lecture 11: cross-sectional studies

Question 1

cross-sectional study

Answer 1

observational studies that capture health/disease and exposure statuses AT THE SAME TIME –> retrospective

a “snapshot” of all elements; seeks associations, NOT causation

aka prevalence study–entire population or a subset is selected to study.

Question 2

where does data come from?

Answer 2

questionnaires/surveys (new or existing database)

OR

physical assessments (labs, clinical, or psychological tests)

Question 3

2 approaches to cross-sectional studies

Answer 3

1. collect data from each member of the population– more frequently utilized in city/state-level populations
2. take a sample of the population and draw inferences to the remainder (generalizable)– more frequent for US-level data

Question 4

strengths of cross-sectional studies

Answer 4

quick and easy for researcher because uses data already collected
less expensive
can be analyzed like case-control or cohort study
useful for estimating PREVALENCE
useful for answering many different research questions

Question 5

weaknesses of cross-sectional studies

Answer 5

prevalent cases may represent survivors (survival bias)
difficult to study diseases of low frequency (might not catch any in randomness grab)
NOT able to calculate INCIDENCE rates
NO temporal relationships can be established of presumed cause/effect

Question 6

example cross-sectional surveys

Answer 6

NHANES
NHIS
NAMCS
NHCS
BRFSS

Question 7

NHANES

Answer 7

National Health and Nutrition Examination Survey

• -assesses the health and nutritional status of adults and children
• -uses interviews and physical examinations; people have to come to THEM/trailers set up
• -sample represents the US population

Question 8

NHIS

Answer 8

National Health Information Survey

• -principle source of information on health of the civilian, non-institutionalized population
• -data collection through a personal household interview
• -core questions used + supplemental depending on health issues of the year

Question 9

NAMCS

Answer 9

National Ambulatory Medical Care Services

• -based on sample of visits to a non-federal, non-institutional physicians primary engaged in direct patient care
• -random area, dr. office, week of charts, and random charts used

Question 10

NHCS

Answer 10

National Hospital Care Survey

• -survey designed to describe national patters of healthcare delivery in non-federal hospital-based settings
• -integrates NHDS, NHAMCS, and DAWN

Question 11

BRFSS

Answer 11

Behavioral Risk Factor Surveillance System

• -based on telephone health surveys, health risk factors, preventive health practices, and health care access primarily related to chronic disease and injury
• -monthly data collection