Satoko Ezoe’s research while affiliated with Shimane University and other places

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Publications (19)


Figure 1. Subject enrollment flow diagram.
Figure 3. Relationship between STAI scores and 4 periods before and after objective structured clinical examination (OSCE). One-way repeatedmeasures analysis of variance: P < .001 (state and trait anxiety). Solid line indicates STAI scores (state anxiety). Dotted line indicates STAI scores (trait anxiety). Values are expressed as the mean ± standard deviation (error bars). Bonferroni correction was conducted for each period. Abbreviations: STAI, state-trait anxiety inventory.
Figure 4. Relationship between u-8-OHdG levels and 4 periods before and after objective structured clinical examination (OSCE). One-way repeatedmeasures analysis of variance: P = .300. Values are expressed as the mean ± standard deviation (error bars). Abbreviations: u-8-OHdG, urinary 8-hydroxy-2ʹ-deoxyguanosine.
Figure 5. Relationship between u-5-HT levels and 4 periods before and after objective structured clinical examination (OSCE). Upper: u-5-HT levels in 4 periods before and after OSCE. Lower: Two-way analysis of variance by Friedman ranking for 4 periods before and after the OSCE. One-way repeatedmeasures analysis of variance: P = .097. Values are expressed as the mean ± standard deviation (error bars). Abbreviations: u-5-HT, urinary 5-hydroxytryptamine.
Figure 6. Relationship between s-HHV-6 levels and 4 periods before and after objective structured clinical examination (OSCE). Upper: s-HHV6 levels in 4 periods before and after OSCE. Lower: Two-way analysis of variance by Friedman ranking for 4 periods before and after OSCE. Friedman test: P = .022. Horizontal background indicates median −75%, dotted background indicates median −25%. Median and max values are shown. Numbers indicate the median (min-max).
Effects of Psychological and Physical Stress on Oxidative Stress, Serotonin, and Fatigue in Young Females Induced by Objective Structured Clinical Examination: Pilot Study of u-8-OHdG, u-5HT, and s-HHV-6
  • Article
  • Full-text available

October 2021

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63 Reads

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5 Citations

International Journal of Tryptophan Research

Tadayuki Iida

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Yasuhiro Ito

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Miho Kanazashi

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[...]

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Satoko Ezoe

Background To establish a method to prevent and manage fatigue caused by psychological and physical stress in young females, early detection factors, such as understanding of fatigue and causes of psychological and physical stress, as well as a review of early management of psychiatric disease, are important. With increasing knowledge regarding the diverse causes of stress, it is important to select biomarkers with consideration of the types of stress burden and mechanisms underlying the development of physical symptoms. The methods used to search for stress characteristics is an issue that needs to be addressed. However, consensus regarding objective assessment methods for impaired mental health is lacking. Methods We examined the effects of an objective structured clinical examination (OSCE), considered to be a uniform source of psychological and physical stress, on biomarkers of oxidative stress and fatigue in 16 third-year female medical university students (21.3 ± 2.1 years old) in Japan with a normal menstrual cycle. A self-administered questionnaire consisting of Zung’s Self-rating Depression Scale (SDS) and State-Trait Anxiety Inventory (STAI) was used to assess subjective stress. Furthermore, stress-related biomarkers (urinary 8-hydroxy-2ʹ-deoxyguanosine [u-8-OHdG], urinary 5-hydroxytryptamine [u-5-HT], and salivary human herpesvirus-6 [s-HHV-6]) were examined at 1 month, 1 week, and 1 day before, and 1 week after the OSCE. Results The results indicated that the OSCE did not have effects on u-8-OHdG, a biomarker of oxidative stress. However, u-5-HT and s-HHV-6 were found to be elevated in examinations performed prior to the OSCE. Conclusions The present findings suggest that u-5-HT and s-HHV-6 levels can be used for objective assessment of mental and physical fatigue in young females, including that produced not only by knowledge regarding an upcoming OSCE, but also by skill and attitude aspects related to that examination.

