Ebook Applied epidemiologic principles and concepts - Clinicians’ guide to study design and conduct : Part 2
➤ Gửi thông báo lỗi ⚠️ Báo cáo tài liệu vi phạmNội dung chi tiết: Ebook Applied epidemiologic principles and concepts - Clinicians’ guide to study design and conduct : Part 2
Ebook Applied epidemiologic principles and concepts - Clinicians’ guide to study design and conduct : Part 2
7 Ecologic studiesDesign, conduct, and interpretation7.1IntroductionEcologic studies are sometimes not understood in epidemiologic or medical settings Ebook Applied epidemiologic principles and concepts - Clinicians’ guide to study design and conduct : Part 2s due to the limited or low frequency of its utilization in evidence discovery. Ecologic designs reflect investigations in which the unit of observation is the group and the analysis is performed on the group and not individual level. This design is feasible in assessing an association when the expo Ebook Applied epidemiologic principles and concepts - Clinicians’ guide to study design and conduct : Part 2sure and outcomes are available on the group level. In this context, ecologic studies may serve the purpose for generating hypothesis for individual-lEbook Applied epidemiologic principles and concepts - Clinicians’ guide to study design and conduct : Part 2
evel studies. Often, data are available on aggregate measure of the exposure and outcome of interest. Additionally, causal association with ecologic d7 Ecologic studiesDesign, conduct, and interpretation7.1IntroductionEcologic studies are sometimes not understood in epidemiologic or medical settings Ebook Applied epidemiologic principles and concepts - Clinicians’ guide to study design and conduct : Part 2tive to 19960 with higher pesticide exposure. does this design imply the protective effect of CaP mortality by pesticide exposure? Such an inference cannot be drawn given the reality of population dynamics in terms of migration since CaP mortality in 19810 may be due to CaP patients or individuals m Ebook Applied epidemiologic principles and concepts - Clinicians’ guide to study design and conduct : Part 2oving to 19810 from 19960 and other zip codes with higher levels of pesticides. Also, such a design restricts the individual-level data on confoundingEbook Applied epidemiologic principles and concepts - Clinicians’ guide to study design and conduct : Part 2
in addressing the confounding effect of comorbidity, income, education, etc., factors observed to influence CaP mortality.This chapter describes ecol7 Ecologic studiesDesign, conduct, and interpretation7.1IntroductionEcologic studies are sometimes not understood in epidemiologic or medical settings Ebook Applied epidemiologic principles and concepts - Clinicians’ guide to study design and conduct : Part 2ic designs are presented as well as ecologic fallacy. The advantages and limitations of ecologic design are addressed, notably confounding as a mixing effect of the third variable in the association between the exposure and the outcome of interest. The advantages include public access data, low-cost Ebook Applied epidemiologic principles and concepts - Clinicians’ guide to study design and conduct : Part 2 data acquisition, and the feasibility of evaluating community-level intervention.7.2Ecologic studies: DescriptionEcologic designs, also called group-Ebook Applied epidemiologic principles and concepts - Clinicians’ guide to study design and conduct : Part 2
level ecologic studies, correlational studies. or aggregate studies, obtain data at the level of a group or community often by making use of routinely7 Ecologic studiesDesign, conduct, and interpretation7.1IntroductionEcologic studies are sometimes not understood in epidemiologic or medical settings Ebook Applied epidemiologic principles and concepts - Clinicians’ guide to study design and conduct : Part 2e level exposure by two groups or populations and the assessment of outcome.rather than the individual, is the unit of study and its analysis, such a study is correctly characterized as ecologic. This design involves the comparison of aggregate data on risk factors and disease prevalence from differ Ebook Applied epidemiologic principles and concepts - Clinicians’ guide to study design and conduct : Part 2ent population groups in order to identify associations. Because all data are aggregate at the group level, relationships at the individual level cannEbook Applied epidemiologic principles and concepts - Clinicians’ guide to study design and conduct : Part 2
ot be empirically determined but are rather inferred. Thus, because of the likelihood of an eco-logic fallacy, this type of study provides weak empiri7 Ecologic studiesDesign, conduct, and interpretation7.1IntroductionEcologic studies are sometimes not understood in epidemiologic or medical settings Ebook Applied epidemiologic principles and concepts - Clinicians’ guide to study design and conduct : Part 2e joint distribution of variables within the group. This focus places the need for ccologic inference about effects on group levels.1 The questions is: Why conduct an ecologic study given critique of this method among some epidemiologists? The rationale involves feasibility and data reliability and Ebook Applied epidemiologic principles and concepts - Clinicians’ guide to study design and conduct : Part 2accuracy in generating testable hypothesis. Hcologic studies are conducted given no initial data on a health problem, no individual-level data, data aEbook Applied epidemiologic principles and concepts - Clinicians’ guide to study design and conduct : Part 2
re available al group-level. and limited research resources and time (rapid conduct).rhe advantages of ecologic design include its ability for hypothe7 Ecologic studiesDesign, conduct, and interpretation7.1IntroductionEcologic studies are sometimes not understood in epidemiologic or medical settings Ebook Applied epidemiologic principles and concepts - Clinicians’ guide to study design and conduct : Part 2ccologic studies may be obtained from published literature or public access database, rendering the conduct less time-consuming and inexpensive. While ecologic fallacies had been observed to be the main disadvantage of ecologic design, individual-level studies are not completely immune from ecologic Ebook Applied epidemiologic principles and concepts - Clinicians’ guide to study design and conduct : Part 2 fallacies, implying careful ascertainment of the exposure and disease variables in the conduct of ecologic studies.Ecologic studies 135Ecologic desigEbook Applied epidemiologic principles and concepts - Clinicians’ guide to study design and conduct : Part 2
