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 |
|---|---|
| Glossary | https://www.alternix.com/blogs/glossary-of-terms/mortality-rate |
| Wikipedia | http://en.wikipedia.org/wiki/Mortality_rate |
| Wikidata | https://www.wikidata.org/wiki/Q58702 |
| Knowledge Graph | https://www.google.com/search?kgmid=/m/01b4_q |
