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Biomedical subjects

Toshiyuki Ojima

Publications and source records attributed to Toshiyuki Ojima.

At least 19 recordsLinked to original sources
PubMed2006

Childhood leukemia and magnetic fields in Japan: a case-control study of childhood leukemia and residential power-frequency magnetic fields in Japan.

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.

Acute Disease↗
PubMed2006

Prevalence and risk factors for hepatitis C virus infection in Mongolian children: Findings from a nationwide survey.

Although the hepatitis C virus (HCV) infection is one of the major causes of chronic hepatitis and hepatocellular carcinoma (HCC) in Mongolia, its prevalence among children and routes of transmission are largely unknown. The aim of the study was to determine the prevalence of anti-HCV antibodies and the possible risk factors for transmission among school children using representative national data. A nationwide cross-sectional survey among elementary school children was conducted in four main geographical regions and the metropolitan area of Mongolia, through multistage, stratified, random cluster sampling. Serum samples from 1,145 children (response rate, 93%; 592 boys and 553 girls; age range, 7-12 years), which represented nearly 2% of the second grade population in Mongolia, were tested for HCV antibodies with a third-generation immunoradiometric assay (IRMA). Positive samples were further evaluated by a third-generation immunoblot assay (RIBA). A standardized questionnaire concerning the socio-demographic characteristics and potential risk factors was used. Overall, seven subjects were confirmed to be anti-HCV seropositive, giving a prevalence of 0.6% (95% CI: 0.15-1.0%). The prevalence of anti-HCV increased with age. In the multivariate logistic regression analysis, adjusted for age, sex, and residence, the history of dental manipulation (odds ratio [OR] = 15.4; 95% CI: 1.4-164.8) and surgery (OR = 8.3; 95% CI: 1.5-45.6) were associated independently with the presence of anti-HCV. These findings suggest that contaminated equipment used in the dental and surgical manipulations probably played a predominant role in HCV transmission among Mongolian children. Strict guidelines on disinfection and sterilization procedures of medical instruments have to be introduced and should be followed to improve the control of HCV infection in Mongolia.

Child↗
PubMed2006

Hepatitis delta virus infection in mongolia: analyses of geographic distribution, risk factors, and disease severity.

The prevalence and risk factors for hepatitis delta virus (HDV) infection among Mongolian school children were assessed by detecting the antibody against HDV and HDV RNA, and through structured interviews. The study subjects consisted of 181 children with the past or ongoing hepatitis B virus infection who were investigated during the nationwide serosurvey conducted in 2004. The prevalence of antibody to HDV was 6.1%, with the proportion of 13.6% among hepatitis B surface antigen (HBsAg)-positive subjects, all of whom had HDV RNA. Multivariate logistic regression analyses showed that injections (> 11 times) (odds ratio [OR] = 8.31, 95% confidence interval [CI] = 1.28-54.07) and blood sampling (> 3 times) (OR = 5.34, 95% CI = 1.12-25.53) in health care settings, hospitalization (> 3 times) (OR = 6.20, 95% CI = 1.18-32.71), and cohabitating with patients with chronic hepatitis (OR = 4.57, 95% CI = 1.26-16.55) predicted the seropositivity for antibody to HDV. These results suggest that parenteral exposures in health care settings and household transmission are the main routes of HDV transmission among Mongolian children.

Antibodies, Viral↗
PubMed2006

[Is the incidence of schizophrenia declining?: an investigation of the examination rates in the psychiatric clinics of a medical school hospital and a general hospital].

PURPOSE: Some researchers in Europe, America and Oceania have recently reported that the incidence of schizophrenia is declining. We investigated changes in the proportion of schizophrenic patients to the total number of patients in two Japanese hospitals during the last decade. SUBJECTS AND METHODS: The subjects were patients who first consulted the psychiatric clinic of Jichi Medical School or the psychiatric clinic of Kamitsuga General Hospital between December 1993 and November 1994 or between December 2003 and November 2004. Both clinics accepted new patients without prior appointments. Patients were classified using ICD-10 criteria (F0-F9, G40). The sex distribution of the patients and the mean age at first contact were compared for the two time periods. The proportion of schizophrenia (F2 in the ICD-10 criteria) to the total number of patients was compared for the two time periods after standardizing the populations with regard to age using the "1985 model population in Japan." RESULTS: A decade ago, 398 patients first contacted the psychiatric clinic of the medical school hospital, compared with 958 patients in the recent investigation. A decade ago, 166 patients first contacted the psychiatric clinic of the general hospital, compared with 407 patients in the recent investigation. No differences in the sex ratios of the two groups were noted. The mean age of the patients visiting the medical school significantly increased by 3.5 years (36.9 to 40.4 years), while that of the patients visiting the general hospital significantly increased by 10.0 years (46.2 to 56.2 years). The proportion of schizophrenia patients in the medical hospital decreased from 8.5% to 6.9%, while that in the general hospital decreased from 11.0% to 5.4%. Only the change in the proportion of schizophrenia patients at the general hospital was significant. CONCLUSION AND DISCUSSION: The facts that the mean age of first-contact patients has risen and that the number of first-contact patients has increased approximately 2.5-fold suggests a change in the composition of first-contact patients in the last decade. We have some reservations regarding the comparison of these two groups. Although the actual number of first-contact patients with schizophrenia increased in both clinics, we found that the proportions of schizophrenia patients decreased in both clinics after standardizing the populations with regard to age. This finding must be investigated in view of other factors, including the overall age distribution of first-contact patients, increases in the proportions of affective disorders and organic mental disorders, and so on.

