研究者業績

小池 創一

コイケ ソウイチ  (Soichi Koike)

基本情報

所属
自治医科大学 地域医療学センター(地域医療政策部門) 教授

J-GLOBAL ID
201401010545471969
researchmap会員ID
B000237449

外部リンク

論文

 72
  • Manabu Akahane, Toshio Ogawa, Soichi Koike, Seizan Tanabe, Hiromasa Horiguchi, Tatsuhiro Mizoguchi, Hideo Yasunaga, Tomoaki Imamura
    AMERICAN JOURNAL OF MEDICINE 124(4) 325-333 2011年4月  査読有り
    OBJECTIVE: We examined the effects of sex on out-of-hospital cardiac arrest outcomes. There is evidence that women are more likely to survive cardiac arrest than men. However, few large studies have examined these sex differences in detail. It is unknown whether the female survival advantage is age-specific or whether sex affects neurologic outcomes after cardiac arrest events. METHODS: Data were analyzed from a nationwide population-based out-of-hospital cardiac arrest database (between January 2005 and December 2007) involving 318,123 patients (male: 188,357, female: 129,766) to assess the effects of sex on out-of-hospital cardiac arrest outcomes in Japan. We selected 276,590 patients aged 20 to 89 years with out-of-hospital cardiac arrest and compared the frequencies of initial cardiac rhythms, 1-month survival rates, and favorable neurologic outcome rates between sexes. RESULTS: The incidence of out-of-hospital cardiac arrest was higher in men than in women (men: 0.12%; women: 0.07%). Men were witnessed more often while out-of-hospital cardiac arrest was occurring (men: 42.1% and women: 36.9%), typically presented with initial ventricular fibrillation/ventricular tachycardia rhythms, and had a higher 1-month survival rate overall after out-of-hospital cardiac arrest events (men: 5.2% and women: 4.3%). However, the rate of survival with a favorable neurologic outcome for women aged 30 to 49 years was significantly higher than that for men within the same age range. Among patients initially presenting with ventricular fibrillation/ventricular tachycardia, the rate of survival with favorable neurologic outcome was higher for women than men in the group aged 40 to 59 years. CONCLUSION: Our results suggest that men have a higher 1-month survival rate after out-of-hospital cardiac arrest because of a higher frequency of ventricular fibrillation/ventricular tachycardia presentation compared with women. Although patients of both sexes with out-of-hospital cardiac arrest initially presenting with ventricular fibrillation/ventricular tachycardia exhibited similar overall survival rates, the rate of survival with favorable neurologic outcome was significantly higher for women than men in the group aged 40 to 59 years. (C) 2011 Elsevier Inc. All rights reserved. The American Journal of Medicine (2011) 124, 325-333
  • Hideo Yasunaga, Hiroaki Miyata, Hiromasa Horiguchi, Seizan Tanabe, Manabu Akahane, Toshio Ogawa, Soichi Koike, Tomoaki Imamura
    INTERNATIONAL JOURNAL OF HEALTH GEOGRAPHICS 10 26 2011年4月  査読有り
    Background: Little is known about the effects of geographic variation on outcomes of out-of-hospital cardiac arrest (OHCA). The present study investigated the relationship between population density, time between emergency call and ambulance arrival, and survival of OHCA, using the All-Japan Utstein-style registry database, coupled with geographic information system (GIS) data. Methods: We examined data from 101,287 bystander-witnessed OHCA patients who received emergency medical services (EMS) through 4,729 ambulatory centers in Japan between 2005 and 2007. Latitudes and longitudes of each center were determined with address-match geocoding, and linked with the Population Census data using GIS. The endpoints were 1-month survival and neurologically favorable 1-month survival defined as Glasgow-Pittsburgh cerebral performance categories 1 or 2. Results: Overall 1-month survival was 7.8%. Neurologically favorable 1-month survival was 3.6%. In very low-density (<250/km(2)) and very high-density(>= 10,000/km(2)) areas, the mean call-response intervals were 9.3 and 6.2 minutes, 1-month survival rates were 5.4% and 9.1%, and neurologically favorable 1-month survival rates were 2.7% and 4.3%, respectively. After adjustment for age, sex, cause of arrest, first aid by bystander and the proportion of neighborhood elderly people >= 65 yrs, patients in very high-density areas had a significantly higher survival rate (odds ratio (OR), 1.64; 95% confidence interval (CI), 1.44 - 1.87; p < 0.001) and neurologically favorable 1-month survival rate (OR, 1.47; 95% CI, 1.22 - 1.77; p < 0.001) compared with those in very low-density areas. Conclusion: Living in a low-density area was associated with an independent risk of delay in ambulance response, and a low survival rate in cases of OHCA. Distribution of EMS centers according to population size may lead to inequality in health outcomes between urban and rural areas.
