Dental Epidemiology II Flashcards
Dental Epidemiology is the scientific study of ___ and ___ of oral health-related events and ___ in specified human ____ and the application of this study to ___l of oral health related problems. It seeks to answer three broad questions:
Dental Epidemiology is the scientific study of distribution and determinants of oral health-related events and disease in specified human populations and the application of this study to control of oral health related problems. It seeks to answer three broad questions:
Three general questions
1 ___ __ ___ experience oral disease and related conditions?
2___ ___ ___ to the onset of oral disease?
3 __ __ __ __ to improve the oral health of populations?
Three general questions 1 Which population groups experience oral disease and related conditions? 2 What factors contribute to the onset of oral disease? 3 What can be done to improve the oral health of populations?
Oral Epidemiologists investigate… • Dental___, • Oral___ and ___ ___, • ___diseases, ___and dentofacial ____, • ___ __ affect/affected by oral health
Oral Epidemiologists investigate… • Dental caries, • Oral cancer, oral mucosal lesions, • Periodontal diseases, craniofacial and dentofacial anomalies, • Systemic diseases affect/affected by oral health
- Water fluoridation (Morb Mortal Wkly Rep. 1999 Apr 2;48(12):241-3): One of the Ten Great Public Health Achievements – United States, 1900 – 1999. Fluoridation of drinking water began in 1945 and in 1999 reaches an estimated 144 million persons in the United States. Fluoridation safely and inexpensively benefits both children and adults by effectively preventing tooth decay, regardless of socioeconomic status or access to care. Fluoridation has played an important role in the reductions in tooth ___ (40%-70% in children) and of tooth___ in adults (40%-60%) (Burt BA, Eklund SA. Dentistry, dental practice, and the community. Philadelphia, Pennsylvania: WB Saunders Company, 1999:204-2)
- Water fluoridation (Morb Mortal Wkly Rep. 1999 Apr 2;48(12):241-3): One of the Ten Great Public Health Achievements – United States, 1900 – 1999. Fluoridation of drinking water began in 1945 and in 1999 reaches an estimated 144 million persons in the United States. Fluoridation safely and inexpensively benefits both children and adults by effectively preventing tooth decay, regardless of socioeconomic status or access to care. Fluoridation has played an important role in the reductions in tooth decay (40%-70% in children) and of tooth loss in adults (40%-60%) (Burt BA, Eklund SA. Dentistry, dental practice, and the community. Philadelphia, Pennsylvania: WB Saunders Company, 1999:204-2)
- Tooth loss: the final Healthy People 2010 report highlighted that among the several oral health objectives (Objective 21) that are part of this government sponsored, public health initiative, the proportion of adults aged 35–44 years with __ __ __ ___ due to caries or periodontal disease (objective 21-3) increased by 26.7% between 1988–94 and 1999–2004, from 30% to 38%, moving toward the 2010 target of 40%. During the same period, the proportion of adults aged 65–74 years who experienced ___ __ ___ (objective 21-4) declined by 17.2%, from 29% to 24%, moving toward the 2010 target of 22%.
- Tooth loss: the final Healthy People 2010 report highlighted that among the several oral health objectives (Objective 21) that are part of this government sponsored, public health initiative, the proportion of adults aged 35–44 years with no permanent tooth loss due to caries or periodontal disease (objective 21-3) increased by 26.7% between 1988–94 and 1999–2004, from 30% to 38%, moving toward the 2010 target of 40%. During the same period, the proportion of adults aged 65–74 years who experienced complete tooth loss (objective 21-4) declined by 17.2%, from 29% to 24%, moving toward the 2010 target of 22%.
What is an Index? A ____ way to describe a specific ___ or ____. In dentistry, a common used index is the ____ index that has been used in dentistry for over 70 years
What is an Index? A uniform way to describe a specific characteristic or problem. In dentistry, a common used index is the DMFT index that has been used in dentistry for over 70 years
The DMFT index is a:
- Good indicator of__ __ __k[s
- ____
- Lower scores ___ oral health
- ____ and records past history
- Describes the prevalence of __ __ in a particular individual or population
- ___ expression the caries prevalence
The DMFT index is a: • Good indicator of dental health status • Reliable • Lower scores better oral health • Cumulative and records past history • Describes the prevalence of dental caries in a particular individual or population • Numeric expression the caries prevalence
Limitations of the DMFT index:
- Assumes that all ____teeth were carious – this can result in an ____ of caries experience
- Cannot assess if the tooth has previously been____ because of caries, orthodontic or periodontal reasons
- Can ____ caries experience in patients with ____ restorations
- DMFT scores often are ___ – scores at the___ of the distribution and ____ to identify the susceptible population
- Variations on ___ for surveys
- Variation on __ ___
For deciduous teeth dmft index is written in __ __
Limitations of the DMFT index: • Assumes that all filled teeth were carious – this can result in an overestimation of caries experience • Cannot assess if the tooth has previously been extracted because of caries, orthodontic or periodontal reasons • Can overestimate caries experience in patients with preventive restorations • DMFT scores often are skewed – scores at the extreme of the distribution and difficult to identify the susceptible population • Variations on sampling for surveys • Variation on data collection For deciduous teeth dmft index is written in lower case
By definition, causality is a relationship that describes and analyzes __- and ____
The epidemiologist Kenneth Rothman defines causation in his book as “An event, condition, or characteristic __ __ the ___ ___ __ __ ___”
By definition, causality is a relationship that describes and analyzes cause and effect.