Age Distribution↗
PubMed2005

Congener profiles of PCDDs, PCDFs, and dioxin-like PCBs in the breast milk samples in Tokyo, Japan.

Exposure to dioxins has raised much public concern recently. We determined the congeners' distribution of polychlorinated-dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (dl-PCBs) in the breast milk samples collected in Tokyo, Japan. Breast milk was taken from 240 mothers, 30 days after delivery in 1999 and 2000 in Tokyo, Japan. The actual concentration and TEQ concentration of PCDDs (14 congeners), PCDFs (15 congeners), and dl-PCBs (12 congeners), and each congener's contribution to the total TEQ level were calculated. Among all the samples, PCDDs accounted for 34.8%, PCDFs accounted for 23.5%, dl-PCBs accounted for 41.7%, which was also similar in the breast milk from the primiparae and secundiparae. The main contributors to the total TEQ with increasing percentages were 2,3,4,7,8-PeCDF, 1,2,3,7,8-PeCDD and 3,3',4,4',5-PCB (#126), and they accounted for more than 65% of the total TEQ. Detailed congener analysis in breast milk samples is effective to understand dioxin sources.

Benzofurans↗
PubMed2005

Relationship of PCDD/F and Co-PCB concentrations in breast milk with infant birthweights in Tokyo, Japan.

OBJECTIVE: To observe how PCDD/F and Co-PCB concentrations in breast milk relate to infant birthweights in Tokyo, Japan. STUDY DESIGN: Breast milk samples were collected from 240 mothers (aged 25-34years old) residing in Tokyo to measure the concentrations of polychlorinated dibenzo-p-dioxins (PCDDs; 14 congeners), polychlorinated dibenzofurans (PCDFs; 15 congeners), and coplanar polychlorinated biphenyls (Co-PCBs; 12 congeners) in the breast milk fat. Individual milk samples (about 50ml) were obtained 30days after delivery, between the months of June and September in 1999 and 2000. The relationship of the infant birthweights with the PCDD/F and Co-PCB concentrations was observed. RESULTS: The birthweights were negatively correlated the concentrations of many of the PCDD/F and Co-PCB congeners, with the mean toxic equivalent quantities (TEQs) of the Co-PCBs, and with the sum of the PCDD, PCDF and Co-PCBs, although their correlation coefficients were less than 0.200. Multiple regression analysis showed octachlorodioxin was statistically significant explanatory variate. CONCLUSIONS: There were slight relationship between the dioxins levels of breast milk and the birthweights of the infants.

Adult↗
PubMed2005

Associations between dietary intake and breast milk dioxin levels in Tokyo, Japan.

BACKGROUND: The presence of dioxins in breast milk has gained much attention recently. However, in Japan the relationship between the consumption of different foods and the human breast milk dioxin concentrations is still unclear. METHODS: Breast milk was taken from 240 mothers residing in Tokyo, Japan to measure and analyze the concentrations of polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, and coplanar poly-chlorinated biphenyls contained in the fat. Individual milk samples were obtained from the mothers 30 days after delivery in 1999 and 2000. The data of the mothers' diets before pregnancy were collected by means of food frequency and amount estimation. Spearman correlation analysis and stepwise multiple linear regression were used to analyze the data. RESULTS: The concentrations of dioxins in breast milk were influenced mainly by the mother's age and history of breast-feeding. All the Spearman correlation coefficients were less than 0.20. Pork, roast ham, sausage, salt codfish and tempura had negative correlations with breast milk dioxins. CONCLUSIONS: History of breast-feeding and the mother's age should be considered and emphasized in this kind of analysis. The cause effect relationship between dietary intake and breast milk dioxin levels were still uncertain.

