Module 3: Health Statistic and Epidemiology PDF

MODULE 3 CHN II Population Groups and HEALTH STATISTIC AND EPIDEMIOLOGY Community as Clients LEARNING OBJECTIVES This module defines epidemiology and demonstrates its practical applications in public health. This powerful tool can be utilized to take advantage of routinely collected health...

MODULE 3 CHN II Population Groups and HEALTH STATISTIC AND EPIDEMIOLOGY Community as Clients LEARNING OBJECTIVES This module defines epidemiology and demonstrates its practical applications in public health. This powerful tool can be utilized to take advantage of routinely collected health statistics as well as surveillance data for health indicators. PART I A. Tools 1. Demography 2. Health Indicators  Sources of Data ❖ Crude Birth Rate  Population Size ❖ Crude Death Rate  Composition ❖ Infant Mortality Rate  Distribution ❖ Maternal Mortality Rate ❖ Specific Rate of Mortality  HEALTH STATISTICS AND EPIDEMIOLOGY A. Tools 1. DEMOGRAPHY Demography (from prefix demo- from Ancient Greek δῆμος dēmos, meaning "the people", and -graphy from γράφω graphō, implies "writing, description or measurement". It is the statistical study of populations, especially human beings. As a very general science, it can analyze any kind of dynamic living population, i.e., one that changes over time or space. Demography encompasses the study of the size, structure, and distribution of these populations, and spatial or temporal changes in them in response to birth, migration, ageing, and death.  HEALTH STATISTICS AND EPIDEMIOLOGY A. Tools 1. DEMOGRAPHY Population size Population size is the actual number of individuals in a population. Population density is a measurement of population size per unit area, i.e., population size divided by total land area. Population composition Population composition is the description of a population according to characteristics such as age, sex, race and marital status. These data are often compared over time using population pyramids.  HEALTH STATISTICS AND EPIDEMIOLOGY A. Tools 1. DEMOGRAPHY Spatial distribution A spatial distribution is the arrangement of a phenomenon across the Earth's surface and a graphical display of such an arrangement is an important tool in geographical and environmental statistics. Sources of Data: - Population census - Registration of Vital data - Health Survey - Studies and researches  HEALTH STATISTICS AND EPIDEMIOLOGY A. Tools 2. HEALTH INDICATORS Rates and Ratios: Rate – show the relationship between a vital event and those persons exposed to the occurrence of said event, within a given area and during a specified unit of time, it is evident that the person experiencing the event. (Numerator) must come from the total population exposed to the risk of same event (Denominator). Ratio – is used to describe the relationship between two (2) numerical quantities or measures of events without taking particular consideration of the time or place. These quantities need not necessarily represent the same entities, although the unit of measure must be the same for both numerator and denominator of the ratio.  HEALTH STATISTICS AND EPIDEMIOLOGY A. Tools 2. HEALTH INDICATORS Crude or General Rates – referred to the total living population. It must be presumed that the total population was exposed to the risk of the occurrence of the event. Specific Rate – the relationship is for a specific population class or group. It limits the occurrence of the event to the portion of the population definitely exposed to it.  HEALTH STATISTICS AND EPIDEMIOLOGY A. Tools 2. HEALTH INDICATORS Crude Birth Rate – a measure of one characteristic of the natural growth or increase of a population  HEALTH STATISTICS AND EPIDEMIOLOGY A. Tools 2. HEALTH INDICATORS Crude Death Rate – a measure of one mortality from all causes which may result in a decrease of population  HEALTH STATISTICS AND EPIDEMIOLOGY A. Tools 2. HEALTH INDICATORS Infant mortality Rate – measure the risk of dying during the 1st year of life. It is a good index of the general health condition of a community since it reflects the changes in the environment and medical condition of a community.  HEALTH STATISTICS AND EPIDEMIOLOGY A. Tools 2. HEALTH INDICATORS Maternal Mortality Rate – measures the risk of dying from cause related to pregnancy, childbirth and puerperium. It is an index of the obstetrical care needed and received by women in a community.  HEALTH STATISTICS AND EPIDEMIOLOGY A. Tools 2. HEALTH INDICATORS Specific Death Rate – describes more accurately the risk of exposure of certain classes or group to particular diseases. To understand the forces of mortality, the rates should be made specific provided the data are available for both the population and the event in their specification. Specific rates render more comparable and thus reveal the problem of public health  HEALTH STATISTICS AND EPIDEMIOLOGY A. Tools 2. HEALTH INDICATORS Leading Causes of Morbidity diseases within a specified population group and time period. Calculation:  Frequency counts of disease in rank order from high to low.  HEALTH STATISTICS AND EPIDEMIOLOGY A. Tools 2. HEALTH INDICATORS Leading Causes of Mortality are defined as underlying cause of death categories or major ICD (International Cause of Death) groupings (such as Diseases of the Heart, Malignant Neoplasms, Accidents, etc) that usually account for large numbers of deaths within a specified population group and time period. Calculation: Frequency counts of deaths by cause of death grouping or category sorted in rank order from high to low. Determining and monitoring the leading causes of death is considered a primary and important indicator of a geographic area’s (country, state, county) overall health status or quality of life.  