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Smartphone Addiction and Sleep Quality Associated with Depression in University Students in Japan

October 2019

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311 Reads

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3 Citations

Smartphones have developed rapidly in recent years, with their use becoming widespread and an established part of daily life. Along with the development of various applications, smartphone addiction or dependence has been routinely reported, and indicated to be associated with such conditions as sleep problems and depression. In order to examine the relationships of smartphone use, sleep quality, chronotype, and physical exercise, with a depressive state, the authors administered a self-reporting questionnaire survey, which included the Japanese version of the Smartphone Dependence Scale (J-SDS), the Pittsburg Sleep Quality Index (PSQI), the Morningness-Eveningness Questionnaire (MEQ), and the Beck Depression Inventory (BDI), to 119 university students in Japan. Results of multivariate logistic regression analysis indicated that scores for the J-SDS and PSQI were significantly related to BDI score. These findings suggest that smartphone addiction and poor sleep quality are associated with the depressive state in students in Japan.


Relationships of Smartphone Dependence With Chronotype and Gender in Adolescence

January 2019

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34 Reads

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1 Citation

Smartphone use has rapidly developed in recent years and become an established part of daily life in many countries. As various applications have been developed as communication tools for use with smartphones, allowing the internet to become more accessible, patterns of dependence have been routinely reported particularly among adolescents. In this chapter, the authors reviewed the previous studies about the relationships of smartphone dependence to chronotype and gender among adolescents. Chronotype refers to preference for sleep-wake timing: for example, morning types go to bed, get up, and experience peak alertness and performance earlier in the day than do evening types. It was found that the light emitted from media screen in the evening before bedtime may delay the circadian rhythm. In addition, excessive smartphone use may lead to sleep disturbances. Recent studies suggested that evening types and females may be more prone to become smartphone dependent.


Smartphone Dependence of University Students and Parental Rearing Attitudes

January 2018

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46 Reads

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1 Citation

We investigated associations between smartphone dependence and perceived parental rearing attitudes. We administered a set of self-reporting questionnaires to 195 medicaluniversity students designed to evaluate these factors. For females, the maternal high care/high protection group had statistically significantly higher scores for smartphone dependence than the low care/low protection group. No such relationship was apparent for male respondents. These findings suggest, at least for females, that smartphone dependence may be associated with perceived rearing attitudes.



Table 1 . Factor loading for 29 variables of smartphone dependence for common factors (FC1, FC2, FC3, FC4, FC5) a in 149 university students extracted by factor analysis.
Figure 2. Relationship of hours of smartphone use while in bed with J-SDS score in 149 university students; †: p <0.01, ‡: p < 0.001 (Bonferroni's multiple comparison test).
Development of Japanese Version of Smartphone Dependence Scale

January 2016

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512 Reads

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17 Citations

Open Journal of Preventive Medicine

We designed a Japanese version of the Smartphone Dependence Scale (J-SDS) for university students, and assessed its validity and reliability. For development of this scale, we initially selected 43 preliminary items based on previous studies of Internet and mobile phone dependence. Each response was scored using a Likert scale (0, 1, 2, 3), with higher scores indicating greater dependence. After administering the preliminary scale to 149 university students, the final 29 items were selected according to exploratory factor analysis. The final scale consisted of 5 factors: 1) craving and withdrawal, 2) overuse and tolerance, 3) virtual life orientation, 4) disturbance of concentration in class, and 5) physical symptoms. Reliability coefficient (Cronbach’s alpha) values for the 5 factors and total J-SDS were 0.87, 0.87, 0.76, 0.77, 0.69, and 0.92, respectively. We then summed the Likert scores for each item to provide a quantitative overall smartphone dependence score, with higher scores indicating greater dependence. The J-SDS score became significantly higher with longer hours of smartphone use (p < 0.001). Our results suggest that the J-SDS is a reliable and valid scale for screening university students who may be at risk of developing smartphone dependence.


Relationship of Smartphone Dependence to General Health Status and Personality Traits among University Students

January 2016

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211 Reads

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17 Citations

Open Journal of Preventive Medicine

We investigated associations between smartphone dependence and general health status or personality traits. To 197 medical university students, we administered a set of self-reporting questionnaires designed to evaluate these parameters. For males, smartphone dependence positively correlated with somatic symptoms, anxiety and insomnia, and emotional instability, and negatively correlated with agreeableness. For females, smartphone dependence positively correlated with somatic symptoms, severe depression, and extraversion, and negatively correlated with social dysfunction. These findings suggest that smartphone dependence may be associated with general health status or personality traits and that there may be a gender difference in these associations.


