Epi - L5 - Cross-Sectional Studies Flashcards

1
Q

what are cross sectional studies?

A

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.

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2
Q

what does cross-sectional studies focus on?

A

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)
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3
Q

what else can you say about cross-sectional studies in regards to their way of collecting information or what it is?

A

they’re large-scale, national SURVEYS or DATABASES capturing different aspects of the ‘population’ (including samples representing the US pop)

-

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4
Q

what are the two Cross-Sectional approaches?

A
  1. collect data on each member of the population

2. take a SAMPLE of the pop and draw influences to the remainder (generalizable)

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5
Q
  1. collect data on each member of the pop example
A
  • pregnancy-smoking data from KC Health Dept.

- more frequently utilized in city/state-level evaluations, if data already tracked (ongoing collection)

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6
Q
  1. taking sample
A

from frequent approach (for US level data)

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7
Q

what are the two common broad approaches to collection of study data/ information?

A
  1. Questionnaires/ Surveys (new or existing database)
    - either directly from patients/ caregivers or their medical records
  2. 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

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8
Q

what are the strengths of Cross Sectional studies?

A
  • 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
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9
Q

what are the weaknesses of Cross Sectional studies?

A
  • 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
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10
Q

What does the NCHS stand for?

A

the National Center for Health Statistics

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11
Q

What are some examples of Cross-Sectional Surveys from NCHS?

A
  1. National Health and nutrition examination survey (NHANES)
  2. National Health Interview Survey (NHIS)
  3. National Ambulatory Medical Care Survey (NAMCS)
  4. National Hospital Care Survey (NHCS)
  5. Behavioral Risk Factor Surveillance System (BRFSS)
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12
Q

what is NHANES?

A

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
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13
Q

what is NHIS

A

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

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14
Q

what is NAMCS?

A

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
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15
Q

What is NHCS?

A

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)
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16
Q

what is BRFSS?

A

A state-based system of telephone health surveys that collects information on health risk BEHAVIORS, preventive health PRACTICES, and health care ACCESS primarily related to chronic disease and injury

  • look out for “responder bias”