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N Hamajima

Publications and source records attributed to N Hamajima.

At least 127 records · Page 7Linked to original sources
PubMed1992

[Reappraisal of Zelen's method in randomized controlled trials].

This paper discusses Zelen's method (a study design with pre-randomization) in randomized controlled trials from the following aspects: 1) compliance of patients with a randomly assigned treatment; 2) infringement of patients' right to choose treatments; and 3) unfairness that only patients assigned to a new treatment are allowed a choice of treatments. The reason Zelen's method is rarely used in the United States or European countries seems to be the lower compliance of treatments in Zelen's method than in the conventional design of randomized controlled trials. Considering the present study practice in Japan, where study subjects are not completely informed by randomized assignment of treatments, Zelen's method is thought to be more practical, and not inferior to the conventional design in terms of compliance.

Humans↗
PubMed1992

[Attributable risk percent under an effect modifier and legal causality].

Among civil trials there are cases which are influenced by evidence derived from epidemiologic studies. In such cases, causality of a factor (X) illegitimately introduced by defendants is considered to be measured with an epidemiologic measure, attributable risk percent (AR%) expressing the level of risk. This paper aims to discuss calculations and interpretations of AR% in complicated cases where plaintiffs themselves introduced an additional risk factor (Y) for the alleged health injury. When X is not an effect modifier, AR% of X adjusted for Y can be simply adopted for arriving at a judgement of causality. Where Y is an effect modifier, and is not an indispensable item in the plaintiffs' daily life (e.g., smoking), the AR% of X for those not exposed to Y and also the AR% for those exposed to Y may both need to exceed a legally determined threshold, in order for X to be legally acknowledged as being causal to the alleged injury. The role of epidemiologists for such trials is to determine the AR% of X for each level of Y, and to advise the court on a realistic range of the AR%s.

Effect Modifier, Epidemiologic↗
PubMed1991

Effects of the consumption of cigarettes, alcohol and foods on serum concentrations of carotenoids, retinol and tocopherols in healthy inhabitants living in a rural area of Hokkaido.

The relationship between serum concentrations of carotenoids, tocopherols and retinol and the consumption of cigarettes, alcohol and foods was investigated in 835 healthy inhabitants (aged 35-79 years) of a rural area of Hokkaido. Serum concentrations of beta-carotene (BC), alpha-carotene (AC), lycopene (LY), beta-cryptoxanthin (BX), zeaxanthin (including lutein, ZX), canthaxanthin (CX) and beta-tocopherol (including gamma-tocopherol, BT) were higher in females than in males, while serum retinol (RE) concentrations were lower. Serum alpha-tocopherol (AT) concentrations were the same for both sexes. The serum values of BC, BX, AC, LY and ZX for males were inversely associated with the consumption of cigarettes in multiple-regression analysis. The serum values of BC, AC and BX for males were inversely associated with alcohol consumption, while serum RE values were positively related to alcohol consumption for both sexes. There were significant relations between serum values of BC, AC, and ZX and the intake frequencies of carrots, tomatoes, milk and/or green-leaf vegetables, especially for females, and between serum BX values and the intake of oranges, juices and fruits. Serum RE and AT concentrations were not associated with any food intake, and BT concentrations were associated with the intake of tomatoes and juices for males.

Adult↗
PubMed1991

[Epidemiology and civil trials].

The role epidemiology in courts has become increasingly important both in the United States and in Japan, especially in the field of product liability. In the United States, attributable risk percent (AR%) is used in civil trials as a measure to judge whether alleged factors caused health disturbances of plaintiffs. Most epidemiologists believe that an AR% of more than 50%, ie, relative risk more than 2, supports causality of alleged factors, because "preponderance of evidence" is regarded as a fundamental legal rule in the United States. In Japan, judges in courts require a more strict standard for proof of facts, which means that a much higher AR% may be needed to convince judges. The role of epidemiologists in courts may be to show a plausible range of AR%, based on design, execution, and analysis of quoted epidemiologic studies. Standards for accepting plaintiffs' allegation should be discussed in the legal framework of Japan.

Epidemiology↗
PubMed1991

Grade 3 bladder cancer with lamina propria invasion (pT1): characteristics of tumor and clinical course.

