2.1 Study design and population
Lifelines is a multi-disciplinary prospective population-based cohort
study examining in a unique three-generation design the health and
health-related behaviours of 167,729 persons living in the North of the
Netherlands. It employs a broad range of investigative procedures in
assessing the biomedical, socio-demographic, behavioural, physical and
psychological factors which contribute to the health and disease of the
general population, with a special focus on multi-morbidity and complex
genetics. Baseline examinations in individuals aged 6 months to 93 years
took place between 2006 and 2013 with follow-ups visits every 5 years
and follow-up questionnaires in between.11 The
Lifelines cohort study was approved by the Medical Ethics Committee of
the University Medical Center Groningen, Groningen, The Netherlands
(2007/152). All subjects gave written informed consent.
For the TRACKER study, subjects between 4 and 18 years of age at
baseline, who had completed the questionnaire about allergic diseases
and a follow-up questionnaire concerning food allergies, were included.