COMMUNITY
INTERVENTION TRIALS
AUTHOR
Dr. A. K. AVASARALA
MBBS, M.D.
PROFESSOR & HEAD
DEPT OF COMMUNITY
MEDICINE & EPIDEMIO...
PROMPT
• I WISH TO DEVELOP AN
EPIDEMIOLOGY COURSE FOR
TEACHING, AS THERE IS GOOD
RESPONSE, NATIONALLY AND
INTERNATIONALLY ...
LEARNING OBJECTIVES
1. READER IS EXPECTED TO
LEARN THE NATURE & SCOPE
OF COMMUNITY INTERVENTIONS
2. THE PRECAUTIONS AND ST...
PERFORMANCE OBJECTIVES
• READER CAN DESIGN AND
PERFORM COMMUNITY
INTERVENTION TRIALS
• HE CAN PROMOTE THE
HEALTH OF THE CO...
TYPES
• PRIMARY PREVENTIVE
TYPE (COMMUNITY
INTERVENTION TRIALS (CIT)
NATURE OF STUDIES
• INTERVENTION STUDIES
• NOT JUST OBSERVATIONS
• EXPERIMENTATIONS
COMMUNITY INTERVENTION
TRIALS (CIT )
• THE MAIN PURPOSE IS TO
REDUCE THE OCCURRENCE
OF DISEASES AND DEATHS
EARLY IN LIFE I...
WHY CIT ?
.
THE HEALTH STATUS OF
A COMMUNITY.
CHANGE TO HEALTHIER LIFESTYLE
BY HIGH-RISK GROUPS
CHANGE THE
BEHAVIOR OF OTH...
GENERAL OBJECTIVES
•TO INCREASE HEALTH KNOWLEDGE
OF THE WHOLE COMMUNITY ,
• TO DEVELOP POSITIVE AND RIGHT ATTITUDE
•IN THE...
SPECIFIC OBJECTIVES
TO MEASURE VERIFIABLE CHANGES IN:
1. HEALTH KNOWLEDGE IMPROVEMENT
2. ATTITUDE
3. BEHAVIOR
STEPS OF CONDUCTING CIT
1. SETTING
2. STUDY DESIGN
3. INTERVENTION METHODS
4. EVALUATION OF INTERVENTION
5. LIMITATIONS OF...
IDEAL SETTING
• COMMUNITY IS THE
IDEAL SETTING
STUDY DESIGN
• QUASI - EXPERIMENTAL TYPE
THE INVESTIGATOR WILL NOT BE
HAVING AS MUCH OF A CHANCE OF
RANDOM ALLOCATION OF T...
SELECTION OF REFERENCE
AND INTERVENTION
POPULATIONS
• DESIRABLE TO HAVE ALMOST
IDENTICAL REFERENCE AND
INTERVENTION POPULA...
NESTED OR EMBEDDED
DESIGN
Pooled intervention
REFERENCE POPULATION
EMBEDDED DESIGN
EMBEDDED TYPE WILL HELP
• IN REDUCING SECULAR
DIFFERENCES
• IN REDUCING CONFOUNDING
BIAS AS THE BOTH KNOWN...
REFERENCE POPULATION
THE ONE WITH WHICH THE
RESULTS OBTAINED FROM
THE TRIAL ON THE
INTERVENTION POPULATION
ARE COMPARED, A...
INTERVENTION POPULATION
• THE EXPERIMENTAL
POPULATION RANDOMLY
SELECTED FROM A COUNTRY OR
REGION AND ALMOST IDENTICAL
AND ...
UNDERSTANDING SOCIETAL
CONDITIONS
• COMMONNESS OF TERRITORY,
• MORTALITY PATTERN,
• MORBIDITY PATTERN,
• FERTILITY PATTERN...
COLLECTING BASE LINE
INFORMATION
• PREPARING THE BASE LINE
LEVELS OF RISK FACTORS,
MORTALITY RATES
INTERVENTION CONCEPT
• IDEA IS TO BRING ABOUT THE
ATTITUDINAL CHANGE IN THE
PEOPLE TO ALTER THEIR
NEGATIVE LIFE STYLES AND...
INTERVENTION BY SOCIAL
COGNITION/LEARNING
SOCIAL COGNITION/LEARNING
WHEREIN THE CHANGE OF
BEHAVIOR CAN BE ACHIEVED
THROUGH...
INTERVENTION BY REASONED
ACTION AND PLANNED
BEHAVIOR
WHERE THE CHANGE CAN BE
BROUGHT ABOUT BY ADAPTING THE
INFORMATION GIV...
INTERVENTION BY
PERSUASIVE COMMUNICATION
• CONTINUOUS PERSUASIVE
COMMUNICATION TO THE
PEOPLE THROUGH MASS MEDIA
LIKE MOVIE...