  • Toshio Ogawa, Manabu Akahane, Soichi Koike, Seizan Tanabe, Tatsuhiro Mizoguchi, Tomoaki Imamura
    BMJ 342(7792) 321 2011年2月5日  査読有り
    Objective: To compare the effectiveness of cardiopulmonary resuscitation (CPR) with chest compression only and conventional CPR on outcomes after cardiopulmonary arrest out of hospital. Design: Nationwide population based observational study. Setting: A nationwide emergency medical service system in Japan. Population: All consecutive patients with out of hospital cardiopulmonary arrest, January 2005 to December 2007 in Japan, witnessed at the moment of collapse. Lay people attempted chest compression only CPR (n=20 707) or conventional CPR (mouth to mouth ventilation and chest compression) (n=19 328), and patients were transferred to hospital by ambulance. Main outcome measures: Factors associated with better outcomes (assessed with X2, multiple logistic regression analysis, odds ratios and their 95% confidence intervals): one month survival and neurologically favourable one month survival rates defined as category one (good cerebral performance) or two (moderate cerebral disability) of the cerebral performance categories. Results: Conventional CPR was associated with better outcomes than chest compression only CPR, for both one month survival (adjusted odds ratio 1.17, 95% confidence interval 1.06 to 1.29) and neurologically favourable one month survival (1.17, 1.01 to 1.35). Neurologically favourable one month survival decreased with increasing age and with delays of up to 10 minutes in starting CPR for both conventional and chest compression only CPR. The benefit of conventional CPR over chest compression only CPR was significantly greater in younger people in non-cardiac cases (P=0.025) and with a delay in start of CPR after the event was witnessed in non-cardiac cases (P=0.015) and all cases combined (P=0.037). Conclusions: Conventional CPR is associated with better outcomes than chest compression only CPR for selected patients with out of hospital cardiopulmonary arrest, such as those with arrests of non-cardiac origin and younger people, and people in whom there was delay in the start of CPR.
  • Soichi Koike, Toshio Ogawa, Senzan Tanabe, Shinya Matsumoto, Manabu Akahane, Hideo Yasunaga, Hiromasa Horiguchi, Tomoaki Imamura
    Critical care (London, England) 15(3) R120 2011年  査読有り
    INTRODUCTION: The relationship between collapse to emergency medical service (EMS) cardiopulmonary resuscitation (CPR) interval and outcome has been well documented. However, most studies have only analyzed cases of cardiac origin and Vf (ventricular fibrillation)/pulseless VT (ventricular tachycardia). We sought to examine all causes of cardiac arrest and analyze the relationship between collapse-to-EMS CPR interval and outcome in a nationwide sample using an out-of-hospital cardiac arrest (OHCA) registry. METHODS: This was a retrospective observational study based on a nationwide OHCA patient registry in Japan between 2005 and 2008 (n = 431,968). We included cases where collapse was witnessed by a bystander and where collapse and intervention time were recorded (n = 109,350). Data were collected based on the Utstein template. One-month survival and neurologically favorable one-month survival were used as outcome measures. Logarithmic regression and logistic regression were used to examine the relation between outcomes and collapse-to-EMS CPR interval. RESULTS: Among collapse-to-EMS CPR intervals between 3 and 30 minutes, the logarithmic regression equation for the relationship with one-month survival was y = -0.059 ln(x) + 0.21, while that for the relationship with neurologically favorable one-month survival was y = -0.041 ln(x) + 0.13. After adjusting for potential confounders in the logistic regression analysis for all intervals, longer collapse-to-EMS CPR intervals were associated with lower rates of one-month survival (odds ratio (OR) 0.93, 95% confidence interval (CI): 0.93 to 0.93) and neurologically favorable one-month survival (OR 0.89, 95% CI 0.89 to 0.90). CONCLUSIONS: Improving the emergency medical system and CPR in cases of OHCA is important for improving the outcomes of OHCA.