Adult↗
PubMed2005

Mortality among persons with a history of Kawasaki disease in Japan: can paediatricians safely discontinue follow-up of children with a history of the disease but without cardiac sequelae?

AIM: To clarify the question of whether patients with Kawasaki disease suffer a higher mortality rate after the incidence of the disease in comparison with age-matched healthy individuals. METHODS: Between July 1982 and December 1992, 52 collaborating hospitals collected data on all patients having a new, definite diagnosis of Kawasaki disease. Patients were followed up until 31 December 2001 or their death. The expected number of deaths was calculated from Japanese vital statistics data and compared with the observed number. RESULTS: Of 6576 patients enrolled, 29 (20 males and 9 females) died. The standardized mortality ratio (SMR: the observed number of deaths divided by the expected number of deaths based on the vital statistics in Japan) was 1.15 (95% CI: 0.77-1.66). In spite of the high SMRs during the acute phase, the mortality rate was not high after the acute phase for the entire group of patients. Although the SMR after the acute phase was 0.75 for those without cardiac sequelae, six males (but none of the females) with cardiac sequelae died during this period; and the SMR for the male group with cardiac sequelae was 1.95 (95% CI: 0.71-4.25). The mortality from congenital anomalies of the circulatory system was elevated, but no increase in cancer deaths was observed. CONCLUSION: Although it was not statistically significant, the mortality rate among males with cardiac sequelae due to Kawasaki disease appeared to be higher than in the general population. On the other hand, the mortality rates for females with the sequelae and both males and females without sequelae were not elevated.

Child↗
PubMed2004

Use of laboratory data to identify risk factors of giant coronary aneurysms due to Kawasaki disease.

BACKGROUND: Although some laboratory findings are known to be indicators of the risk of giant coronary aneurysm formation among Kawasaki disease patients, an appropriate cut-off point to predict aneurysm formation is not clear. METHODS: One hundred and five patients with giant coronary aneurysms were selected from the 15th and 16th nationwide surveys of Kawasaki disease in Japan. A total of 2936 patients without Kawasaki disease were recruited from a single hospital as a control group. Odds ratios were calculated for six laboratory data with specific values as cut-off points. Receiver operating characteristic (ROC) curves were observed to determine the most appropriate laboratory tests and cut-off points. RESULTS: Hematocrit, leukocyte count, neutrophil proportion, and hemoglobin had one or more peaks of odds ratio for specific cut-off points, but they did not have a clear cut-off point for the predictor according to the receiver operating characteristic curves. Alanine aminotransferase (ALT) increased the risk of giant coronary aneurysms continuously so no clearly appropriate cut-off point was identified. Serum sodium concentration of 135 mEq/L had a peak of odds ratio, and those with <135 mEq/L had the highest odds ratio (4.78). This value seemed appropriate with a sensitivity of 78% and specificity of 57%, although the predictive positive value was as small as 5%. CONCLUSION: The author's propose that a serum sodium concentration of <135 mEq/L at the patient's first visit to hospital may be a predictor of giant coronary aneurysms due to Kawasaki disease.

Blood Chemical Analysis↗
PubMed2004

Population attributable fraction of smoking to low birth weight in Japan.

BACKGROUND: The purpose of this study is to quantify the population attributable fraction of active and passive smoking for low birth weight in Japan. METHODS: A population-based case-control study was conducted by mailing self-report questionnaires. The cases were all singleton low birth weight babies who were born between 1 January 1998 and 30 June 1999 in Tochigi prefecture, Japan. The controls were randomly selected from all singleton babies who were born during the same period as cases in the prefecture. RESULTS: The number of cases and controls were 286 and 404, respectively. Population attributable fractions of active smoking during and before pregnancy were 7.0% and 8.8%, respectively. Population attributable fraction of passive smoking at home was 15.6% and at the workplace was 1.1%. Combined population attributable fraction of both active and passive smoking was 17.3%. CONCLUSION: Public education to eliminate passive smoking for pregnant women and smoking prevention in adolescence is very important in order to reduce the risk of low birth weight.

Adult↗
PubMed2004

Comparative study about methods of suicide between Japan and the United States.

