Scientific Concept of the National Cohort (status ... - Nationale Kohorte

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A.3 Study design
For the National Cohort, we adapted questions about drug consumption that have been
used in other studies (Bundeszentrale für gesundheitliche Aufklärung 462 , National Health
and Nutrition Examination Survey (NHANES) 463 , LifeGene 464 , Constances 465 ). Drugs that
will be covered in the questionnaires include cannabis, ecstasy, LSD, amphetamine, cocaine,
crack, heroin, sniffing agents, psychoactive plants, and doping substances, and lifetime
and 12-month prevalence of use of the respective drugs will be queried.
Health-related quality of life, subjective health
Self-rated (subjective) health and health-related quality of life (HRQoL) are important factors
related to the risk for chronic diseases (physical and mental) as well as to the degree
of health care utilization. The concepts of subjective health and HRQoL include essential
information about the participant’s perception of their physical and mental health status 466.
It has been shown that self-rated health is a valid indicator for overall health status and
mortality. As shown in a review of almost 30 studies, self-rated health predicts mortality, independently
of other relevant factors 467 . Due to the predictive value of subjective health and
HRQoL, these concepts are of particular public health relevance. Evaluating the impact of
several diseases on subjective health status and HRQoL, on the one hand, and self-rated
health and HRQoL as exposure variables for diseases, on the other, constitute interesting
topics for future research.
Instruments:
Validated and internationally established instruments will be used to assess health-related
quality of life (WHOQOL-Bref 468 , EQ-5D 469, 470 ).The WHOQOL-Bref assesses the individual's
perceptions in the context of their culture and value systems and their personal goals,
standards, and concerns. It measures the following broad domains: physical health, psychological
health, social relationships, and environment. The EQ-5D instrument covers the
five dimensions mobility, self-care, usual activities, pain/discomfort, and anxiety/depression
and can be used to calculate aggregated outcomes as quality-adjusted life years (QALYs),
e.g., by using the algorithm developed by Greiner et al. 471 .
Other personal characteristics
Additional information on personal characteristics and early life factors that may be associated
with subsequent disease or that are important to correctly interpret associations with
other factors will be obtained with short questionnaire modules. The modules will include
questions related to, for example, adoption versus bodily descent from parents, siblings,
having been breast fed, birth weight, weight history, and phenotypic information on complexion,
hair, and eye color.
A.3.2.2 Specific interview and questionnaire modules
An overview of specific interview and questionnaire modules that were mainly proposed by
the thematic working groups is given in Table 3.5.
For the more intensively investigated subgroup (n=40,000, Level 2), several questionnaire
modules will be more comprehensive than those used for Level 1 participants, partly guided
by additional physical examinations included in the intensified program that may require
more in-depth questionnaire information.
A.3