Research projects

The present study project investigated the association between job stressors and cancer incidence, as well as its mechanisms, by conducting two prospective cohort studies (old and new cohort studies) and smaller prospective and cross-sectional epidemiologic studies on the mediators between job stressors and cancer incidence (physiological parameters, such as immune functions, oxidative DNA damage, and health-related behaviors such as diet). The project tested the following associations: (1) the association of job stressors based on the two major theories of job stress, i.e., "demand-control-support model" and "effort-reward imbalance model", with all cancer incidence (as well as site-specific cancer incidences), (2) the association of other psychosocial factors at work with all cancer incidence, and (3) the association of the job stressors with physiological parameters (immune functions, oxidative DNA damage) and health-related behaviors (smoking, drug, and diet). As the results of the present research project, it is suggested that the job stressors increase the all-cancer incidence. Part of the association seems to be explained by oxidative DNA damage caused by the job stressors. Diet and other health-related behaviors may not play a major role in connecting the job stressors and cancer incidence.

本研究では,職業性ストレスモデルとして代表的な「仕事の要求度-コントロール-サポートモデル」と「努力-報酬不均衡モデル」の2つを取り上げ,1)職業性ストレスが健康に及ぼす影響の個人差とそのメカニズムを,対処行動に注目して明らかにすること,2)職場環境と個人の双方を考慮したストレス対処プログラムを開発し,その効果評価を行うこと,の2点を目的とした.本年度は以下の4点に関する検討を行った. 1.文献レビュー 職業性ストレスモデルのうち,特に「仕事の要求度-コントロール-サポートモデル」に注目し,同モデルのメカニズムとその個人差要因についての文献を収集した. 2.実証研究 「仕事の要求度-コントロール-サポートモデル」の個人差要因の1つとしてストレス対処方法に注目し,精神的健康状態,職務満足感,仕事のパフォーマンスとの関連について縦断データを用いて検討した. 3.eラーニングを用いた介入 従業員のストレス対処能力の向上を目的に開発されたeラーニング教材を用いて無作為化対照試験を行い,教材の学習効果を検討した. 4.グループワークによる介入 従業員のストレス対処能力の向上を目的としたグループワーク形式の研修を行い,無作為化対照試験デザインを用いて,研修効果を検討した. 5.UWES-Jの開発 仕事に関する積極的態度を測定するためのUtrecht Work Engagement Scaleを日本語に翻訳し,企業従業員300名のデータを用いて,信頼性と妥当性の検討を行った.

1.職業性ストレスと心理学的ストレスとの関連についてのレビュー 職業性ストレスに関する主要な3つの理論モデル(NIOSH職業性ストレスモデル,仕事の要求度-コントロールモデル,努力-報酬不均衡モデル)について概説した.次に,それらの理論モデルのうち,仕事の要求度-コントロールモデルに焦点を当て,このモデルと心理学における諸要因との関連について言及した.最後に,心理学的ストレスモデルに基づいて行った筆者らのコーピングに関する実証研究を紹介した. 2.職業性ストレスと対処行動との関連がストレス反応に及ぼす影響についての実証的研究 職業性ストレスに対するコントロール行動としての積極的対処と非積極的対処との相互作用が,心理的ストレス反応に及ぼす影響を検討した.質問紙調査の結果,積極的対処によるストレス反応の低減効果は,特に,対処努力を必要とする状況において,他の対処方略の影響を受けることが明らかになった.具体的には,「問題から距離を置く」「周囲に援助を求める」という対処方法は,積極的対処によるストレス低減効果を促進したのに対して,行動・感情を抑制する対処方法は,その効果を阻害していた.これらの結果より,どの種類の対処方法を積極的対処方法と組み合わせるかによって,個人の健康が大きく異なることが示唆された. 3.職業性ストレスに対する対処能力の向上を目的とした介入研究 職業性ストレスに対する対処能力の向上に焦点を当てたストレスマネジメントプログラムを実施し,その効果を質問紙調査により検討した.心理教育,グループディスカッション,ロールプレイ,リラクゼーション訓練から構成されるプログラムを実施した結果,積極的対処と同僚からのサポートに関して,有意な介入効果が認められた.さらに,参加者の特徴を考慮に入れた分析の結果,特定の下位集団に焦点を合わせてプログラムを構成・実施することにより,対処能力の向上,ソーシャルサポートの増加,ストレス反応の低減がより促進される可能性が示唆された.

