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Featured researches published by Masakazu Washio.


Inflammatory Bowel Diseases | 2005

Dietary risk factors for inflammatory bowel disease A Multicenter Case‐Control Study in Japan

Naomasa Sakamoto; Suminori Kono; Kenji Wakai; Yoshihiro Fukuda; Masamichi Satomi; Takashi Shimoyama; Yutaka Inaba; Yoshihiro Miyake; Satoshi Sasaki; Kazushi Okamoto; Gen Kobashi; Masakazu Washio; Tetsuji Yokoyama; Chigusa Date; Heizo Tanaka

&NA; To evaluate the role of dietary factors in the etiology of inflammatory bowel disease (IBD), we conducted a multicenter hospital‐based case‐control study in a Japanese population. Cases were IBD patients aged 15 to 34 years [ulcerative colitis (UC) 111 patients; Crohns disease (CD) 128 patients] within 3 years after diagnosis in 13 hospitals. One control subject was recruited for each case who was matched for sex, age, and hospital. A semiquantitative food frequency questionnaire was used to estimate preillness intakes of food groups and nutrients. All the available control subjects (n = 219) were pooled, and unconditional logistic models were applied to calculate odds ratios (ORs). In the food groups, a higher consumption of sweets was positively associated with UC risk [OR for the highest versus lowest quartile, 2.86; 95% confidence interval (CI), 1.24 to 6.57], whereas the consumption of sugars and sweeteners (OR, 2.12; 95% CI, 1.08 to 4.17), sweets (OR, 2.83; 95% CI, 1.38 to 5.83), fats and oils (OR, 2.64; 95% CI, 1.29 to 5.39), and fish and shellfish (OR, 2.41; 95% CI, 1.18‐4.89) were positively associated with CD risk. In respect to nutrients, the intake of vitamin C (OR, 0.45; 95% CI, 0.21 to 0.99) was negatively related to UC risk, while the intake of total fat (OR, 2.86; 95% CI, 1.39 to 5.90), monounsaturated fatty acids (OR, 2.49; 95% CI, 1.23 to 5.03) and polyunsaturated fatty acids (OR, 2.31; 95% CI, 1.12 to 4.79), vitamin E (OR, 3.23; 95% CI, 1.45 to 7.17), and n‐3 (OR, 3.24; 95% CI, 1.52 to 6.88) and n‐6 fatty acids (OR, 2.57; 95% CI, 1.24 to 5.32) was positively associated with CD risk. Although this study suffers from the shortcoming of recall bias, which is inherent in most retrospective studies (prospective studies are warranted to confirm the associations between diet and IBD risk), the present findings suggest the importance of dietary factors for IBD prevention.


Cancer Science | 2004

Serum phytoestrogens and prostate cancer risk in a nested case‐control study among Japanese men

Kotaro Ozasa; Masahiro Nakao; Yoshiyuki Watanabe; Kyohei Hayashi; Tsuneharu Miki; Kazuya Mikami; Mitsuru Mori; Fumio Sakauchi; Masakazu Washio; Yoshinori Ito; Koji Suzuki; Kenji Wakai; Akiko Tamakoshi

The purpose of this study was to examine whether a high serum concentration of phytoestrogens reduces the risk of prostate cancer in a case‐control study nested in a community‐based cohort in Japan (Japan Collaborative Cohort (JACC) Study). Information on lifestyles and sera of the subjects were collected in 1988–90, and they were followed up to 1999. Incident and dead cases of prostate cancer and controls were matched for study area and age. Phytoestrogens and sex hormones in sera stored at −80°C were measured in 2002. Of 14,105 male subjects of the cohort who donated their sera, 52 cases and 151 controls were identified. Three datasets were analyzed; 1) all subjects, 2) 40 cases and 101 controls after excluding subjects with low testosterone levels who were suspected of having had medical intervention, and 3) 28 cases and 69 controls with prostate specific antigen level of ∼10.0 ng/ml. The odds ratio (OR) for the highest level to the lowest was 0.38 (95% confidence interval (CI); 0.13, 1.13) for genistein, 0.41 (0.15, 1.11) for daidzein, and 0.34 (0.11, 1.10) for equol for the second dataset. Genistein and daidzein showed similar findings in the third one. Equol and equol/daidzein ratio showed consistent findings in all three datasets (OR=0.39, 95% CI; 0.13, 0.89, trend P=0.02 for the first dataset). Their effects seemed to be independent of serum sex hormones. In conclusion, serum genistein, daidzein, and equol seemed to dose‐dependently reduce prostate cancer risk. (Cancer Sci 2004; 95: 65–71)