  • Soichi Koike, Shinya Matsumoto, Tomoko Kodama, Hiroo Ide, Hideo Yasunaga, Tomoaki Imamura
    HEALTH POLICY 98(2-3) 236-244 2010年12月  査読有り
    Objectives: To investigate trends of specialty distribution and physicians' career paths in Japan, and to discuss potential policy implications. Methods: Distribution of main area of practice, relation between board-certified specialists and reported main area of practice, and migration of main area of practice by career stage were analyzed in data from the National Physician Survey, collected between 1996 and 2006. Results: The percentages of physicians involved in internal medicine, surgery, neurosurgery, pediatrics, ophthalmology, obstetrics and gynecology and otorhinolaryngology decreased from 1996 to 2006. Overall, the numbers reported for the main area of practice matched the number of board-certified specialists. Among physicians who began their careers as internal medicine physicians in the 1996 registration cohort, the proportion of those engaged in internal medicine fell from 82.5% in 1996, to 43.6% in 2000, to 37.0% by their 10th year. Among five registration cohorts analyzed, 9.1-16.8% of the surgical specialties group switched their main area of practice to internal medicine within 10 years. Conclusions: While there is a general trend toward specialization, it is important to balance between general practice and specialization to strengthen health care systems. Developing a certification system and maintaining the quality of specialist physicians are also crucial. (C) 2010 Elsevier Ireland Ltd. All rights reserved.
  • Hiroo Ide, Soichi Koike, Hideo Yasunaga, Tomoko Kodama, Kazuhiko Ohe, Tomoaki Imamura
    WORLD JOURNAL OF SURGERY 34(8) 1748-1755 2010年8月  査読有り
    A surgical workforce is essential for providing surgical services to the community. However, little is known about surgeons' career changes in circumstances where physicians can freely choose their specialty. Differing career transitions among surgical specialties were hypothesized. Longitudinal data were obtained for all physicians in Japan, giving a total of 4,302,844 items of data (for 390,368 physicians) from 1972 to 2006. Descriptive statistics for all physicians and surgeons were calculated in 1976, 1986, 1996, and 2006. "Active surgeons" (working at hospitals), "primary care surgeons" (working at clinics), and "retired surgeons" were analyzed among physicians licensed in 1972, 1982, and 1992 for the subspecialties of general surgery, orthopedic surgery, neurosurgery, urology, and "other" surgeries. Survival analysis and Cox's proportional hazard analysis were conducted to examine factors affecting career changes. During the study period, the greatest change was observed in the increased number of surgeons per 100,000 physicians. The percentage of female surgeons and surgeons registered in a surgical subspecialty also increased greatly. Significant differences, by sex, age, and subspecialty, were shown in survival analyses for surgeons' career changes in the transition from active surgeons to primary care surgeons or retired surgeons. Surgical specialty was still a significant factor for predicting career transition, even after adjustment for the surgeons' characteristics. The current study elucidated the differences in career transitions among surgical specialties. Given the observed findings, policy makers should consider more detailed and effective measures for retaining surgeons in active practice.
  • Soichi Koike, Tomoko Kodama, Shinya Matsumoto, Hiroo Ide, Hideo Yasunaga, Tomoaki Imamura
    BMC HEALTH SERVICES RESEARCH 10 101 2010年4月  査読有り
    Background: Physicians who serve as public health specialists at public health centers and health departments in local or central government have significant roles because of their public health expertise. The aim of this study is to analyze the retention and career paths of such specialists in Japan. Method: We analyzed the data of seven consecutive surveys, spanning 1994 to 2006. We first analyzed the 2006 survey data by sex, age group, and facility type. We then examined the changes over time in the proportion of physicians working in public health administration agencies. We also examined the distribution of the facility types and specialties in which physicians worked both before beginning and after leaving their jobs. These analyses were performed by using physician registration numbers to cross-link data from two consecutive surveys. Results: The proportion of physicians working in public health administration agencies was 0.7% in 2006. The actual numbers for each survey ranged between 1,800 and 1,900. The overall rate remaining in public health administration agencies during the two-year survey interval was 72.8% for 1994-1996. The ratio declined to 67.2% for 2004-2006. Among younger physicians with 1-10 years of experience, the retention rate showed a sharp decline, dropping from 72.6% to 50.0%. Many of these physicians came from or left for a hospital position, with the proportion entering academic hospital institutions increasing in recent years. In many cases, physicians left or entered internal medicine clinical practices. Conclusion: At present in Japan, the number of physicians who leave and the number who begin a position are almost the same; thus, some of the problems associated with physicians leaving are yet to become apparent. However, the fact that the retention period is shortening for younger physicians may represent a future problem for ensuring the quality of physicians in public health administration agencies. Possible strategies include: increasing the number of physicians entering positions; reducing the number leaving positions; and creating a system where physicians can easily reenter positions after leaving while also establishing a revolving door type of career development system, involving both public health departments and hospital clinical departments.
