Mikizo Okamoto

A community-based, case-control study evaluating mortality reduction from gastric cancer by endoscopic screening in Japan.

Aims Although the incidence of gastric cancer has decreased in the last 3 decades, it remains the second leading cause of cancer death worldwide. In Asian countries, the burden of gastric cancer has remained, and cancer screening is normally expected to reduce gastric cancer death. We conducted a community-based, case-control study to evaluate the reduction of mortality from gastric cancer by endoscopic screening. Methods Case subjects were defined as individuals who had died of gastric cancer between 2003 and 2006 in 4 cities in Tottori Prefecture, and between 2006 and 2010 in Niigata City, Japan. Up to 6 control subjects were matched by sex, birth year (±3 years), and the residence of each corresponding case subject from the population lists in the study areas. Control subjects were required to be disease-free at the time when the corresponding case subjects were diagnosed as having gastric cancer. The odds ratios (ORs) were calculated for those who had participated in endoscopic or radiographic screening before the reference date when the case subjects were diagnosed as having gastric cancer, compared with subjects who had never participated in any screening. Conditional logistic-regression models for matched sets were used to estimate the ORs and 95% confidence intervals (CIs). Results The case subjects consisted of 288 men and 122 women for case subjects, with 2,292 matched control subjects. Compared with those who had never been screened before the date of diagnosis of gastric cancer in the case subjects, the ORs within 36 months from the date of diagnosis were 0.695 (95% CI: 0.489–0.986) for endoscopic screening and 0.865 (95% CI : 0.631–1.185) for radiographic screening. Conclusions The results suggest a 30% reduction in gastric cancer mortality by endoscopic screening compared with no screening within 36 months before the date of diagnosis of gastric cancer.

Metabolic syndrome and incidence of liver and breast cancers in Japan

AIM OF THE STUDY To clarify the relationship between the presence of metabolic syndrome and the incidence of cancer in a general Japanese population. METHODS A retrospective cohort study was conducted among 8329 male and 15,386 female subjects between 1992 and 2000. The analysis used five definitions of metabolic syndrome. The information on the site-specific cancer was obtained from the population-based cancer registry. A Cox proportional hazard model was adapted for the statistical analyses. The average follow-up period was 9.1 years. RESULTS The National Cholesterol Education Program Adult Treatment Panel III 2001 criteria of metabolic syndrome revealed that the hazard ratio of metabolic syndrome for liver cancer was 1.89 (95% confidence interval (CI) 1.11-3.22) for males, and 3.67 (CI 1.78-7.57) for females. The hazard ratio for female breast cancer was 2.87 (CI 1.67-4.94). When the analysis was limited to postmenopausal women (55 years of age or older), the ratio increased to 6.73 (CI 2.93-15.43). The NCEP-ATPIII 2001 criteria were superior to the other four proposed criteria for predicting the incidence of cancer. In the statistical model, which included all components of the metabolic syndrome and the metabolic syndrome (present or absent), high blood glucose was a significant associated factor for all sites and liver cancers, whereas the metabolic syndrome was found to be a significant associated factor for breast cancer. CONCLUSION Metabolic syndrome may play an important role in the incidence of breast cancer. High fasting plasma glucose level is considered to be useful as an associated factor for the incidence of all-sites and liver cancer.

Sensitivity of endoscopic screening for gastric cancer by the incidence method

Although radiographic screening for gastric cancer has been conducted in Japan, it is anticipated that endoscopy will become a new screening method because of its high detection rate. The sensitivities of endoscopic and radiographic screening were calculated by the detection method and the incidence method based on the results of community‐based screening in Japan. There were 56,676 screenings for gastric cancer using endoscopy and radiography from April 2002 to March 2007 in Yonago, Japan. The target age group was from 40 to 79 years. Screen‐detected and interval cancers were investigated based on a screening database linked to the Tottori Cancer Registry. All gastric cancers diagnosed within 1 year after a negative screen were considered interval cancers. Based on the screening history, these were divided into prevalence screening and incidence screening. Prevalence screenings included 7,388 for endoscopic screening and 5,410 for radiographic screening, whereas incidence screenings included 18,021 for endoscopic screening and 11,417 for radiographic screening. The sensitivity of prevalence screening calculated by the incidence method was 0.886 (95% confidence interval [CI] = 0.698–0.976) for endoscopic screening and 0.831 (95% CI = 0.586–0.964) for radiographic screening; however, the difference was not significant (p = 0.626). The sensitivity of incidence screening calculated by the incidence method was 0.954 (95% CI = 0.842–0.994) for endoscopic screening and 0.855 (95% CI = 0.637–0.970) for radiographic screening (p = 0.177). Endoscopic screening for gastric cancer had a higher sensitivity than radiographic screening by the incidence method in both screening rounds. However, further study is needed to evaluate mortality reduction and to estimate overdiagnosis with endoscopic screening for gastric cancer.

