the social and genetic determinants of poor health and social disadvantage. To achieve this we will build a cluster of family cohorts and develop novel, interdisciplinary study designs and methodology. Family data encompass a broader range of exposures within and across generations than data on individuals only, providing a more comprehensive view of life-course epidemiology. Furthermore, family data enable stronger causal inference by allowing for comparisons of family members with differing degrees of shared genetic and environmental exposures.

Building on existing data and expertise, we bring together two complementary types of data: 1) family-based register data with long follow-ups of large cohorts and 2) twin data with in-depth information of participants and their genetic makeup. We will develop and document family cohorts for three research initiatives that rely on the internationally unique linked Finnish data: 1) a multigenerational data set of up to five generations for examining intergenerational associations in health and social disadvantage; 2) a data set of participants with different degrees of relatedness (twins, siblings, cousins etc.) for estimating heritability and familial clustering of ill health; 3) harmonised data sets of family cohorts born over 50 years apart for assessing changes in the importance of early life circumstances on adult health.
We will also adapt and share new study designs and methods, organise training and build an international research network for sharing expertise and facilitate access to these exceptional data for top scientists around the world.

The consortium builds research infrastructure with diversity and flexibility for long-term research needs and innovative ideas yet to surface. Understanding how families transmit ill health and social disadvantage across generations highlight new opportunities for improving population health.

Researchers: Hanna Remes, Heta Moustgaard

Long-term changes in socioeconomic mortality differentials

Even as overall mortality levels have steadily declined over time, differentials between socioeconomic groups are large in Finland and these have been increasing over the last decades. While the contribution of individual level characteristics to mortality has been widely examined, these do not fully explain the differentials and the observed increases, which points to a need to assess other features that may be associated with processes leading to growing disparities. Accordingly, increasing evidence suggest that, beyond individual characteristics, the varied settings in which people are embedded may condition the effects of individual characteristics and contribute to mortality differentials and their changes over time. Therefore, the purpose of the study is to explore long-term changes in socioeconomic mortality differentials within a framework that combines both individual and contextual influences. The study employs individual-level total population register data covering nearly half a century. Adopting a long-term perspective with a focus processes occurring at different contextual levels, the study will contribute to the existing literature with new insights on the factors underlying mortality differentials.

Researcher: Ulla Suulamo

Medication Use among Children and Adolescents – Family and Area Determinants

This project funded by the Social Insurance Institution of Finland (Kela) assesses how characteristics of the family and residential area predict prescription medication use among Finnish children and adolescents. It aims to establish whether the Finnish welfare state with its universal health insurance provides children and adolescents equal access to treatment and health irrespective of their socioeconomic background.

Specifically we ask:

1) How do family factors such as family structure, parental socioeconomic position, and parental employment predict prescription medication use among children and adolescents?

2) How do neighbourhood characteristics such as the educational structure and unemployment rate predict prescription medication use among children and adolescents?

3) Do neighbourhood characteristics predict medication use even when family characteristics are controlled for – i.e. are there true neighbourhood effects in medication use.

The project uses register data on all Finnish children born between 1987 and 2015, nested in families and postal-code areas, followed up until the end of 2018. Medication use is identified from the National Prescription Register of the Social Insurance Institution covering the total population of Finland and including all reimbursed purchases of prescription medications. The data enable the longitudinal and multilevel assessment of the predictors of medication use. Within-family and within-individual designs will be used for stronger causal inference.

Researchers: Heta Moustgaard, Elina Hiltunen, Nina Jokirinne

Reproductive history and mortality

Reproductive history is known to affect the life expectancy of women. International evidence suggests that women with two children have lower mortality than those with fewer children. This study will contribute to the debate on reproductive history and cause-specific mortality in contemporary populations, and examine how the number of biological children and the timing of childbirth relate to the later-life mortality of Finnish men and women. A novel feature of the study is that it will control for parents’ childhood living conditions, which, to our knowledge, has not been done in the previous studies.

Key words: mortality, reproductive history, fertility

Researcher: Elina Einiö

Social inequalities in health and mortality in a comparative perspective

Social inequalities in health are a major challenge to public health in Europe and reducing them is a priority for the European Union. While there is little reason to believe that findings on social inequalities in health obtained in the Finnish context would be unique to Finland, or more generally to a Nordic welfare state, an important part in demonstrating causation is validation of findings in different populations and societal contexts. Comparative studies are ideally placed at achieving this. In addition, comparative studies of populations in different countries may help us understand the limits of explanations of social inequalities in health obtained in particular settings, and caution against uncritical extrapolation of results to other countries. Such studies also help situate analyses of health inequalities within the wider socio-political context and are an important way to assess how macro-level social conditions and policies may affect health inequalities. Many of our comparative studies are carried out with data collected in the ‘Rotterdam group’ headed by prof Mackenbach – a research collaboration that has been going on for about three decades; most recently for example in the context of EU-funded projects DEMETRIQ and EURO-GBD-SE. In addition, comparative studies between the Nordic and Baltic countries as well as the US have formed an added backbone of this research tradition. Ongoing work will focus on comparisons of social inequalities in health from a cohort perspective as well as assess changes in social inequalities in mortality in the Nordic and Baltic countries during economic downturns.

Researcher: Pekka Martikainen