  • Soichi Koike, Hiroo Ide, Hideo Yasunaga, Tomoko Kodama, Shinya Matsumoto, Tomoaki Imamura
    MEDICAL EDUCATION 44(3) 289-297 2010年3月  査読有り
    Objectives This study analyses and discusses recent changes in young Japanese doctors' career paths, in terms of their distribution in different types of facilities and specialties, following changes to the postgraduate clinical training system in 2004. Methods Data from the National Survey of Physicians, Dentists and Pharmacists conducted by Japan's Ministry of Health, Labour and Welfare were used for this study. Results After the introduction of the new postgraduate training system, 2 years of clinical training became mandatory and a doctor-to-facility matching system was introduced. Since then, more young doctors have migrated from academic hospitals to non-academic hospitals. The number of first-year doctors at non-academic hospitals increased, whereas the number at academic hospitals decreased. In terms of the distribution of doctors per specialty, the decreasing tendency of doctors to choose internal medicine and surgery has accelerated. These results illustrate the significant changes that have affected young doctors' career paths since the new system was introduced. Conclusions Designing and providing desirable postgraduate clinical training and achieving appropriate doctor distribution are important policy issues. Appropriate policy interventions regarding a mechanism to ensure the appropriate distribution of doctors should be established and attention should be paid to expanding doctors' choices and increasing patient satisfaction and general cost-effectiveness.
  • Hideo Yasunaga, Hiromasa Horiguchi, Seizan Tanabe, Manabu Akahane, Toshio Ogawa, Soichi Koike, Tomoaki Imamura
    CRITICAL CARE 14(6) 2010年  査読有り
    Introduction: There are inconsistent data about the effectiveness of prehospital physician-staffed advanced cardiac life support (ACLS) on the outcomes of out-of-hospital cardiac arrest (OHCA). Furthermore, the relative importance of bystander-initiated cardiopulmonary resuscitation (BCPR) and ACLS and the effectiveness of their combination have not been clearly demonstrated. Methods: Using a prospective, nationwide, population-based registry of all OHCA patients in Japan, we enrolled 95,072 patients whose arrests were witnessed by bystanders and 23,127 patients witnessed by emergency medical service providers between 2005 and 2007. We divided the bystander-witnessed arrest patients into Group A (ACLS by emergency life-saving technicians without BCPR), Group B (ACLS by emergency life-saving technicians with BCPR), Group C (ACLS by physicians without BCPR) and Group D (ACLS by physicians with BCPR). The outcome data included 1-month survival and neurological outcomes determined by the cerebral performance category. Results: Among the 95,072 bystander-witnessed arrest patients, 7,722 (8.1%) were alive at 1 month, including 2,754 (2.9%) with good performance and 3,171 (3.3%) with vegetative status or worse. BCPR occurred in 42% of bystander-witnessed arrests. In comparison with Group A, the rates of good-performance survival were significantly higher in Group B (odds ratio (OR), 2.23; 95% confidence interval, 2.05 to 2.42; P < 0.01) and Group D (OR, 2.80; 95% confidence interval, 2.28 to 3.43; P < 0.01), while no significant difference was seen for Group C (OR, 1.18; 95% confidence interval, 0.86 to 1.61; P = 0.32). The occurrence of vegetative status or worse at 1 month was highest in Group C (OR, 1.92; 95% confidence interval, 1.55 to 2.37; P < 0.01). Conclusions: In this registry-based study, BCPR significantly improved the survival of OHCA with good cerebral outcome. The groups with BCPR and ACLS by physicians had the best outcomes. However, receiving ACLS by physicians without preceding BCPR significantly increased the number of patients with neurologically unfavorable outcomes.
  • Shinya Matsumoto, Yoshiyuki Kanagawa, Soichi Koike, Manabu Akahane, Hiroshi Uchi, Satoko Shibata, Masutaka Furue, Tomoaki Imamura
    BMC Research Notes 3 129 2010年  査読有り
    Background. Recently, methods for measurement of dioxins in the blood have improved. Also, techniques for analyzing large quantities of data have been developed, such as data mining. Even in subjects with elusive characteristics, it is becoming possible to find previously unknown characteristics by checking all combinations of symptoms. Findings. Using association analysis of the data mining technique, we extracted and compared combinations with a strong relationship between recent symptoms (2001-2004) and recent blood PeCDF levels, and between past symptoms (1986-1989) and recent PeCDF levels, in physical, blood, dermatological, dental and ophthalmological examinations. Patients with a higher PeCDF level were more likely to present with symptoms included in the diagnostic criteria, such as pigmentation. In addition, we obtained evidence that recent PeCDF levels had a stronger relationship with recent than past symptoms. Conclusions. Recent PeCDF levels should not be compared directly with past symptoms. However, as the excretion rate of PeCDF has been constant, it is probable that PeCDF levels were higher in the past if recent PeCDF levels were also high. The study confirmed a relationship between past PeCDF levels and past clinical symptoms. For symptoms included in the diagnostic criteria, there was a stronger relationship between PeCDF levels and past symptoms than recent symptoms. Alleviation of symptoms in each patient or aging weakened the relationship between PeCDF levels and symptoms. © 2010 Matsumoto et al licensee BioMed Central Ltd.