To determine the clinical characteristics of grade 3 tumors with lamina propria invasion (pT1), we reviewed the data of 217 patients with superficial bladder cancer who had initially been treated by transurethral resection (193 patients) and fulguration (4), supravesical resection (13) or partial cystectomy (7). We classified the patients into four groups according to histological grade and stage of disease: group 1) grade 0 or 1, pTa tumors (n = 58); group 2) grade 2, pTa tumors (n = 106); group 3) grade 2, pT1 tumors (n = 30); and group 4a) grade 3, pT1 tumors (n = 23). Grade 3, pT1 tumors were significantly related to nonpapillary growth (p = 0.0002), multiple tumors (p = 0.005) and irritative bladder symptoms (p = 0.01). The 5-year progression rates were 0% for group 1, 5% for group 2, 8% for group 3, and 18% for group 4a. The respective 5-year survival rates were 97%, 91%, 83% and 79%. All five patients with grade 3, pT1 tumors who had originally undergone total cystectomy (group 4b) remained alive free of disease for a median follow-up 57 months, establishing a far better survival rate than that for group 4a. These findings show that patients with grade 3, pT1 tumors face a high probability of progression and poor chance of survival. Immediate radical treatment is indicated when tumors recur after initial transurethral resection.

Aged↗
PubMed1990

[How to deal with equivocal subjects in statistical analysis of randomized controlled trials].

In randomized controlled trials, it is likely that several subjects with atypical features are registered. In this paper, it was discussed from a statistical point of view how properly the subjects with the following atypical features could be dealt with; 1) subjects who were found to be not eligible for the trial after randomization, 2) subjects who did not receive the assigned regimen by the treatment protocol, 3) subjects whose outcome was ambiguous as the designated endpoint, and 4) subjects who were ambiguous whether to be regarded as censored cases. It was also emphasized that informations on equivocal subjects should be masked in the committee which is responsible for the statistical judgement. Plausible examples were added to assist the readers to understand the rules discussed here.

Humans↗
PubMed1990

Changes in serum concentrations of beta-carotene and changes in the dietary intake frequency of green-yellow vegetables among healthy male inhabitants of Japan.

Serum levels of beta-carotene among 147 healthy male inhabitants were measured twice with an interval of one year in order to determine the relationship between changes in serum beta-carotene levels and changes in the dietary intake of green-yellow vegetables. A positive association was found to exist between changes in the intake frequency of green-yellow vegetables and changes in serum beta-carotene levels, whereas changes in alcohol intake and smoking were discovered to be negatively associated with changes in serum beta-carotene levels. The positive association between changes in the intake frequency of green-yellow vegetables and changes in serum beta-carotene levels was preserved after adjustment for these negative factors.

Adult↗
PubMed1990

Multi-drug combination therapy with vincristine-melphalan-cyclophosphamide-prednisolone was more effective than cyclophosphamide-prednisolone in stage III myeloma. The Nagoya Myeloma Cooperative Study Group.

A cooperative randomized clinical trial to compare the effectiveness of multi-drug combination chemotherapy (VMCP), vincristine-melphalan-cyclophosphamide-prednisolone) with CP (cyclophosphamide-prednisolone) for the treatment of multiple myeloma was performed. When the whole group of patients was evaluated, the choice of chemotherapy (VMCP or CP) was not a significant prognostic factor associated with response or survival by uni- or multivariate analysis, and the difference between the survival curves of the treatment groups was only marginally significant. However, when the analysis was confined to stage III patients, the choice of chemotherapy became a significant prognostic factor associated with both response rate and survival, and the statistical difference between survival curves was significant. Taking the disease characteristics of multiple myeloma into consideration, the better result obtained with multi-drug combination chemotherapy in the treatment of stage III patients is consistent with other studies supporting the superiority of multi-drug combination chemotherapy for patients with overt systemic disease.

Aged↗
PubMed1990

Family history of cancer and mortality among patients gastrectomized because of benign gastric diseases.

A preliminary result from a cohort study on the association of a family history of cancer with mortality is discussed in this paper. Among 2200 patients (1912 males and 288 females) gastrectomized because of benign gastric diseases, 274 male patients, and 40 female patients had a family history of cancer. During 2750 person-years of observation, 22 patients with the family history of cancer were found to be dead and 111 patients without the family history died during 17,527 person-years, giving a relative risk of 1.26 (not significant). We focused on the male subjects that were followed up for more than 10 years; however, the observed/expected ratio of cancer deaths for subjects with a family history of cancer was about four times higher than that for those without family history. Since case-control studies on family history are vulnerable to biased recall and interchangeability of cases, more cohort studies like the present study should be conducted to assess the association of the family history of cancer.

