cross-sectional studies

Question 1

cross-sectional

Answer 1

observational studies that capture health/disease and exposure statuses at the same time

• aka: prevalence study
• called cross-sectional because information gathered represents what is occurring at a point in time or time-frame a-cross a large population, acquired without regard to exposure or disease/outcome status
• a snap-shot in time of all elements
• entire population or a subset is selected for study
• focuses simultaneously on disease and population characteristics, including exposures, health status, health-care utilization, or etc.
• -> seeks associations (not causation)
• -> generates and tests hypotheses
• -> by repetition in different time periods, can be used to measure change/trends (not in same patients)
• many are large-scale national surveys or databases capturing different aspects of the ‘population’ (including samples representing the US population)
• captures all information collectively at once (exposures and outcomes)
• useful for estimating elements of ‘prevalence’
• other observational format (cohort or case-control) can be born out of cross-sectional studies)
• have multiple stage probability of selection; e.g. randomly select large metro areas –> randomly select zip codes in that area –> randomly select doctor’s office, etc.

Question 2

2 cross-sectional approaches

Answer 2

1. collect data on each member of the population

2. take a sample of the population and draw inferences to the remainder (generalizable)

Question 3

2 common approaches to collection of study data/information

Answer 3

1. questionnaires/surveys (new or existing) (directly from patients or from records)
2. physical assessments

Question 4

NCHS

Answer 4

National Center for Health Statistics; a division of the CDC

Question 5

strengths of cross-sectional

Answer 5

• quick and easier for the researcher when using data already collected (already collected and deidentified- exempt IRB approval)
• less expensive than any form of prospective study
• can be analyzed like a case-control or cohort study (regarding group allocation)
• useful for estimating prevalence rates
• useful for answering research questions about a myriad of exposures and diseases using same data

Question 6

weaknesses of of cross-sectional studies

Answer 6

• prevalent cases may represent survivors (representing those that have data in the system)
• difficult to study diseases of low frequency
• unable to generate incidence rates
• problems in determining temporal relationship of presumed cause and effect (because exposure and disease histories are taken at same time)

Question 7

NHANES

Answer 7

National Health and Nutrition Examination Survey

• assesses the health and nutritional status of adults and children (combines interviews and physical exams- medical, dental, etc)
• survey sample is selected to represent the US population of all ages (oversampling persons greater than 60 years, african americans and hispanics

Question 8

NHIS

Answer 8

National Health Interview Survey

• source of information on health of civilian, non-institutionalized population
• data collected through personal household interview
• consists of a set of core questions that remain largely unchanged and a set of supplements used to respond to public health data needs as they arise
• can add new questions every year to address new changes in society

Question 9

NAMCS

Answer 9

National Ambulatory Medical Care Survey

• national survey designed to meet the need for objective, reliable information about the provision and use of ambulatory medical care services in the US
• based on a sample of visits to non-federal, non-institutional (office-based) physicians primarily engaged in direct patient care
• physician offie, urgent care, and hospital ERs as long as patients don’t stay

Question 10

NHCS

Answer 10

National Hospital Care Survey

• national survey designed to describe national patterns of healthcare delivery in non-federal (non VA) hospital-based settings
• -> discharges from inpatient departments and institutions, and visits to EDs, outpatient departments and ambulatory surgery centers

-integrates 3 previous cross-sectional surveys: National Hospital Discharge Survey (NHDS), National Hospital Ambulatory Medical Care Survey (NHAMC), and Drug-Abuse Warning Network (DAWN)

Question 11

BRFSS

Answer 11

Behavioral Risk Factor Surveillance System

• state-based system of telephone health surveys that collects information on health risk behaviors, preventative health practices, and health care access primarily related to chronic disease and injury
• monthly data collection
• youth BRFSS conducted by questionnaires in schools