PRECEDE-PROCEED MODEL
INTERVENTION
The PRECEDE process
• Predisposing,
• Reinforcing, and
• Enabling
• Constructs in
• Edu...
SOCIAL MARKETING
INTERVENTION
• PREVENTIVE HEALTH SERVICES ARE
THE PRODUCTS TO BE MARKETED
AND THE TARGET AUDIENCE, COSTS
...
EVALUATION OF INTERVENTION
1. ENDPOINTS TO BE MEASURED
2. CHANGES IN KNOWLEDGE, ATTITUDE AND
PRACTICE
3. MEANS AND PREVALE...
EVALUATION METHODS
• POPULATION SURVEYS ARE
CARRIED OUT BOTH IN THE
REFERENCE AND INTERVENTION
POPULATIONS SIMULTANEOUSLY
...
TECHNIQUES OF MEASUREMENT
• QUESTIONNAIRES – ORAL WRITTEN,
OR COMPUTERIZED ONES ARE USED
DURING THE SURVEYS
• *ANALYTICAL ...
ROSENTHAL EFFECT
• THE INDIVIDUAL’S NATURE OR
PREFERENCE TO ENHANCE OR
REDUCE THE VALUE OF THE
ENDPOINT WHILE TESTING OR
R...
CEILING EFFECT
• CEILING EFFECT IS SAID
TO BE PRESENT IN THE
COMMUNITY WHEN A
PART OR WHOLE OF THE
COMMUNITY POSSESSES
PER...
PRECAUTIONS:
1. NET CHANGES ARE MEASURED
UNIFORMLY IN A STANDARDIZED
AND SIMILAR MANNER IN BOTH THE
REFERENCE (CONTROL) AN...
INTENTION TO TREAT
PRINCIPLE
• THE “INTENTION TO TREAT”
PRINCIPLE, THAT IS, ONCE
RANDOMIZED, ALWAYS
ANALYZED – IS TO BE
ST...
NET CHANGE MEASUREMENT
I0
I1R0
R1
RELATIVE
CHANGE
FINAL SURVEYBASE-LINE
RISK
FACTOR
LEVEL
MULTIVARIATE
REGRESSION MODEL
• FORMULA:
Y = AGE + TIME1 +TIME2
+(COMMUNITY * TIME1)
+(COMMUNITY * TIME2)
FACTORS AFFECTING THE
EVALUATION:
1. DELAY OF THE DEVELOPMENT OF
THE RISK FACTORS HINDERS THE
EVALUATION
1. INTENSITY AND ...
THE SUCCESS OF CIT
1. THE SOCIETAL CONDITIONS AND
ENVIRONMENT
2. AVAILABILITY OF THE OTHER HELPING
SOCIAL HEALTH STRUCTURE...
LIMITATIONS-1
• THE RANDOMIZATION CAN NOT
BE ACHIEVED STRICTLY
The sampling method may be
having inherent error or the
sam...
LIMITATIONS-2
• CHANGES IN MORTALITY AND
MORBIDITY TAKE SEVERAL YEARS
TO OCCUR
Though it is true to larger extent
particul...
EFFECT OF IMMIGRATION INTO
AND EMIGRATION
• IMMIGRATION INTO AND EMIGRATION
FROM ANY OF THE TWO COMMUNITIES
UNDER TRIAL WI...
PERSONAL EXPERIENCE
COMMUNITY FLUORIDATION
FOR DENTAL CARIES 1990
• START / DURATION: 1992,
5 YEARS
• POPULATION: 8000, SH...
NORTH KARELIA PROJECT
• START / DURATION: 1972;
10YEARS INTERVENTION.
• POPULATION: 180000
INHABITANTS, AGES 25–59
YEARS.
...
CORONARY RISK FACTOR
STUDY (CORIS)
• START / DURATION: 1979; 4 YEARS
OF INTERENTION.
• POPULATION: 11700 WHITE
PERSONS, AG...
STANFORD FIVE CITY PROJECT
• START / DURATION: 1980;
5 YEARS INTERENTION.
• POPULATION: 122800, AGES
12 – 74 YEARS.
• INTE...
MINNESOTA HEART HEALTH
PROGRAM
• START / DURATION: 1980: 5 – 6
YEARS OF INTERVENTION.
• POPULATION: 231000 ADULTS.
• INTER...
PAWTUCKET HEART
HEALTH STUDY
• START / DURATION: 1981,
7 YEARS INTERVENTION.
• POPULATION: 72000 WORKING
CLASS PEOPLE.
• I...
