M3

• Ratio


  A comparison of any two values calculated by dividing one interval or ratio-scale variable by the other
• Proportion


  Type of ratio in which the numerator is included in the denominator
• Rate


  Measure of the frequency with which an event occurs in a defined population over a specified period of time
• Epidemiologic measures


  • Events (numerator)
  • Population at risk (denominator)
• Epidemic


  Affects a greater than expected number of individuals at the same time
• Endemic


  Normal occurrence in a population
• Pandemic


  Geographically widespread, epidemic in >1 continent
• Prevalence


  Proportion of persons who have a condition during a particular time, includes both new and pre-existing cases
• Incidence


  Occurrence of new cases of disease or injury in a population over a specified period of time
• Absence of symptoms may not necessarily connote a healthy condition: medical examination/diagnostic tests
• Varying degrees of states of health
• Difficult to qualify and quantify health
• Quantitative measures can be used to describe various aspects of health status of the population
• Uses of health indicators

  • Determine factors in causation and control of disease
  • Identify public health problems and needs
  • Indicate priorities for resource allocation
  • Monitor implementation of health programs
  • Evaluate health programs
• Crude Birth Rate (CBR)

  Measures how fast people are added to the population

  
• General Fertility Rate (GFR)

  The reproductive age group for women in some countries is defined as 15-49 years of age

  
• Crude Death Rate (CDR)


  Measures rate at which mortality occurs in a given population

  
• Infant Mortality Rate


  A sensitive index of the health conditions of the general population
• Poor population: 60-150 infant deaths per year.

  Severe conditions: ≥ 200 infant deaths per 100 births per year
• High Infant Mortality Rate means low levels of health standards which maybe secondary to poor maternal and child health care, malnutrition, poor environmental sanitation or deficient health service delivery
• Neonatal Mortality Rate


  Infant deaths under 28 days old
• Perinatal Mortality Rate


  Infant deaths from 28 weeks gestation to 7 days
• Post-Neonatal Mortality Rate


  Infant deaths from 28 days old to < 1 year
• Maternal Mortality Rate


  Measures rate at which mortality occurs among those bearing children
• Swaroop's Index


  A special kind of proportionate mortality ratio, sensitive indicator of the standards of healthcare
• Case Fatality Rate


  Indicates how much of the afflicted die from the disease, the probability of dying from a certain disease
• Circumstances when the specific rate cannot be used: 1) Frequency of the event of interest (i.e the numerator) is known for the subgroups of the population, 2) Size of the subgroups (i.e denominators) is unknown, 3) Number of people at risk for the event are too small to provide stable estimates of the specific rates, 4) If the number of people at risk is large in each of the subgroups of interest, SPECIFIC RATES provides the most information, and these should be sought whenever possible
• Cause-Specific Death Rate


  Measures how fast individuals in a population are dying from a specific cause, measures the impact of a certain cause in the population in terms of mortality
• Demography


  Statistical study of populations, their size, structure, distribution, and spatial or temporal changes in response to birth, migration, aging, and death
• Aspects of demography

  • Fertility
  • Mortality
  • Migration
  • Marriage
  • Social mobility
• Demography is used to determine the number & distribution of a population in certain area for planning, priority setting, & fund allocation, determine growth (or decline) & dispersal of population in the past, establish a "casual relationship" between population trends & various aspects of social organization, and predict future developments & their possible consequences
• Sex Ratio


  Compares the number of males to the number of females
• Sex Structure


  Compares the sex ratio across different categories/levels of another characteristic
• Median Age


  The value which cuts-off the upper 50% and lower 50% of the ages of the population, used to gauge whether the population is young or old
• Age-Dependency Ratio


  The computed value represents the number of dependents that need go be supported by every 100 persons in the economically active groups
• Population Pyramid


  A graphical presentation of the age and sex composition of the population, describes demographic trends of the population in the past
• Health indicators are quantitative measures that describe and summarize various aspects of health status of the population, expressed as ratios, proportions, or rates
• Uses of health indicators

  • Determine factors that may contribute to causation and control of disease
  • Identify public health problems and needs
  • Indicate priorities for resource allocation (health economics)
  • Monitor health program implementation
  • Evaluate health programs
• There are several data for epidemiologic studies of public health collected by different government and private agencies and are usually made available publicly

  
• Prevalence data are determined by surveys, these data are used to create rates and ratios and are used for health planning