Modern Epidemiology, 4th edition. TL Lash, TJ VanderWeele, S Haneuse, KJ Rothman. Wolters Kluwer, 2021.
Modern Epidemiology, 4th edition. TL Lash, TJ VanderWeele, S Haneuse, KJ Rothman. Wolters Kluwer, 2021.
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DOI:
10.1007/s10654-021-00778-w
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发表时间:
2021-08
影响因子:
13.6
通讯作者:
Ahlbom A
中科院分区:
文献类型:
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作者:
Ahlbom A
Epidemiology is defined by its subject matter rather than by its methods, it says in the book, just like other branches of science. Yet, a textbook in epidemiology is typically about methods and theory which may have spurred confusion. The first sentence in the book states that epidemiology is the science that studies disease occurrence and health states in human populations. Descriptive epidemiology measures how disease frequency and other health indicators vary with time, place, and person; MacMahon, who used a similar definition of epidemiology in his groundbreaking textbook, organized parts of it according to these parameters. Etiologic, or analytic, epidemiology assesses the effect of exposures, including causes, on disease frequency. Although the vast majority of academic epidemiology seems to belong to the second category, Modern Epidemiology emphasizes the need for descriptive studies. However, it also states that there is often no clear border between descriptive and analytic epidemiology, and they are not treated separately in the book, except that there is a chapter about surveillance. Modern epidemiology started to develop only in the middle of the twentieth century, the book says, although some examples of sophisticated epidemiology had appeared earlier. It is a reasonable guess that the development of modern epidemiology started because new research questions required new tools. This was when epidemiology started to investigate diseases that manifested long time after start of exposure, where the outcome was rare, and multiple causes were abundant. Epidemiology gradually turned into a scientific discipline in its own rights. Fundamental concepts needed to be defined and also named such that they could be used in reports and discussions, and it was a sine qua non for the turn of epidemiology into a distinctive discipline. Given how epidemiology is defined the most fundamental concepts are those that are used to measure disease frequency. It is a little disappointing to note that there still is not a unified terminology in this respect and that the authors sense a need to offer alternative terms for core concepts. It is a relief to see that the awkward cumulative incidence is gone and replaced with the logical incidence proportion, but prevalence is still prevalence and not, the analog, prevalence proportion. It is noteworthy that the book spends 25 pages on measures of incidence and prevalence, a topic that may seem rather trivial, and perhaps had been so if the measures had only occurred in life table like models. But reality makes things complicated because the populations and situations where these measures will actually be calculated vary widely and are often unfriendly to epidemiology. The involved complexities must be appreciated to get the numbers right but are often downplayed in books and teaching.Right after the introductory chapter that defines epidemiology and before everything else are two chapters about causal inference, one about reasoning embodied in canonical frameworks, as the authors phrase it, and one about mathematical models of causation, including directed graphs and also the classical pie models. The prominent placement of these topics is logical but also a testament to the central and explicit role that causality has been given in epidemiology. These chapters are succinct but contain a wealth of ideas about causation and its assessment. Interestingly enough, though, the authors hold back from defining causation or causal variable. Indeed, the book says that what constitutes a cause remains an issue of debate and discussion. One of the topics is whether a variable must be manipulable to be …