著者
鈴木 越治 小松 裕和 頼藤 貴志 山本 英二 土居 弘幸 津田 敏秀
出版者
一般社団法人日本衛生学会
雑誌
日本衛生学雑誌 (ISSN:00215082)
巻号頁・発行日
vol.64, no.4, pp.786-795, 2009 (Released:2009-10-02)
参考文献数
53
被引用文献数
2 1

A central problem in natural science is identifying general laws of cause and effect. Medical science is devoted to revealing causal relationships in humans. The framework for causal inference applied in epidemiology can contribute substantially to clearly specifying and testing causal hypotheses in many other areas of biomedical research. In this article, we review the importance of defining explicit research hypotheses to make valid causal inferences in medical studies. In the counterfactual model, a causal effect is defined as the contrast between an observed outcome and an outcome that would have been observed in a situation that did not actually happen. The fundamental problem of causal inference should be clear; individual causal effects are not directly observable, and we need to find general causal relationships, using population data. Under an “ideal” randomized trial, the assumption of exchangeability between the exposed and the unexposed groups is met; consequently, population-level causal effects can be estimated. In observational studies, however, there is a greater risk that the assumption of conditional exchangeability may be violated. In summary, in this article, we highlight the following points: (1) individual causal effects cannot be inferred because counterfactual outcomes cannot, by definition, be observed; (2) the distinction between concepts of association and concepts of causation and the basis for the definition of confounding; (3) the importance of elaborating specific research hypotheses in order to evaluate the assumption of conditional exchangeability between the exposed and unexposed groups; (4) the advantages of defining research hypotheses at the population level, including specification of a hypothetical intervention, consistent with the counterfactual model. In addition, we show how understanding the counterfactual model can lay the foundation for correct interpretation of epidemiologic evidence.
著者
鈴木 越治 小松 裕和 頼藤 貴志 山本 英二 土居 弘幸 津田 敏秀
出版者
日本衛生学会
雑誌
日本衛生学雑誌 (ISSN:00215082)
巻号頁・発行日
vol.64, no.4, pp.796-805, 2009 (Released:2009-10-02)
参考文献数
56
被引用文献数
1 2

Confounding is frequently a primary concern in epidemiological studies. With the increasing complexity of hypothesized relationships among exposures, outcomes, and covariates, it becomes very difficult to present these hypotheses lucidly and comprehensively. Graphical models are of great benefit in this regard. In this article, we focuse on directed acyclic graphs (DAGs), and review their value for confounder selection, categorization of potential biases, and hypothesis specification. We also discuss the importance of considering causal structures before selecting the covariates to be included in a statistical model and the potential biases introduced by inappropriately adjusting statistical models for covariates. DAGs are nonparametric and qualitative tools for visualizing research hypotheses regarding an exposure, an outcome, and covariates. Causal structures represented in DAGs will rarely be perfectly “correct” owing to the uncertainty about the underlying causal relationships. Nevertheless, to the extent that using DAGs forces greater clarity about causal assumptions, we are able to consider key sources of bias and uncertainty when interpreting study results. In summary, in this article, we review the following three points. (1) Although researchers have not adopted a consistent definition of confounders, using DAGs and the rules of d-separation we are able to identify clearly which variables we must condition on or adjust for in order to test a causal hypothesis under a set of causal assumptions. (2) We also show that DAGs should accurately correspond to research hypotheses of interest. To obtain a valid causal interpretation, research hypotheses should be defined explicitly from the perspective of a counterfactual model before drawing DAGs. A proper interpretation of the coefficients of a statistical model for addressing a specific research hypothesis relies on an accurate specification of a causal DAG reflecting the underlying causal structure. Unless DAGs correspond to research hypotheses, we cannot reliably reach proper conclusions testing the research hypotheses. Finally, (3) we have briefly reviewed other approaches to causal inference, and illustrate how these models are connected.
著者
津田 敏秀 馬場園 明 三野 善央 松岡 宏明 山本 英二
出版者
The Japanese Society for Hygiene
雑誌
日本衛生学雑誌 (ISSN:00215082)
巻号頁・発行日
vol.51, no.2, pp.558-568, 1996-07-15 (Released:2009-02-17)
参考文献数
73
被引用文献数
1 2

Changes of causal inference concepts in medicine, especially those having to do with chronic diseases, were reviewed. The review is divided into five sections. First, several articles on the increased academic acceptance of observational research are cited. Second, the definitions of confounder and effect modifier concepts are explained. Third, the debate over the so-called “criteria for causal inference” was discussed. Many articles have pointed out various problems related to the lack of logical bases for standard criteria, however, such criteria continue to be misapplied in Japan. Fourth, the Popperian and verificationist concepts of causal inference are summarized. Lastly, a recent controversy on meta-analysis is explained. Causal inference plays an important role in epidemiologic theory and medicine. However, because this concept has not been well-introduced in Japan, there has been much misuse of the concept, especially when used for conventional criteria.
著者
山本 英二
出版者
信州大学
雑誌
基盤研究(C)
巻号頁・発行日
2001

