Epidemiological concepts english
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Epidemiology is the study of the distribution and determinants of health-related states in populations and aims to control health problems through understanding disease frequency, distribution, and determinants. Key measurements include rates, ratios, and proportions for assessing mortality, morbidity, and natality, which help identify causes of diseases and inform public health management. The document emphasizes the importance of epidemiological methods, including observational and experimental studies, for understanding health trends and informing health policies.
Epidemiological concepts english
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- 2. Epidemiology is defined as "The study of the distribution and determinants of health related states or events in specified populations, and the application of this study to the control of health problems.
- 3. Epidemiology also includes study of the health services used by the population, and to measure their impact. Epidemiology, like public health itself, is often more concerned with the well- being of society as a whole, than with the well- being of individuals.
- 4. There are three main components of epidemiology. 01. Disease frequency; 02. Distribution of disease; and 03. Determinants of disease.
- 5. The basic measure of disease frequency is a rate or ratio. These rates are essential for comparing disease frequency in different populations or subgroups of the same population in relation to suspected causal factors. Such comparisons may yield important clues about causes of the disease.
- 6. The study of how the disease is distributed in human populations is an important component of epidemiology. It is the study of pattern of disease occurrence in a community. The patterns may lead to the generation of hypotheses about causative factors or risk factors.
- 7. A main feature of epidemiology is to test aetiological hypotheses and identify the underlying causes (or risk factors) of disease. This requires the use of epidemiological principles and methods.
- 8. Epidemiology has three main aims: To describe disease and other health related event patterns in human populations. To identify the causes of diseases and other health related events (also known as aetiology). To provide data essential for the management, evaluation and planning of services for the prevention, control and treatment of disease and other health related events.
- 9. The measurements in epidemiology are many few of them are grouped as : a. Measurement of mortality b. Measurement of morbidity c. Measurement of disability d. Measurement of natality
- 10. The basic tools of measurement in epidemiology are : 1. Rates 2. Ratios, and 3. Proportions
- 11. A rate measures the occurrence of some particular event (disease or death) in a population during a given time period. It is expressed as per 1000 or per 10000 or per 100000. Example crude death rate.
- 12. It expresses a relation in size between two random quantities. Broadly, ratio is the result of dividing one quantity by another. It is expressed in the form of: x: y or x/y Example- sex-ratio, doctor-population ratio.
- 13. A proportion is a ratio which indicates the relation in magnitude of a part of the whole. The numerator is always included in the denominator. A proportion is usually expressed as a percentage.
- 14. Crude Death Rate- It is defined as "the number of deaths (from all causes) per 1000 estimated mid-year population in one year, in a given community or place“. The crude death rate is calculated from the formula: CDR=
- 15. for example – a community have 15000 mid year population and number of death during the whole year from 1st January to 31st December is 750 than As per formula- CDR= 750/15000x1000 per 1000 = 50/1000 is crude death rete
- 16. Specific Death Rate- when death rate is specific to a condition than it is known as specific death rate. It may be disease specific, age specific or specific to any other variable such as sex, housing, class etc. SDR=
- 18. Case fatality Rate- Case fatality rate means the killing power of a disease. Case fatality rate is normally used in acute infectious diseases. It is defined as no. of deaths due to a disease per 100 cases of the disease. CFR
- 19. Infant mortality Rate- infant mortality rate is defined as the ratio of deaths under 1 year of age in a given year to the total number of live births in the same year. It is measured by the this formula.
- 20. Maternal mortality Rate- maternal mortality rate is defined as the ratio of deaths of mothers due to pregnancy related causes the total number of live births in the same year. It is measured by the this formula.
- 21. Incidence Rate- "the number of NEW cases of a particular disease occurring in a defined population during a specified period of time". It is given by the formula :
- 22. Prevalance - The term "disease prevalence" is defined as all current cases of a disease (old and new) existing at a given point in time, or over a period of time in a given population
- 23. The commonly used disability rates fall into two groups: (a) Event-type indicators and (b) person-type indicators (a) Event-type disability rates i) Number of days of restricted activity ii) Bed disability days iii) Work-loss days (or school-loss days) within a specified period
- 24. (b) Person-type disability rates i) Limitation of mobility: For example, confined to bed, confined to the house, special aid in getting around either inside or outside the house. ii) Limitation of activity: For example, limitation to perform the basic activities of daily living (ADL) eating, washing, dressing, going to toilet, moving about & limitation in major activity, ability to work at a job, ability to housework, etc.
- 25. crude birth rate - Birth rate is the simplest natality rate and is defined as "the number of live births per 1000 estimated mid-year population in a given year". It is given by the formula:
- 26. General fertility rate - It is defined as the "number of live births per 1000 women in the reproductive age- group (15-44 or 49 years) in a given year“ .It is given by the formula:
- 27. General fertility rate - It is defined as the "number of live births per 1000 women in the reproductive age- group (15-44 or 49 years) in a given year“ .It is given by the formula:
- 28. Basic epidemiologic methods are based on careful observation and use of valid comparison groups to assess whether what was observed, such as the number of cases of disease in a particular area during a particular time period or the frequency of an exposure among persons with disease, differs from what might be expected.
- 29. Basic epidemiologic methods are based on careful observation and use of valid comparison groups to assess whether what was observed, such as the number of cases of disease in a particular area during a particular time period or the frequency of an exposure among persons with disease, differs from what might be expected. Main methods are observational studies and experimental studies. These are also known as epidemiological studies or research studies.
- 30. By – SURESH KUMAR ( Nursing Tutor )