A Long-term Study of the Association between the Relative Poverty Rate and Suicide Rate in Japan

December 2015

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107 Reads

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8 Citations

Journal of Forensic Sciences

The annual number of suicides in Japan totaled around 23,000 in 1997 and abruptly increased to around 31,000 in 1998. This figure has remained high since then. This abrupt increase in the number of suicides was primarily due to an increase in suicides occasioned by economic concerns. The association between various economic factors and suicide must be studied in detail and over the long term in order to ascertain the association between economic concerns and suicide. This study examined the relative poverty rate and the suicide rate in Japan over 30 years and discussed the association between those two rates. The results suggest that the relative poverty rate may be associated with the suicide rate for both sexes. This association is true for men in particular. The organizations and professionals involved in implementing suicide prevention measures should be cognizant of the current findings and consider formulating additional specific measures.


Analysis of oxidative stress expressed by urinary level of biopyrrins and 8-hydroxydeoxyguanosine in patients with chronic schizophrenia: Oxidative stress in schizophrenia

May 2015

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41 Reads

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22 Citations

Psychiatry and Clinical Neurosciences

Previous studies have supported the claim that psychological stress induces the production of reactive oxygen species (ROS). Several authors have suggested that patients with psychiatric disorders show high levels of oxidative stress markers. We examined different oxidative stress markers in patients with chronic schizophrenia. This study included 29 patients with chronic schizophrenia and 30 healthy volunteers. The concentration of urinary biopyrrins and 8-hydroxydeoxyguanosine (8-OHdG), as measure by enzyme-linked immune-sorbent assay, were normalized to the urinary concentration of creatinine. Psychiatric symptoms were assessed by the administration of the Brief Psychiatric Rating Scale (BPRS). The concentration of biopyrrins in patients with chronic schizophrenia was significantly higher when compared of healthy volunteers. The correlation between biopyrrins level and the duration of illness was highly significant. There were no significant differences in the levels of urinary 8-OHdG between the two groups. In schizophrenic patients, the level of urinary biopyrrins showed correlations with BPRS scores, while the level of urinary 8-OHdG did not show correlations with BPRS. Urinary biopyrrins is increased in patients with chronic schizophrenia while urinary 8-OHdG is not increased. These finding suggest that patients with chronic schizophrenia are under the condition of certain oxidative stress. This article is protected by copyright. All rights reserved.


Chronotype and Smartphone Use among Japanese Medical Students

April 2015

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49 Reads

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8 Citations

The authors investigated associations between smartphone use and chronotype. To 196 medical university students, they administered a set of self-reporting questionnaires designed to evaluate smartphone use and chronotype. Respondents were categorized into morning types and evening types: for females, the evening types scored higher for smartphone dependence; the authors also found greater duration of Web browsing service, in particular Twitter, in the evening types. No such correlation was found for male respondents. These findings provide evidence that, particularly for females, smartphone use and/or dependence may be related to chronotype.


Citations (17)


... In addition, an increase in u-5-HT levels was detected 1 week after the examination. 19 We examined the relationship between subjective psychological stress (depression and anxiety) scores and u-5-HT levels in healthy women before and after OSCE psychological stress loading over time. This comparison before and after psychological stress can capture changes in the association between subjective psychological stress and u-5-HT levels under psychological stress. ...

Reference:

Relationship Between Psychological Stress Scores and Urinary 5-HT Levels Over Time Under Psychological Stress
Effects of Psychological and Physical Stress on Oxidative Stress, Serotonin, and Fatigue in Young Females Induced by Objective Structured Clinical Examination: Pilot Study of u-8-OHdG, u-5HT, and s-HHV-6

International Journal of Tryptophan Research

... In the adolescent population, girls are more influenced by mobile phones and are more prone to develop various forms of addictive behaviour such as compulsive texting, and frequent use of social media applications (Ezoe & Toda, 2019;Lister-Landman et al., 2017;Yang et al., 2018). Cross-cultural research indicates that gender differences in the use of mobile phones in adolescents is not a global phenomenon, as there are differences among participants from Peru, Guatemala/Mexico, and Spain and those from Ireland, Pakistan, and India (Chóliz et al., 2016). ...

Relationships of Smartphone Dependence With Chronotype and Gender in Adolescence
  • Citing Chapter
  • January 2019

... In recent years, studies have reported the association between mobile phone addiction and depression among University students in different countries. Specifically, a series of cross-sectional research revealed that mobile phone addiction is positively associated with depressive symptoms among college students in Turkey, Japan, South Korea, Austrian, and Lebanon (20)(21)(22)(23)(24)(25). A prospective cohort study found that a bidirectional longitudinal relationship between duration of mobile phone use and severity of depression (26). ...

