Epidemiology - Wikipedia
distribution – should be addressed to WHO Press through the WHO web site Prevention and control of CVDs: The need for integrated and complimentary strategies .. hypertension and diabetes link CVD to renal disease. Epidemiology is the study and analysis of the distribution (who, when, and where ) and determinants of health and disease . Epidemiology research to examine the relationship between these biomarkers analyzed at the molecular level, and disease was . Case-control studies select subjects based on their disease status. Epidemiology is the study of the distribution and determinants of but also to the relationship of that number to the size of the population. public health interventions to control and prevent disease in the community.
Random error is just that: It can occur during data collection, coding, transfer, or analysis. Examples of random error include: Random error affects measurement in a transient, inconsistent manner and it is impossible to correct for random error. There is random error in all sampling procedures. This is called sampling error.
Epidemiological basis for preventive strategies
Precision in epidemiological variables is a measure of random error. Precision is also inversely related to random error, so that to reduce random error is to increase precision. Confidence intervals are computed to demonstrate the precision of relative risk estimates. The narrower the confidence interval, the more precise the relative risk estimate. There are two basic ways to reduce random error in an epidemiological study.Masonic Con 2017 - The Prevalence of Clandestine Freemasonry in the US
The first is to increase the sample size of the study. In other words, add more subjects to your study. The second is to reduce the variability in measurement in the study.
This might be accomplished by using a more precise measuring device or by increasing the number of measurements. Note, that if sample size or number of measurements are increased, or a more precise measuring tool is purchased, the costs of the study are usually increased.
There is usually an uneasy balance between the need for adequate precision and the practical issue of study cost. Systematic error[ edit ] A systematic error or bias occurs when there is a difference between the true value in the population and the observed value in the study from any cause other than sampling variability.
An example of systematic error is if, unknown to you, the pulse oximeter you are using is set incorrectly and adds two points to the true value each time a measurement is taken. The measuring device could be precise but not accurate.
Because the error happens in every instance, it is systematic. Conclusions you draw based on that data will still be incorrect.
But the error can be reproduced in the future e. A mistake in coding that affects all responses for that particular question is another example of a systematic error. The validity of a study is dependent on the degree of systematic error. Validity is usually separated into two components: Internal validity is dependent on the amount of error in measurements, including exposure, disease, and the associations between these variables.
Good internal validity implies a lack of error in measurement and suggests that inferences may be drawn at least as they pertain to the subjects under study. External validity pertains to the process of generalizing the findings of the study to the population from which the sample was drawn or even beyond that population to a more universal statement. This requires an understanding of which conditions are relevant or irrelevant to the generalization.
Internal validity is clearly a prerequisite for external validity. Pattern refers to the occurrence of health-related events by time, place, and person. Time patterns may be annual, seasonal, weekly, daily, hourly, weekday versus weekend, or any other breakdown of time that may influence disease or injury occurrence.
Personal characteristics include demographic factors which may be related to risk of illness, injury, or disability such as age, sex, marital status, and socioeconomic status, as well as behaviors and environmental exposures. Characterizing health events by time, place, and person are activities of descriptive epidemiology, discussed in more detail later in this lesson.
Epidemiology is also used to search for determinants, which are the causes and other factors that influence the occurrence of disease and other health-related events. Epidemiologists assume that illness does not occur randomly in a population, but happens only when the right accumulation of risk factors or determinants exists in an individual. They assess whether groups with different rates of disease differ in their demographic characteristics, genetic or immunologic make-up, behaviors, environmental exposures, or other so-called potential risk factors.
Ideally, the findings provide sufficient evidence to direct prompt and effective public health control and prevention measures. Health-related states or events Epidemiology was originally focused exclusively on epidemics of communicable diseases 3 but was subsequently expanded to address endemic communicable diseases and non-communicable infectious diseases.
By the middle of the 20th Century, additional epidemiologic methods had been developed and applied to chronic diseases, injuries, birth defects, maternal-child health, occupational health, and environmental health.
Then epidemiologists began to look at behaviors related to health and well-being, such as amount of exercise and seat belt use. Now, with the recent explosion in molecular methods, epidemiologists can make important strides in examining genetic markers of disease risk. Indeed, the term health-related states or events may be seen as anything that affects the well-being of a population.
In the case presented by Bhati, for example, cash incentives are used to encourage childbirth in health care institutions in India, where homebirth remains traditional.
The warning is that, despite good intentions, health promotion incentives can backfire if they lack adequate cultural sensitivity.
Emergency Response Emergencies are extreme situations Viens and Selgelid where threats to public health can be exceptionally severe.