本研究では、平成13年度から15年度にかけて、フィールドワークをおこない、偽文書に関する古文書調査を全国各地で実施した。そして平成16年度は、3ヶ年の調査のデータをもとに報告書と古文書目録の作成に専念した。その概要は以下に述べるとおりである。1.主要な調査先は、長野県木曾郡大桑村定勝寺、長野県長野県立歴史館、山梨県山梨市窪八幡神社、山梨県甲府市山梨県立図書館甲州文庫、東京都文京区東京大学史料編纂所、東京都千代田区国立公文書館、などである。2.調査の方法は、史料所蔵機関の目録を検索して、古文書を閲覧、調査し、真偽を鑑定した。そのうえで関連する周辺情報を収集して、偽文書の作成者、作成時期、作成理由などを突き止めていった。3.なかでも長野県木曾郡大桑村定勝寺では、これまで未公開であった古文書の悉皆調査を実現することができた。調査した古文書は、すべて目録を編成し、デジタルカメラで撮影し、画像データを収集した。整理した古文書は総点数1551点におよび、信州大学人文学部日本史研究室編『長野県木曾郡大桑村須原定勝寺古文書目録』として刊行することができた。また調査成果の一部は、『ブックレット定勝寺』に掲載され、一般向けの啓蒙書として広く社会に還元することができた。とくに木曾地方が美濃国から信濃国に変わった時期を確定するという新発見をすることができた。4.偽文書の鑑定技術に関しては、現状記録方式による総合的な古文書調査が有効であることが確認することができた。とくに江戸時代に作成された偽文書は、関連する近世の古文書を調査することで、ほとんど作成時期や作成理由を特定できることがわかった。またデジタルカメラによる画像情報は、きわめて有効であることもわかった。5.4年間の研究成果は、学術論文8編、口頭発表1編、学術書3編、古文書目録1編として公表することができた。
著者
山本 英二
出版者
日本結晶成長学会
雑誌
日本結晶成長学会誌 (ISSN:03856275)
巻号頁・発行日
vol.23, no.5, pp.422-429, 1996-12-25 (Released:2017-05-31)
参考文献数
48

This article reviews recent studies on the crystallization phenomena and operation for the preparation of pharmaceuticals and functional foods. Main interests are focused on selective crystallizotion of polymorphs and solvent mediated phase transition, clathrative crystallization of green tea polyphenol with cyclodextrin, crystallization of maltose accompanying anomerization process, crystallinity and functionalities of drug, and the modification ofcrystal habits by controlling agitation condition for improvement of sparation by filtration.
著者
津田 敏秀 馬場 明園 三野 善央 山本 英二 宮井 正弥 茂見 潤
出版者
日本衛生学会
雑誌
日本衞生學雜誌 (ISSN:00215082)
巻号頁・発行日
vol.55, no.2, pp.462-473, 2000-07-15
被引用文献数
1 2

As a condition to achieving an agreement of recognition on the causal relationship in medicine, we firstly explained Hume's problem and counterfactual model. We, however, emphasized that we believe in the existence of causality on medical issues in our daily lives. Therefore, we illustrated conditions when we usually believe in causality. On the other hand, we criticized two well-known key phrases, "lack of mechanism in epidemiology" and "black box in epidemiology", which have often been used in Japan for skeptic viewpoints against epidemiologic methods even if epidemiology is often used to elucidate a causal effect in medicine in the world. We emphasized that a priori determinations of levels for inference of mechanism is necessary. And, the level and feature of mechanism should be defined in concrete expressions. After explanation of these basic concepts, we mentioned a classic view on specific diseases and non-specific diseases which have not been sufficiently discussed enough yet in Japan. As an example, we used the statements in the Japanese Compensation Law for the Health Effect by Environmental Pollution. In Japan, the classification of these diseases has been confused with that between manifestational criteria of diseases and causal criteria of them. We described the basic concepts to illustrate the causal relationship between non-specific disease and its exposure by using attached figures. Actually, we cannot recognize disease occurrence as a specific disease for several reasons. We indicated that we can recognize the magnitude of effect by causal relationships in medicine as a quantitative continuous variable.
著者
津田 敏秀 三野 善央 山本 英二 松岡 宏明 馬場園 明 茂見 潤 宮井 正彌
出版者
日本衛生学会
雑誌
日本衞生學雜誌 (ISSN:00215082)
巻号頁・発行日
vol.52, no.2, pp.511-526, 1997-07-15
被引用文献数
2 1