BACKGROUND: Suicide is one of the most important public health issues in both Japan and the United States. This study is to clarify the differences in methods of suicide between the two countries, among various races within the United States, and between genders and age-groups. METHODS: Vital statistics mortality data and the estimated population in 1999 in Japan and in the United States were used. Age-adjusted mortality rates were calculated using the age-specific total population of Japan and the United States as a standard population. In addition, the proportionate distribution of suicide methods was calculated. RESULTS: Age-adjusted mortality rates from suicide in Japan were about 2 times higher for males and 3 times higher for females compared with the United States. The most common method among both genders in Japan was hanging, followed by jumping from a high place. In the United States, it was firearms among both genders, followed by hanging among males and drugs among females. For Asians in the United States, hanging was the method of choice for about half among both genders; hanging was the most common method for the age group of 40 years or more among males and for all age groups among females. Firearms were the method of choice for the 20-39 age group among males. CONCLUSIONS: Although the overall suicide rates among Asians in the United States were lower than Japan, the methods were similar to those in Japan.

Adolescent↗
PubMed2003

Associations between nondipping of nocturnal blood pressure decrease and cardiovascular target organ damage in strictly selected community-dwelling normotensives.

BACKGROUND: In hypertensives, nondippers are more likely than dippers to suffer silent, as well as overt, hypertensive target organ damage. In this study, we investigated whether a nondipper status was associated with target organ damage in normotensives. METHODS: We performed ambulatory blood pressure (BP) monitoring, echocardiography, and carotid ultrasonography and measured natriuretic peptides and urinary albumin (UAE) in 74 normotensive subjects with the following criteria: 1) clinical BP <140/90 mm Hg; 2) average 24-h ambulatory BP <125/80 mm Hg. RESULTS: The left ventricular mass index (LVMI) and the relative wall thickness (RWT) measured by echocardiography were greater in nondippers than dippers (LVMI: 103 +/- 26 v 118 +/- 34 g/m(2), P <.05; RWT: 0.38 +/- 0.07 v 0.43 +/- 0.09, P <.01). Plasma atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) were higher in nondippers than dippers (ANP: 14 +/- 10 v 36 +/- 63 pg/mL, P <.01; BNP: 16 +/- 12 v 62 +/- 153 pg/mL, P <.05). There were no significant differences in UAE and intima-media thickness measured by carotid ultrasonography. CONCLUSIONS: Normotensive nondipping may not reflect renal damage, but may have a predominant effect on cardiac damage. Nondipping of nocturnal BP seems to be a determinant of cardiac hypertrophy and remodeling, and may result in a cardiovascular risk independent of ambulatory BP levels in normotensives.

Aged↗
PubMed2003

Case-control study of giant coronary aneurysms due to Kawasaki disease.

BACKGROUND: Epidemiologic features of the formation of giant coronary aneurysm due to Kawasaki disease and its risk factors are not still clear. METHODS: One hundred and five patients with giant coronary aneurysms were selected from the 15th and 16th nationwide surveys of Kawasaki disease in Japan. With all other patients reported from the same hospital as a control group, odds ratios (OR) were calculated for some potential risk factors. RESULTS: Some factors affecting the formation of giant coronary aneurysms were revealed. Of these factors, the following were considered to be useful for the treatment of patients with Kawasaki disease: male sex (OR compared with females = 1.99), 0 years old (OR compared with 1-2 years = 1.71), visiting the hospital on 1-3 days of illness (OR compared to 4-6 days = 1.72), leukocyte count (OR with 1000 /mm3 increase = 0.56), neutrophil concentration among leukocyte (OR with 10% increase = 1.11), hemoglobin concentration (OR with 1 mg/dL increase = 0.73), alanine aminotransferase level (ALT; OR with 10 IU/dL increase = 1.02) and serum sodium level (OR with 1 mEq/L increase = 0.80). CONCLUSIONS: The observation of 105 cases with giant coronary aneurysms due to Kawasaki disease reported in the nationwide survey provides information about some risk factors and other considerations about the aneurysms.

Case-Control Studies↗
PubMed2003

Increase in systolic blood pressure of > or = 30 mm Hg and/or diastolic blood pressure of > or = 15 mm Hg during pregnancy: is it pathologic?