Annals of Epidemiology | 2000

Relation between green tea consumption and the severity of coronary atherosclerosis among Japanese men and women

Shizuka Sasazuki; Hiroko Kodama; Kouichi Yoshimasu; Ying Liu; Masakazu Washio; Keitaro Tanaka; Shoji Tokunaga; Suminori Kono; Hidekazu Arai; Yoshitaka Doi; Tomoki Kawano; Osamu Nakagaki; Kazuyuki Takada; Samon Koyanagi; Koji Hiyamuta; Takanobu Nii; Kazuyuki Shirai; Munehito Ideishi; Kikuo Arakawa; Masahiro Mohri; Akira Takeshita

PURPOSE To examine the relation between green tea consumption and arteriographically determined coronary atherosclerosis. METHODS Study subjects were 512 patients (302 men and 210 women) aged 30 years or older who underwent coronary arteriography for the first time at four hospitals in Fukuoka City or one hospital in an adjacent city between September 1996 and August 1997. Lifestyle characteristics including green tea consumption were ascertained before arteriography by a questionnaire supported with interview. RESULTS 117 men (38.7%) and 50 women (23.8%) had significant stenosis of one or more coronary arteries. Green tea consumption tended to be inversely associated with coronary atherosclerosis in men, but not in women. An evident, protective association between green tea and coronary atherosclerosis was observed in a subgroup of 262 men excluding those under dietary or drug treatment for diabetes mellitus. In this subgroup, after adjustment for traditional coronary risk factors and coffee, odds ratios of significant stenosis for consumption of 2-3 cups and 4 or more cups per day were 0.5 (95% confidence interval 0.2-1.2) and 0.4 (0.2-0.9), respectively, as compared with a consumption of one cup per day or less. CONCLUSIONS The results indicate that green tea may be protective against coronary atherosclerosis at least in men.


Psychiatry and Clinical Neurosciences | 2004

Factors related to feelings of burden among caregivers looking after impaired elderly in Japan under the Long‐Term Care insurance system

Yumiko Arai; Keigo Kumamoto; Masakazu Washio; Teruko Ueda; Hiroko Miura; Kei Kudo

Abstract  Since the 1970s, the burden of caregiving has been the subject of rather intense study, a trend that will continue with the rapid graying of populations worldwide. Since the Long‐Term Care insurance system began in 2000, few cross‐sectional studies have attempted to identify factors related to the feelings of burden among caregivers looking after the impaired elderly in Japan. In the present report, among 46 pairs of caregivers and impaired elderly, the elderly receiving regular nurses’ visits in Kyoto Prefecture, Japan were assessed for problems with activities of daily living, the severity of dementia, the presence of behavioral disturbance, and cognitive impairment. The caregivers were asked to complete questionnaires in relation to their feelings of burden and caregiving situation. The results indicated that caregivers of impaired elderly with behavioral disturbances were more likely to feel a ‘heavier burden.’ Those temporarily relieved of caregiving three or more hours a day were less likely to experience ‘heavier’ caregiver burden than those who were not. Moreover, caregivers who found it ‘inconvenient’ to use care services tended to be more likely to feel a ‘heavier’ caregiver burden than those who did not. Recourse to respite services, which are ideally positioned to help, proved inconvenient because of their advance reservation system. More ready access to respite services in emergencies could do much to reduce caregiver burden.


Psychiatry and Clinical Neurosciences | 2001

Caregiver depression predicts early discontinuation of care for disabled elderly at home.

