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General Cohort & Factsheets

The general population cohort of Lifelines consists of 167.729 participants, identified with a Lifelines-ID.

Recruitment

Lifelines participants were initially recruited through general practitioners in the three provinces in the northern part of the Netherlands: Groningen, Friesland and Drenthe1).
General practitioners (GP's) invited all their patients between 25 and 50 years old (on Terschelling 18+), resulting in ~81.500 participants at baseline.
These individuals were then asked to invite their family members (parents, partner, children, parents-in-law), resulting in an additional ~64.500 participants at baseline.
~21.500 interested individuals registered directly for baseline participation via the Lifelines website.

Selection criteria

There were no specific inclusion criteria for Lifelines.
GP's were asked to decide which of their patients should be excluded from Lifelines, based on the following list of exclusion criteria provided by Lifelines:

  • terminal illness (life expectancy < 5 years)
  • severe mental illness (i.e. not fully capable to make rational decisions)
  • not being able to visit the GP
  • not being able to fill in the questionnaires
  • not being able to understand the Dutch language

Age groups

Lifelines has participants of all ages.
Children follow a special child protocol until they turn 18. Elderly participants follow the adult protocol plus some additional questions (in assessments 1A, 1B and 1C) and additional measurements (MMSE).
Since baseline, the original distribution of the three age groups (children, adults and elderly) has shifted as follows:

Age group Baseline 2012 2016 2020
Children (0-17) 9% (n=~15.000) 9% 7% 6%
Adults (18-64) 84% (n=~140.000) 82% 80% 78%
Elderly (65+) 7% (n=~12.000) 9% 13% 16%

Gender

Lifelines has ~97,000 female participants (58%) and ~71,000 male participants (42%).
Most questionnaires and measurements are performed in both sexes.
Notable exceptions:

Thus far, the *binary* gender of participants was assessed via self-report and via BRP linkage.
More recently, attention is given to *non-binary* gender within the cohort.

Nationality and Ethnicity

The vast majority of Lifelines participants is born in the Netherlands (97%) and has a Caucasian ethnicity (98%). See also the subsection on Nationality & ethnicity.

Mortality

Click here to learn more about the Lifelines death rate and causes of death.

Family connections

Lifelines includes many participants with a family connection to one another, including 355 twins and 5 triplets. Current and past family connections between participants are identified using:

Based on BRP and self-report, the following Lifelines nuclear families can be identified:

Number of families Child(ren) = LL Participant(s)
Parent = LL participant Total 1 2 3 4 5
Only the mother ~2200 ~1500 ~600 ~80 <10 <10
Only the father ~350 ~250 ~80 ~10 <10 <10
Mother and father ~5000 ~2600 ~2000 ~350 ~40 <10

Other family connections (e.g. grandparent-grandchild, siblings) are present in the cohort as well.

Cohort Facts & Representativity

At baseline, the adult Lifelines cohort was generally representative of the adult population of the north of the Netherlands2). An updated report on the representativity of the current cohort is currently in preparation.

Comprehensive factsheets were developed on a number of health-related topics covered by Lifelines:

In addition, some informative cohort statistics can be found here:

Subcohorts

Subsets of participants have been selected for additional assessments according to assessment-specific criteria. This results in subcohorts that are defined by the availability of certain additional variables.
Some notable examples are:

  • GWAS subcohort (15,000 genotyped participants)
  • UGLI subcohort (38,000 genotyped participants)
  • DEEP subcohort (1,500 participants with extensive metabolomics/microbiomics)
  • DAG3 subcohort (9,500 participants with extensive metabolomics/microbiomics)

Data Linkage

  • Basic information (address, date of birth, sex, birth of children, marriage/divorce, date of death) about our participants is provided by the Dutch citizen registration
  • Information about living environment (or exposome), such as air pollution or LISA-data, can be linked to individual participants via postal codes or x-y coordinates (see also: http://www.gecco.nl)
  • Individual data from governmental registries (i.e. causes of death, socio-economic data) can be linked to Lifelines health-related data via Statistics Netherlands
  • Individual results from pathological tests (i.e. biopsies) can be linked to Lifelines health-related data (including self-reported cancer) via PALGA and ZorgTTP
  • Individual longitudinal prescription medication data from Dutch pharmacies can be linked to Lifelines health-related data (including self-reported medication) via IADB (the Pharmlines initiative)
1)
Scholtens, S., Smidt, N., Swertz, M.A., Bakker, S.J.L., Dotinga, A., Vonk, J.M., van Dijk, F., van Zon, S.K.R., Wijmenga, C., Wolffenbuttel, B.H.R., et al. (2015). Cohort Profile: LifeLines, a three-generation cohort study and biobank. Int. J. Epidemiol. 44, 1172–1180
2)
Klijs, B. et al. (2015). Representativeness of the LifeLines Cohort Study. PloS One 10, e0137203
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cohort.txt · Last modified: 2024/05/16 12:29 by trynke