Lecture 20 - Cross-Section Studies

Question 1

What is a cross sectional study?

Slides 3-4

Answer 1

• observational study that simultaneously looks at disease and exposure status (both of which are already know)
• no initial need for group allocation
• evaluates for associations not causations
• study of prevalence

Question 2

What are the two approaches to a cross sectional study?

Slide 7

Answer 2

• collect data on all members of the population (smaller populations; city/state)
• collect data on a sample from the population and generalize (larger populations; regional/national)

Question 3

What are the approaches to data collection in cross-sectional studies?

(Slide 8)

Answer 3

• questionnaires/surveys (includes reviewing medical records)
• physical assessments (includes lab work)

Question 4

What are the strengths of cross-sectional studies?

Slide 9

Answer 4

• data is already collected (quick and easy)
• less expensive
• can be analyzed like a case-control or cohort study
• useful for answering multiple research questions

Question 5

What are the weaknesses of cross-sectional studies?

Slide 10

Answer 5

• prevalent cases may represent survivors (can’t assess those who are deceased)
• difficult to study rare diseases
• can’t generate incidence rate
• difficult to determine temporal relationship of cause and effect

Question 6

What national surveys are frequently used in collecting information for cross-sectional studies?

(Slide 12)

Answer 6

• National Health and Nutrition Examination Survey (NHANES)
• National Health Interview Survey (NHIS)
• National Ambulatory Medical Care Survey (NAMCS)
• National Hospital Care Survey (NHCS)
• Behavioral Risk Factor Surveillance System (BRFSS)

Question 7

What data does NHANES collect, how is it collected, and who is it collected on?

(L20 S14)

Answer 7

National Health and Nutrition Examination Survey

Data collected:

• demographic
• socioeconomic
• dietary
• medical and dental examination
• lab tests

Collection method:

• examination
• interviews

Survey sample:

• US population of all ages
• oversampling of individuals >60 y/o, African Americans, and Hispanics

Question 8

What data does NHIS collect, how is it collected, and who is it collected on?

(L20 S18)

Answer 8

National Health Interview Survey

Data collected:
-general health related questions

Collection method:
-home interview

Survey sample:

• civilian US population of all ages
• non-institutionalized individuals

Question 9

What data does NAMCS collect, how is it collected, and who is it collected on?

(L20 S21)

Answer 9

National Ambulatory Medical Care Survey

Data collected:
-provision and use of ambulatory medical care services

Collection method:
-review of charts

Survey sample:
-non-federal, non-institutional office visits

Question 10

What data does NHCS collect, how is it collected, and who is it collected on?

(L20 S25)

Answer 10

National Hospital Care Survey

Data collected:
-information related to healthcare delivery in hospital based settings

Collection method:
-chart reveiw

Survey sample:
-non-federal hospital-based settings (inpatient departments, ED, outpatient departments, ambulatory surgical centers)

Question 11

What data does BRFSS collect, how is it collected, and who is it collected on?

(L20 S27)

Answer 11

Behavioral Risk Factor Surveillance System

Data collected:

• risk behaviors
• preventative health practices
• health care access

Collection method:
-phone interveiws

Survey sample:
-adults (>18 y/o)