Yumiko Arai; Midori Sugiura; Masakazu Washio; Hiroko Miura; Kei Kudo

Abstract This longitudinal study investigates the caregiving experiences among Japanese caregivers who provided informal care at home for disabled elderly between 1998 and 1999. Forty‐seven caregivers of the impaired elderly continued caregiving at home in Matsuyama Town, a rural area of northern Japan, while 18 caregivers discontinued it. The mean score of the Center for Epidemiologic Studies Depression Scale in 1998 among those who gave up caregiving was significantly higher than that of those who continued caregiving, indicating that depression predicts early discontinuation of care in the home. This is one of the few studies in Japan to suggest that initial caregiver depression is a factor in the decision to terminate care for the disabled elderly at home.


Journal of Bone and Mineral Metabolism | 2004

Dietary habits and risk of ossification of the posterior longitudinal ligaments of the spine (OPLL); findings from a case-control study in Japan.

Kazushi Okamoto; Gen Kobashi; Masakazu Washio; Satoshi Sasaki; Tetsuji Yokoyama; Yoshihiro Miyake; Naomasa Sakamoto; Kaori Ohta; Yutaka Inaba; Heizo Tanaka

The relation between dietary habits and the risk of ossification of the posterior longitudinal ligaments of the spine (OPLL) was investigated in a case-control study conducted in Japan from 1998 to 2001. Prevalent OPLL cases (n = 69) were identified and individually matched by age and sex with community controls (n = 138) randomly selected from the general population in Hokkaido. A self-administered food-frequency questionnaire was used to assess habitual dietary intake. The odds ratio (OR) and its 95% confidence interval (CI) were estimated, using conditional logistic regression models to compute the OR adjusted for a history of diabetes mellitus. We found that frequent consumption of pickles (salted products) was significantly associated with an increased risk of OPLL, with an adjusted OR of 1.6 (95% CI, 1.1 to 2.2). The adjusted OR for nondaily consumers of rice was 3.0 (95% CI, 2.4 to 3.7). Frequent consumption of chicken (adjusted OR, 0.5; 95% CI, 0.3 to 0.98) and soy foods (adjusted OR, 0.4; 95% CI, 0.2 to 0.7) was significantly associated with a decreased risk of OPLL. Our findings suggest that dietary habits may constitute independent risk factors for OPLL. Further studies will be needed to prospectively determine the relationship between dietary habits and OPLL risk.


Public Health | 1997

Risk factors for methicillin-resistant Staphylococcus aureus (MRSA) infection in a Japanese geriatric hospital.

Masakazu Washio; Tetsuya Mizoue; Tomoko Kajioka; Takahiro Yoshimitsu; Masahiro Okayama; Tadashi Hamada; Takesumi Yoshimura; Masatoshi Fujishima

A case control study on MRSA infection was carried out, with the purpose of evaluating the effect of age, gender, hypoalbuminemia, the limitation of activities of daily living (ADL), the administration of antibiotics and the use of the new cephems which include third generation cephalosporins and monobactam and carbapenems, on the occurrence of MRSA infection among the inpatients in a geriatric hospital. From April 1991 to March 1994, 285 patients underwent a bacterial culture in the various clinical aspects. 118 patients were positive for MRSA, who were then used as cases while 167 patients who were negative for MRSA were used as controls. The level of serum albumin and the ADL score were lower in the MRSA group than in the non-MRSA group (P < 0.01) while the number of antibiotics administered before bacterial culture was greater in the MRSA group than in the non-MRSA group (P < 0.01). The third generation cephems were more commonly used in the MRSA positive patients than the negative patients (P < 0.01). Even after controlling for the other factors, hypoalbuminemia (OR = 1.73, 95% CI = 1.27-2.36), the limited ADL (partially limited vs without limitation: OR = 1.88, 95% CI = 1.19-2.96, completely limited vs without limitation: OR = 2.50, 95% CI = 1.64-3.82), the use of antibiotics other than the third generation cephems (vs without antibiotics: OR = 1.73, 95% CI = 1.20-2.50) and the administration of the third generation cephems (vs without antibiotics: OR = 3.12, 95% CI = 2.16-4.50) increased the risk of MRSA infection.