The epidemiologist Kenneth Rothman defines causation in his book as “An event, condition, or characteristic without which the disease would not have occurred”
Remember!!
- “Cause” is different from ___ of exposure to health outcomes
- “Correlation __ __ imply causation
Remember!!
- “Cause” is different from association of exposure to health outcomes
- “Correlation does not imply causation
In the past, a British medical statistician, Sir Bradford Hill (1897-1991) described a set of criteria that are known as the “___ of ___”. In other words, for a relationship to be causal it should meet the described criteria.
In the past, a British medical statistician, Sir Bradford Hill (1897-1991) described a set of criteria that are known as the “Tenets of Causality”. In other words, for a relationship to be causal it should meet the described criteria.
Keep in mind this short list when you are reading a scientific article or evaluating is a relationship is causal or not!!
Temporality –___ has preceded the ____ in time;
Consistency – reported from ___ ___
Strength – the stronger the association the less likely it is due to a___ ___
Biologic gradient – follows a currently___ ___ process
Specificity – ___ ___? Many effects?
Plausibility- with ___ ___
Coherence – compatible__ __ and ___
Experimental Evidence – condition can be ___
Analogy – consider the effect of __ ___
Keep in mind this short list when you are reading a scientific article or evaluating is a relationship is causal or not!!
Temporality – exposure has preceded the disease in time;
Consistency – reported from different investigations;
Strength – the stronger the association the less likely it is due to a biasing factor;
Biologic gradient – follows a currently accepted pathobiologic process
Specificity – one effect? Many effects?
Plausibility- with existing knowledge
Coherence – compatible existing theory and knowledge
Experimental Evidence – condition can be altered
Analogy – consider the effect of similar factors
- Risk
“The ____ that an ___ will ___” (John Last. A Dictionary of Epidmeiology).
For example, what is the probability that an individual living in a non-fluoridated community will develop caries? Is this probability higher when compared to an individual living in a fluoridated community?
Based on this example and from what we know from scientific evidence, we can conclude that an individual living in a non-fluoridated is at a greater risk for caries disease when compared to individuals that live in a fluoridated community.
- Risk
“The probability that an event will occur” (John Last. A Dictionary of Epidmeiology).
For example, what is the probability that an individual living in a non-fluoridated community will develop caries? Is this probability higher when compared to an individual living in a fluoridated community?
Based on this example and from what we know from scientific evidence, we can conclude that an individual living in a non-fluoridated is at a greater risk for caries disease when compared to individuals that live in a fluoridated community.
- Incidence
Frequency of a __ __during a ___ ___ of ___
___ ___ __
___
__ __
__ __
- Incidence
Frequency of a new event during a specific period of time.
newly developed disease
mortality
case fatality
recurrent disease
- Prevalence
Measures the frequency of an ___ ___
- ___ prevalence: at a __ in ___
- ___ prevalence: during a __ ___
- ___ prevalence: ___ ____ frequency of an event
- Prevalence
Measures the frequency of an existing disease…
- Point prevalence: at a point in time
- Period prevalence: during a given period
- Cumulative prevalence: cumulative lifetime frequency of an event
Example:
- HIV prevalence: The number of people living with HIV—with or without a diagnosis of AIDS—at a point in time.
- HIV incidence: The number of people who become newly infected with HIV in a given period.
Example:
- HIV prevalence: The number of people living with HIV—with or without a diagnosis of AIDS—at a point in time.
- HIV incidence: The number of people who become newly infected with HIV in a given period.
