Health & Nutrition:
Human Health

APPENDIX B
Epidemiological Terms, Techniques, & Sources Of Data

One definition of epidemiology is "the study of the occurrence of disease in human populations." This field offers a framework for determining objectively the importance of health problems in some target population. Descriptive data can show the magnitude (how large or small in size or extent) and distribution (how wide or narrow the range) of health problems in a population in order to suggest how important these health problems are in terms of morbidity, disability, or mortality. By examining the risk factors for health problems, these investigations can provide information about the possible causes of these health problems. These causes may well become the focus of future health education programs.

Going through the process of determining which health problems should receive priority serves three functions: 1) to establish the relative importance of various health problems in the target population as a whole and in its population subgroups; 2) to provide a basis for setting program priorities among the various health problems and the population subgroups; and 3) to aid in distributing responsibilities among the collaborating professionals, organizations/agencies, and departments.

In epidemiology, comparisons are made to determine the relative importance of health problems in a population. For instance, data of interest in one community can be compared with similar data in other communities, the state, or the nation as a whole; or data can be compared for different health problems in the same community; or data can be compared for several subgroups within a community based on age, race, or gender.

Health Status Indicators in Populations

General sources of data on these indicators include:

• National Center of Health Statistics
• Centers for Disease Control
• Other Agencies of the Department of Health & Human Services
• Local or State Health Departments
• Bureau of the Census (publishes the annual Statistical Abstract of the United States)
• Professional Journals and Associations
• World Health Organization

A partial list of more specific resources of data for these indicators would include:

1. Resource: "State" Vital Statistics

   Source: Your State Health Department

   Typical Contents:

   • Overview of state statistics
   • Natality: Births, demographics of mother, place and method of delivery, birth weight, prenatal care, pregnancy risk factors, infant health and viability
   • Mortality: Fetal; infant and maternal deaths; leading causes of death; traumatic injury deaths; deaths by age, sex and race
   • Figures of death by cause and age groups
   • Tumor registry information including tables and trends for leading cancer incidence and prevalence data
   • Induced abortions: Trends and tables
   • Marriage and marital terminations: Trends and tables
   • Vital Statistics Tables of natality, mortality, marital status, communicable diseases, population by county in table format showing data by the following variables:
2. Resource: Behavioral Risk Factor Surveillance System (BRFSS) survey.

   The BRFSS is an annual surveillance survey conducted by each state with the support of the Centers for Disease Control and Prevention. Health-related behavioral risk factors are monitored on a monthly basis of randomly selected adults within each state. Year to year trends can be determined from survey results.

   Source: State Health Department: Office of Health Promotion and Disease Prevention

   Contents: Note: Although states may individualize some questions in the survey, a core set of questions is asked which include the following:

   • Automobile Safety:
     • Seat belt non-usage
     • Drinking and driving
   • Hypertension:
     • High blood pressure checked
     • Blood pressure checked
   • Overweight
   • Sedentary Lifestyle
   • Tobacco Use:
     • Cigarette smoking
     • Smokeless tobacco use
   • Alcohol Consumption:
     • Acute drinking
     • Chronic drinking
   • Blood Cholesterol:
     • Awareness: Cholesterol checked
     • Ever told cholesterol was high
   • Diabetes
   • Health Care Access
   • Mammograms and Breast Exam:
     • Ever had a mammogram & breast exam (Women 40 and older)
     • Mammogram in last two years (Women 50 and older)
   • Pap Test

3. Resource: Youth Risk Behavior Surveillance System (YRBS).

   This is an epidemiologic surveillance system established by the Centers for Disease Control and Prevention to help monitor behaviors that influence the health of youth and put youth at risk for significant health and social problems. The survey focuses on students in the 7th and 8th grades although many states choose to include students in grades 9 through 12. Reports are printed every other year.

   Source: State Health Department: Office of Health Promotion and Disease Prevention; State Department of Education; other sponsors that may include Board of Crime Control, insurance companies, etc.