  • Soichi Koike, Tomoko Kodama, Shinya Matsumoto, Hiroo Ide, Hideo Yasunaga, Tomoaki Imamura
    MEDICAL TEACHER 32(6) E239-E247 2010年  査読有り
    Background: In 2004, a new postgraduate medical training system was introduced in Japan and a shift of new graduates from university hospitals to other postgraduate education hospitals happened. Aim: The aim of this study is to analyse the past trends on postgraduate medical education choices and subsequent career options to discuss possible outcomes of the current shift and policy implications. Methods: Data from the national physician survey from 1976 to 2006 were analysed. The proportion change of physicians started their career in university hospitals was calculated. The career paths for physicians by different residency type were presented. Results: More than 90% of physicians experienced university hospital work at least once in their 20-year careers. In their first 10 years of their career, physicians who started their residency in a university hospital tended to spend more years working in university hospitals, and those who started in other post-graduate training hospitals tended to spend less in university hospitals. Then, these groups presented quite similar patterns in their career choices. Conclusions: University hospitals need to strengthen their function as continuing education and career development centres and to adopt a less paternalistic approach, as fewer residents start their career in university hospitals.
  • Hiroo Ide, Hideo Yasunaga, Soichi Koike, Tomoko Kodama, Takashi Igarashi, Tomoaki Imamura
    PEDIATRICS INTERNATIONAL 51(5) 645-649 2009年10月  査読有り
    Background: Currently, there is a shortage of hospital pediatricians in Japan. In the present study, using data from the Survey of Physicians, Dentists, and Pharmacists in Japan, we analyzed the dynamics and distribution of pediatricians, using a time series approach. Methods: The total number of pediatricians, the ratios of hospital-working and female pediatricians, their mean age and geographic distribution in 1974, 1984, 1994, and 2004 were determined. The dynamics of pediatricians were analyzed by identifying the annual number of physicians participating in and withdrawing from pediatrics, and by following up withdrawal rates from pediatrics and movement rates from hospitals. The withdrawal rates of male and female pediatricians registered in 1992, 1994, and 1996 were also analyzed. Results: The number of pediatricians per 10 000 children increased from 1.9 to 7.4 between 1974 and 2004. The percentage of women among pediatricians was significantly higher than that of women among all physicians in 2004 (P < 0.01). The numbers of physicians who withdrew from pediatrics increased from the periods 1985-1994 to 1995-2004. Younger pediatricians tended to leave pediatrics earlier than elder pediatricians. There were no differences in the withdrawal rates of pediatricians between men and women registered in 1992, 1994, and 1996. Conclusions: It is anticipated that the number of pediatricians in Japan will decrease in the near future unless practical strategies are implemented to improve the early withdrawal of younger pediatricians and the current working conditions of female pediatricians.
  • Soichi Koike, Hideo Yasunaga, Shinya Matsumoto, Hiroo Ide, Tomoko Kodama, Tomoaki Imamura
    HEALTH POLICY 92(2-3) 244-249 2009年10月  査読有り
    Objectives: To make future estimates of physician distributions in hospitals and clinics to better understand the impact of recent health policy changes in post graduate clinical education, and to discuss possible policy implications. Methods: Analyze National Surveys Data conducted from 1972 to 2004. Multistate Life Table was used to make future estimations of numbers of physicians in hospitals and clinics. Results: A typical Japanese physician's career would start from academic hospitals, and move through non-academic hospitals to clinics. After the introduction of the new post-graduate clinical training system in 2004, more medical school graduates started their careers at non-academic hospitals. Recently, the flow of physicians from academic hospitals to non-academic hospitals has been declining while the flow from academic hospitals to clinics has slightly increased. We also observed a shift of physicians from hospitals to clinics. From the data we estimated that the number of physicians working at clinics will be almost equal to those at non-academic hospitals in 2016, for the first time in 30 years. Conclusions: It is important to discuss the appropriate sharing of roles, responsibilities, and cooperation among medical facilities in line with the observed changes of career paths and physician distributions (C) 2009 Elsevier Ireland Ltd, All rights reserved.