HEALTH STATISTICS AND EPIDEMIOLOGY A. Tools 2. HEALTH INDICATORS Life expectancy, estimate of the average number of additional years that a person of a given age can expect to live. The most common measure of life expectancy is life expectancy at birth. Life expectancy is a hypothetical measure. It assumes that the age-specific death rates for the year in question will apply throughout the lifetime of individuals born in that year. PART II Philippine Health Situation 1)Demographic profile 2) Health Profile DEMOGRAPHIC PROFILE 95% 76% OF HOUSEHOLDS USE IMPROVED TOILET USE AN FACILITIES. IMPROVED SOURCE OF DRINKING WATER PSA DEMOGRAPHIC PROFILE Electricity: 93% of households have electricity. Clean fuel for cooking: Half of households (51%) use clean fuel for cooking.  DEMOGRAPHIC PROFILE Tobacco smoking inside the home: In 28% of households, someone smokes inside the house on a daily basis, and in 8% of households someone smokes inside on a weekly basis. DEMOGRAPHIC PROFILE Household composition: On average, households in the Philippines have 4.2 members, and 21% of households are female-headed.  DEMOGRAPHIC PROFILE Birth registration: 92% Of children under age 5 had their births registered with the civil authorities; this includes 68% with a birth certificate and 24% whose birth was registered but who do not have a birth certificate. DEMOGRAPHIC PROFILE School attendance: 94% Of girls age 6-11 attend primary school, as compared with 93% Of boys. The net attendance ratio (NAR) drops in secondary school: 83% Of girls and 74% Of boys age 12-17 attend secondary PART III A. Epidemiology and the nurse 1) Definition of Related term 2) Natural History of Disease 3) Epidemiological Triangle 4) Epidemiological Process and Investigation  EPIDEMIOLOGY Epidemiology is the study of occurrences and distribution of diseases as well as the distribution and determinants of health state or events in specified population, and the application of this study to the control of health problems. This emphasizes that epidemiologist are concerned not only with deaths, illness and disability, but also with more positive health states and with the means to improve health. EPIDEMIOLOGY Two main areas of investigation are concerned in the definition, the study of the distribution of disease and the search for the determinants (causes) of the disease and its observed distribution. The first area describes the distribution of health status in terms of age, gender, race, geography to health and diseases. EPIDEMIOLOGY Two main areas of investigation are concerned in the definition, the study of the distribution of disease and the search for the determinants (causes) of the disease and its observed distribution. The second area involves explanation of the patterns of disease distribution. In terms of causal factors. Many disciplines seek to learn about the causes of the diseases; the special contribution of epidemiology is its search for concordance between the known or suspected causes of the disease and the known patterns to investigate for possible causal roles. EPIDEMIOLOGY Consequently, we speak of the epidemiology of heart disease, measles or accidents because each disease has the same elements; the disease determinants, the human population in which the disease occurs, and the distribution of the disease in the population.  EPIDEMIOLOGY Epidemiology therefore is the backbone of the prevention of the disease. In order to control a disease effectively, the condition surrounding its occurrence and the favoring the development of the disease must first be known. Complete the clinical picture of chronic disease and describe their natural history Search for causes of health and disease by comparing the experience of groups that are clearly defined by their composition, inheritance, experience, behaviour and environment  EPIDEMIOLOGY Natural History of Disease The history of disease is its course overtime, starting from prepathogenesis stage to its termination. While clinical data of patients with various stages of the disease are usually put together to determine the natural history of a particular disease, a prospective cohort study could pilot it better because of the benefit of observing the cohort from the time that the member are disease-free to the time the develop the biased through termination. The applicable level of prevention that is administered to the patient is dependent on the stage of the disease when the patient was diagnosed.  