   Contents:

   • Intentional and Unintentional Injuries:
     • Seat belt non-usage
     • Riding in vehicle with drinking driver
     • Drinking and driving
     • Involved in physical fight
     • Suicide - contemplated or planned
   • Tobacco, Alcohol or Other Drug Use
   • Sexual Behaviors
   • Violence
   • Nutrition and Dietary Behavior
   • Physical Activity

4. Resource: Kids Count Data Book is a project of the Annie E. Casey Foundation to track the status of children in the United States. The Foundation funds most states to help gather bench marks of child well-being.

   Source: To identify the source of the report within your state, contact:

   The Annie E. Casey Foundation
   One Lafayette Place
   Greenwich, CT -6830
   FAX: (203) 661-5127
   Tel.: (203) 661-2773

   Contents:

   • Percent low birth-weight babies
   • Infant mortality rate
   • Child death rate
   • Percent of all births to single teens
   • Juvenile violent crime arrest rate: ages 10-17
   • Percent graduating from high school on time
   • Teen violent death rate: ages 15-19
   • Percent teens not in school and not in labor force
   • Percent children in poverty
   • Percent children in single-parent family
   • Population under age 18
   • Minority Population under age 18
   • Children 5-17 who do not speak English at home
   • Women in labor force with children
   • Children with both parents in labor force
   • Children not living with a parent
   • Median income of families with children
   • Mother-headed families receiving child support
   • Percent of children without health insurance
   • Percent of children living in overcrowded housing
   • Percent of children living in houses without complete plumbing or kitchen facilities
   • Percent of children living in severely distressed neighborhoods

5. Resource: "Consensus Set of Health Status Indicators for the General Assessment of Community Health Status - United States"

   Source: Morbidity and Mortality Weekly Report, July 12, 1991/Vol.40/no.27

   Contents: This consensus set of indicators was developed by public health representatives to establish a core set of indicators to assist communities in assessing general health status and to focus efforts in reaching the HEALTHY PEOPLE 2000 objectives. The consensus set includes 18 health status indicators that should be available through state data listed below.

   In addition, a second list of data which needs to augment the health status indicators is defined but not readily available from data resources. This second list would increase a community's ability to plan programs and data to support these indicators should be sought in the future.

6. Resource: HEALTHY PEOPLE 2000: National Health Promotion and Disease Prevention Objectives

   Source:
   

   Superintendent of Documents
   Government Printing Office
   Washington, D.C. 20402-9325
   Full Report, S/N 017-001-00474-0 at $31.00 each
   Summary Report, S/N 017-001-00473-1 at $9.00 each

   Contents: Includes health promotion and disease prevention objectives developed by 300 national membership organizations for Americans for the year 2000. Goals are set by age groups and special populations. Broad areas included are for health promotion, health protection, preventive services, surveillance and data systems, and age-related objectives. Both reports include research-based evidence and resources to support the objectives.

7. Resource: HEALTHY COMMUNITIES 2000 Model Standards. Guidelines for Community Attainment of the Year 2000 National Health Objectives

   Source:
   

   American Public Health Association
   1015 Fifteenth Street, N.W.
   Washington, D.C. 20005
   Stock No. 013K $35.00 each for nonmembers
   $24.50 for APHA members
   $ 7.00 per book for shipping and handling

   Contents: This resource "puts the objectives of Healthy People 2000 into practice and encourages communities to establish achievable community health targets. It covers the priority areas and age groups used in Healthy People 2000 and includes all of the national objectives."

