Study Design

Question 1

What are the optimal study conditions

Answer 1

Individual Nutrition Data and Health Outcomes Data, Interventional & Disease Outcomes (prevention)

Question 2

What is the GOLD STANDARD?

Answer 2

If we feed a X vs. a Placebo to a group of ABCs at a dose of D for a duration of T there will be more/less of IT.

Question 3

Observational studies prove

Answer 3

Association

Question 4

Interventional studies prove

Answer 4

Cause & Effect

Question 5

Ecological Study: Diet data sources?

Answer 5

Diet data sources include food imports, food exports, agricultural data.

These studies try to determine the AVAILABILITY of food for an AVERAGE PERSON.

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Question 6

Ecological Study: Health Outcome data sources?

Answer 6

Health outcome data sources include national morbidity and mortality data

Question 7

Ecological Study: Examples?

Answer 7

CHD in 40 different countries, CHD in 7th Day Adventist Men

Question 8

Ecological Study: Limitations?

Answer 8

Alternate hypotheses, and no individual level data

Question 9

Ecological Study: Advantages?

Answer 9

Quick & cheap, able to consider a WIDE range of differences in diet

Question 10

What are the two types of observational studies that use individual level diet data

Answer 10

Case-Control Studies; Cohort Studies

Question 11

Case-Control Study: Limitations?

Answer 11

Alt. hypotheses, temporal relationship unclear, recall bias

Question 12

Case-Control Study: Advantages?

Answer 12

Quick and cheap, particularly appropriate for RARE disease (birth defects)

Question 13

Case-Control Study: Examples?

Answer 13

Tofu & Breast Cancer

Prenatal Vitamins & Neural Tube Defects

Question 14

Cohort Study: Limitations?

Answer 14

Alternative hypotheses, expensive & long

Question 15

Cohort Study: Advantages?

Answer 15

Establishes prospective nature of relationship between diet and health (TEMPORAL SEQUENCE), Examines the achievable range of diet variability (lowest to highest intake)

Question 16

Cohort Study: Examples?

Answer 16

Wheat in Iowa Women’s diet & Heart Disease, Mediterranean Diet & Greek Survival, Fish Oil in male health professionals

Question 17

Animal/Cell Study: Limitations?

Answer 17

extrapolating to human health

Question 18

Animal/Cell Study: Advantages?

Answer 18

establishes biological plausibility

Question 19

Clinical Trials: Limitations?

Answer 19

Generalizability, population, dose, duration, effect attributable to what was eat vs what was replaced, risk factor benefits may not lead to improved health outcomes, usually focuses on one health outcome not overall health, SPECIFIC ANSWER TO SPECIFIC QUESTION

Question 20

Clinical Trials: Advantages?

Answer 20

Cause & effect established, Human relevance clear, end points are clinically relevant

Question 21

Clinical Trial: Examples?

Answer 21

HOPE Vitamin E study, Beta-Carotene Study, folic acid for neural tube defects