Nephron | 1994

Alpha Tocopherol Improves Focal Glomerulosclerosis in Rats with Adriamycin-lnduced Progressive Renal Failure

Masakazu Washio; Fumio Nanishi; Seiya Okuda; Kaoru Onoyama; Masatoshi Fujishima

The effect of d-alpha-tocopherol on the progression of renal dysfunction was investigated in rats injected with adriamycin (ADR), a model of progressive glomerulosclerosis associated with the nephrotic syndrome. Treatment with d-alpha-tocopherol was started 1 day before or 1 day after ADR injections (BE-TOC or AF-TOC rats). When compared to rats without d-alpha-tocopherol treatment (ADR-CON rats), the serum total cholesterol and triglyceride levels were significantly lower in the BE-TOC and AF-TOC groups. In week 16, the LDL cholesterol level and the atherogenic index were both significantly lower in BE-TOC and AF-TOC rats than in ADR-CON rats. The urinary protein, serum creatinine, blood urea nitrogen, malondialdehyde, and systolic blood pressure levels as well as the glomerulosclerosis score were high in ADR-CON rats, and reduced in BE-TOC or AF-TOC rats. There were no significant differences in body weight and serum albumin between the three groups in week 16. It is concluded that d-alpha-tocopherol can improve hyperlipidemia and ameliorate glomerulosclerosis in rats with ADR-induced progressive renal failure. Thus, d-alpha-tocopherol may have the potential for clinical application to treat focal glomerulosclerosis.


Spine | 2004

High body mass index after age 20 and diabetes mellitus are independent risk factors for ossification of the posterior longitudinal ligament of the spine in Japanese subjects: a case-control study in multiple hospitals.

Gen Kobashi; Masakazu Washio; Kazushi Okamoto; Satoshi Sasaki; Tetsuji Yokoyama; Yoshihiro Miyake; Naomasa Sakamoto; Kaori Ohta; Yutaka Inaba; Heizo Tanaka

Study Design. A sex- and age-matched case-control study was carried out. Objectives. To facilitate early prediction, prevention, and treatment of ossification of the posterior longitudinal ligament of the spine, the authors analyzed histories of past illness, past body mass indexes, and body pliableness by nature, adjusted for other factors considered to be risk factors. Summary of Background Data. The cause of ossification of the posterior longitudinal ligament of the spine has not yet been elucidated in detail, although many possible causative factors have been suggested, including gender, diabetes mellitus, trauma, hormonal imbalance, and dietary habits. Methods: A self-administered questionnaire was obtained from 69 patients with ossification of the posterior longitudinal ligament of the spine and 138 sex- and age-matched control participants who were free of spinal disease, randomly selected from participants in a health checkup in a town. After univariate analysis, a stepwise method was applied to select significant factors in multivariate analysis. Results. A multivariate analysis revealed that the following three indicators were independent potent risk factors for ossification of the posterior longitudinal ligament of the spine: history of diabetes mellitus, history of lumbago, and maximum body mass index before manifestation ≥25, after adjustment for other possible lifestyle risk factors. Conclusion. Excessive weight gain between 20 and 40 years of age, diabetes mellitus, and lumbago were found to be independent risk factors for ossification of the posterior longitudinal ligament of the spine. Follow-up studies, including the addition of hospital-based control participants and analysis of genetic polymorphisms, will be needed in the future.


International Journal of Urology | 2007

Diabetes mellitus and kidney cancer risk: The results of Japan Collaborative Cohort Study for Evaluation of Cancer Risk (JACC Study)

Masakazu Washio; Mitsuru Mori; Mmh Khan; Fumio Sakauchi; Yoshiyuki Watanabe; Kotaro Ozasa; Kyohei Hayashi; Tsuneharu Miki; Masahiro Nakao; Kazuya Mikami; Yoshinori Ito; Tatsuhiko Kubo; Kenji Wakai; Akiko Tamakoshi

Background:  Diabetes mellitus (DM) is reported as being a risk factor associated with kidney cancer in Western countries. The incidence of both kidney cancer and DM is lower in Japan than the other developed countries, albeit on the rise.

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Mitsuru Mori

Sapporo Medical University

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Gen Kobashi

Dokkyo Medical University

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Fumio Sakauchi

Sapporo Medical University

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Kotaro Ozasa

Radiation Effects Research Foundation

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