Stage of Stage of subclinical Stage of clinical Resolution stage susceptibility disease disease The person is The person is The patient The patient NATUR not yet sick still apparently now either but may be healthy since manifests recovers exposed to clinical recognizable completely AL the risk factors of the manifestations of the disease signs and symptoms for from the disease HISTOR disease, for are not yet example, becomes a instance, shown, vaginal chronic case multiple sex although bleeding. with or Y OF partners in pathologic Tertiary level without the case of changes have of prevention disability or cervical already is applicable dies. DISEAS cancer. occurred. to limit the Primary level Secondary disability and of prevention level of restore the E such as health education and immunization prevention like Pap smear can detect this functional capability of the patient. early stage so that prompt treatment can be initiated to avoid progression of the disease. EPIDEMIOLOGIC TRIAD OR TRIANGLE MODEL The Epidemiology Triangle consists of three components- host, environment and agent. The model implies that each must be analyzed and understood for comprehensions and prediction of patterns of a disease a change in any of the component will alter an existing equilibrium to increase or decrease the frequency of the disease. We focus on human and the forces within him and within the environment that influence his state of health. From this view point, the human is the host organism, other organism like animals are considered only as they relate to the human health. The host is any organism the harbors and provides nourishment for another organism. EPIDEMIOLOGIC TRIAD OR TRIANGLE MODEL EPIDEMIOLOGIC TRIAD OR TRIANGLE MODEL Agent is the intrinsic property of microorganism to survive and multiply in the environment to produce disease. Causative agent is the infectious agent or its toxic component that is transmitted from the source of infection to the susceptible body. EPIDEMIOLOGIC TRIAD OR TRIANGLE MODEL The state of the host at any given time is a result of the interaction of genetic endowment with environment over the entire lifespan. Environment is the sum total of all external condition and influences that affects the development of an organism which can be biological, social and physical. The environment affects both the agent and the host.  EPIDEMIOLOGIC TRIAD OR TRIANGLE MODEL Three components of the environment: 1. Physical environment - is composed of the inanimate surrounding such as the geophysical condition of the climate. 2. Biological environment-makes up the living things around us such as plants and animal life. 3. Socio – economic environment- which may be in the form of level of economic development of the community, presence of social disruption and the like. APPROACH TO DISEASE AND ITS DETERMINANTS The present epidemiology approach is based on the interaction of the host, the causative agent, and the environment. Essentially, epidemiology patterns depend upon these factors which influence the probability of contact between an infectious agent and a susceptible host. The presence of infectious materials varies with the duration and the extent of its excretion from an infected person the climatic conditions affecting survival of the agent, route of entry into the host and the existence of alternative reservoirs or host of the agent. APPROACH TO DISEASE AND ITS DETERMINANTS The availability of susceptible host depend upon the extend mobility and interpersonal contact within the population group, and the degree and duration of immunity from previous infection with the same or related agent. Classification of Agents, Host and Environmental Factors which determine the occurrence of Disease in Human Population. APPROACH TO DISEASE AND ITS DETERMINANTS Classification of Agents, Host and Environmental Factors which determine the occurrence of Disease in Human Population APPROACH TO DISEASE AND ITS DETERMINANTS Classification of Agents, Host and Environmental Factors which determine the occurrence of Disease in Human Population APPROACH TO DISEASE AND ITS DETERMINANTS Classification of Agents, Host and Environmental Factors which determine the occurrence of Disease in Human Population APPROACH TO DISEASE AND ITS DETERMINANTS Classification of Agents, Host and Environmental Factors which determine the occurrence of Disease in Human Population EPIDEMIOLOGICAL PROCESS AND INVESTIGATION Disease Distribution The methods and technique of epidemiology are desired to detect the cause of a disease in relation to the characteristic of the person who has it or to a factor present in his environment. Since neither population and environment of different times or places are similar, these characteristics and factor are called: Epidemiology variables. These variables are studied since they determine the individual and population at greatest risks of acquiring particular disease, and knowledge of these associations may have predictive value.  EPIDEMIOLOGICAL PROCESS AND INVESTIGATION For the purpose of analyzing epidemiology data, it has been found helpful to organize that data according to the variables of time, person and place; 1. Time - refers both to the period during which the cases of the disease being studied were exposed to the source of infection and the period during which the illness occurred. The common practice is to record the temporal occurrence of disease according to date, when appropriate, the hour of onset of symptoms. Subsequently, all similar cases are grouped or examined for various span of time: An epidemic period, a year, or a number of consecutive years. This analysis of cases by time enables the formulation of hypotheses concerning time and source of infection, mode of transmission, and causative agent.  EPIDEMIOLOGICAL PROCESS AND INVESTIGATION For the purpose of analyzing epidemiology data, it has been found helpful to organize that data according to the variables of time, person and place; 1. Time - refers both to the period during which the cases of the disease being studied were exposed to the source of infection and the period during which the illness occurred. Epidemic period: a period during which the reported number of cases of a disease exceed the expected or usual number for that period.  