Smartphone Addiction and Sleep Quality Associated with Depression in University Students in Japan

... As a result, oxidative stress induces the oxidation of the major biological constituents of DNA, lipids, and proteins, resulting in an increase in oxidative stress in the body, as evidenced by higher levels of 8-OHdG and MDA in serum and urine [42]. Therefore, the serum level of the aforementioned parameters can be used as an indicator of oxidative stress status [43]. ...

Effects of Psychological Stress from a National License Examination on the Urine 8-Hydroxy-Deoxyguanosine Levels in Young Female Students, Taking into Account the Menstrual Cycle

Open Journal of Preventive Medicine

... Regarding personality traits, extraversion (Smetaniuk, 2014) was anticipated to be positively related to technoference. Negative correlations were supposed to be found with emotional stability , agreeableness (Toda et al., 2016), conscientiousness (Lachmann et al., 2017;Philips, 2018) and intellect (Barr et al., 2015). ...

Relationship of Smartphone Dependence to General Health Status and Personality Traits among University Students

Open Journal of Preventive Medicine

... Ultimately, we involved nine related scales, as detailed in Table 1. (Lemmens et al., 2015) 2 Problematic Online Gaming Questionnaire POGQ (Demetrovics et al., 2012) 3 Gaming Addiction Scale GAS (Lemmens et al., 2009) 4 Problem Video Game Playing Scale PVP (Tejeiro Salguero & Morán, 2002) 5 Video Game Dependency Scale VGDS (Rehbein et al., 2010) 6 Smartphone Addiction Scale SAS (Kwon et al., 2013) 7 Mobile Phone Problem Use Scale MPPUS (Bianchi & Phillips, 2005) 8 Mobile Phone Addiction Index MPAI (Leung, 2008) 9 Mobile Phone Dependence Questionnaire MPDQ (Ezoe et al., 2016) We listed the constructs from the nine scales in Table 1, removed those not applicable to our research context, merged similar ones, and obtained nine main constructs that can be used for the PGS-Adolescent scale. These constructs are tolerance, withdrawal, salience, conflict, escape, daily-life disturbance, health, schooling disruption, and problems (see Table 2). ...

Development of Japanese Version of Smartphone Dependence Scale

Open Journal of Preventive Medicine

... It has been suggested that mobile phone served as a stress-coping tool which included wishful thinking and behavioral efforts to escape or avoid problem. 22 Addictive behaviors can be considered as maladaptive coping strategies of responding to life stressors. 23 Negative life events are important sources of durative pressure which can have a substantial impact on those who experience them, leaving people tense, confused and withdrawn. ...

Mobile Phone Use and Stress-Coping Strategies of Medical Students
  • Citing Article
  • October 2014

... Our results indicated an association between the poverty rate and suicide rates. The poverty ratio represents the percentage of the population whose average monthly consumer expenditure per capita is below the poverty line, indicating the incidence of poverty [15]. A previous study found that poverty is associated with suicide rates in Japan [16]. ...

A Long-term Study of the Association between the Relative Poverty Rate and Suicide Rate in Japan
  • Citing Article
  • December 2015

Journal of Forensic Sciences

... Similar results were found in the study of Japanese students, where also weak (r = -0.16) statistically significant correlation was found between problematic smartphone use and the evening chronotype [35]. However, it should be mentioned that problematic smartphone use was assessed by a different instrument (Mobile Phone Dependence Questionnaire) in that study. ...

Chronotype and Smartphone Use among Japanese Medical Students
  • Citing Article
  • April 2015

... Urinary 8-OHdG serves as a reliable and non-invasive biomarker of oxidative stress, and higher levels of urinary 8-OHdG indicate increased oxidative stress and potential DNA damage within cells (11). Elevated levels of urinary 8-OHdG have been associated with various pathogeneses linked to oxidative stress, including Clinical relevance of urinary 8-hydroxydeoxyguanosine levels in patients undergoing prostate biopsy aging, metabolic diseases (12), cardiovascular diseases (13), neurodegenerative disorders (14) and cancer (15). In a previous immunohistochemical study, 8-OHdG was detected more in prostate cancer tissues than in benign prostate tissues (16). ...

Analysis of oxidative stress expressed by urinary level of biopyrrins and 8-hydroxydeoxyguanosine in patients with chronic schizophrenia: Oxidative stress in schizophrenia
  • Citing Article
  • May 2015

Psychiatry and Clinical Neurosciences