CONCLUSIONS
• DUE TO OUR INTERVENTIONS,
REDUCTION IN HARMFUL
LIFESTYLES/RISK FACTORS
WILL OCCUR THEREBY
LEADING TO THE RED...
REFERENCES
• Brian Mac Mahan - Epidemiology:
principles & methods
• Roger Detels, James Mc Even-Oxford
Text Book of Public...
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Community intervention trials

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  • Author profile :-After medical graduation, worked for 17 years in the field as primary care physician in primary health centres, area hospitals, mobile medical units, cholera combat team, filarial control project, casualty department, divisional secondary care hospitals Then completed post graduation in public health medicine/preventive &social medicine &epidemiology and teaching medical graduates and post graduates, nursing students, physiotherapy students, primary care personnel for the last 15 years. At present ,working as Professor & Head of the department of Community medicine & Epidemiology contributing to the cause of epidemiological spread and growth in India as Indian super course epidemiology developer . Other THIRTEEN super course lectures of author can be accessed at www. pitt.edu/~super1/faculty/lecturers/htm
  • Intervention trials are usually of two types. Primary preventive type of interventions which can be done on communities as a whole (community intervention trials) and Secondary preventive therapeutic type of studies will be mostly carried out on the individuals or patients in hospital setting clinical trials)
  • Here the investigator, by means of some intervention verifies the causal association , hence an interventional study ,not just an observation as in analytical studies. . Here, to make the trials more scientific and accurate, the study population is randomized (variation is minimized) and controlled (Biases, the systemic errors during the study are minimized or avoided) by various means, hence an experimentation.
  • . This can be best achieved through the public health approach of modifying the behavior/lifestyles of the communities as a whole in the right direction. But this task is very difficult as it requires, not only altering the lifestyles of the people but also maintaining and promoting them. The goal of any community intervention trial is promotion of peoples’ health as a whole
  • Reduction in risk factors will have a large impact on the health status of a community. Change to healthier lifestyle by high-risk groups will also change the behavior of other members of the society. Interventions aimed and focused at specific diseases may also affect the incidence or course of other diseases. Health activities in communities enhance the confidence in the people and thereby their involvement and acceptance.
  • . TO MEASURE NET CHANGES IN 4.Means and prevalences of risk factor/s 5. Specific and total mortality rates, 6. Premature deaths, 7 .Specific morbidity, 8. Total morbidity and 9 .Disability rates . Net changes (reductions are expected) in base-line levels( measured at the middle and terminal phase of the intervention)
  • Community is the ideal setting as all events of life will occur in it and the secondary social structures like schools, churches, play grounds, health facilities, youth clubs etc will be available to help during intervention for motivation to bring about attitudinal change and for applying intervention measure on large scale.
  • He has to select intervention communities as they are and compare with the other already existing communities or with the national population as reference population.
  • Intervention and reference communities may be different and distant with each other. It is desirable to have both these communities in close proximity not only for the sake of practical feasibility for conducting the trial but also as it will enhance the sharing the commonness of territory, mortality pattern, morbidity pattern, fertility pattern, customs ,secular trends etc. .
  • Sometimes, several intervention and reference communities may be embedded in the whole country or region and their test results are compared.
  • Thus these designs will help in reducing the biases and increase the validity of the trial and allow for generalization to similar populations and for policy formulations. Presence of medical services and medical treatment also should not differ in the two populations. Improved medical treatment in one community will have a positive influence on morbidity and mortality thereby affects the endpoints and evaluation.
  • These can be a country as a whole, or a region, or a specific population like for e.g. school children, infants or cardiac patients for whom the application of the trial results will be beneficial. There may be initial differences in these populations itself. They may contain urban areas, rural areas, people with different socio-economic status, living in different places with varying geographical and seasonal characteristics and having different life-styles. But these areas or regions may also be inter-related in some aspects.
  • . Urban & rural divisions, People with different socio-economic status, People living in different places with varying geographical and seasonal characteristics People having different life-styles. Availability Of helping structures like schools, churches, play grounds, health facilities, youth clubs .
  • .Means and prevalences of risk factor/s . Specific and total mortality rates, . Premature deaths, .Specific morbidity, Total morbidity and .Disability rates . of the both the populations must be prepared and kept ready for future evaluation and interpretation.
  • It includes the .five phases of social, epidemiological, behavioral/environmental, and educational/organization administration/policy diagnosis .
  • The endpoints i.e. Outcomes are to be measured simultaneously in both the communities. The total disease reduction is most welcome rather than decrease in one or two diseases’ incidences.
  • Independent samples without much of age, gender, socioeconomic status differences are randomly selected and surveyed. An additional survey has to be carried out after some years to know about the persistence of the altered behavioral practice.
