Mortality rate

Mortality Rate Definition and Calculation

  • Mortality rate is a measure of the number of deaths in a particular population, scaled to the size of that population, per unit of time.
  • It is typically expressed in units of deaths per 1,000 individuals per year.
  • Mortality rate is distinct from morbidity and incidence rate.
  • The crude death rate is a specific mortality rate measure that looks at mortality from all causes in a given time interval for a given population.
  • The formula to calculate mortality rate is (deaths/population) * 10^n, where n is the conversion factor to another unit.

Crude Death Rate Globally

  • The crude death rate is the mortality rate from all causes of death for a population.
  • It is calculated as the total number of deaths during a given time interval divided by the mid-interval population, per 1,000 or 100,000.
  • The CIA estimates the global crude death rate to be 7.7 per 1,000 people in a population per year.
  • The leading causes of death globally in 2016 were ischaemic heart disease, stroke, chronic obstructive pulmonary disease, lower respiratory infections, and Alzheimer's disease and other dementias.
  • Decrease in mortality rate is one of the reasons for population increase.

Related Measures of Mortality

  • Perinatal mortality rate includes fetal deaths past 22 or 28 completed weeks of pregnancy and deaths among live-born children up to 7 completed days of life, divided by the number of births.
  • Maternal mortality rate is the number of deaths of mothers assigned to pregnancy-related causes during a given time interval, divided by the number of live births.
  • Infant mortality rate is the number of deaths among children 1 year of age during a given time interval divided by the number of live births.
  • Child mortality rate (under-five mortality rate) is the number of deaths of children less than 5 years old, divided by the number of live births.
  • Standardized mortality ratio (SMR) compares the number of deaths in a given population to the number of deaths expected in a standard population.

Use in Epidemiology

  • Epidemiologists use estimation to predict correct mortality rates as exact rates are often difficult to obtain.
  • Language barriers, health infrastructure issues, conflict, and other reasons contribute to the difficulty in predicting mortality rates.
  • Maternal mortality estimation faces additional challenges due to stillbirths, abortions, and multiple births.
  • Definitions of stillbirth vary across countries, with some considering it after 20 weeks gestation and others after 28 weeks.
  • Vital statistics and census data are ideal sources for mortality estimation.
  • Vital statistics and census data may not be available in developing countries, conflict zones, areas affected by natural disasters, and humanitarian crises.
  • Household surveys or interviews are often used to assess mortality rates.
  • Various methods are employed to estimate mortality rates through household surveys.
  • These methods help overcome the lack of vital statistics and census data.
  • Household surveys provide valuable information about mortality rates in specific populations.

Sampling Methods and Mortality Statistics

  • Sisterhood method estimates maternal mortality by contacting women in populations and asking about deaths among sisters.
  • Orphanhood surveys estimate mortality by questioning children about the mortality of their parents.
  • Widowhood surveys estimate adult mortality by asking about the deceased husband or wife.
  • Limitations of the sisterhood method include cases where sisters may have died before the sister being interviewed was born.
  • Limitations of orphanhood surveys include the adoption effect and biases introduced by multiple children reporting on the same parents.
  • Sampling refers to the selection of a subset of the population to gain information about the entire population.
  • Cluster sampling is an approach where each member of the population is assigned to a group (cluster), and then clusters are randomly selected.
  • Cluster sampling is often combined with stratification techniques, called multistage sampling.
  • Cluster sampling is the approach most often used by epidemiologists.
  • Cluster sampling may not be ideal in areas of forced migration due to significant sampling error.
  • Causes of death vary greatly between developed and less developed countries.
  • The crude death rate has decreased globally over the years.
  • There is a negative relationship between per capita income and crude death rate.
  • Mortality due to malnutrition accounted for 58% of total mortality in 2006.
  • Approximately two-thirds of the global daily deaths are due to age-related causes.
  • Low income and a low standard of living are associated with increased mortality rates.
  • Malnutrition resulting from a low standard of living can make people more susceptible to diseases.
  • Lack of hygiene, sanitation, and access to proper medical care contribute to higher mortality rates.
  • Short-term price increases have historically been associated with higher mortality rates.
  • National income is the largest factor in mortality rates being higher in low-income countries.
  • Children under 5 years old in lower-income countries have a higher chance of dying from preventable diseases.
  • Malaria, respiratory infections, diarrhea, perinatal conditions, and measles are common causes of death in developing nations.
  • After the age of 5, preventable causes of death level out between high and low-income countries.
  • Mortality rates are influenced by factors such as crude death rate, cause-specific death rate, and infant mortality rate.
  • The top 10 causes of death globally include diseases like cardiovascular diseases, cancer, and respiratory diseases.
  • Socioeconomic status has a significant impact on mortality rates, with lower socioeconomic groups experiencing higher mortality rates.
  • Access to healthcare services and quality of healthcare play a crucial role in determining mortality rates.
  • Lifestyle factors such as smoking, diet, and physical activity can contribute to higher mortality rates.
  • Environmental factors, including pollution and exposure to hazardous substances, can increase mortality rates.
  • Infectious diseases and epidemics can cause a sudden increase in mortality rates.
  • Mortality rates have been declining globally over the past century due to improvements in healthcare, sanitation, and living conditions.
  • Non-communicable diseases, such as cardiovascular diseases and cancer, are now the leading causes of death

Mortality rate Data Sources

Reference URL
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