研究者業績

長崎 一哉

ナガサキ カズヤ  (Kazuya Nagasaki)

基本情報

所属
藤田医科大学 医学部 総合診療科 講師
学位
博士(医学)(2023年3月 筑波大学)

ORCID ID
 https://orcid.org/0000-0002-8312-7802
J-GLOBAL ID
202101003932959634
researchmap会員ID
R000030062

主要な論文

 70
  • Kazuya Nagasaki, Yuka Kawase, Yuji Nishizaki, Taro Shimizu, Yu Yamamoto, Kiyoshi Shikino, Takashi Watari, Hiroyuki Kobayashi, Yasuharu Tokuda
    Academic Medicine 2026年4月1日  
  • Kazuya Nagasaki, Yuji Nishizaki, Taro Shimizu, Yu Yamamoto, Kiyoshi Shikino, Koshi Kataoka, Hiroyuki Kobayashi, Yasuharu Tokuda
    Scientific reports 15(1) 16925-16925 2025年5月15日  
    Japan's workplace reforms, including a 60-hour weekly work limit for medical residents, that has been in effect from April 2024, have raised concerns about compliance and its impact on training quality. This study analyzed data from 17,967 residents who participated in the General Medicine In-Training Examination from 2019 to 2022, focusing on weekly duty hours, clinical responsibilities, and training environments. Duty hours increased from 2019 to 2021, before declining in 2022. The proportion of residents working over 60 h per week decreased from 57 to 49%, while those working under 50 h increased from 12 to 19%. Concurrently, the percentage of residents managing zero to four inpatients rose from 18 to 39%. University hospital residents reported shorter duty hours but fewer patient encounters and diminished clinical exposure compared to community hospital residents. These findings underscore the educational consequences of duty-hour restrictions, particularly in university hospitals, where reduced clinical responsibilities may compromise competency-based training. The results highlight the need for balanced policies that ensure compliance while maintaining sufficient clinical exposure. Future reforms should prioritize equitable workload distribution, increased clinical opportunities, and targeted interventions to address disparities between hospital types, thereby ensuring the dual goals of resident well-being and high-quality medical education.
  • Kazuya Nagasaki, Hiroyuki Kobayashi
    Journal of general and family medicine 24(6) 323-331 2023年11月  査読有り筆頭著者
    This article examines the impact of working-hour restrictions on the well-being, performance, and education of medical residents in Japan. Despite Japan's plan to introduce new regulations for resident working hours by 2024, there is still an ongoing debate regarding their appropriateness. This review provides a comprehensive overview of the current regulations of resident working hours worldwide, with a specific focus on weekly hours. The varying regulations are highlighted, including the 80-hour-per-week regulation in the United States and the 48-h-per-week regulation in the European Union influencing other regions. The article also discusses the effectiveness of working-hour restrictions on residents' mental health, with shorter working hours having potentially greater benefits. However, the impacts on medical safety and resident education are mixed, and further reduction in working hours must be carefully considered to avoid adverse effects. The planned changes to working-hour limits for residents in Japan offer a unique opportunity to gain new evidence on the impact of such regulations, which will be of interest to policymakers and researchers worldwide.
  • Kazuya Nagasaki, Yuji Nishizaki, Tomohiro Shinozaki, Taro Shimizu, Yu Yamamoto, Kiyoshi Shikino, Sho Fukui, Sho Nishiguchi, Masaru Kurihara, Kohta Katayama, Hiroyuki Kobayashi, Yasuharu Tokuda
    Postgraduate medical journal 99(1176) 1080-1087 2023年6月2日  査読有り筆頭著者
    PURPOSE: In 2024, the Japanese government will enforce a maximum 80-hour weekly duty hours (DHs) regulation for medical residents. Although this reduction in weekly DHs could increase the self-study time (SST) of these residents, the relationship between these two variables remains unclear. The aim of the study was to investigate the relationship between the SST and DHs of residents in Japan. METHODS: In this nationwide cross-sectional study, the subjects were candidates of the General Medicine In-Training Examination in the 2020 academic year. We administered questionnaires and categorically asked questions regarding daily SST and weekly DHs during the training period. To account for hospital variability, proportional odds regression models with generalized estimating equations were used to analyse the association between SST and DHs. RESULTS: Of the surveyed 6117 residents, 32.0% were female, 49.1% were postgraduate year-1 residents, 83.8% were affiliated with community hospitals, and 19.9% worked for ≥80 hours/week. Multivariable analysis revealed that residents working ≥80 hours/week spent more time on self-study than those working 60-70 hours/week. Conversely, residents who worked <50 hours/week spent less time on self-study than those who worked 60-70 hours/week. The factors associated with longer SST were sex, postgraduate year, career aspiration for internal medicine, affiliation with community hospitals, academic involvement, and well-being. CONCLUSION: Residents with long DHs had longer SSTs than residents with short DHs. Future DH restrictions may not increase but rather decrease resident SST. Effective measures to encourage self-study are required, as DH restrictions may shorten SST.