  • Variations can occur during the collection, testing, storage of samples for measuring the biochemical outcomes, if they are collected differently, tested differently and by different persons.. It is always wise to compare the results with some other external or internal laboratories which are standardized as external and internal controls for cross checking Seasonal variations can also occur in risk factor levels and if not considered, will cause serious lapses in measurement. Hence collection, storage, testing of samples should be done in a standardized manner that too at the same time to reduce seasonal variations and observer
  • When their risk has reached the upper limits and stagnated (ceiled), it leads either to an over or under estimation of the reality. in this situation the multivariate model will be very useful.
  • 3. Seasonal trends in diseases , behavioral styles, and geographical differences have to be taken into account during analysis and evaluation. 4. 5. The specific and total mortality in both the populations has to be pinpointed at the beginning of the trial as it serves as a benchmark for future evaluation
  • Once the population is allocated by randomization for intervention, all the randomized persons have to be considered for analysis and evaluation irrespective of their participation. That means, the non-response has also to be included and analyzed in similar manner along with those who have participated.
  • Classical method of Net change measurement:- Net change= percentage of change in the intervention community minus percentage of change in the reference community I o =Initial value of the outcome in intervention community I 1 =Final value of the outcome in intervention community R0=Initial value of the outcome in the reference community R1=Final value of the outcome in the reference community FORMULAE a) {(I 1 – I 0 ) / I 0 } - {(R 1 – R 0 ) / R 0 } = ( I 1 / I 0 ) - ( R 1 / R 0 ) b) {(I 1 – R 0 ) / I 0 X R 1 } – 1 (Direct confidence interval estimations). c) {(I 1 – I 0 – R 1 ) / R 0 } + 1 (When reference population is considered as base level)
  • Y = Is linear regression : Continuous risk factor like systolic BP, cholesterol in logistic regression: dichotomous (Like smoking, hypertension). Age = Age of individual in years at the time of observation. Community = Intervention or Reference. Time 1 = Sample at midtime or other sample. Time 2 = Final sample (after intervention) or other. The interaction terms (multiplicative terms of community x Time 1 and multiplicative terms of community x Time 2 ) represent the intervention effect at midtime and after the intervention period).
  • . Variations (seasonal, locality ,initial differences) in health indicators affect the evaluation and .Structural and social context of the intervention community also decides the evaluation procedure.. Last but not the least, there is no general agreement on the measurement of the impact
  • a) Availability of the other helping social health structures like hospitals, health oriented activity groups, health facilities, churches, playgrounds and voluntary organizations facilitate in applying intervention and also in monitoring and evaluation. b) Positive preventive climate, if available, is very much beneficial and if not available, it has to be created by means of prior community sensitization. c) the need for the trial must be felt by the community as a dire necessity e.g. any public health problem causing high morbidity, mortality or disability as community participation will be maximum in those circumstances, even though this factor may lead to bias during the sampling for the study. d)Practical feasibility, financial and time constraints are to be met prior to the commencement of the trial.
  • Changes after intervention do not guarantee the health improvement--- Though there is no guarantee of health improvement in objective terms, subjective improvement in health knowledge is very often observed and it is definitely a plus point for any community.
  • These changes in biological markers, if the markers are specific to a disease will serve as outcome assessment indicators at an earlier date. To some extent morbidity pattern can be predicted in advance.
  • subjective bias . Measurement of subjective end-points like symptoms, signs and relief of pain will cause much difficulty during evaluation due to subjective bias. Response rate- Ideally at least 70% response is to be achieved in both the communities. If the non-response is high ,it has to be minimized to the maximum possible extent. The increase in response should be equal in both the communities or else the response bias creeps into the trial.