EPIDEMIOLOGICAL PROCESS AND INVESTIGATION For the purpose of analyzing epidemiology data, it has been found helpful to organize that data according to the variables of time, person and place; 1. Time - refers both to the period during which the cases of the disease being studied were exposed to the source of infection and the period during which the illness occurred. Year: For many diseases the incidence (Frequency of occurrence) is not uniform during each of 12 consecutive months. Instead, the frequency is greater in one season the any of the others. This seasonal variation is associated with variation in the risk of exposure of susceptible to the source of infection.  EPIDEMIOLOGICAL PROCESS AND INVESTIGATION For the purpose of analyzing epidemiology data, it has been found helpful to organize that data according to the variables of time, person and place; 1. Time - refers both to the period during which the cases of the disease being studied were exposed to the source of infection and the period during which the illness occurred. Period of Consecutive years: recording the reported cases of a disease over a period of year-by weeks, months or year of occurrence-useful in predicting the probable future incidence of the disease and in planning appropriate prevention and control programs. EPIDEMIOLOGICAL PROCESS AND INVESTIGATION For the purpose of analyzing epidemiology data, it has been found helpful to organize that data according to the variables of time, person and place; 2. Person- refers to the characteristics of the individual who were exposed and who contacted the infection or the disease in question. Person can be described in terms of their inherent or their acquired characteristics (such as age, race sex, practices, customs); and the circumstances under which they live (social, economic and environmental condition). Age: for most diseases, there is more variation in disease frequency by age than any other variable-and for this reason age is considered the single most useful variable associated in describing the occurrence and distribution of disease. This usefulness is largely a consequence of the association between a person’ age and their: a) Potential for exposure to a source of infection b) Level of immunity or resistance c) Physiologic activity at the tissue level (which sects the manifestation of a disease subsequent to infection EPIDEMIOLOGICAL PROCESS AND INVESTIGATION For the purpose of analyzing epidemiology data, it has been found helpful to organize that data according to the variables of time, person and place; 2. Person- refers to the characteristics of the individual who were exposed and who contacted the infection or the disease in question. Person can be described in terms of their inherent or their acquired characteristics (such as age, race sex, practices, customs); and the circumstances under which they live (social, economic and environmental condition). Sex and occupation: In general, males experience higher mortality rates than female for a wide range of diseases. It is the female however who have higher morbidity rates. This is also because of differing pattern of behavior between sexes or activities as recreation, travel, occupation which result in different opportunities for exposure to a source of infection EPIDEMIOLOGICAL PROCESS AND INVESTIGATION For the purpose of analyzing epidemiology data, it has been found helpful to organize that data according to the variables of time, person and place; 3. Place- refers to the features, factor or conditions which existed in or described the environment in which the disease occurred. It is the geographic area described in terms of street, address, city, municipality, province, region or country. The association of a disease with a place implies that the factors of greatest etiologic importance are present either in the inhabitants or in the environment or both. EPIDEMIOLOGICAL PROCESS AND INVESTIGATION For the purpose of analyzing epidemiology data, it has been found helpful to organize that data according to the variables of time, person and place; 3. Place- refers to the features, factor or conditions which existed in or described the environment in which the disease occurred. It is the geographic area described in terms of street, address, city, municipality, province, region or country. The association of a disease with a place implies that the factors of greatest etiologic importance are present either in the inhabitants or in the environment or both. Urban / Rural Differences: in general, disease spreads more rapidly in urban areas than in rural areas primarily because of the greater population density of urban area rural provides more opportunities for susceptible individual to come into contact with a source of infection. EPIDEMIOLOGICAL PROCESS AND INVESTIGATION For the purpose of analyzing epidemiology data, it has been found helpful to organize that data according to the variables of time, person and place; 3. Place- refers to the features, factor or conditions which existed in or described the environment in which the disease occurred. It is the geographic area described in terms of street, address, city, municipality, province, region or country. The association of a disease with a place implies that the factors of greatest etiologic importance are present either in the inhabitants or in the environment or both. Socio-economic areas: different communities can be usually divided into geographic areas which are relatively homogenous with respect to the socio- economic circumstances of the residents. It commonly has been observed that the incidence rate of many diseases, both communicable and chronic, varies inversely with differences in large geographic areas within a country; geographic variations in the incidence of infectious diseases commonly results from variation in the geographic distribution of the reservoirs or vectors of the disease or in the ecological requirement of the disease agent.  