With the rapid increase of the number of the nursing university, the importance of the evaluation of the nursing practice ability required by the end of graduation of the university increases. Therefore, it is urgent to develop a common test available in the nursing university throughout Japan to evaluate quality of Student's competency and knowledge required for a nursing student by a stage to begin the clinical trial in hospitals. I received a scientific research funds subsidy from 2008 through 2010 and, for the purpose of developing such common test to evaluate ability and knowledge required before the clinical trials in hospitals, 1,500 multiple choice items from 18 nursing domains were made and carried out monitor trials based on paper-pencil tests and computer tests (by means of CBT : Computer Based Testing) for the 730 students and 220 students respectively., By comparing both results,it follows that the usefulness of the computer examination was confirmed in comparison with of the paper-pencil tests,

Effects of cognitive stress (time pressure, concurrent tasks, cognitive conflict) and emotional stress (anxiety) on working memory were examined. Time pressure in discrimination tasks accelerated the stimulus evaluation process measured by P300 latency and response preparation process estimated by LRP latency, depending on task requirements. Cognitive conflict in a flanker task affected the response times. The response times in congruent trials became longer as the amount of conflict in the preceding incongruent trial increased. This suggested the cognitive control mechanism of response inhibition, a part of which was supported by central executive function. The working memory in sentence comprehension was affected by time pressure, concurrent tasks, and state anxiety. Time pressure interfered with the construction of text-based model of the legend. The random generation as a secondary task delayed the sentence verification time and attenuated the semantic priming effect reflected in N400 amplitude, suggesting the disturbance of context formation in a central executive. The secondary tasks affecting the phonological loop did not raise these disturbing effects. The relation between capacity of working memory and reading strategy was dependent on emotional states. Compensatory strategies such as a reading regression were more frequent for low-span than for high-span readers. However, anxiety evoked by negative feedback of the reading performance increase the use of this compensatory strategy of high-span readers, probably in order to reduce the load in working memory coping with a consumption of working memory resource caused by anxiety. The anxiety also affected self referent processing. In an incidental learning task, participants with less anxiety showed the self-reference effect. However, increased anxiety diminished this memory phenomenon. Besides, cognitive and affective factors in social communication and stress coping behavior were investigated.

The research shows the association of socioeconomic status (SES) such as income, educational attainment, employment, with health behaviors, preventive service use, circulatory disease risk factors, nutrition, poor mental health, somatic complaints, and the use of medical care. The associations between SES and health were mediated by health behaviors and inner and outer psychosocial factors. Social class and related psychosocial factors may affect brain function. Among people with low social class, brain and somatic responses may be blunted in risky decision making, with weakened typical reactions in prefrontal cortex, insula, striatum, and autonomic nervous system. Psychological reactions associated with social class were found to be associated with abnormal gene expressions related to immune and inflammation.

The aim of this study was to develop Japanese version of CREW (Civility, Respect, and Engagement with Work) program and to examine the effectiveness of it. The CREW intervention uses a group process to improve levels of workplace civility in order to improve the quality of worklife. We conducted the newly developed program in a hospital in Japan (September 2014 - February 2015), and midpoint evaluation showed the improvement of work engagement score among nurses that dominated participants.

We evaluated the effect of a stress management program using the work-environment improvement approach on psychological distress with a controlled trial design, and the effect of an Internet-based cognitive behavioral therapy (CBT) program on depression with a randomized controlled trial design among workers. We also investigated the effect of a CBT on activity (blood flow) of frontal brain measured by brain imaging technique, and the differential effect by serotonin transporter polymorphism. The stress management program using the work-environment improvement approach failed to show a significant intervention effect on psychological distress. The Internet-based CBT program showed a significant intervention effect on depression at six-month follow-up and significantly lower incidence of major depression at 12-month follow-up in the intervention group than the control group. The CBT program showed a non-significant, but slightly increased activity of frontal brain of the participants. No clear differential effect of the CBT program by serotonin transporter polymorphism was found.

Our multidisciplinary team established a large scale panel data of working populations. Within the framework of an annually repeated survey of important indices, we investigated the health effects of occupational stress. By making full advantage of panel data, we were able to control several confounders including time-invariant confounders. We found that occupational stress predicted mental health disorders but that workplace social capital/support prevented the onset of mental health disorders and deterioration of inflammatory markers. Work-family conflict and health behaviors such as leisure-time physical activity and smoking mediated the association between occupational stress and workers’ health indices. A single nucleotide polymorphism interacted with occupational work stress to produce psychological distress. Finally we developed a database consisted of 14,000 workers for further analyses on occupational stress and workers’ health.

There was only a few prospective cohort studies of mental disorders in a community population in the world. The present study conduct a prospective mental health epidemiology re-interviewing 1,859 respondents to the World Mental Health Survey Japan that was conducted about 10 years ago. Trained interviewers visited a total of 1,465 respondents in Nagasaki, Okayama, and Tamano cities, and interviewed 581, and obtained saliva samples for genomic analysis from 475.

The aim of this study was to investigate the role of work-life balance in the relationship between job stress and worker well-being as individual factors. Literature review and cross-sectional and longitudinal studies confirmed the health impairment process (i.e., job demands→work-to-family conflict→ill-health) and the motivational process (i.e., job resources→work-to-family positive spillover→motivation). Crossover effects of ill-health and motivation between husbands and wives among dual-earner couples were also confirmed.