  • DESIGN: THE ENTIRE POPULATION OF SHEILANAGAR, 8000 POPULATION WAS INCLUDED IN THE INTERVENTION EVALUATION: PREINTERVENTION READINGS OF FLOURIDE SCHOOL CHILDREN SURVEY 11% COMMUNITY SURVEY13% RESULTS: AFTER5 YEARS, SCHOOL SURVEY 1.8%, COMMUNITY 4% ( T.A.V.N RAJU ET ALL , DEPT OF COMMUNITY MEDICINE, ANDHRA MEDICAL COLLEGE, VISAKHAPATNAM
  • DESIGN : ONE INTERVENTION, ONE(LATER TWO) REFERENCE GROUP(S). EVALUATION : THREE(LATER FIVE) INDEPENDENT SAMPLES. RESULTS: AFTER 20 YEARS STILL A DECLINE IN RISK FACTORS OBSERVED; INITIALLY STRONGER DECLINE IN TOTAL MORTALITY, AFTER 15 YEARS SIMILAR AS REST OF FINLAND. (Vartiainen et. Al. 1994)
  • DESIGN : TWO INTERVENTION GROUPS(ONE LOW INTENSITY, ONE HIGH INTENSITY INTERVENTION), ONE REFERENCE GROUP. EVALUATION:I NDEPENDENT ANDCOHORT SAMPLES BEFORE AND AFTER INTERVENTION, SURVEYS AT 4 YEAR INTERVALS PLANNED.. RESULTS :LOW INTENSITY INTERVENTION ACHIEVES AS MUCH REDUCTION OF RISK FACTORS AS HIGH INTENSITY, MORTALLY EVALUATION PENDING. ROOSOUW ET. AL. 1993)
  • DESIGN : TWO INTERVENTION GROUPS, TWO REFERENCE GROUPS,ONE FOR MORTALITY AND MORBIDITY TREND MONITORING ,BASED ON THREE COMMUNITY STUDY. EVALUATION :2 YEAR DISTANCES INDEPENDENT AND COHORT SAMPLES.. RESULTS :REDUCTION AT SOME RISK FACTORS AND TOTAL MORTALITY RISK SCORE –15%, NOT SIGNIFICANT IN INDEPENDENT SAMPLES. (FARQUHAR ET AL. 1990)
  • DESIGN : THREE INTERVENTION GROUPS, THREE REFERENCE GROUPS,MATCHED ON SIZE, TYPE AND DISTANCE FROM MINNEAPOLIS. EVALUATION :INDEPENDENT AND COHORT SAMPLES. RESULTS :NOT SUCCESSFUL IN REDUCING RISK FACTORS MORE THAN FAVOURABLE SECULAR TRENDS, MORTALITY EVALUATION PENDING (LUEPKER ET AL. 1994 )
  • DESIGN :ONE INTERVENTION GROUP, ONE REFERENCE GROUP. EVALUATION :FORMATIVE AND PROCESS EVALUATION, SIX BIENNAL HOUSEHOLD SURVEYS. ( CARLETON ET AL. 1995)
  • But sometimes the change seen may be minimal or even contrasting. Due to the difficulty in sustenance of the altered behavior and other problems, only very few community trials are successful and there is very little change or reduction seen in risk factor levels/morbidity /mortality rates (expected outcomes).
  • Transcript of "Community intervention trials"

    1. 1. COMMUNITY INTERVENTION TRIALS AUTHOR Dr. A. K. AVASARALA MBBS, M.D. PROFESSOR & HEAD DEPT OF COMMUNITY MEDICINE & EPIDEMIOLOGY PRATHIMA INSTITUTE OF MEDICAL SCIENCES, KARIMNAGAR, A.P.. INDIA: +91505417 avasarala@yahoo.com
    2. 2. PROMPT • I WISH TO DEVELOP AN EPIDEMIOLOGY COURSE FOR TEACHING, AS THERE IS GOOD RESPONSE, NATIONALLY AND INTERNATIONALLY FROM THE FACULTY TEACHING EPIDEMIOLOGY, FOR MY PREVIOUS THIRTEEN EPIDEMIOLOGY LECTURES
    3. 3. LEARNING OBJECTIVES 1. READER IS EXPECTED TO LEARN THE NATURE & SCOPE OF COMMUNITY INTERVENTIONS 2. THE PRECAUTIONS AND STEPS IN CONDUCTING COMMUNITY TRIALS 3. ABLE TO ANALYSE AND INTERPRET THE RESULTS
    4. 4. PERFORMANCE OBJECTIVES • READER CAN DESIGN AND PERFORM COMMUNITY INTERVENTION TRIALS • HE CAN PROMOTE THE HEALTH OF THE COMMUNITY AS A WHOLE BY RISK FACTOR REDUCTION TRIALS
    5. 5. TYPES • PRIMARY PREVENTIVE TYPE (COMMUNITY INTERVENTION TRIALS (CIT)
    6. 6. NATURE OF STUDIES • INTERVENTION STUDIES • NOT JUST OBSERVATIONS • EXPERIMENTATIONS
    7. 7. COMMUNITY INTERVENTION TRIALS (CIT ) • THE MAIN PURPOSE IS TO REDUCE THE OCCURRENCE OF DISEASES AND DEATHS EARLY IN LIFE IN THE WHOLE COMMUNITY, HENCE THE NAME.