Case-Control Studies↗
PubMed1990

[Statistical evaluation of determinants of progression of superficial bladder cancer by proportional hazards model].

To evaluate clinical and pathological factors present at the initial consultation which affect disease progression, we reviewed data from 223 patients with superficial bladder cancer (pTa and pT1) who were initially treated at Nagoya University Hospital between January 1973 and December 1987. The factors included in the present analysis were age, sex, symptoms, interval between initial symptoms and first consultation, location of tumor, size, number, endoscopic shape, histological pattern of growth, grade and stage. The median duration of the follow-up after initial treatment was 46 months. Of the 223 patients, 17 died: 8 (3.6%) of bladder cancer and the remaining 9 (4.0%) of unrelated causes. Disease progression developed in 12 patients (5.4%): muscle invasion of the bladder wall in 11 and lung metastasis in one. The interval between initial treatment and progression ranged from 4 to 108 months, with a median of 11.5 months. Of the 12 patients, 9 (75%) had disease progression within 2 years. Progression was significantly associated with poor prognosis (p less than 0.001): the 5-year actuarial survival rates were 47.1% and 92.8% in patients with and without progression, respectively. Univariate analysis by Cox's proportional hazards model demonstrated that characteristics such as irritative bladder symptoms, higher-grade tumors, invasion into lamina propria, and nonpapillary growth seen at initial consultation were significantly related to disease progression. Cox's proportional hazards model produced hazard ratios of 10.2 in irritative bladder symptoms (yes vs. no), 6.3 in histological grade (grade 3 vs. grades 0-2), 4.9 in stage (pT1 vs. pTa), and 4.7 in pattern of growth (papillary vs. nonpapillary).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1990

[Clinical study of urinary cytology in bladder tumors--analysis of factors related with positivity of urinary cytology].

To clarify the clinical and pathological determinants affecting the sensitivity of urinary cytology, we reviewed cytological findings from 119 patients with bladder cancer who were initially treated between January 1982 and March 1988. Cytological specimens obtained from voided urine were stained by the Giemsa and Papanicolaou techniques, and were classified into three categories of malignant cells: positive, suspicious, and negative. Of 311 specimens examined, 114 (37%) were positive, 81 (26%) were suspicious, and the remaining 116 (37%) were negative. The overall positive rate, or sensitivity, was 50% (60 out of 119 patients). The sensitivities were 7% for patients with grade 1 tumors, 42% for grade 2 tumors, and 97% for grade 3 tumors. Univariate analysis by logistic regression analysis revealed that grade, stage, histological pattern of growth, size and number of tumors, and patient age were significantly related with the positivity of voided urinary cytology. The logistic regression model, as a multivariate analysis, demonstrated that grade was the most important determinant affecting the positive cytologic finding, followed by number of tumors with statistical significance. We conclude that the lower sensitivity in conventional urinary cytology for low-grade tumors necessitates new adjuncts, including immunocytochemistry and flow cytometry, to lower the false-negative rate.

Adult↗
PubMed1990

Mortality of hematopoietic disorders and hair dye use among barbers.

A total of 8,316 barbers were followed up from 1976 to 1987 to examine the relations between hair dye use and deaths from hematopoietic disorders. The follow-up rate was about 95%. Three leukemia deaths and two malignant lymphoma deaths were observed in this cohort. The observed deaths were less than the expected number calculated from age- and sex-specific mortality of the general population in Japan (3.8 and 3.0, respectively). No deaths from aplastic anemia or the other hematopoietic disorders were observed.

Adult↗
PubMed1989

Low incidence of acute graft-versus-host disease by the administration of methotrexate and cyclosporine in Japanese leukemia patients after bone marrow transplantation from human leukocyte antigen compatible siblings; possible role of genetic homogeneity. The Nagoya Bone Marrow Transplantation Group.

Japanese patients with leukemia who received bone marrow from human leukocyte antigen (HLA)-compatible siblings had a low incidence of acute graft-versus-host disease (GVHD). Twenty-five (21%) of 120 patients developed moderate (grade II) to severe (grades III to IV) acute GVHD. Severe GVHD was only seen in patients older than 20 years of age. It is also notable that only 2 (5%) of 39 patients who received the combination of methotrexate and cyclosporine (MTX/CSP) for the prevention of GVHD developed grade II acute GVHD, and none developed grades III to IV acute GVHD. Thirteen (30%) of 44 patients receiving MTX alone and 10 (27%) of 37 patients receiving CSP alone developed grades II to IV acute GVHD. Multivariate life-table analysis indicated that the prophylaxis by MTX/CSP was the risk factor for the low incidence of grades II to IV acute GVHD. Compared with the reported incidence of acute GVHD in the patients of the United States, lower incidence of acute GVHD in Japanese BMT patients might be attributable to a lesser degree of genetic diversity in histocompatibility antigens among Japanese.

