Kyohei Hayashi

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

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)

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

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.

Prevalence and mortality of ulcerative colitis and Crohn's disease in Japan.

SummaryA descriptive epidemiological study of ulcerative colitis and regional enteritis or Crohn’s disease in the general population in Japan was conducted. Mortality rates were based on death certificate records and prevalence rates on the statistics of public aid patients with intractable diseases. Between 1969 and 1985, age-adjusted mortality rates from ulcerative colitis gradually decreased. For regional enteritis, these rates did not change.The prevalence of ulcerative colitis in Japan from April 1, 1984 to March 31, 1985 was 7.85 per 100,000 (6.44 for males, 9.22 for females). The prevalence of Crohn’s disease was 1.86 (2.25 for males, 1.48 for females). These figures are one fourth to one fortieth of the rates in Western countries.

Multivariate analysis of factors affecting postoperative survival in malignant astrocytoma

SummaryFifty-eight patients with supratentorial malignant astrocytoma were analyzed statistically to evaluate the actors most important for predicting postoperative survival. Clinical information such as age, sex, duration of preoperative symptom, Karnofsky score at admission and at discharge, location of tumor, amount of tumor removal, number of operations, and postoperative survival in months, together with data on radiation and chemotherapy were analyzed by chi square test, t-test, and multivariate analysis. Cytofluorometric DNA quantification using paraffin embedded specimens was also performed in 20 cases and these data were also evaluated.Multiple correlation coefficient, and therefore the total statistical accuracy, increased to 0.824 when data of DNA quantification, percentages of S phase cells and of polyploid cells, were included. Multivariate analysis revealed that 6 items were the major factors for predicting postoperative survival, i.e. the location of tumor, the Karnofsky score at discharge, the percentage of S phase cells, the number of operations, the percentage of polyploid cells, and the amount of tumor removed. Based on this analysis, the estimated survival time could be expressed as a formula.

Helicobacter pylori infection and atrophic gastritis: a nested case-control study in a rural town in Japan.

A seroepidemiologic, nested case-control studywas conducted to evaluate the risk for atrophicgastritis associated with Helicobacter pylori infection.Atrophic gastritis was diagnosed on the basis of serum pepsinogen levels: pepsinogen I level≤70 ng/ml and pepsinogen I/pepsinogen II ratio≤3.0. Cases were 23 men and 39 women who were notdiagnosed with atrophic gastritis in 1987, but who were diagnosed with the condition in 1992. Controlswere the 120 men and 282 women who did not meet theserologic criteria for atrophic gastritis in either timeperiod. Neither cases nor controls had a history of upper gastrointestinal operations.Helicobacter pylori infection at the initial survey wasassociated with a significantly increased risk ofatrophic gastritis incidence for both sexes combined(odds ratio = 3.72; 95% confidence interval,1.78-7.79; P = 0.0005). Cigarette smoking andconsumption of alcohol and green-yellow vegetables werenot associated with incidence of atrophicgastritis.

Various S-GOT/S-GPT Ratios in Nonviral Liver Disorders and Related Physical Conditions and Life-Style

The relationship between the GOT/GPT ratio in nonviral liver disorders and underlying physical condition and life-style were evaluated. The subjects were 12,808 male railway company workers who underwent an annual health checkup. Nonviral liver disorders were defined as elevated transaminases (GOT > 76 IU/liter or GPT > 86 IU/liter, while negative for hepatitis B and C markers (282 cases). Controls were 9783 males with normal findings for GOT, GPT, and γ-GTP. By logistic regression analysis, GOT-dominant liver disorders were significantly related to alcohol consumption, hypertriglyceridemia, and diabetes mellitus. They were still significant on multivariate analysis. GPT-dominant liver disorders were significantly related to obesity, less exercise, hypercholesterolemia, and hypertriglyceridemia. Obesity and hypercholesterolemia were significant on multivariate analysis. In conclusion, the relationship between hypertriglyceridemia or diabetes mellitus and GOT-dominant disorders, which was not explained empirically, could indicate another pathogenesis for nonviral liver disorders, such as underlying insulin resistance.

