Lecture 13 Flashcards
(30 cards)
How might one set up a double-blind, cross over study?
- Double-blind study: in which neither researcher nor test subjects know which treatment is being given to whom.
- Cross over study: in which the control group and the test group are switched during the study, to ensure that both groups will respond in the same manner to the presence or absence of the test condition
How can double-blind and cross over studies remove some of the problems in experiments?
- Can be combined to further control over variables
What is a meta-analysis?
- a quantitative, formal, epidemiological study design used to systematically assess previous research studies to derive conclusions about that body of research
- groups a number of studies investigating the same question (from quiz)
What are the major challenge(s) of nutritional epidemiology?
- Self-reporting of nutritional intake in many even very current studies of nutrition, you will find that the “independent variable” of what was eaten is “self-reported” – meaning the individuals had to describe their eating
What was the London Cholera outbreak of 1832?
= People were getting sick of Cholera and no one knew the cause. John Snow made a map of where the cases were occurring, realized all of them were centered around one well. Water source everyone was using. He had the handle pump broken and Cholera deceased
How was John Snow’s approach to the Cholera Outbreak a foundational epidemiological study?
He discovered that the outbreak was being caused by a water well and mapped out the cases to pinpoint the source
What are the different sorts of observational studies?
- Cross sectional study
- Longitudinal study
What is the difference between cross-sectional study and longitudinal study?
- Cross-sectional study: assesses individuals from different areas and tracks changes over time
- Longitudinal study: assesses one individual and tracks their changes over time
What are the strengths and weaknesses of prospective and retrospective studies?
What was the London Cholera Outbreak of 1832?
- Outbreak of Cholera in London; not sure why or how cases were spreading
How was John Snow’s approach a foundational epidemiological study?
- He mapped out the cases and discovered they centered around a well that was the main water source for that town of people. He broke the lever for the wall and cholera cases ceased
What is a cross-sectional study?
- a study design in which data is collected from a population at a single point in time. Observe variables without influencing them
What is a longitudinal study?
- A research design where data is repeatedly collected from the same individual over a period of time
What is a prospective study? Strengths and weaknesses?
- The study begins in the present and toward the future
What is a retrospective study? Strengths and weaknesses?
- Study starts in the present and goes back to the past
What is NHANES and its basic features?
- National Health and Nutrition Examination Survey
- The survey combines interviews, physical examinations and laboratory tests
How is the NCHS involved with NHANES?
- A survey research program conducted by the National Center for Health Statistics (NCHS) to assess the health and nutritional status of adults and children in the US and to track changes over time.
What were the main objections raised by Archer et al. to the food consumption/energy intake component of the NHANES studies?
- The reliance on memory-based dietary assessment methods (M-BMs) to inform dietary policy continues despite decades of unequivocal evidence that M-BM data bear little relation to actual energy and nutrient consumption
- claims that the energy intakes estimated from self-reporting are often unrealistically low
What is the cause of the low rEI/TEE ratios in the objections raised by Archer et al. ?
- under-reporting in surveys
- reliance on memory
- verbal interview techniques
- reliance on nutritional energy estimates
What is the Nurses Health Study and the findings about BMI and CVD that emerged from it?
- A series of prospective studies that examine epidemiology and the long-term effects of nutrition, hormones, environment, and nurses’ work-life on health and disease development. The studies have been among the largest investigations into risk factors for major chronic diseases ever conducted.
- High BMI increased the risk ratio for BMI/CVD about 4x
What is the Framingham Heart Study (FHS)?
- The objective of the FHS was to identify the common factors or characteristics that contribute to CVD by following its development over a long period of time in a large group of participants who had not yet developed overt symptoms of CVD or suffered a heart attack or stroke
How has FHS evolved and continued over time?
- Since 1948 subjects continued to return to the study every 2 years; 1971 the study enrolled a second generation to participate in similar experiments
- 1994 the first Omni cohort of FHS enrolled because Framingham became a more diverse community
- 2002 the third generation of participants enrolled
What results came from the FHS?
- much common knowledge about heart disease; findings further emphasized the need for preventing, detecting, and treating risk factors of cardiovascular disease in their earliest stages
What is the scope and importance of the Global Burden of Disease study?
- health effects of dietary risks in 195 countries- a systemic analysis for different aspects of pathology