PATTERNS OF OCCURRENCE AND DISTRIBUTION The variables of disease as to person, time and place are reflected in distinct pattern of occurrence and distribution in a given community. Distinct patterns are recognized as: sporadic, endemic and epidemic occurrences. The following are the characteristic features of those patterns of disease occurrence; 1. Sporadic -occurrence in the Philippines. In a given year, there are few unrelated cases in a given locality. The cases are few and scattered, so that there is no apparent relationship between them and they occur on and off, intermittently, through a period of time. Rabies occurs sporadically in the Philippine. In a given year, there are few. Cases during certain weeks of the year, while there are no cases at all during the other weeks. During the week when the few cases are occurring, the cases are scattered throughout the country, so that the cases are not related at all to the cases in other area. PATTERNS OF OCCURRENCE AND DISTRIBUTION The variables of disease as to person, time and place are reflected in distinct pattern of occurrence and distribution in a given community. Distinct patterns are recognized as: sporadic, endemic and epidemic occurrences. The following are the characteristic features of those patterns of disease occurrence; 2. Endemic - occurrence is the continuous occurrence throughout a period of time, of the usual number of cases in a given locality. The disease is therefore always occurring in the locality and the level of occurrence is more or less constant through a period of time. The level of occurrence maybe low or high when the given level is continuously maintained, then the pattern maybe low endemic or high endemic as the case maybe. The disease is more or less inherent in that locality, it is in a way already identifiable with the locality itself. PATTERNS OF OCCURRENCE AND DISTRIBUTION The variables of disease as to person, time and place are reflected in distinct pattern of occurrence and distribution in a given community. Distinct patterns are recognized as: sporadic, endemic and epidemic occurrences. The following are the characteristic features of those patterns of disease occurrence; 3. Epidemic-- occurrence is of unusually large number of cases in relatively short period of time. The is a disproportion ate relationship between the number of cases and the period of occurrence, the more acute is the disproportion, the more urgent and serious is the problem. The number of cases is not in itself necessarily big or large, but such number of cases when compared with the usual number of cases may constitute an epidemic in a given locality, as long as that number is so much more than the usual number in that locality. It is therefore not the absolute largeness of the number of cases but its relative largeness in comparison with the usual number of cases which determine an epidemic occurrence. PATTERNS OF OCCURRENCE AND DISTRIBUTION The variables of disease as to person, time and place are reflected in distinct pattern of occurrence and distribution in a given community. Distinct patterns are recognized as: sporadic, endemic and epidemic occurrences. The following are the characteristic features of those patterns of disease occurrence; 4. Pandemic is the simultaneous of epidemic of the same disease in several countries. It is another pattern of occurrence from an international perspective.  OUTLINE OF PLAN FOR EPIDEMIOLOGY INVESTIGATION 1. Establish fact of presence of epidemic Verify Diagnosis – do clinical and laboratory studies to confirm the date ✓ Is the disease that which is reported to be? ✓ Are all the cases due to the same disease? Reporting Is it reasonably complete? Is it prompt enough so the present situation? Is there an unusual prevalence of the disease? ✓ Post experience of a given community ✓ Relation to nature of disease ✓ Which cases may be considered epidemic and which are endemic?  OUTLINE OF PLAN FOR EPIDEMIOLOGY INVESTIGATION 2. Establish time and space relationship of the disease Are the cases limited to or concentrated in any particular geographical subdivision of the affected community? Relation of cases by days of onset of the first known cases – maybe done by days, week or months. 3. Relation to characteristic of the group of community Relation of cases to age, group, sex, color, occupation school attendance, past immunization, etc. Relation of sanitary facilities, especially water supply, sewerage disposal, general sanitation of homes, relation to animal or insect vectors. Relation to milk and food supply Relation of cases and known carries if any  OUTLINE OF PLAN FOR EPIDEMIOLOGY INVESTIGATION 4. Correlation of all data obtained Summarize the data clearly with the aid of such tables and charts which are necessary to give a clear picture of the situation Build up the cases for the final conclusion carefully utilizing all the evidence available. Establish the source of the epidemic and the manner of the spread, if possible. Make suggestion as to the control, if disease is still present in community and as to prevention of future outbreaks. END OF LECTURE