Acute Disease↗
PubMed1989

Serum concentration of beta-carotene and intake frequency of green-yellow vegetables among healthy inhabitants of Japan.

Serum levels of beta-carotene were measured among healthy inhabitants (671 males and 948 females) of 2 towns in Japan to determine the association between the levels and intake frequency of green-yellow vegetables. Those individuals who consumed green-yellow vegetables frequently showed higher levels of serum beta-carotene than those who ate them less often. The influences of alcohol drinking, smoking, obesity and age on serum beta-carotene levels were similarly observed for the 2 areas. The factors listed above were used for adjustment, giving a significant association between intake frequency of green-yellow vegetables and serum beta-carotene level. The proportion of the subjects who rarely consumed green-yellow vegetables was larger among smokers than among non-smokers. There was a large difference in serum beta-carotene levels between the 2 towns, which could not be explained by alcohol drinking and smoking. Women showed statistically significantly higher serum beta-carotene levels than men.

Adult↗
PubMed1989

[Hazard ratio estimated from a proportional hazard model including two strongly correlated prognostic factors].

Estimates of hazard ratio from hypothetical survival data were examined, under the condition that the survival is affected by two prognostic factors X1 and X2 with two discrete values (0, 1) which are strongly correlated. Survival curves from the data were assumed to fit an exponential function. As an example, following numbers of subjects were used; 100 cases with X1 = 0 and X2 = 0, 10 cases with X1 = 1 and X2 = 0, 10 cases with X1 = 0 and X2 = 1, and 100 cases with X1 = 1 and X2 = 1. When the hazard ratio of X1 = 1 or X2 = 1 to X1 = 0 and X2 = 0 was 3, univariate analysis gave reasonable estimates around 3. Under the same condition, estimates of hazard ratio from multivariate analysis including the two variables X1 and X2 varied widely, depending on the survivals of 20 cases with X1 = 1 X2 = 0 or X1 = 0 X2 = 1. Probability of having extremely deviated estimates was demonstrated. The result illustrated successfully some points we should take into account when proportional hazard models including strongly correlated variables are applied.

Actuarial Analysis↗
PubMed1989

[Explanatory essay for researchers who plan to analyse their clinical data using Cox's proportional hazard model].

Proportional hazard model was proposed by Cox as a multivariate model suitable for evaluation of prognostic factors and/or therapeutic effects. This paper aims at explaining fundamental concepts of the model for clinical researchers, as clear as possible. The relationship between hazard ratio and survival curves is demonstrated using an example of survivals calculated from an exponential function. Usage of computer programme SAS is described in brief for the readers who plan to analyse their own clinical data by this model.

Analysis of Variance↗
PubMed1989

Influence of risk factors on long-term survival following acute myocardial infarction: a follow-up study in central Japan.

The long-term survival rate following acute myocardial infarction (AMI) was studied in 358 patients in central Japan who were monitored for 8 to 20 years after discharge from hospital for AMI. Fifteen-year cardiac survival rates were 65% in males and 72% in females. In both sexes, the survival rate decreased with increasing age at the time of AMI. The survival rate was significantly lower in recurrent MI than in first MI patients. Those who had smoked cigarettes before AMI or had hyperlipidemia during hospitalization did not show any significant decrease in cardiac survival rate, which may be due to cessation of smoking or control of hyperlipidemia after AMI. The 15-year survival rate was significantly lower in patients with a past history of angina pectoris or hypertension. Patients with a large infarct had a lower survival rate, as did those with a large cardiothoracic ratio on chest x-ray, and those who received digitalis during hospitalization. On the other hand, patients who were administered anticoagulants during hospitalization had a higher survival rate. Multiple regression analysis gave similar results. In conclusion, factors that reduced long-term survival rate after AMI were older age at time of the first attack, reduced cardiac function, and a history of angina pectoris or hypertension. Anticoagulant therapy appeared to improve the long-term survival rate.

Age Factors↗