   SET OF INDICATORS FOR ASSESSING COMMUNITY HEALTH STATUS
   REACHING HEALTHY PEOPLE 2000 OBJECTIVES

   Indicators of Health Status Outcome:

   1. Infant mortality (deaths less than one year)

      Death Rates for:

   2. Motor vehicle crashes
   3. Work-related injury
   4. Suicide
   5. Lung cancer
   6. Breast cancer
   7. Cardiovascular disease
   8. Homicide
   9. All causes

      Reported Incidence of:

   10. AIDS
   11. Measles
   12. Tuberculosis
   13. Primary and secondary syphilis

       Indicators of Risk Factors:

   14. Low birth weight babies
   15. Births to adolescents (females 10-17 years)
   16. Prenatal care not received in first trimester
   17. Childhood poverty
   18. Air quality below U.S. EPA standards

8. Resource: U.S. Statistical Abstract

   Source:

   U.S. Department of Commerce
   Economics & Statistics Administration
   Bureau of the Census

   This publication can be ordered from any of the following agencies:

   1. Superintendent of Documents
      Government Printing Office
      FAX: (202) 512-2250
      PHONE: (202) 512-1800
      In paper bound: Order No. 003-024-08756-1; Price $32
      In cloth bound: Order No. 003-024-08757-0; Price $38

   2. National Technical Information Service (NTIS)
      FAX: (703) 321-8547
      PHONE: (703) 487-4650
      In paper bound: Order No. PB94-209855; Price $32
      In cloth bound: Order No. PB94-209848; Price $32
      (Note: NTIS offers a two-book set for $58 which includes the U.S. Statistical Abstract and the County and City Data Book; Special Order No. PB95-123972LKB.)

   3. U.S. Department of Commerce
      Economics & Statistics Administration
      Census Bureau, Customer Services
      PHONE: (301) 457-4100
      In CD-ROM, U.S. Statistical Abstract - Price $50

   Contents: Primarily includes national data in the areas listed below:

   • Population information and vital statistics such as births, deaths, life expectancy, marriages, and divorces
   • Health expenditures and insurance, people with disabilities, and food consumption information
   • Education projections and attainment
   • Crime arrests, victimizations, juveniles, child abuse and neglect cases, court cases, prisoners and inmates
   • Geography and environment
   • Parks, recreation, and travel
   • Federal, state, and local government finances and employment
   • National defense and veterans affairs
   • Social welfare expenditures, public aid, federal food programs, child support and child care
   • Labor force, occupation projections, productivity, health and pension plans
   • Disposable personal income, money income of families, and poverty status
   • Prices, banking, finance, and insurance
   • Business enterprises and manufactures
   • Communications, energy, and science
   • Transportation on land, air, and water
   • Agriculture and national resources
   • Construction spending, home sales, and other housing characteristics
   • Domestic trade and foreign commerce

9. Resource: County and City Data Book

   Source:
   

   U.S. Department of Commerce
   Economics & Statistics Administration
   Bureau of the Census

   This publication can be ordered in paper copy for $40 from either the Government Printing Office or the National Technical Information Service (NTIS) for $40 using the appropriate telephone or fax numbers listed above for the U.S. Statistical Abstract. Stock numbers for this book from these respective agencies are:

   Government Printing Office-No. 003-024-08753-7
   NTIS-No.PB-94-140993AFY
   
   County and City Data Book is also available on CD-ROM for $150. Call the Customer Services Branch, Bureau of the Census at (301) 457-4100.

   Contents: Data are available at the national, state, and county level (as well as for cities in the U.S. with populations of 25,000 or more in 1990) in the following areas:

   • Area and population characteristics
   • Vital statistics, health care, social programs, and crime
   • Education, money income, and poverty
   • Housing, building permits
   • Journey to work, labor force, personal income
   • Agriculture, manufacturers, wholesale and retail trade
   • Service industries, banking, and federal govenment employment
   • Veterans, state and local government, and elections

10. Resource: CDC-AIM is a Centers for Disease Control and Prevention-APEXPH Information Manager computerized package divided into two freestanding elements called CDC-AIM - Vital Statistics and CDC-AIM - Hospital Data.