OBJECTIVE: To determine whether a rise in systolic blood pressure (SBP) > or = 30 mm Hg and/or diastolic blood pressure (DBP) > or = 15 mm Hg in the absence of hypertension during pregnancy is associated with adverse pregnancy outcomes. METHOD: We conducted a retrospective, longitudinal study of 1,498 pregnant women without hypertension or proteinuria in the first trimester. The blood pressure levels measured during the first (7.8 +/- 2.3 weeks), second (20.7 +/- 1.2 weeks), and third trimesters (38.6 +/- 1.5 weeks) were analyzed. The perinatal outcome was compared between women who exhibited a rise in SBP > or = 30 mm Hg and/or DBP > or = 15 mm Hg during pregnancy (large Delta BP group) and women who did not (small Delta BP group) using one way analysis of variance, chi-square test, or Fisher's exact test. The contribution of gestational hypertension and a large Delta BP to the development of adverse pregnancy outcomes was evaluated using multivariate logistic regression analysis. RESULTS: Of 1441 women who remained normotensive (SBP < 140 mm Hg and DBP < 90 mm Hg) during pregnancy, 238 (16.5%) and 1,203 (83.5%) belonged to the large Delta BP and small Delta BP groups, respectively. There were no significant differences between the two groups in the occurrence rate of gestational proteinuria, preterm deliveries, low-birth-weight infants, or small-for-gestational age infants. A large Delta BP was not a risk factor in itself for the occurrence of gestational proteinuria or small-for-gestational age infants after controlling for the effect of gestational hypertension. CONCLUSION: A rise in SBP > or = 30 mm Hg and/or DBP > or = 15 mm Hg is not a risk factor of adverse outcome among women who remain normotensive during pregnancy.

Adult↗
PubMed2003

Respiratory symptoms correlating to smoking prevalence: the National Nutrition Survey and the National Life-style Survey in Japan.

BACKGROUND: Although the fact that smoking habits have adverse effects on health, whether the high proportion of smokers elevates the prevalence of symptoms relating to the smoking in a community is still unknown. METHODS: An ecologic study about whole Japan was conducted. Age-adjusted smoking prevalence was calculated using the National Nutrition Survey data from 1986 through 1995 by prefecture and sex. Age-adjusted respiratory symptom prevalence were observed using the National Life-style Survey data in 1995. Correlation among 46 and/or 43 prefectures was examined by sex. RESULTS: There was a negative correlation between smoking prevalence and wheezing prevalence among males (r = -0.301). Among females, positive correlations were observed on the symptoms of nasal obstruction (r = 0.355), nasal discharge (r = 0.344), sore throat (r = 0.481), cough (r = 0.350), sputum (r = 0.594), wheezing (r = 0.451), palpitation (r = 0.363), dyspnea (r = 0.587), and frontal chest pain (r = 0.472). CONCLUSIONS: Smoking prevalence was deeply related to respiratory symptoms among females in Japan.

Female↗
PubMed2003

Analyses of fatal cases of Kawasaki disease in Japan using vital statistical data over 27 years.

BACKGROUND: Chronological changes in mortality and case fatality rates from Kawasaki disease covering an extended period in Japan are still unknown. METHODS: We analyzed 679 deaths of patients in Japan whose underlying cause was Kawasaki disease, by using the data of vital statistics between 1972 and 1998. RESULTS: The male-to-female ratio of the number of deaths was 2.07 and the mean age at death in males was higher. Two unusual increases in the epidemic years, 1982 and 1986, were observed in the chronological changes of the number of deaths. The mortality rate of males was higher than that of females, with a few exceptional years, and the annual mortality rates were high in three epidemic years. The age-specific mortality rate was highest in infants under one year of age. Prefectures with high mortality rate clustered in some regions. The case fatality rate decreased annually, declining to as low as 0.2% among those who were born in 1986 and thereafter; and unusual increases in the case fatality rate affected by these three epidemic years were not repeated. CONCLUSIONS: The case fatality rate from Kawasaki disease in Japan decreased during the 27 years of observation: improvements in treatment might account for this.

Age Factors↗
PubMed2003

Birth cohort effect of the mortality rate from congenital heart disease in Japan.

BACKGROUND: The mortality rate from congenital heart disease in Japan had decreased partly because the great improvement of medical treatment and care. Therefore, the patients who would have died of congenital heart disease in younger age in the past may be alive to be adult, and the number of adults with congenital heart disease might increase. If the management of such adults did not improve, the mortality rate from congenital heart disease might increase because of the increased number. METHODS: Using the Japanese vital statistics from 1960 through 1999, we observed the time series of the mortality rate from congenital heart disease by age and sex. The birth cohort consisted of those who were bone in 5-year period starting in 1960. The mortality rate was the sum of the number of death in every five years divided by the population of the center year. RESULTS: The transition of the mortality rate from congenital heart disease for age group 0 to 4 years was decreased since 1973. Other age groups showed decreased mortality rate since late 1960's. The birth cohort analyses showed that the mortality rate of each birth cohort was decreased as time passed, especially the age group 5 to 9 years old and 10 to 14 years old. CONCLUSION: Birth cohort effect of mortality from congenital heart disease exists in Japan.

Adolescent↗