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Yoshika Kurokawa

Bio: Yoshika Kurokawa is an academic researcher from National Institute for Environmental Studies. The author has contributed to research in topics: Population & Diesel exhaust. The author has an hindex of 18, co-authored 32 publications receiving 911 citations.

Papers
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Journal ArticleDOI
TL;DR: The results provided additional evidence that high MF exposure was associated with a higher risk of childhood leukemia, particularly of ALL, and controlling for some possible confounding factors did not alter the results appreciably.
Abstract: Residential power-frequency magnetic fields (MFs) were labeled as a possible human carcinogen by the International Agency for Research on Cancer panel. In response to great public concern, the World Health Organization urged that further epidemiologic studies be conducted in high-exposure areas such as Japan. We conducted a population-based case-control study, which covered areas inhabited by 54% of Japanese children. We analyzed 312 case children (0-15 years old) newly diagnosed with acute lymphoblastic leukemia (ALL) or acute myelocytic leukemia (AML) in 1999-2001 (2.3 years) and 603 controls matched for gender, age and residential area. Weekly mean MF level was determined for the child's bedroom. MF measurements in each set of a case and controls were carried out as closely in time as possible to control for seasonal variation. We evaluated the association using conditional logistic regression models. The odds ratios for children whose bedrooms had MF levels of 0.4 microT or higher compared with the reference category (MF levels below 0.1 microT) was 2.6 (95% CI=0.76-8.6) for AML+ALL and 4.7 (1.15-19.0) for ALL only. Controlling for some possible confounding factors did not alter the results appreciably. Even an analysis in which selection bias was maximized did not fully explain the association. Most of the leukemia cases in the highest exposure category had MF levels far above 0.4 microT. Our results provided additional evidence that high MF exposure was associated with a higher risk of childhood leukemia, particularly of ALL.

123 citations

Journal ArticleDOI
TL;DR: Prevalences of periodic limb movement‐like and restless legs‐like symptoms among Japanese adults were investigated and the latter symptom was significantly associated with insomnia.
Abstract: Prevalences of periodic limb movement-like and restless legs-like symptoms among Japanese adults were investigated. The latter symptom was significantly associated with insomnia.

88 citations

Journal ArticleDOI
01 Nov 1997-Sleep
TL;DR: It is suggested that road traffic noise raises the sound level in bedrooms in such zones, and consequently the prevalence rate of insomnia among the residents, and that noise-induced insomnia is an important public health problem, at least in highly urbanized areas.
Abstract: In an effort to identify risk factors for insomnia and determine the contribution of nightime road traffic volume to insomnia in the general population, a questionnaire survey was carried out among 3,600 adult Japanese women living in eight urban residential areas. The crude prevalence rate of insomnia was 11.2%. Multivariate analysis revealed that aging, living with a child/children aged six or younger, undergoing medical treatment, experiencing major life events, having an irregular bedtime, having a sleep apnealike symptom, and living near a road with a heavy volume of traffic are risk factors for insomnia. Taking into account other risk factors, there was a level-response relationship between the nighttime traffic volume of main roads and the risk of insomnia in the subjects living in the zones 0-20 m from these roads. These results suggest that road traffic noise raises the sound level in bedrooms in such zones, and consequently the prevalence rate of insomnia among the residents, and that noise-induced insomnia is an important public health problem, at least in highly urbanized areas. To confirm this, a further study on noise exposure is needed.

83 citations

Journal ArticleDOI
TL;DR: Findings suggest that chronic stress or fatigue resulting from long commuting time or extensive overtime caused individuals to be in a sympathodominant state, which can induce cardiovascular abnormalities or dysfunctions related to the onset of heart disease.
Abstract: To investigate the possible effects of long commuting time and extensive overtime on daytime cardiac autonomic activity, the short-term heart rate variability (HRV) both at supine rest and at standing rest of 223 male white-collar workers in the Tokyo Megalopolis was examined. Workers with a one-way commute of 90 min or more exhibited decreased vagal activity at supine rest and increased sympathetic activity regardless of posture, and those doing overtime of 60 h/month or more exhibited decreased vagal activity and increased sympathetic activity at standing rest. These findings suggest that chronic stress or fatigue resulting from long commuting time or extensive overtime caused these individuals to be in a sympathodominant state. Although these shifts in autonomic activities are not direct indicators of disease, it can be hypothesized that they can induce cardiovascular abnormalities or dysfunctions related to the onset of heart disease. Assessment of the daily and weekly variations in HRV as a function of daily life activities (such as working, commuting, sleeping, and exercising) among workers in Asia-Pacific urban areas might be one way of studying the possible effects of long commuting time, and extensive overtime, on health.