The aim of this study was to investigate the impacts of work-life balance among Japanese dual-earner parents with preschool child(ren) (aged 0-6 years old) on (1) one’s own health, (2) one partner’s health through interactions between the members of couple, and (3) their child(ren)’s health through parenting behaviors. Four-year longitudinal survey revealed positive and negative effects of work-life balance not only on one’s own health but also on one partner’s and one child(ren)’s health and potential mechanisms to explain the relationship among them.

本研究の目的は，乳幼児期の子ども（0～6歳児）を持つ共働き夫婦を対象として，ワーク・ライフ・バランスに注目した健康支援プログラムを新たに開発し，その有効性を大規模な無作為化比較試験によって評価することである。2年目にあたる平成28年度（一部内容を平成29年度に繰越）では，以下の成果を得ることができた。 1. パイロット研究で使用する健康支援プログラムが作成された。プログラムは最大7回の集合研修を想定し，1回あたり最大60分の時間枠を想定して構成された。プログラムの内容は，参加者の多様なニーズに対応させるため，毎回異なるテーマを設定した。知識だけでなく動機づけの向上，参加者相互の交流促進による行動変容を促すため，講師による講義のほか，参加者自身が主体的に関わるワークも準備した。 2. 2つの事業所（製造業，医療機関）の従業員を対象としたパイロット研究（集合研修）を行った。製造業では合計7回，医療機関では合計5回のプログラムを実施した。研修の前後には質問紙調査も行い，各種指標を研修前後で比較した。しかしながら，職場では集合研修が可能な時間が限定され（40-60分），研究協力者の参加協力を得るのに困難を要した。 3. これらの困難に対処するために，研究費の一部を平成29年度に繰越し，時間的制約の少ない個別研修（映像とeラーニングの組合せによる7種類の教材）プログラムを追加開発し，パイロット研究（個別研修）を実施した。個別研修の前後にはWEB上で質問紙調査を行い，集合研修と同様の指標を研修前後で比較した。 当初，2つの事業所におけるパイロット研究（集合研修）を通じて支援プログラムの内容を確定し，平成29年度からの無作為化比較試験につなげる予定であった。しかしながら，パイロット研修を行った職場では，集合研修が可能な時間が限定され（40-60分），研究協力者の参加協力を得るのに困難を要した。 研究遂行上，支援プログラムの継続受講を前提とした研修効果を明らかにするには，参加者の協力が不可欠であるため，研修方法として個別研修を新たに追加することとした。 そのため，研究費の一部を平成29年度に繰越し，時間的制約の少ない個別研修（映像とeラーニングの組合せによる7種類の教材）プログラムを追加開発し，パイロット研究（個別研修）を実施し，その効果を集合研修と同様の指標を研修前後で比較した。 平成30年度では，平成28年度から29年度にかけて実施されたパイロット研究（集合研修，個別研修）の結果にもとづき，プログラムの内容と実施方法を整理したうえで，多施設（地域）共同研究による無作為化比較試験による本介入を行う。全国に複数の拠点を設定し，拠点ごとに参加者を無作為に2群（介入群，待機群）に分割する。対象は乳幼児期の子ども（0～6歳児）を持つ共働き労働者（夫，妻のどちらかでOK）とする。各拠点において各群80人のリクルートを目標とする。 リクルートに先立ち，各拠点におけるコーディネーターの育成，倫理審査の申請，臨床試験登録を行う。 参加者には，パイロット研究で作成された支援プログラムを集合形式で実施する。1回半日（3時間程度）とし，合計2回の研修とする。参加者が集まりやすい週末に実施する予定である。会場は，地域・大学・保育園などの会議室などを利用する。参加者相互の交流を促すため，1回あたりの参加人数は最大40人程度とする。介入前，介入終了直後，介入終了3ヶ月後に調査票への回答を求める。

The purpose of this study is to reduce the stress among Japanese hospital nurses by studying stress coping and assertion methods on a web-site, and to improve nurses' mental health status. 1. The web-based learning program for nurses was made referring to the stress management program for regular workers. The program was composed of nurse's career identity (CI) and assertion (AS) skill. 2. The learning effect of the CI program was evaluated with randomized control trial (RCT) for nurses. Participants were randomly assigned to the intervention and the control groups, and given a questionnaire before and after study, and one month post-study. A seventy-minute web-based learning session was given to the intervention group over 3 weeks and thereafter to the control group. As a result, several CI improved in the intervention group after study, while several CI worsened in the control group. Though "Interpersonal relationship difficulty" among stressors improved in the intervention group, it worsened in the control group. 3. The learning effect of the AS program was evaluated with RCT for nurses. As a result, "Knowledge of AS" rose just after study, but decreased one month later in the intervention group. No change was recognized in the control group regarding AS mind and action, though "Frankness" rose in the intervention group one month later. Concerning stress and mental health status, "Irritation" decreased just after the study, and "Quantitative load" decreased one month later in the intervention group. Using ANCOVA, "Knowledge of AS" in the intervention group was found to be significantly higher than that in the control group, and "Depression" in the intervention group tended to improve. These results indicate that CI, AS, job stress, and mental health status improved after web-based learning program among Japanese hospital nurses.