  • Shinya Matsumoto, Manabu Akahane, Yoshiyuki Kanagawa, Soichi Koike, Takesumi Yoshimura, Chikage Mitoma, Satoko Shibata, Hiroshi Uchi, Masutaka Furue, Tomoaki Imamura
    CHEMOSPHERE 77(5) 658-662 2009年10月  査読有り
    Yusho (oil disease) is the name given to a food poisoning incident caused by rice bran oil that occurred in west Japan in 1968. The causative agents of Yusho are currently considered to be polychlorinated biphenyls (PCBs) and their by-products, such as dioxin like compounds. The levels of 2,3,4,7,8-penta-cholorodibenzofuran (PeCDF) are measured in the blood of Yusho patients who attend medical check-ups. The objectives of this study were to determine the half-life of PeCDF in these patients. Linear regression analysis was performed with the binary logarithm of PeCDF blood levels in Yusho patients as the dependent variable and the measurement year as the independent variable. The linear coefficient determined in this analysis is the reciprocal of the half-life. The half-life of PeCDF varied among patients. Among patients with PeCDF blood levels of 50 pg g(-1) or higher, there were two groups: one showing a half-life of approximately 7 years and the other showing no reduction in PeCDF levels over time. The results indicate that there is a group of patients whose PeCDF levels are maintained at a high level. Our study suggests that a more complicated model is required to explain PeCDF excretion in humans. (C) 2009 Elsevier Ltd. All rights reserved.
  • Soichi Koike, Shinya Matsumoto, Tomoko Kodama, Hiroo Ide, Hideo Yasunaga, Tomoaki Imamura
    BMC HEALTH SERVICES RESEARCH 9 180 2009年10月  査読有り
    Background: Japan has experienced two large changes which affect the supply and distribution of physicians. They are increases in medical school enrollment capacity and in the proportion of female physicians. The purpose of this study is to estimate the future supply of physicians by specialty and to predict the associated impact of increased female physicians, as well as to discuss the possible policy implications. Methods: Based on data from the 2004 and 2006 National Survey of Physicians, Dentists and Pharmacists, we estimated the future supply of physicians by specialty, using multistate life tables. Based on possible scenarios of the future increase in female physicians, we also estimated the supply of physicians by specialty. Results: Even if Japan's current medical school enrollment capacity is maintained in subsequent years, the number of physicians per 1000 population is expected to increase from 2.2 in 2006 to 3.2 in 2036, which is a 46% increase from the current level. The numbers of obstetrician/gynecologists (OB/GYNs) and surgeons are expected to temporarily decline from their current level, whereas the number of OB/GYNs per 1000 births will still increase because of the declining number of births. The number of surgeons per 1000 population, even with the decreasing population, will decline temporarily over the next few years. If the percentage of female physicians continues to increase, the overall number of physicians will not be significantly affected, but in specialties with current very low female physician participation rates, such as surgery, the total number of physicians is expected to decline significantly. Conclusion: At the current medical school enrollment capacity, the number of physicians per population is expected to continue to increase because of the skewed age distribution of physicians and the declining population in Japan. However, with changes in young physicians' choices of medical specialties and as the percentage of female physicians increases, patterns of physician supply will vary between specialties. Specialties less often chosen by young physicians and where males have dominated will face a decline in physician supply. These results highlight the necessity for developing a work environment that attracts female physicians to these types of specialties. This will also lead to improved gender equality in the workforce and more effective use of human resources.
  • Manabu Akahane, Shinya Matsumoto, Yoshiyuki Kanagawa, Soichi Koike, Chikage Mitoma, Satoko Shibata, Hiroshi Uchi, Takesumi Yoshimura, Masutaka Furue, Tomoaki Imamura
    DIOXIN 2009Organohalogen Compounds 71 800-804 2009年8月1日  
  • Hiroo Ide, Soichi Koike, Tomoko Kodama, Hideo Yasunaga, Tomoaki Imamura
    HUMAN RESOURCES FOR HEALTH 7 73 2009年8月  査読有り
    Background: In Japan, physicians freely choose their specialty and workplace, because to date there is no management system to ensure a balanced distribution of physicians. Physicians in Japan start their careers in hospitals, then become specialists, and then gradually leave hospitals to work in private clinics and take on primary care roles in their specialty fields. The present study aimed to analyse national trends in the distribution and career transitions of physicians among types of facilities and specialties over a 30-year period. Methods: We obtained an electronic file containing physician registration data from the Survey of Physicians, Dentists and Pharmacists. Descriptive statistics and data on movement between facilities (hospitals and clinics) for all physicians from 1974, 1984, 1994 and 2004 were analysed. Descriptive statistics for the groups of physicians who graduated in 1970, 1980 and 1990 were also analysed, and we examined these groups over time to evaluate their changes of occupation and specialty. Results: The number of physicians per 100 000 population was 113 in 1974, and rose to 212 by 2004. The number of physicians working in hospitals increased more than threefold. In Japan, while almost all physicians choose hospital-based positions at the beginning of their career, around 20% of physicians withdrew from hospitals within 10 years, and this trend of leaving hospitals was similar among generations. Physicians who graduated in 1980 and registered in general surgery, cardiovascular surgery or paediatric surgery were 10 times more likely to change their specialty, compared with those who registered in internal medicine. More than half of the physicians who registered in 1970 had changed their specialties within a period of 30 years. Conclusion: The government should focus primarily on changing the physician fee schedule, with careful consideration of the balance between office-based physicians and hospital-based physicians and among specialties. To implement effective policies in managing health care human resources, policy-makers should also pay attention to continuously monitoring physicians' practising status and career motivations; and national consensus is needed regarding the number of physicians required in each type of facility and specialty as well as region.