ns are used to for geographical comparisons of diseases such as the correlation between childhood brain cancer in certain regions in the United States7 Ecologic studiesDesign, conduct, and interpretation7.1IntroductionEcologic studies are sometimes not understood in epidemiologic or medical settings Ebook Applied epidemiologic principles and concepts - Clinicians’ guide to study design and conduct : Part 2s can be generated on the association between brain cancer and extra virgin olive oil. However, care must be exercised in the interpretation of such ecologic studies given the potentials for confounding such as age. sex. socioeconomic status, education, access to primary care. etc. Ecologic studies Ebook Applied epidemiologic principles and concepts - Clinicians’ guide to study design and conduct : Part 2are also useful in assessing lime and secular trends in disease. While rales of acute conditions such as bronchiolitis fluctuates over lime, chronic dEbook Applied epidemiologic principles and concepts - Clinicians’ guide to study design and conduct : Part 2
isease rates tend to remain stable over time. Ecologic studies may be used to generate hypothesis if disease rales illustrate a correlation with envir7 Ecologic studiesDesign, conduct, and interpretation7.1IntroductionEcologic studies are sometimes not understood in epidemiologic or medical settings Ebook Applied epidemiologic principles and concepts - Clinicians’ guide to study design and conduct : Part 2ring the summer months. Migrant studies remain a typical example of ecologic designs for hypothesis generation. These studies provide the opportunity to examine genetic, environmental, and gene-environment association or determinant of disease. For example if a migrant population in the United Slate Ebook Applied epidemiologic principles and concepts - Clinicians’ guide to study design and conduct : Part 2s (i.e.. Asians) are observed to have a higher incidence of CaP in the United States compared to Asians in Asia, the higher rate of CaP among Asians iEbook Applied epidemiologic principles and concepts - Clinicians’ guide to study design and conduct : Part 2
n the United States may be due to environmental condition in the United States. Also, the observed higher incidence of Cap among Asians in the United 7 Ecologic studiesDesign, conduct, and interpretation7.1IntroductionEcologic studies are sometimes not understood in epidemiologic or medical settings Ebook Applied epidemiologic principles and concepts - Clinicians’ guide to study design and conduct : Part 2ancies in general. Race/ethnicity. mortality, chronic obstructive pulmonary disease, and occupation illustrate correlation. African Americans have higher age-adjusted mortality compared to whiles and are more likely to be employed in a low-paying job which correlates with higher mortality. On the ba Ebook Applied epidemiologic principles and concepts - Clinicians’ guide to study design and conduct : Part 2sis of these correlations. hypothesis on the association between COPD incidence and low paying jobs could be generated.BOX 7.1 ECOLOGIC DESIGNEcologicEbook Applied epidemiologic principles and concepts - Clinicians’ guide to study design and conduct : Part 2
design or aggregate study refers to an observational study in which all variables are group measures, implying the group as the unit of analysis, in 7 Ecologic studiesDesign, conduct, and interpretation7.1IntroductionEcologic studies are sometimes not understood in epidemiologic or medical settings Ebook Applied epidemiologic principles and concepts - Clinicians’ guide to study design and conduct : Part 2 dimensions, namely, exploratory versus analytic, and whether subjects are grouped by place (mulliple-group model), time (time-trend model) or place and time (mixed model).//. Morgenstern, " Ecologic Studies in Epidemiology: Concepts, Principles, and Methods.” Annu Rev Public Health 16 (1995): 61 81 Ebook Applied epidemiologic principles and concepts - Clinicians’ guide to study design and conduct : Part 2.ỉ 36 Applied epidemiologic principles and concepts7.2.1 Conducting an e cologic studyTo conduct an ecologic study, we need to have aggregate informatEbook Applied epidemiologic principles and concepts - Clinicians’ guide to study design and conduct : Part 2
ion on groups or subpopulations on the dependent or outcome variable of interest and the independent. explanatory, or predictor variable. For example,7 Ecologic studiesDesign, conduct, and interpretation7.1IntroductionEcologic studies are sometimes not understood in epidemiologic or medical settings Ebook Applied epidemiologic principles and concepts - Clinicians’ guide to study design and conduct : Part 2etermine alcohol consumption in these three populations. Finally, we correlate alcohol consumption and stroke prevalence in these three populations. If alcohol is a risk for the development of stroke, the population with the highest alcohol consumption will be associated with the highest prevalence Ebook Applied epidemiologic principles and concepts - Clinicians’ guide to study design and conduct : Part 2of stroke. Alternately, if alcohol consumption per capita is protective, then the population with the highest alcohol consumption will be associated wEbook Applied epidemiologic principles and concepts - Clinicians’ guide to study design and conduct : Part 2
ith the lowest prevalence of stroke.BOX 7.2 TYPES OF ECOLOGIC DESIGNS•Exploratory—refers to the design where there is no specific exposure of interest7 Ecologic studiesDesign, conduct, and interpretation7.1IntroductionEcologic studies are sometimes not understood in epidemiologic or medical settings Ebook Applied epidemiologic principles and concepts - Clinicians’ guide to study design and conduct : Part 2surement of the primary variable or exposure of interest, which becomes part of the analysis•Multiple-group design—involves the comparison of rate of disease among regions during the same period, with the purpose of identifying spatial patterns that may be suggestive of environmental etiology•This m Ebook Applied epidemiologic principles and concepts - Clinicians’ guide to study design and conduct : Part 2ay be etiologic or exploratory in nature.•Time trends—also called time series, refers to the ecologic design that compares disease or specific eventsEbook Applied epidemiologic principles and concepts - Clinicians’ guide to study design and conduct : Part 2
occurrence over time in a geographically defined population•Like multiple-group design, this may be etiologic or exploratory in nature.•Mixed designs—Gọi ngay
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