Kondo's "Incidence of Minamata Disease in Communities along the Agano River, Niigata, Japan (Jap. J. Hyg. 51: 599-611; 1996)" is critically reviewed. The data of the article were obtained from most of the residents living in the Agano river villages where Minamata disease was discovered in June, 1965. However, sampling proportions were much different between in the population base and in the cases. The method of identification of cases from the data and the reason for the difference were not clearly demonstrated. The citations of reference articles are insufficient despite the fact that other epidemiologic studies on methyl-mercury poisoning have been reported not only in Japan, but also around the world. His"analysis of the recognized patients" is erroneous. Both the sampling scheme of information of hair mercury and the modeling of the analysis are based on Kondo's arbitrary interpretation, not on epidemiologic theory. His "analysis of the rejected applicants" is also erroneous. His calculations of the attributable proportion are incorrect and self-induced in both the assignments of data and analysis of data. Kondo has failed to study the epidemiologic theories in light of changes in the field. Therefore, his article is lacking in epidemiologic theory, a logical base and scientific inference.<BR>In Japan, epidemiologic methodology has rarely been used in studies on Minamata Disease in either Kumamoto and Niigata. The government has used neurologically specific diagnosis besed on combinations of symptoms to judge the causality between each of symptoms and methyl-mercury poisoning. Epidemiologic data obtained in Minamata, Kumamoto in 1971 indicate that the criteria set by the government in 1977 have produced much more false-negative patients than false-positive patients. As a result, a huge number of symptomatic patients, including those with peripheral neuropathy or with constriction of the visual field, did not receive any help or compensation until 1995. The authors emphasize that the causal relationship between each symptom and methyl-mercury exposure should be reevaluated epidemiologically in Japan.
著者
津田 敏秀 馬場園 明 三野 善央 松岡 宏明 山本 英二
出版者
日本衛生学会
雑誌
日本衞生學雜誌 (ISSN:00215082)
巻号頁・発行日
vol.51, no.2, pp.558-568, 1996-07-15
被引用文献数
3 2 3

Changes of causal inference concepts in medicine, especially those having to do with chronic diseases, were reviewed. The review is divided into five sections. First, several articles on the increased academic acceptance of observational research are cited. Second, the definitions of confounder and effect modifier concepts are explained. Third, the debate over the so-called "criteria for causal inference" was discussed. Many articles have pointed out various problems related to the lack of logical bases for standard criteria, however, such criteria continue to be misapplied in Japan. Fourth, the Popperian and verificationist concepts of causal inference are summarized. Lastly, a recent controversy on meta-analysis is explained. Causal inference plays an important role in epidemiologic theory and medicine. However, because this concept has not been well-introduced in Japan, there has been much misuse of the concept, especially when used for conventional criteria.
著者
山本 英二 渡邉 匡一 山田 健三 佐藤 全敏 西田 かほる
出版者
信州大学
雑誌
基盤研究(C)
巻号頁・発行日
2011-04-28

本研究では、これまで荒唐無稽で信憑性に欠けるとして研究対象と見られてこなかった偽文書や由緒書を活用して、近世日本における歴史認識と記憶の問題について取り組んだ。具体的には、長野県木曾郡王滝村御嶽神社を事例に、これまで19世紀以降に展開すると考えられがちであった由緒を、17世紀にさかのぼって分析・検討した。本研究では、従来の研究では手薄であった寺社縁起と由緒の関係に着目して、その由緒を論じた。またアーカイブズ学の方法論を活用して、史料群自体が有する歴史的言説について明らかにした。今回の研究では、戦前・戦後を通じてその全貌が明らかでなかった御嶽神社の古文書整理を完遂することができた。
著者
浅原 慶一 合田 泰志 下村 友紀 藤原 康浩 瀬川 和子 雀部 貴美代 山本 英二 塚口 裕子
出版者
日本医療薬学会
雑誌
病院薬学 (ISSN:03899098)
巻号頁・発行日
vol.21, no.1, pp.15-21, 1995-02-10
参考文献数
10
被引用文献数
4

As intravenous hyperalimentation (IVH) prepared from IVH basic solution and amino acid solution has become popular, lactic acidosis is receiving attention as a serious adverse reaction. Therefore, thiamine is added to IVH in order to prevent this adverse reaction. However, sodium sulfite (SS), added as a stabilizer to many IVH basic solutions and most amino acid solutions, degrades thiamine. Recently, since an amino acid solution without SS has been developed, it is now possible to prepare IVH without SS. In this study, we measured the time courses of the residual concentrations of both SS and thiamine in the 12 kinds of IVH containing multivitamin and investigated the relationship between the SS concentration and the stability of thiamine from the viewpoint of degradation kinetics. From the kinetic analysis results, the degradation rate of SS in the IVH stored in a bag was faster than that stored in a glass bottle. The degradation rate of SS in the IVH was very fast when SS is not included in the IVH basic solution. The degradation of thiamine in IVH was regarded as the apparent first-order degradation process and the degradation rate as being proportional to the SS concentration. The second-order degradation rate constant of thiamine by SS was not affected by the pH of IVH. Stabilization of thiamine by glucose was inferred by comparing the degradation rate of thiamine caused by SS in IVH and that in buffered solution without glucose.