  • Hiroo Ide, Hideo Yasunaga, Tomoko Kodama, Soichi Koike, Yuji Taketani, Tomoaki Imamura
    JOURNAL OF OBSTETRICS AND GYNAECOLOGY RESEARCH 35(4) 761-766 2009年8月  査読有り
    Aim: A shortage of obstetricians and gynecologists (OB/GYNs) in Japan has been highlighted. We conducted a descriptive and retrospective cohort study using data from the Survey of Physicians in Japan, and analyzed the dynamics of OB/GYNs. Methods: We calculated the total numbers of OB/GYNs, their average age, the percentage of female OB/GYNs, hospital OB/GYNs, and the number of OB/GYNs in rural areas in 1974, 1984, 1994 and 2004. We determined the number of physicians who participated in and left the specialty of obstetrics and gynecology. The withdrawal rates of OB/GYN,; who graduated in 1972, 1982 and 1992 were retrospectively followed using survival analysis. Results: The overall number of physicians has increased, while the number of OB/GYNs has remained almost unchanged over the past 30 years. The percentage of female OB/GYNs has increased. Fewer new graduates chose obstetrics and gynecology, the withdrawal rate of current OB/GYNs decreased, and their average age (50.8 years) increased. The trend in withdrawal rates did not differ significantly among the generations. Conclusions: The gravest problem in the OB/GYNs workforce is the continued decline in newly graduated OB/GYNs. Improvements in working conditions and job satisfaction are considered vital.
  • Yoshiyuki Kanagawa, Shinya Matsumoto, Soichi Koike, Tomoaki Imamura
    PEDIATRIC ALLERGY AND IMMUNOLOGY 20(4) 347-352 2009年6月  査読有り
    Food allergy patients are known to present with allergic reactions to multiple allergens, but extrapolating these associations is difficult. Data mining, a procedure that analyzes characteristic combinations among large amounts of information, is often used to analyze and predict consumer purchasing behaviour. We applied this technique to the extrapolation of food allergen associations in allergy patients. We sent 1510 families our 'Questionnaire survey for the prevention of food allergies'. Responses noting 6549 allergens came from 878 families with 1383 patients, including 402 with anaphylaxis. Some results of the survey have already been published and here we presented the results of our association analysis of combinations of food allergens. Egg, milk, wheat, peanuts, and buckwheat are the most common food allergens. The most common simultaneous combinations of these allergens were 'egg-milk', 'egg-wheat', and 'milk-wheat'. The occurrence probability of a combination (i.e. one person suffering from a certain allergen also suffers from another) is called 'confidence'. Confidence was higher for 'chicken-egg', 'abalone-salmon eggs', and 'matsutake mushroom-milk'. As well, the combinations of 'crab-shrimp', 'squid-shrimp', and 'squid-crab' also indicated higher values in a statistical examination of the occurrence probabilities of these allergen combinations (Z-score). From the results of the association analysis, we speculated that some food allergens, such as abalone, orange, salmon, chicken, pork, matsutake mushroom, peach and apple did not independently induce food allergies. We also found that combinations, such as 'crab-shrimp', 'squid-shrimp', 'squid-crab', 'chicken-beef', and 'salmon-mackerel' had strong associations.
