The STRIREG study is a retrospective longitudinal general population-based register study including all individuals who had had at least one plasma Tg measurement between 1st January 2000 and 31st December 2021 at Karolinska University Laboratory or Unilabs AB in Region Stockholm (population 2.41 million 2021). The exclusion criteria were a lack of a unique Swedish personal identification number (PIN). The index population consisted of 1,460,184 individuals between the age 0 and 107 years. The index population was extended to form the complete cohort (n=3,607,819) by associating the parents and the siblings (n=2,147,635) to the indexes by interlinkage of personal identification numbers via the Multi-Generation register (see below).

The study baseline for the index population was defined as the date for participant's first Tg measurement.

Hypertriglyceridemia (hTG) is associated with atherosclerotic cardiovascular disease, pancreatitis, and non-alcoholic fatty liver disease in large population-based studies. Less is known about the impact on hereditary hTG and cardiometabolic disease status for the development of hTG and its associated cardiometabolic outcomes. hTG remains a target for lipid lowering therapies and with new pharmacological interventions being developed, there is a need to identify patients that will benefit most from treatment with these new medicines.

The population-based observational Stockholm hyperTRIglyceridemia REGister (STRIREG) study include 1,460,184 index individuals that have measured plasma triglycerides in the clinical routine in Region Stockholm, Sweden, between 1st January 2000 and 31st December 2021. The laboratory measurements also included basic haematology, blood lipid panel, liver function tests and HbA1c. Using the Swedish Multi-Generation register, 2,147,635 parents and siblings to the indexes were identified to form the complete study cohort. Laboratory data from participants were combined with data from several national registers that provided information on cause of death, medical diagnoses, dispensed medicines, and socioeconomic factors including country of birth, education level and marital status.

The multigenerational longitudinal STRIREG cohort provides a unique opportunity to investigate different aspects of familial hTG as well as heredity for other metabolic diseases. Important outcome measures include mortality, cardiovascular mortality, major cardiovascular events, development of incident diabetes, and non-alcoholic fatty liver disease. The STRIREG study will provide a deeper understanding of the impact of heredity on hTG and associated cardiometabolic complications.

Inclusion Criteria: All individuals who had had at least one plasma Triglyceride measurement between 1st January 2000 and 31st December 2021 at Karolinska University Laboratory or Unilabs AB in Stockholm County Sweden.

Exclusion Criteria: No Swedish social security number.

Populationbased cohort originating from Stockholm County. with all individuals who had had at least one plasma Triglyceride measurement between 1st January 2000 and 31st December 2021 at Karolinska University Laboratory or Unilabs AB in Stockholm County Sweden. The first degree relatives are parents and siblings to the index patients identified through the Swedish Multi-Generation Register.