Exposure Assessment in Nutrition and Health Research
Institution
Wageningen University (WUR)
Detailed notes of the e-learning cases and theory modules from the course Exposure Assessment in Nutrition and Health Research (HNE-32806). Complete and detailed notes, ideal when making the e-learning and perfect for studying for the exam.
Exposure Assessment in Nutrition and Health Research
All documents for this subject (1)
1
review
By: Prutsser • 7 year ago
Seller
Follow
Veertje93
Reviews received
Content preview
E-learning Notes
woensdag 22 maart 2017
8:41
Introduction
Detailed learning goals of the module
After studying the module you will be able to
• choose the appropriate design,
• choose the appropriate analysis method,
• conduct the analysis,
• interpret results,
of reproducibility and validation studies.
To become able to do this, you will learn to discuss the concepts,
principles and aims of reproducibility and validity of exposure
assessment at the level of both the individual and the population. This
includes quantification of random and systematic errors and implications
for observed levels of intake, for ranking people according to their intake
and for measures of association.
Exercise: Exposure assessment dilemma
For this study a FFQ was used to assess dietary intake. To decide which
method will be used the researchers took all the pros and cons into
account that are mentioned in the table. Of course, also other aspects
were taken into account e.g. reference period, characteristics of target
group, desired information with respect to specific nutrients/foods etc.
Because of practical reasons (time, money, required number of subjects
etc) it is not always feasible to use the most precise and most accurate
assessment method. Often there is a kind of dilemma: Doing large scale
studies and using less precise and accurate exposure assessment
methods, or using more accurate and precise methods and performing a
small scale study. For now it is important to realize that dietary intake is
often assessed with error.
Exercises: Errors in expo assessment (implications)
Random errors in dietary assessment may lead to dilution (in other words
attenuation) of associations.
Systematic errors in dietary assessment may lead to flawed
recommendations.
Exercises: Evaluation studies (reproducibility and validation
studies)
Validity (or accuracy) Degree to which a method accurately measures
the aspect of dieat that it was designed to measure, i.e. the "true value
over a specific period of time. This refers to systematic error (bias).
Depending on the research question, validity refers to validity of mean
intake of a population, validity of usual intake of an individual, validity
of ranking of individuals or validity of associations between intake and a
health parameter.
Reproducibility: Ability of a method to yield similar (consistent) results
on repeated occasions under similar conditions. It refers to random error.
Reproducibility can be quantified in two ways:
- Precision: this refers to lack of random error, quantified in terms of
standard deviation of a measurement (variance around estimate).
For example because of day-to-day variation, between person
variation and sample variability
- Reliability: Ability of a method to distinguish between subjects
(i.e. to rank them consistently on two or more occasions). Thus this
refers to the consistency of ranking, not to validity of ranking. It
can be quantified in terms of correlation coefficients
HNE-32806 Pagina 1
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller Veertje93. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $4.81. You're not tied to anything after your purchase.