Examples include epidemics, other natural disasters e. As noted in cases previously discussed, public health policies and practices often give rise to conflicts between the rights and liberties of individuals, on the one hand, and the goal to promote public health, on the other.
During emergencies, therefore, it may be more necessary than in other contexts to resort to liberty infringing measures. In the case of a severe epidemic, for example, social distancing measures such as isolation and quarantine might be justified despite the fact that they interfere with one of the most basic human rights, freedom of movement.
- Lesson 1: Introduction to Epidemiology
Emergencies also often put unprecedented pressure on limited resources and thus require difficult ethical decisions regarding resource allocation. Given the spectre of a future severe influenza pandemic, for example, there has been much debate about who should be given priority for resources like antivirals, vaccines, and ventilators if as may be expected need outstrips supply Verweij Emergencies, finally, also often call for urgent action.
Disease Prevention and Control - Public Health Ethics: Cases Spanning the Globe - NCBI Bookshelf
So, decisions must be made quickly, and other time-saving measures may be needed to mitigate harm. While urgent research might be needed to understand and control an epidemic caused by a novel pathogen, for example, it has been argued that the usual procedures for ethical clearance of research which can be very slow might need to be altered in the case of emergency research in particular WHO The issue of urgency is well illustrated by the case presented by Peacock and colleagues.
In the event of a major bioterrorist attack involving anthrax, it might be necessary to vaccinate large numbers of people quickly. Administration of vaccine shortly after exposure is important because anthrax vaccine provides prophylactic protection.
Because anthrax vaccine has not been tested in children, however, its use in children would require informed consent of parents according to U. In a scenario where huge numbers of children would need to be vaccinated quickly, however, going through usual informed consent processes might take too much time and perhaps lead to unrest among those waiting to be vaccinated. This motivates examination of possible ways to hasten the consent process, for example, via group information sessions rather than the usual one-on-one consent process.
While group consent procedures may facilitate more timely vaccination of children, the question is whether, or the extent to which, group sessions would ultimately compromise informed consent and whether such compromise would be justified by public health benefits.
As with other cases presented in this chapter, the case presented by Peacock et al. Quick consent to a vaccine that has not been studied in children may likewise be difficult in cases where parents are generally skeptical about vaccine safety.
The case presented by Viens and Smith explores a range of ethical challenges associated with mass evacuation that might be called for in an emergency scenario involving a major hurricane. Among other issues, this case raises questions about when evacuation should be voluntary or mandatory while the latter, like isolation and quarantine, would involve interference with freedom of movement ; whether, or how, mandatory evacuation should be enforced; whether there are duties to rescue those who refuse to comply with calls for evacuation; whether such people should be financially sanctioned if they are in fact rescued; who should be given special assistance with evacuation efforts, and how those in need of assistance should be prioritized; whether it might be acceptable to abandon unstable patients who cannot be moved or for whom movement would be excessively expensive ; whether compensation might be due to those who suffer financial or other loss as a result of compliance with calls for voluntary or mandatory evacuation; and whether there should be legal protections against price gouging of commodities like gasoline.
Conclusion This chapter has illustrated ways in which ethical issues associated with disease prevention and control involve conflicting rights and values, tensions between individual and community interests, and tensions involving cultural beliefs and practices. While the cases discussed in this chapter provide a good overview of many of the most important and difficult ethical issues associated with disease prevention and control, the discussion above reveals that their resolution would require resolution of both empirical questions about the extent to which alternative values would likely be promoted or compromised by one practice or policy or another and philosophical questions about how to balance legitimate values in cases of conflict.
It is also important to recognize that resolution of any of the specific issues in the cases discussed above would not necessarily imply resolution of the more general issues raised by these cases. Resolving the question of whether or not there should be mandatory measles vaccination in Spain, for example, would not resolve the question of whether there should be mandatory vaccination of measles in other countries, or whether there should be mandatory vaccination against other diseases in Spain or elsewhere.
A virtue of case studies is that context is crucial to the empirical questions that ethical issues partly turn on. Privacy, the state, and disease surveillance in America. University of California Press. The moral foundations of professional ethics. Is there a moral obligation not to infect others? British Medical Journal Principles and practice of public health surveillance.
A moderate pluralist approach to public health policy and ethics. Public Health Ethics 2 2: Case discussion in response to obesity surveillance in school children. In Population and public health ethics: Cases from research, policy, and practice, 26— University of Toronto Joint Centre for Bioethics. Moral principles for allocating scarce medical resources in an influenza pandemic.