81 citations

Journal ArticleDOI
TL;DR: It is suggested that healthy male white-collar workers' job stress disrupts nightly sleep, and also that their insufficient sleep at night causes daytime sympathetic predominance.
Abstract: To investigate the relationships among the amount of job stressors, self-reported sleep quality, and daytime autonomic activities, a questionnaire survey was conducted for 223 healthy male white-collar workers, and their short-term heart rate variability (HRV) was also examined. Half of the subjects complained of nightly poor sleep quality. Self-reported poor sleep quality was associated with a qualitative aspect of job stressors characterized by high amounts of “job difficulty”, less amounts of “achievement in job”, and less amounts of “support by colleagues”, and also with high amounts of personal distress and difficulty in changing their mood. Those who complained of poor sleep quality exhibited sympathetic predominance and reduced heartbeat intervals at standing rest, although job stressors was not correlated to HRV. These results suggest that their job stress disrupts nightly sleep, and also that their insufficient sleep at night causes daytime sympathetic predominance. However, the amount of job stressors was not directly associated with HRV. Further studies should focus on the relationships among chronic job stress, the satisfaction of sleep demands, and the daily and long-term variation in cardiac autonomic activities.

76 citations


Cited by
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TL;DR: It is the opinion of the writing group that the overall evidence is consistent with a causal relationship between PM2.5 exposure and cardiovascular morbidity and mortality.
Abstract: In 2004, the first American Heart Association scientific statement on “Air Pollution and Cardiovascular Disease” concluded that exposure to particulate matter (PM) air pollution contributes to card...

5,227 citations

Journal ArticleDOI
TL;DR: The association between insomnia and major depressive episodes has been constantly reported: individuals with insomnia are more likely to have a major depressive illness and longitudinal studies have shown that the persistence of insomnia is associated with the appearance of a new depressive episode.

3,112 citations

Journal ArticleDOI
TL;DR: Modification of the criteria for the diagnosis of restless legs syndrome is modified to better reflect that increased body of knowledge, as well as to clarify slight confusion with the wording of the original criteria.

2,834 citations

01 Jan 2016

1,715 citations

Journal ArticleDOI
Hye-Geum Kim1, Eun-Jin Cheon1, Dai-Seg Bai1, Young Hwan Lee1, Bon-Hoon Koo1 
TL;DR: The current neurobiological evidence suggests that HRV is impacted by stress and supports its use for the objective assessment of psychological health and stress.
Abstract: Objective Physical or mental imbalance caused by harmful stimuli can induce stress to maintain homeostasis. During chronic stress, the sympathetic nervous system is hyperactivated, causing physical, psychological, and behavioral abnormalities. At present, there is no accepted standard for stress evaluation. This review aimed to survey studies providing a rationale for selecting heart rate variability (HRV) as a psychological stress indicator. Methods Term searches in the Web of Science®, National Library of Medicine (PubMed), and Google Scholar databases yielded 37 publications meeting our criteria. The inclusion criteria were involvement of human participants, HRV as an objective psychological stress measure, and measured HRV reactivity. Results In most studies, HRV variables changed in response to stress induced by various methods. The most frequently reported factor associated with variation in HRV variables was low parasympathetic activity, which is characterized by a decrease in the high-frequency band and an increase in the low-frequency band. Neuroimaging studies suggested that HRV may be linked to cortical regions (e.g., the ventromedial prefrontal cortex) that are involved in stressful situation appraisal. Conclusion In conclusion, the current neurobiological evidence suggests that HRV is impacted by stress and supports its use for the objective assessment of psychological health and stress.

972 citations