Experimental:
___ __ ___
___ ___ ___
Observational
___(testing a hypothesis)
___Study (Sampling based on ___)
__ ___ Study (Sampling based on ____)
__ ___ Study
____ Study (Not testing a hypothesis)
Experimental:
Randomized Controlled Trial
Non Randomized Designs
Observational
Analytical (testing a hypothesis)
Cohort Study (Sampling based on exposure)
Case-Control Study (Sampling based on outcome)
Cross sectional Study
Descriptive Study (Not testing a hypothesis)
Randomized controlled trials
Investigator____ the exposure
Patients are assigned on a random basis to ___ or ___ groups
Randomization comes down to the fact that we need half to get dose and half to get something else
We can’t have people pick bc that would destroy the randomization
We don’t want to introduce a ___s into the study
___ and ___ protect us from this
Randomized controlled trials
Investigator assigned the exposure
Patients are assigned on a random basis to treatment or placebo groups
Below is a short video describing the randomization in a clinical trial: https://youtu.be/F42oSGNX0k8
Randomization comes down to the fact that we need half to get dose and half to get something else
We can’t have people pick bc that would destroy the randomization
We don’t want to introduce a bias into the study
Randomization and blinding protect us from this
Non-randomized trials
In certain cases ___ is ___ ___ but a trial is still conducted
Non-randomized trials
In certain cases randomization is not possible but a trial is still conducted
Cohort Study
Data are obtained from groups who have been___ (smokers), or __ ___ (non-smokers), to the new technology or factor of interest (in this case cigarette smoking).
No __ of exposure is made by the researcher – it is an observational study
____ study; exposure ____ disease and it is a great study design to___ ____
___, requires __ __ follow-up and time
____ __ __ ___ can be a challenge
Cohort Study
Data are obtained from groups who have been exposed (smokers), or not exposed (non-smokers), to the new technology or factor of interest (in this case cigarette smoking).
No allocation of exposure is made by the researcher – it is an observational study
Prospective study; exposure precedes disease and it is a great study design to generate hypothesis
Expensive, requires long-term follow-up and time
Loss to follow-up is can be a challenge
Case-Control Studies
Examines __ ___ in relation to a disease;
Subjects are defined as ___ and ___
Exposure ____ are compared.
____ study; challenging __ ___
Cost-effective way to examine____ disease (when compared to cohort studies)
Sometimes challenging for subjects to____ past exposures and error in answering questionnaires can be a serious limitation in this study design
Case-Control Studies
Examines multiple exposures in relation to a disease;
Subjects are defined as cases and controls
Exposure histories are compared.
Retrospective study; challenging control selection
Cost-effective way to examine rare disease (when compared to cohort studies)
Sometimes challenging for subjects to recall past exposures and error in answering questionnaires can be a serious limitation in this study design
Cross-Sectional Studies
All information refers to the __ ___in t___
“___”
Measure __ ___
Can also assess the relationship between ___ __ and __ ___
___ ___ are cross-sectional studies
Cross-Sectional Studies
All information refers to the same point in time
“Snapshots”
Measure disease prevalence
Can also assess the relationship between disease prevalence and possible exposures
Population surveys are cross-sectional studies
2.1. Confounding
From the Latin “confundere”
It must be correlated with both ___ and ____
The effect measure, for example, risk is distorted because of the association of the exposure that influence the outcome of the study
Counfounding variable: A variable that is related to both ___ ___and the ____ variable of interest in a research study
Have sig effect on the response variable which confounds the explanatory variable
2.1. Confounding
From the Latin “confundere”
It must be correlated with both exposure and disease
The effect measure, for example, risk is distorted because of the association of the exposure that influence the outcome of the study
Counfounding variable: A variable that is related to both group membership and the responsible variable of interest in a research study
Have sig effect on the response variable which confounds the explanatory variable
Selection bias: It is an error that occurs because of systematic differences between the ___y ____ and the __ ___ For example, in a hospital-based case control study that only enrolls volunteers who come to a particular hospital, that population maybe very different from the general population. And why this is important? Selection bias can invalidate study results since study conclusions may not be generalizable to the general population. Common in ____ (case-control studies) and __ ___studies.
Selection bias: It is an error that occurs because of systematic differences between the study population and the general population. For example, in a hospital-based case control study that only enrolls volunteers who come to a particular hospital, that population maybe very different from the general population. And why this is important? Selection bias can invalidate study results since study conclusions may not be generalizable to the general population. Common in retrospective (case-control studies) and cross-sectional studies.
Recall bias: Also common in___ ___studies. In the figure below is an example of a case-control study collecting nutritional information from a study subject. It is of course exaggerated but when collecting detailed information from sometime in the past we can make systematic errors in recalling the information and introducing recall bias in the study!
Recall bias: Also common in case-control studies. In the figure below is an example of a case-control study collecting nutritional information from a study subject. It is of course exaggerated but when collecting detailed information from sometime in the past we can make systematic errors in recalling the information and introducing recall bias in the study!
Publication bias – when studies that show a statistically __ ___e are more likely to get accepted for publication when compared to studies that showed no difference!
Publication bias – when studies that show a statistically significant difference are more likely to get accepted for publication when compared to studies that showed no difference!
