Demography has two faculty positions (professor and university lecturer) in the University of Helsinki and currently around 10 researchers (research assistants, doctoral students and post-doctoral researchers) are employed by external funding from the Academy of Finland, the European Union, Finnish government and several private foundations in the Population Research Unit. Our research is published in international scientific peer-reviewed journals including leading journals of demography and sociology of health (e.g. Demography and Social Science and Medicine), epidemiology (e.g. International Journal of Epidemiology and American Journal of Epidemiology), as well as other fields of science (e.g. Addiction and American Journal of Clinical Nutrition).

The research in the Population Research Unit has traditionally stemmed from the excellent Finnish longitudinal population-based register data sources, which still create an invaluable source of information for scientific research. The research unit maintains individual-level register-based data sets designed for the analysis of different demographic and social phenomena. These data link large representative samples of individual-level census records on socio-demographic characteristics with outcome data on causes of death, hospital discharge diagnoses, medication use, pensions, and crime. In the recent years, other data sets with questionnaire-based information, biomedical measures and genetic data have also become an important part of research at the PRU.

A particular long-term aim of the team is to provide novel evidence on the factors influencing current trends and causes of social differences in health and well-being in the Finnish society and globally. Social differentials in health and well-being are driven by a range of more distal socio-structural processes such as educational and labour market processes, income distribution, regional contexts and long-term social transformations such as population ageing and family change, and more proximate individual-level factors, such as individual characteristics, behaviours and psychosocial circumstances.

The team has developed multidimensional causal frameworks for the study of the social determinants of health and used quasi-experimental and natural experimental study designs to quantify the effects of policies (alcohol tax changes), societal shocks (mass unemployment) or life-events (retirement) to make stronger causal inferences. Further, we have intensively used family designs allowing us to disentangle the effects of social and genetic family background from the causal effects of social and other exposures to health. The latest developments include analyzing how measured genetic polymorphisms interact with psychosocial factors when predicting obesity and cardio-vascular mortality. These different types of analyses contribute to our theoretical understanding of social determinants of health in pinpointing the relative importance of various causal factors and causal pathways leading to adverse and beneficial outcomes in health and well-being.

International collaboration has also allowed us to analyze these processes in the global context. Traditionally our strongest contacts have been to the USA and European countries (especially other Nordic countries, the UK and the Netherlands), but in the recent years, we have developed strong collaboration with researchers also in Japan and China. For example, our research project comparing Finland, Japan and the UK has allowed us to analyze socio-economic health differences in these three very different industrialized nations and our collaborative twin study covering data from 23 countries to analyze how society modifies the effect of genetic and environmental factors on obesity, other key human anthropometric measures, and their associations with socio-economic factors.

International and national research collaboration

Research collaboration – both national and international – and researcher mobility are key factors in maintaining and developing the quality of research and doctoral training. The research unit has a wide international research network and a large part of research is carried out and published in international collaborations with leading scholars. In the period 2012-2017, the Unit’s researchers published with foreign academics from more than 20 countries working in more than 40 research groups, and collaborated with other Finnish universities and national research centres. Some of the most important international partnerships include University College London, London School of Economics, Erasmus Medical Centre, University of Pennsylvania, Harvard School of Public Health, University of Toyama, Osaka City University, Stockholm University, Karolinska Institutet, Oslo University College and University of Copenhagen, and Max Planck Institute for Demographic Research in Rostock. The members of the Unit have made both long- and short-term research visits in foreign universities mentioned above and the principal investigators have also hosted several international guest researchers and seminars. The principal investigators of the unit have also supervised and examined several doctoral dissertations in foreign universities.

In Finland we work in co-operation with the Department of Public Health at the Medical Faculty, University of Helsinki, the National Institute for Health and Welfare, the Finnish Institute of Occupational Health, the Finnish Centre for Pensions, the Finnish Institute for Molecular Medicine and Research, and the Research Institute of the Finnish Economy.

Doctoral training

Since 1994 the Unit has been responsible for the doctoral programme ‘Population, Health and Living Conditions’. The principal aim of the programme is to train researchers who are able to play leading roles in research on population health and well-being. This goal can be achieved through (1) rigorous instruction in the theoretical approaches, methods, and empirical analyses, and (2) incorporation of students into departmental research projects that will eventually lead into independent research. The doctoral training is closely intertwined with the Unit’s general focus and research projects, and is run in collaboration with medical sociologists (Faculty of Medicine) and social psychologists.

The doctoral training is based on a twice-a-month research seminar and courses on the theory and methods of demography and social epidemiology. The doctoral programme also organises teaching together with other doctoral programmes. Training has been international for more than 20 years with foreign visitors and teachers participating in the seminar work. A permanent annual doctoral training programme with Swedish partners (Centre for Health Equity Studies, Stockholm University/Karolinska Institutet) has continued for over fifteen years. In addition, research training with Scottish colleagues (Medical Research Council/Social and Public Health Sciences Unit, University of Glasgow) has been frequent for more than twenty years, with the more recent joint PhD-seminars with the University College London, University of Manchester, and Örebro University. PhD students also often visit these collaborating centres.

Several generations of PhDs have found employment in the private and public sector as well as in academic and other research positions. About 4-5 students graduate from the doctoral programme annually and we currently have about 30 students.

Societal impact

We foster societal interaction e.g. by working closely with the Ministry of Health and Social Affairs, the National Institute for Health and Welfare (THL), the Finnish Institute of Occupational Health, Statistics Finland, the Finnish Centre for Pensions, the Research Institute of the Finnish Economy (ETLA) and the Social Insurance Institution (Kela). The Unit staff have also actively published in Finnish-language journals and books with a broader reader base and they are frequently approached by the media for interview. Our research has also received international media coverage (e.g., Los Angeles Times, Washington Post) and has been presented at the Houses of Parliament of the United Kingdom.

Our scientific results have improved the understanding on the social determinants of health in the Finnish society as well as globally. For example, we have demonstrated large social differentials in mortality and health in Finland and that in the 21st century, these differentials have first increased and then decreased mostly due to changes in alcohol-related mortality. Importantly, our analyses of the reduction of alcohol taxes in Finland demonstrated an increase in alcohol-related mortality in the socially disadvantaged groups. Our comparative evidence further demonstrates that the Nordic social welfare system has not been able to produce smaller differentials than elsewhere in Europe.

We have actively participated in governmental working groups that aim to improve the data base on social determinants of health and strengthen the links between research and practice. Our research has been used to set targets for the reduction of socioeconomic inequalities in health and mortality in the national action plan. The Unit’s researchers have attracted funding for policy relevant research topics such as national and global health promotion, public health, the demand and funding for long-term care, and the means for reduction of social inequalities in Europe. Most of the research within the Unit provides evidence for prevention, health promotion and improving the level and equal distribution of health.

Although the majority of the Unit’s research is published in international scientific journals, we acknowledge that the dissemination of scientific knowledge into practice requires publications in lay journals and textbooks with a wider audience. We have thus published and participated in several textbooks, encyclopedia entries as well as articles in vocational journals in Finnish.