  • Tomoaki Imamura, Shinya Matsumoto, Manabu Akahane, Yoshiyuki Kanagawa, Soichi Koike, Bunichi Tajima, Shiro Matsuya, Hiroshi Uchi, Satoko Shibata, Masutaka Furue
    BMC Research Notes 2 27 2009年  査読有り
    Background. Yusho an intoxication caused by oral dioxins and polychlorinated biphenyls occurred in 1968. Patients suffered from various systemic symptoms, including general fatigue, nausea, muscular and articular pain, acneform eruptions, black comedones, cutaneous and oral pigmentation, and increased eye discharge. The major causative factor was the contamination of rice oil with 2,3,4,7,8-penta-chlorodibenzofuran (PeCDF). Recent technical advances have allowed us to measure blood levels of PeCDF. However, there is little information on which symptoms and laboratory data are directly associated with PeCDF levels. Methods. Yusho patients underwent annual medical check-ups from 2001 to 2003. Blood PeCDF levels were correlated with the presence or absence of symptoms in medical, hematological, dermatological, dental and ophthalmological examinations. This study analyzed all combinations by using the association analysis. This is the most suitable method to evaluate all combinations of the data comprehensively. This method was used to determine the rate of patients with high PeCDF level in the population with each symptom, and to extract combinations of three symptoms which were strongly associated with high PeCDF level. Results and Conclusion. The rate of the patients with high PeCDF level was high in populations with high uric acid, black comedones (face), second highest quartile of age, or high urea nitrogen. The combination of three symptoms associated with the highest rate of patients with high PeCDF level was "high uric acid, female sexuality, and history of acneform eruptions", followed by "history of Yusho in and after 1968, high cholesterol level, and subjective symptoms." This analysis newly suggested that PeCDF concentration may be associated with history of dermatological symptoms, high uric acid, and elevated erythrocyte sedimentation rate. © 2009 Imamura et al.
  • Yoshiyuki Kanagawa, Shinya Matsumoto, Soichi Koike, Bunichi Tajima, Noriko Fukiwake, Satoko Shibata, Hiroshi Uchi, Masutaka Furue, Tomoaki Imamura
    ENVIRONMENTAL HEALTH 7 47 2008年10月  査読有り
    Background: The Yusho poisoning incident, which was caused by rice bran oil contaminated with polychlorinated biphenyls (PCBs), polychlorinated quarterphenyls (PCQs) and polychlorinated dibenzofurans (PCDFs) generated by heat denaturation of PCB, occurred in 1968 in western Japan. Annual physical, dermatological, dental, ophthalmological and laboratory examinations were conducted for Yusho patients after the incident. From 2001, blood levels of individual PCDF congeners were also measured. The blood levels of 2,3,4,7,8-pentachlorodibenzofuran (2,3,4,7,8-PeCDF), PCBs and PCQs in Yusho patients were found to be significantly higher than those of the general population. We investigated the relationships between blood concentrations of 2,3,4,7,8PeCDF, PCBs and PCQs in Yusho patients and the items measured in the annual medical examination. Methods: Medical and laboratory examination data from 501 Yusho patients enrolled in the study from 2001 to 2004 were analyzed. The relationships between blood 2,3,4,7,8-PeCDF, PCB and PCQ concentrations and medical/laboratory examination data were investigated using principal components and logistic regression analyses. Results: Serum Concentrations of 2,3,4,7,8-PeCDF, PCBs and PCQs in blood tended to correlate with either acneform eruptions, black comedones, cutaneous and mucosal pigmentation, and hypersecretion of meibomian glands as well as general fatigue, headaches, cough/sputum, abdominal pain, arthralgia, increased blood sugar, increased serum.-GTP and decreased total bilirubin. The majority of these signs and symptoms are included in the diagnostic criteria for Yusho. Conclusion: After Yusho patients had suffered chronic exposure to these chlorinated compounds for more than 35 years, the serum concentration of 2,3,4,7,8-PeCDF in blood was significantly related to arthralgia and decreased albumin/globulin (A/G) ratio; the serum concentration of PCBs was significantly related to ophthalmologic symptoms; and the serum concentration of PCQ to increased total cholesterol. These findings suggest that the co-contaminants may affect other functions than those originally associated with Yusho.
  • 小池 創一
    慶應醫學 81(4) 271-286 2004年11月  
    原著The purpose of this study was to compare the long-term care services in municipalities before and after the introduction of Long-term Care Insurance for the elderly (LTCI) in April 2000, Questionnaires were sent to all municipalides in Japan in November 1999 (before the introduction of (LTCI) and in 2001(after the introduction of LTCI). The questions included the level of care needed for the elderly, the type of service (home or institution-based), and other factors related to the implementation of LTCI. Two hundred and sixty-five municipalities responded to both questionnaires were analyzed in this study. The proportion of elderly who needed care, the pmportion of elderly at care need level 5, and the average care-need level among certified increased and became less variable afterthe introduction of LTCl, In addition, there was a higher correlation between the proportion of elderly who needed care and the number of beds for long-term care per elderly population after the introduction of LTCI. The standardization of eligibility criteria and the changes in the financing system for care for the elderly served as background of these changes. These findings demonstrate that the introduction of LTCI had a significant impact on care for the elderly in municipalities in Japan.

MISC

 74

書籍等出版物

 8

共同研究・競争的資金等の研究課題

 2