    8. 8. WHY CIT ? . THE HEALTH STATUS OF A COMMUNITY. CHANGE TO HEALTHIER LIFESTYLE BY HIGH-RISK GROUPS CHANGE THE BEHAVIOR OF OTHER MEMBERS OF THE SOCIETY INTERVENTIONS AIMED AND FOCUSED AT SPECIFIC DISEASES HEALTH ACTIVITIES IN COMMUNITIES THE CONFIDENCE IN THE PEOPLE AND THEREBY THEIR INVOLVEMENT AND ACCEPTANCE REDUCTION IN RISK FACTORS THE INCIDENCE OR COURSE OF OTHER DISEASES. IMPACT ON LEADS TO AFFECT ENHANCE
    9. 9. GENERAL OBJECTIVES •TO INCREASE HEALTH KNOWLEDGE OF THE WHOLE COMMUNITY , • TO DEVELOP POSITIVE AND RIGHT ATTITUDE •IN THE COMMUNITY • TO INCREASE THE PRACTICE OF POSITIVE HEALTH BEHAVIOR OF THE WHOLE COMMUNITY •THEREBY PREVENTING EARLY DISEASES AND DEATHS IN THE COMMUNITY H E A L T H E D U C A T I O N
    10. 10. SPECIFIC OBJECTIVES TO MEASURE VERIFIABLE CHANGES IN: 1. HEALTH KNOWLEDGE IMPROVEMENT 2. ATTITUDE 3. BEHAVIOR
    11. 11. STEPS OF CONDUCTING CIT 1. SETTING 2. STUDY DESIGN 3. INTERVENTION METHODS 4. EVALUATION OF INTERVENTION 5. LIMITATIONS OF STUDY
    12. 12. IDEAL SETTING • COMMUNITY IS THE IDEAL SETTING
    13. 13. STUDY DESIGN • QUASI - EXPERIMENTAL TYPE THE INVESTIGATOR WILL NOT BE HAVING AS MUCH OF A CHANCE OF RANDOM ALLOCATION OF THE INDIVIDUALS TO THE TWO GROUPS AS IN CLINICAL TRIALS.
    14. 14. SELECTION OF REFERENCE AND INTERVENTION POPULATIONS • DESIRABLE TO HAVE ALMOST IDENTICAL REFERENCE AND INTERVENTION POPULATIONS TO GET THE VALID RESULTS OUT OF COMMUNITY TRIALS.
    15. 15. NESTED OR EMBEDDED DESIGN Pooled intervention REFERENCE POPULATION
    16. 16. EMBEDDED DESIGN EMBEDDED TYPE WILL HELP • IN REDUCING SECULAR DIFFERENCES • IN REDUCING CONFOUNDING BIAS AS THE BOTH KNOWN AND UNKNOWN VARIABLE FACTORS WILL BE EQUALLY DISTRIBUTED IN BOTH THE POPULATIONS.
    17. 17. REFERENCE POPULATION THE ONE WITH WHICH THE RESULTS OBTAINED FROM THE TRIAL ON THE INTERVENTION POPULATION ARE COMPARED, ANALYZED, INTERPRETED AND UTILIZED FOR PREPARING PUBLIC HEALTH POLICY.
    18. 18. INTERVENTION POPULATION • THE EXPERIMENTAL POPULATION RANDOMLY SELECTED FROM A COUNTRY OR REGION AND ALMOST IDENTICAL AND COMPARABLE WITH THE REFERENCE (CONTROL) POPULATION IN POSSESSING ALL ITS CHARACTERISTICS.
    19. 19. UNDERSTANDING SOCIETAL CONDITIONS • COMMONNESS OF TERRITORY, • MORTALITY PATTERN, • MORBIDITY PATTERN, • FERTILITY PATTERN, • CUSTOMS , • SECULAR TRENDS
    20. 20. COLLECTING BASE LINE INFORMATION • PREPARING THE BASE LINE LEVELS OF RISK FACTORS, MORTALITY RATES
    21. 21. INTERVENTION CONCEPT • IDEA IS TO BRING ABOUT THE ATTITUDINAL CHANGE IN THE PEOPLE TO ALTER THEIR NEGATIVE LIFE STYLES AND TO SUSTAIN. • THIS CAN BE ACHIEVED BY MEANS OF THE FOLLOWING SOCIAL SKILL LEARNING TECHNIQUES.
    22. 22. INTERVENTION BY SOCIAL COGNITION/LEARNING SOCIAL COGNITION/LEARNING WHEREIN THE CHANGE OF BEHAVIOR CAN BE ACHIEVED THROUGH INTENSIVE EXPOSURE TO IMPORTANT MODELS LIKE POP STARS, PLAYERS.
    23. 23. INTERVENTION BY REASONED ACTION AND PLANNED BEHAVIOR WHERE THE CHANGE CAN BE BROUGHT ABOUT BY ADAPTING THE INFORMATION GIVEN BY CREDITABLE PERSON FIRST AND SUSTAINING IT BY SELF MANAGEMENT LATER I.E. BY LEARNING THE NECESSARY SKILLS.
