What is SIMPLER?

SIMPLER stands for Swedish Infrastructure for Medical Population-Based Life-Course and Environmental Research.

The purpose of the infrastructure SIMPLER is to provide national and international researchers with data for research about dietary and lifestyle factors as well as genetics, and how they affect our health, particularly in the latter part in life. The knowledge can be used to develop recommendations on diet and lifestyle, to develop new markers for easier and more accurate diagnosis of chronic diseases and their preliminary stages, as well as to develop new individualized treatment methods.

Two cohorts form the basis of SIMPLER: the Swedish Mammography Cohort (SMC) and the Cohort of Swedish Men (COSM). Almost 110,000 persons are included in these two cohorts. The participants have answered questionnaires with questions about their health, diet, and lifestyle on repeated occasions. Two subgroups have also visited the research clinics in Uppsala and Västerås for biometric measurements and sampling, and they create the subcohorts. Analysis of collected samples have provided the infrastructure with several types of data such as iron, glucose, and blood fat levels, but also proteins and metabolites in the blood stream, in addition to genetic variation and gut microbiota.

The foundation for the infrastructure was laid in 1987 when the Swedish National Food Agency, together with the County Councils in Uppsala and Västmanland initiated a questionnaire-based study concerning health among a group of women – the Swedish Mammography Cohort (SMC). At the follow up in 1997, a cohort of men was formed – the Cohort of Swedish Men (COSM).

The Swedish Research Council classified SIMPLER as a national infrastructure in 2014, and has provided financing since 2018. The infrastructure is managed by a consortium consisting of Uppsala University, Karolinska Institutet, Chalmers University of Technology, and Örebro University in collaboration with the County Councils in Uppsala, Västmanland, and Örebro counties. The cohorts have previously been managed by Uppsala University (1987–1996) and Karolinska Institutet (1997–2018) under the direction of Professor Alicja Wolk. What started as a project on diet and health among women, has over the years developed to include a male cohort, repeated assessments of diet and lifestyle factors, and repeated matching with national, regional, and local registers, in addition to sampling of clinical variables and biological samples. As of today, more than 500 scientific papers have been published based on data from the cohorts. Current grants from the Swedish Reserach Council and consortia and collaborating partners have enabled refinement of the cohorts on a larger scale, and have enabled the use of molecular methods to study the importance of genes, proteins, and metabolites for contraction of a disease, disease development and treatment.

The Swedish Mammography Cohort (SMC) consists of women born between 1914 and 1948 in Västmanland and Uppland counties who were invited to participate in the study when they were called to mammography screenings between 1987 and 1990. The Cohort of Swedish Men (COSM) were selected from the population register in Västmanland and Örebro counties, and the first food frequency questionnaire was sent in 1997. The male cohort consist of men born between 1914 and 1952. Both cohorts have been assessed twice more since 1997: in 2008/2009 and in 2019. The women have answered at least six questionnaires and the men at least five. In total, the two cohorts consist of approximately 107,000 participants, and at the assessment in 2019, approximately 38,000 participants responded.

The subcohorts were established in 2003 for women in Uppsala and in 2010 for women and men in Västerås, and included biological sampling and measurement of body composition. The first cycle of examinations in Uppsala was completed in 2009, and a second cycle began in 2015 and was completed in 2023. The third cycle began in 2023 and is ongoing. In Västerås, the first cycle of examinations was completed in 2019, and a second stage began in October 2022.

The biobank of biological samples from the subcohorts consists of samples of blood, urine, stool, and adipose tissue from the subcohorts. In addition, saliva samples from 39,000 men and women have also been collected between 2004 and 2008, and were used for DNA extraction in 2019. In total, there are over 800,000 samples in the biobank and new ones are added continuously.