  • Kazuya Nagasaki, Yuji Nishizaki, Tomohiro Shinozaki, Taro Shimizu, Yu Yamamoto, Kiyoshi Shikino, Sho Fukui, Sho Nishiguchi, Masaru Kurihara, Koshi Kataoka, Yasuharu Tokuda, Hiroyuki Kobayashi
    Scientific reports 12(1) 10626-10626 2022年6月23日  査読有り筆頭著者
    The new duty hour (DH) limit for doctors in Japan will begin in 2024, setting the maximum DHs for postgraduate residents at approximately 80 h weekly. To set appropriate limits, understanding the association between DHs and psychological health is necessary. Thus, we assessed the relationship between residents' psychological health and DHs. We conducted a cross-sectional study involving examinees of the General Medicine In-training Examination 2020. Mental health outcomes were measured dichotomously using the Patient Health Questionnaire-2 for depression and Mini-Z 2.0, for burnout, stress, and satisfaction. Weekly DHs were measured in seven categories at 10-h intervals. The prevalence ratios (PRs) between the DH categories were estimated for each outcome. Of the 6045 residents who provided data on DHs and psychological outcomes, 37.3% showed signs of depression, 21.6% experienced burn out, and 39.2% were highly stressed. In contrast, 62.3% were highly satisfied with their training. Proportions of burnout were higher among residents in Category 6 (≥ 90 and < 100 h; PR 1.36; 95% CI 1.11-1.66) and Category 7 (≥ 100 h; PR 1.36; 95% CI 1.10-1.68) compared with residents in Category 3 (≥ 60 and < 70 h; reference). The results partially support the weekly 80-h DH limit in terms of resident well-being.
  • Kazuya Nagasaki, Yuji Nishizaki, Tomohiro Shinozaki, Hiroyuki Kobayashi, Taro Shimizu, Tomoya Okubo, Yu Yamamoto, Ryota Konishi, Yasuharu Tokuda
    Medical teacher 44(4) 1-8 2021年11月24日  査読有り筆頭著者
    PURPOSE: The relationship between duty hours (DH) and the performance of postgraduate residents is needed to establish appropriate DH limits. This study explores their relationship using the General Medicine In-training Examination (GM-ITE). MATERIALS AND METHODS: In this cross-sectional study, GM-ITE examinees of 2019 had participated. We analyzed data from the examination and questionnaire, including DH per week (eight categories). We examined the association between DH and GM-ITE score, using random-intercept linear models with and without adjustments. RESULTS: Five thousand five hundred and ninety-three participants (50.7% PGY-1, 31.6% female, 10.0% university hospitals) were included. Mean GM-ITE scores were lower among residents in Category 2 (45-50 h; mean score difference, -1.05; p < 0.001) and Category 4 (55-60 h; -0.63; p = 0.008) compared with residents in Category 5 (60-65 h; Reference). PGY-2 residents in Categories 2-4 had lower GM-ITE scores compared to those in Category 5. University residents in Category 1 and Category 5 showed a large mean difference (-3.43; p = 0.01). CONCLUSIONS: DH <60-65 h per week was independently associated with lower resident performance, but more DH did not improve performance. DH of 60-65 h per week may be the optimal balance for a resident's education and well-being.
  • Kazuya Nagasaki, Kiyoshi Shikino, Yoshito Nishimura, Akira Kuriyama, Saori Nonaka, Masashi Izumiya, Tetsuya Makiishi
    Internal medicine (Tokyo, Japan) 60(15) 2405-2411 2021年8月1日  査読有り筆頭著者
    Objective The Mini-Z 2.0 is a new, simple, and nonproprietary tool for assessing physician well-being and burnout. To date, a non-English version of the Mini-Z 2.0 survey has not been validated. Therefore, we aimed to develop a Japanese version of the Mini-Z 2.0 and to evaluate its validity and reliability using survey data from physicians affiliated with an internal medicine academic society. Methods The Mini-Z 2.0 survey was translated into Japanese using a forward-backward translation method. The participants belonged to the American College of Physicians' Japan Chapter. The translated version of the Mini-Z 2.0 survey was distributed to participants using an electronic mailing list. Convergent validity was assessed between burnout and other items using Pearson's product-moment statistic. Structural validity was evaluated using an exploratory factor analysis and confirmatory factor analysis, and reliability was assessed using internal consistency. Results Of the 1,255 physicians and medical residents contacted, 283 responded (22.5%). Burnout was present in 34.6% of the participants, with 48.8% reporting high stress levels. Convergent validity was demonstrated, with satisfactory correlations between burnout and satisfaction, value alignment, work control, and stress. An exploratory factor analysis identified two factors (i.e., Well-Being and Relationships and Work-Related Stressors); however, the three models evaluated using the confirmatory factor analysis revealed a poor fit. Cronbach's alpha for the sample was 0.80. Conclusion The Japanese version of the Mini-Z 2.0 demonstrated good internal consistency and convergent validity. Despite its inadequate structural validity, it can be used to measure physician well-being and related workplace conditions in Japan.
  • Kazuya Nagasaki, Yuji Nishizaki, Tomohiro Shinozaki, Hiroyuki Kobayashi, Yasuharu Tokuda
    JAMA network open 4(3) e210782 2021年3月1日  査読有り筆頭著者
    This cross-sectional study uses information from the General Medicine In-Training Examination survey in Japan to assess the association between resident duty hours and self-study time.

MISC

 52

書籍等出版物

 2

講演・口頭発表等

 34

共同研究・競争的資金等の研究課題

 2

メディア報道

 2