Epi - L5 - Cross-Sectional Studies Flashcards
what are cross sectional studies?
they’re observational studies that CAPTURE HEALTH/DISEASE and EXPOSURE STATUSES AT THE SAME TIME
aka: a PREVALENCE study
* these studies just collect health records; that’s all.
* give away: US (huge) population.
what does cross-sectional studies focus on?
it focuses simultaneously on disease and population characteristics, including exposures, health status, health-care utilization, etc.
- seeks ASSOCIATIONS (NOT CAUSATIONS)
- useful for generating hypothesis –> collecting data from different perspectives aids in this facet.
- by repeating it over different time periods, you can measure changes or trends on society (not on same patients)
what else can you say about cross-sectional studies in regards to their way of collecting information or what it is?
they’re large-scale, national SURVEYS or DATABASES capturing different aspects of the ‘population’ (including samples representing the US pop)
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what are the two Cross-Sectional approaches?
- collect data on each member of the population
2. take a SAMPLE of the pop and draw influences to the remainder (generalizable)
- collect data on each member of the pop example
- pregnancy-smoking data from KC Health Dept.
- more frequently utilized in city/state-level evaluations, if data already tracked (ongoing collection)
- taking sample
from frequent approach (for US level data)
what are the two common broad approaches to collection of study data/ information?
- Questionnaires/ Surveys (new or existing database)
- either directly from patients/ caregivers or their medical records - Phsyical Assessments (may involve lab work, clinical, or psych tests)
- great for assessing health/disease in similar pop as time changes
**many US CSstudies are survey-based products of National Center for Health Statistics (NCHS), division of the CDC
what are the strengths of Cross Sectional studies?
- quicker and easier for the RESEARCHER when using data already collected (compared to original data collection)
- less expensive for RESEARCHER
- can be analyzed like a CC or Cohort study
- useful for estimating PREVALENCE rates
- useful for answering research questions about a myriad of exposures and diseases using same data
what are the weaknesses of Cross Sectional studies?
- prevalence cases may represent survivors only (survivor bias)
- difficult to study diseases of low frequency
- unable to generate incidence rates
- problems in determining temporal relationship of presumed cause and effect
What does the NCHS stand for?
the National Center for Health Statistics
What are some examples of Cross-Sectional Surveys from NCHS?
- 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)
what is NHANES?
National Health and Nutrition Examination Survey
Assesses the health and nutritional status of adults and children
- combines INTERVIEW and PHYSICAL EXAMINATIONS (the how)
- Interviews include demographic, socioeconomic dietary, and health-related questions
- Examination component consists of medical, dental, physiological measurements and laboratory tests
- survey sample is selected to represent the US populate of all ages ; oversampled persons > 60 years old, blacks/ and hispanics
what is NHIS
National Health Interview Survey
principal source of information on HEALTH OF THE CIVILIAN, NON-INSTITUTIONALIZED POPULATION
- survey sample is selected to represent the US pop of all ages
- has central role in other surveys such as the national survey of family growth (NSFG) and the NAMCS/NHCS
=Data are collected through a personal household interview (broad range of health topics)
=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
what is NAMCS?
the National Ambulatory Medical Care Survey
- a national survey designed to meet the need for objective, reliable info 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
What is NHCS?
National Hospital Care Survey
- a combined national survey designed to describe national patterns of healthcare delivery in NON-FEDERAL HOSPITAL-BASED SETTINGS, including:
- discharges from inpatient departments and institutions, and visits to emergency departments, outpatient departments and ambulatory surgery centers
- integrates 3 previous Cross-Sectional Surveys:
1. national hospital discharge surveys (NHDS)
2. NHAMCS
3. Drug-Abuse Warning Network (DAWN)