NS 332: Exam 1 Flashcards
What are the two major types of nutritional science studies?
Epidemiological(Observational) and Interventional(Experimental)
What is the difference between epidemiological (observational) and interventional (experimental) studies?
Epidemiological studies are used to generate the hypothesis.
Interventional studies are used to test the hypothesis generated previously.
What do researchers do during epidemiological studies?
Explore correlations between exposures and outcomes (example: cigarettes and lung cancer)
What do researchers do during interventional studies?
Manipulate one or more factors (independent variables) and measure outcomes (dependent variables) in subjects
What can an interventional study determine?
Causal relationships (if well designed)
What can an epidemiological study determine?
Can establish complex associations/correlations
What is the difference between retrospective and prospective studies?
Retrospective looks back at a subject’s history, while prospective looks at the future.
What are the three types of epidemiological studies?
- Cross-sectional studies
- Retrospective studies
- Prospective cohort studies
What is a cross-sectional study?
Measure various exposures and outcomes simultaneously
Example: a one-time survey
What is a retrospective study?
Assess outcomes before potential causes; compare individuals with and without the condition
What is a prospective cohort study?
Follow the same group of people over a period of time
Example: Framingham Heart Study; followed a small town of people to determine cardiovascular risk
What is the strongest epidemiological study type?
Prospective cohort study
What does it mean when a cause is necessary?
If the cause is not there, the outcome will not occur.
Example: Essential nutrients are necessary for health.
What does it mean when a cause is sufficient?
If the cause is there, the outcome will too.
Example: Being human to being a mammal.
What does it mean when a cause is contributory?
The cause is necessary and/or sufficient (and
thus has effects) only under certain circumstances.
Example: Niacin necessary for preventing Pellagra only when protein (amino acid) consumption is insufficient.
What are some key challenges in human nutrition research?
- Assessment of exposures due to lack of reliable measurements or potential confounding factors or biases
- Assessment of health outcomes of interest because indexes/biomarkers of diseases are used and nutritional assessments are often not specific
What are the deficiencies in assessing habitual dietary intake with 24-hour recall, food frequency questionnaire, and a food record/diary?
*24-hour Recall: Recall bias, may not represent usual intake
*Food frequency questionnaire: food intake patterns limited in accuracy and completeness
*Food record/diary: (most accurate) may not be representative, observer effect (will eat healthier and exercise more)
How is a person’s nutritional status determined?
The health of the person related to how well their diet meets individual needs requirements. Adequate intake leads to optimal function.
What are the four (ABCD) ways of assessing nutritional assessment outcomes?
- Anthropometric Measurements (Waist Size)
- Biochemical Testing (Lab Tests)
- Clinical assessments (Physical examination)
- Dietary assessments (using one of three methods)
What is the difference between primary and secondary deficiencies?
Primary deficiency is caused by inadequate diet or secondary deficiency is caused by a problem in the body
Which assessment method(s) can reveal primary or secondary nutritional deficiency?
Diet history and/or health history
Which assessment method can reveal declining nutrient stores (subclinical) and abnormal functions inside the body (covert)?
Laboratory tests (biochemical testing)
Which assessment method can reveal physical signs and symptoms in the body (overt)?
Physical examination (clinical assessment) and anthropometric measurements
What are some characteristics of a randomized human clinical trial?
“Ideal design” to address human nutritional needs
-Large Scale
-Double Blind
-Placebo Controlled
What are two advantages of randomized human clinical trials?
- Well-designed interventions can prove causality
- Can be directly applied to humans
What are five advantages of randomized human clinical trials?
- Costly and time consuming
- Difficult to control for all confounding factors
- Ethics
- Subjects may not be representative: “Generalizability”?
- Reproducibility?