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

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A.3 Study design
group (dental examination, dental questionnaire, and microbiological data). Well-defined
phenotypes need to be understood as a major prerequisite for future analyses of genome,
metabolome, transcriptome, and microbiome of the intraoral flora (as determined in saliva
samples). Host genome, oral microbiota, serum markers, and subclinical markers could
then be analyzed to study the transition from health to disease more closely. This may help
to identify the time when interventions are most promising and cost effective.
Periodontitis is a widespread infectious disease that leads to chronic inflammation and tooth
loss 627 . While the presence of any gingival or periodontal inflammation has to be taken into
consideration as a surrogate marker for other systemic diseases, tooth loss can be considered
as a disease endpoint 628 . The severity of the disease can be assessed and followed up
on the basis of the local or generalized distribution patterns and of the mean attachment loss.
Procedure of measurement:
For clinical examination of the oral cavity, only measurements that can be easily recorded
and do not require additional devices were chosen. Basic equipment (e.g., a halogen lamp
to illuminate the oral cavity, a Community Periodontal Index, CPI, probe, a dental mirror,
and cotton rolls for drying teeth) as well as a dentist’s chair are needed to carry out the
proposed dental examinations. A standardized protocol adapted from the SHIP study 629
will be available, and standardized training of the nondental professionals will be provided
centrally.
To clinically assess periodontitis, the number of lost teeth as well as attachment loss, measured
with the CPI probe on each of the designated teeth 630 , must be determined.
Cavitations due to caries will be determined according to the WHO standard as tooth-related
D-component of the DMF-Index 630 . Furthermore, implants, dental restorations (fillings,
crowns, and bridges) and the presence of prostheses will be recorded 630 .
The short clinical examination will also identify acute and/or chronic symptoms of temporomandibular
disorders. This examination will encompass mouth opening (active and
passive, measured in cm using disposable Therabite scales), and pain sensitivity on the
temporomandibular joint and the masseter and temporalis muscles (Algometer 631 ).
In a feasibility study, the optimal examination procedure will be tested and selected for application
in the National Cohort.
A.3.3.8 Sense organ functions and diseases
Ophthalmological measurements
Eye-related measurements will focus on retinopathy; however, visual acuity and refraction
will also be determined.
Retinal vascular characteristics are risk indicators for major systemic causes of morbidity,
including diabetes, hypertension, stroke, ischemic heart disease, and all-cause mortality,
even after adjustment for known risks factors 178, 184 . Retinal changes may reflect changes
in other vascular beds (e.g., in the brain or kidney). Unlike other organs, the vascular circulation
of the retina can be directly visualized by taking and analyzing a photograph of the
retina, which is a noninvasive procedure. Retinal photography has already been employed
in population-based studies, for example, in the Atherosclerosis Risk in Communities study
(ARIC), the Cardiovascular Health Study (CHS), and the UK Biobank study.
Using retinal photography, the intra- and interobserver agreement in classifying retinopathy
can be considered as excellent for microaneurysms (K value of 0.81 to 0.91) and retinal
A.3