LifeLines: the pilot study

Multifactorial diseases are by definition the result of multiple risk factors
that are both genetically and environmentally determined. Examples of
multifactorial diseases are depression, COPD, cancer, cardiovascular and
endocrine diseases. Together they comprise the most common disorders in
adulthood and are responsible for the use of the majority of health care
resources. Biomedical and epidemiological research on the etiology of
multifactorial diseases frequently focuses on single determinant - outcome
relations, without taking into account other risk factors, other diseases and
time dependent effects. This has been recognized over the last years and
resulted in new study designs sometimes referred to as *life course
epidemiology*.
Multifactorial diseases may have more in common than generally recognized,
since some risk factors are associated with multiple diseases, as has been
shown for example by low birth weight. A risk factor like smoking results in
lung cancer in some individuals and myocardial infarction in others, whereas it
has a protective effect on dementia, suggesting an individual susceptibility
for specific risk factors. The individual differences that determine which
disease occurs in the presence of a given risk factor are called modifiers.
Since different diseases share identical risk factors, it is clear that a
continuing exclusive focus on associations between single risk factors and
single outcomes will not unravel the unresolved issues of etiology and
individual prognosis of multifactorial diseases. Instead, research has to focus
on the underlying mechanisms why individuals with similar (established) risk
factors develop different diseases, i.e. the modification of the universal risk
factors for multiple disorders.

The aim of the pilot study is to study the logistics of inviting, interviewing
and examining 2000 participants from general practices in Sneek, The
Netherlands. More specifically, to test the invitation procedure, the visiting
schedule, the measurements, and the amount of time necessary per participant to
complete the visits. Also, the equipment and data storage thereof will be
tested. Moreover, a database is created which can also be used for the main
study , and during the pilot study, the use of electronic questionnaires will
be tested. Blood and urine will be collected, and the process of collection,
transportation to the laboratory and analysis and storage will be tested as
well. Samples will be handled the same way as in the main study and can later
be used in the main study.

LifeLines is an observational follow-up study in a large sample of the
population of the northern provinces of the Netherlands. A random sample of
persons between 25 and 50 years of age will be invited by their general
practitioner to participate in the study. Data will be collected and on grounds
of the results of this pilot study, the data collection process in the main
study will be adjusted. The study population in the main study will be followed
for 30 years, with an investigation of the population every 3 to 5 years.
Methods of data collection are matched with other ongoing biobank studies (P3G
consortium), which enables combining datasets to construct large study
populations.

Participants of the study will have to fill in several questionnaires, and
furthermore their length, weight, waist and hip circumferences and blood
pressure will be measured. Their pulmonary function will be tested, an ECG
performed, as well as two psychological tests. Also, we will ask them to
collect urine, and have a blood sample taken. The main results of these tests
will be sent to the participants and their general practitioner, so that
measures can be taken if necessary. Except for the venapuncture there are no
risks involved. Information on DNA tests will not be revealed to participants
and general practitioners.