    24. 24. INTERVENTION BY PERSUASIVE COMMUNICATION • CONTINUOUS PERSUASIVE COMMUNICATION TO THE PEOPLE THROUGH MASS MEDIA LIKE MOVIES, TELEVISION ETC TO CONVINCE THEM TO ADOPT POSITIVE LIFE STYLES CAN ALSO BRING ABOUT A CHANGE IN LIFE STYLE.
    25. 25. PRECEDE-PROCEED MODEL INTERVENTION The PRECEDE process • Predisposing, • Reinforcing, and • Enabling • Constructs in • Educational-environmental • Diagnosis and • Evaluation) PROCEED process follows with implementation, process, and impact and outcome evaluation.
    26. 26. SOCIAL MARKETING INTERVENTION • PREVENTIVE HEALTH SERVICES ARE THE PRODUCTS TO BE MARKETED AND THE TARGET AUDIENCE, COSTS AND BENEFITS HAVE TO BE DEFINED. • PROPER MESSAGES HAVE TO BE DEVELOPED AND EFFECTIVE CHANNELS FOR ACCEPTANCE HAVE TO BE SELECTED.
    27. 27. EVALUATION OF INTERVENTION 1. ENDPOINTS TO BE MEASURED 2. CHANGES IN KNOWLEDGE, ATTITUDE AND PRACTICE 3. MEANS AND PREVALENCES OF RISK FACTORS 4. SYMPTOMS/SIGNS/PAIN REDUCTION 5. SPECIFIC MORBIDITY (OBTAINED FROM PRACTITIONERS, HOSPITALS, AVAILABILITY OF MEDICAL SERVICES AND TREATMENT) 6. SPECIFIC MORTALITY RATES OF THE MOST COMMON DISEASES 7. TOTAL MORTALITY IN THE BOTH COMMUNITIES
    28. 28. EVALUATION METHODS • POPULATION SURVEYS ARE CARRIED OUT BOTH IN THE REFERENCE AND INTERVENTION POPULATIONS SIMULTANEOUSLY THRICE I.E. BEFORE, DURING AND AFTER THE INTERVENTION.
    29. 29. TECHNIQUES OF MEASUREMENT • QUESTIONNAIRES – ORAL WRITTEN, OR COMPUTERIZED ONES ARE USED DURING THE SURVEYS • *ANALYTICAL METHODS – LABORATORY TESTS FOR PHYSICAL AND BIOCHEMICAL PARAMETERS BY TRAINED PERSONNEL DONE BEFORE AFTER CIT TO AVOID OBSERVER VARIATION
    30. 30. ROSENTHAL EFFECT • THE INDIVIDUAL’S NATURE OR PREFERENCE TO ENHANCE OR REDUCE THE VALUE OF THE ENDPOINT WHILE TESTING OR READING THE LABORATORY FINDINGS BECAUSE OF HIS PERSONALITY INFLUENCE HAS ALSO TO BE TAKEN CARE OFF.
    31. 31. CEILING EFFECT • CEILING EFFECT IS SAID TO BE PRESENT IN THE COMMUNITY WHEN A PART OR WHOLE OF THE COMMUNITY POSSESSES PERSONS AT HIGH RISK.
    32. 32. PRECAUTIONS: 1. NET CHANGES ARE MEASURED UNIFORMLY IN A STANDARDIZED AND SIMILAR MANNER IN BOTH THE REFERENCE (CONTROL) AND INTERVENTION POPULATIONS 2. INITIAL DIFFERENCES BETWEEN THE TWO POPULATIONS HAVE TO BE GIVEN DUE CONSIDERATION. THESE MAY BE DUE TO CHANCE OR REGRESSION TO THE MEAN.
    33. 33. INTENTION TO TREAT PRINCIPLE • THE “INTENTION TO TREAT” PRINCIPLE, THAT IS, ONCE RANDOMIZED, ALWAYS ANALYZED – IS TO BE STRICTLY FOLLOWED
    34. 34. NET CHANGE MEASUREMENT I0 I1R0 R1 RELATIVE CHANGE FINAL SURVEYBASE-LINE RISK FACTOR LEVEL
    35. 35. MULTIVARIATE REGRESSION MODEL • FORMULA: Y = AGE + TIME1 +TIME2 +(COMMUNITY * TIME1) +(COMMUNITY * TIME2)
    36. 36. FACTORS AFFECTING THE EVALUATION: 1. DELAY OF THE DEVELOPMENT OF THE RISK FACTORS HINDERS THE EVALUATION 1. INTENSITY AND DENSITY OF INTERVENTION DETERMINES THE EVALUATION STRATEGY 1. STATISTICAL POWER OF THE SAMPLES DETERMINES EVALUATION
    37. 37. THE SUCCESS OF CIT 1. THE SOCIETAL CONDITIONS AND ENVIRONMENT 2. AVAILABILITY OF THE OTHER HELPING SOCIAL HEALTH STRUCTURES 3. POSITIVE PREVENTIVE CLIMATE 4. THE NEED FOR THE TRIAL MUST BE FELT BY THE COMMUNITY AS A DIRE NECESSITY 5. PRACTICAL FEASIBILITY, FINANCIAL AND TIME CONSTRAINTS
    38. 38. LIMITATIONS-1 • THE RANDOMIZATION CAN NOT BE ACHIEVED STRICTLY The sampling method may be having inherent error or the sampled communities may be having inherent differences which can, of course, be minimized with difficulty.