Natural history and epidemiologic studies of peptic ulcer disease in Japan.

Japanese research on the natural history and epidemiology of peptic ulcer disease is presented. Descriptive summaries from several national and regional studies provide information that may be useful for comparison with corresponding information from Western nations.

Proton-pump inhibitor-first strategy versus "step-up" strategy for the acute treatment of reflux esophagitis : a cost-effectiveness analysis in Japan

BackgroundGastroesophageal reflux disease (GERD) is a common condition, and acid-suppressing agents are the mainstays of treatment. For the acute medical management of GERD, two different strategies can be proposed: either the most effective therapy, i.e., proton-pump inhibitors (PPIs), can be given first, or histamine H2-receptor antagonists (H2RAs) can be attempted first (the “step-up” approach).MethodsA clinical decision analysis comparing the PPI-first strategy and the H2RA-first “step-up” strategy for the acute treatment of reflux esophagitis in Japan was performed, using a Markov chain approach.ResultsThe PPI-first strategy was consistently superior to the step-up strategy with regard to clinical outcomes for the patient and with regard to cost-effectiveness (direct cost per patient to achieve clinical success). This superiority was robust within the plausible range of probabilities according to the sensitivity analyses.ConclusionsThe PPI-first strategy is superior to the H2RA-first “step-up” strategy with regard to both efficacy and cost-effectiveness and therefore, the PPI-first strategy is the preferred therapeutic approach for the acute medical treatment of reflux esophagitis.

Helicobacter pylori infection and atrophic gastritis : A case-control study in a rural town of Japan

We enrolled five hundred twenty-one patients with atrophic gastritis and 769 controls in a case-control study of atrophic gastritis and Helicobacter pylori infection and lifestyle factors. The participants had no history of upper gastrointestinal surgery. They were selected from 1,395 adult (35 years or older) residents of a rural town in Kyoto prefecture who participated in an annual health examination in 1987. Atrophic gastritis was diagnosed on the basis of serum pepsinogen levels: pepsinogen I levels (< or = 70 ng/ml) and pepsinogen I/pepsinogen II ratios (< or = 3.0). The presence of immunoglobulin G antibodies to H. pylori indicated H. pylori infection. At the time of the health examination, participants were interviewed about daily lifestyle habits such as use of cigarettes and alcoholic beverages and consumption of green-yellow vegetables. Unconditional logistic regression analysis indicated that H. pylori infection was associated with a significantly increased risk for atrophic gastritis for all participants (odds ratio, 8.17; 95% confidence interval, 5.63-11.84); for men (odds ratio, 10.91; 95% CI, 5.25-22.67); and for women (odds ratio, 7.28; 95% CI, 4.72-11.22). We found no statistically significant relations between lifestyle factors and atrophic gastritis.

Immunization coverage and infant mortality rate in developing countries.

We examined whether immunization coverage (IMC) is one of the predictors of infant mortality rate (IMR), as a single indicator representing the availability of primary health care (PHC) services in developing countries. Multiple regression analysis showed that partial correlation coefficients for IMR with immunization coverage (-0.224), logarithm of per capita GNP (-0.294), total fertility rate (0.269), and adult literacy rate (-0.325) were all statistically significant (p < 0.001) in 97 developing countries which make up more than 97% of the population in all developing countries of the world. Multiple correlation coefficients of IMR with these four variables in 97 countries was 0.921. Thus, more than 80% of variation of IMR in developing countries were explained by the variation of the four variables. The study also showed that IMC was well correlated (simple correlation) with the four indicators of the availability of primary health care services: access to local care (0.730), care of pregnant women (0.603), delivery care (0.666), and infant care (0.553), all of which were statistically significant (p < 0.001) in the 48 developing countries which make up 42% of the population of all developing countries. Multiple correlation coefficients of these four variables was 0.787. About 60% of the variation of IMC will be explained by the variation of the four variables. Thus we conclude that immunization coverage is one of the main predictors of the infant mortality rate. It represents one of the health intervention components which can be used as a proxy indicator of the availability of PHC service in developing countries. Asia Pac J Public Health1994;7(4): 228-32.