    Source: CDC-AIM is in the public domain and may be obtained from your state health department under the health promotion and disease prevention program. Some states do not yet have the CDC-AIM software. To obtain information directly from CDC, contact:

    Mr. Ed Vaughn
    Centers for Disease Control and Prevention
    Mailstop E-20
    1600 Clifton Road
    Atlanta, GA 30333
    
    Phone: (404) 639-1945 FAX: (404) 639-1989

    Contents: CDC-AIM Vital Statistics includes the following:

    • demographic profiles by county (counties can also be aggregated if desired)
    • causes of mortality
    • perinatal indicators
    • years of potential life lost
    • model standards

    CDC-AIM Hospital Data contains data relating to hospital discharges.

    CDC-AIM can be used to gather data for the set of 18 indicators noted in #5 above. CDC-AIM is especially helpful for rural areas as 5 years of data is aggregated for more valid information.

Rates of Death and Disease

Let's say you read the following information: In 1994, your county had 48 fatal injuries, while the state has 1,712. What does this mean? Not much, except that since the state is much bigger the total number of fatal injuries should logically be much larger. To make sense of these numbers, rates must be used.

A rate is the number of events (such as fatal injuries used above) per some multiple of ten (100, 1,000, 100,000, and so on). In the above example,

First, divide the number of deaths in the county by the population of that county;
Next, divide the number of deaths in the state by the population of the state;
Lastly, multiply the results by some multiple of ten to get a value for each that is between 1 and 100.

Let's say that from these calculations, the fatal injury rate in your county is 55.8 deaths per 100,000, and the state's is 36.4 deaths per 100,000. These numbers indicate that the county has a higher rate of fatal injuries than the state does as a whole. (Note: Rates must be adjusted to remove biases that might result from different ages or other characteristics of the two populations. See a and b on the next page for a brief discussion of age-adjusted rates and specific rates.) A rate can be expressed mathematically as: (X/Y) * K

X = numbers of events or cases
Y = population at risk for the event
K = a constant value that is a multiple of ten (usually 100, 1000, or 100,000) by which the rate is expressed

The time period must be standardized in order to compare rates. One year is the most commonly used standard.

Many events can be expressed as rates, such as live births, infant deaths, and mortality. The basic formula still remains the same; only the specific numbers should change.

There are two rates used frequently in measuring the disease (or morbidity) in a population: a) Incidence and b) Prevalence. Incidence measures the new cases of a particular disease within a certain period of time. Prevalence measures the total number of existing disease cases at a particular point in time.

Most of the data available on incidence are based on information reported by physicians when they complete the forms required when one of their patients has a "reportable" disease. Some states now require physicians to report certain noncommunicable diseases (such as occupational lung disease or lead toxicity) so that health officials can respond to environmental health threats.

Prevalence rates are not as good a measure of disease importance as incidence since they are complicated by the prognosis (the likelihood of recovery). Prevalence reflects both the incidence and the duration of the disease. Let's say diseases A and B have the same incidence rates, but disease A is mild while disease B is severe and causes early death. Disease A has a higher prevalence in the population since people can live with a mild disease but die with a serious one. Just looking at the prevalence rates could mislead one in deciding which disease is more important. One powerful illustration of this is seen by comparing common allergies with AIDS. Allergies have a much higher prevalence than AIDS, due to a higher incidence and a much milder disease course. It would be an error to conclude from the higher prevalence rate that allergies are more important since AIDS causes death leading to a low prevalence rate. When comparing prevalence rates, additional information is needed about the severity and duration of the disease to determine which diseases are important.

Earlier we mentioned that rates sometimes must be adjusted to remove biases that might be due to such characteristics as age, race, or sex. Below two types of rates are described that attempt to deal with these biases.

1. Age-Adjusted Rates. Some rates need adjustments to make them comparable. Data from different years or from different locations may need to be age-adjusted to account for different age distributions in the populations.

2. Specific Rates. In order to compare rates between subgroups or for various diseases, a specific rate can be used. It can be calculated for a certain population subgroups based on age, race or gender. A rate for 55-60 year olds is an age-specific rate; a rate for black 18-24 year olds is an age-race-specific rate; a rate for black 55-60 year old men is an age-race-sex-specific rate. Rates can also be calculated for particular causes of death, such as rate of cancer deaths or the rate of lung cancer.