    39. 39. LIMITATIONS-2 • CHANGES IN MORTALITY AND MORBIDITY TAKE SEVERAL YEARS TO OCCUR Though it is true to larger extent particularly with the non-infectious diseases, biochemical/ risk factors changes may be seen comparatively earlier in the intervention community.
    40. 40. EFFECT OF IMMIGRATION INTO AND EMIGRATION • IMMIGRATION INTO AND EMIGRATION FROM ANY OF THE TWO COMMUNITIES UNDER TRIAL WILL AFFECT THE EVALUATION AND TRIAL OBJECTIVES. • ONLY THE LIVING PART OF THE COMMUNITY CAN SERVE AS THE USEFUL DENOMINATOR FOR CORRECT ASSESSMENT. HENCE MIGRATION FACTOR HAS TO BE GIVEN DUE CONSIDERATION.
    41. 41. PERSONAL EXPERIENCE COMMUNITY FLUORIDATION FOR DENTAL CARIES 1990 • START / DURATION: 1992, 5 YEARS • POPULATION: 8000, SHIELANAGAR, VISAKHAPATNAM, • INTERVENTION: FLOURIDATION OF MUNICIPAL WATER SUPPLIES.
    42. 42. NORTH KARELIA PROJECT • START / DURATION: 1972; 10YEARS INTERVENTION. • POPULATION: 180000 INHABITANTS, AGES 25–59 YEARS. • INTERVENTION: COMPREHENSIVE COMMUNITY INTERVENTION, REDUCTION OF ARDIOVASCULAR RISK FACTORS.
    43. 43. CORONARY RISK FACTOR STUDY (CORIS) • START / DURATION: 1979; 4 YEARS OF INTERENTION. • POPULATION: 11700 WHITE PERSONS, AGES 15 – 64 YEARS. • INTERVENTION: COMPREHENSIVE COMMUNITY INTERVENTION, SMALL MASS MEDIA AND INTERPERSONAL (HIGH INTENSE) INTERVENTION; REDUCE CHOLESTOAL BP, SMOKING STRESS, INCREASE PHYSICAL ACTIVITY.
    44. 44. STANFORD FIVE CITY PROJECT • START / DURATION: 1980; 5 YEARS INTERENTION. • POPULATION: 122800, AGES 12 – 74 YEARS. • INTERVENTION: COMPREHENSIVE COMMUNITY INTERVENTION, REDUCE CHOLESTEROL, BP, SMOKING, WEIGHT, INCREASE PHYSICAL ACTIVITY.
    45. 45. MINNESOTA HEART HEALTH PROGRAM • START / DURATION: 1980: 5 – 6 YEARS OF INTERVENTION. • POPULATION: 231000 ADULTS. • INTERVENTION: IMPROVE HEALTH BEHAVIOUR, REDUCE CHOLESTROL, 7 MG/DL, BP 2MMHG, SMOKING 3%, INCRESE PHYSICAL ACTIVITY 50KCAL /DAY, REDUCE CARDIOVASCULAR DISEASE MOBIDITY AND MORTALITY 15%.
    46. 46. PAWTUCKET HEART HEALTH STUDY • START / DURATION: 1981, 7 YEARS INTERVENTION. • POPULATION: 72000 WORKING CLASS PEOPLE. • INTERVENTION: COMMUNITY ACTIVATION
    47. 47. CONCLUSIONS • DUE TO OUR INTERVENTIONS, REDUCTION IN HARMFUL LIFESTYLES/RISK FACTORS WILL OCCUR THEREBY LEADING TO THE REDUCTION IN MORBIDITY, MORTALITY OR DISABILITY RATES.
    48. 48. REFERENCES • Brian Mac Mahan - Epidemiology: principles & methods • Roger Detels, James Mc Even-Oxford Text Book of Public Health • Maxcy-Rosenau-Last, Public Health & Preventive medicine • Brett & Cassens- Public Health Medicine,National Student Series.
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