The relationship between skin symptoms and allergic reactions to Asian dust.

Asian dust events result from displacement of atmospheric pollutants from the Chinese and Mongolian deserts, causing associated health issues throughout Northeast Asia. We investigated the relationship between skin symptoms in Asian dust events and contact allergy to Asian dust and associated metals. Increases in atmospheric levels of heavy metals such as Ni, Al, and Fe occurred during the severe Asian dust event on March 21, 2010. We conducted a case–control study (n = 62) with patch testing to compare skin symptoms on an Asian dust day with metal allergic reactions. Skin symptoms were observed in 18/62 subjects. Nine subjects with skin symptoms (group A) and 11 without (group B) were patch tested for six metals and Asian dust particles. Metal and dust samples were applied to the subjects’ backs for 2 days and the reactions were scored according to the International Contact Dermatitis Research Group guidelines. Differences in the positive rates between the groups were analyzed. Skin reactions to ferric chloride (p = 0.015), aluminum chloride (p = 0.047), nickel sulfate (p = 0.008), and Asian dust particles (p = 0.047) were more common in group A than in group B. Skin symptoms during Asian dust events may be allergic reactions to Asian dust particle-bound metals.

Mortality reduction from gastric cancer by endoscopic and radiographic screening.

To evaluate mortality reduction from gastric cancer by endoscopic screening, we undertook a population‐based cohort study in which both radiographic and endoscopic screenings for gastric cancer have been carried out. The subjects were selected from the participants of gastric cancer screening in two cities in Japan, Tottori and Yonago, from 2007 to 2008. The subjects were defined as participants aged 40–79 years who had no gastric cancer screening in the previous year. Follow‐up of mortality was continued from the date of the first screening to the date of death or up to December 31, 2013. A Cox proportional hazards model was used to estimate the relative risk (RR) of gastric cancer incidence, gastric cancer death, all cancer deaths except gastric cancer death, and all‐causes death except gastric cancer death. The number of subjects selected for endoscopic screening was 9950 and that for radiographic screening was 4324. The subjects screened by endoscopy showed a 67% reduction of gastric cancer compared with the subjects screened by radiography (adjusted RR by sex, age group, and resident city = 0.327; 95% confidence interval [CI], 0.118–0.908). The adjusted RR of endoscopic screening was 0.968 (95%CI, 0.675–1.387) for all cancer deaths except gastric cancer death, and 0.929 (95%CI, 0.740–1.168) for all‐causes death except gastric cancer death. This study indicates that endoscopic screening can reduce gastric cancer mortality by 67% compared with radiographic screening. This is consistent with previous studies showing that endoscopic screening reduces gastric cancer mortality.

The current status of hand washing and glove use among care staff in Japan: its association with the education, knowledge, and attitudes of staff, and infection control by facilities.

ObjectiveHand hygiene is a basic measure to prevent infections. The purpose of this study was to obtain suggestions for the improvement of hand hygiene by evaluating the education, knowledge, and attitudes of care staff at facilities for the elderly in regard to hand washing and glove use, as well as infection control policies by those facilities.MethodsAmong a total of 147 special nursing homes and health service facilities for the elderly in Yamaguchi Prefecture, Japan, questionnaires were sent from October to November 2007 to 56 facilities which had agreed to participate in this survey. Two types of questionnaire, one for the facility manager and the other for care staff, were sent to each facility.ResultsThe questionnaire was responded to by 42 managers (response rate 28.6%) and 1,323 staff members (response rate 26.3%). The rate of compliance with hand hygiene among them was 34.0%. Personal factors promoting hand hygiene were education and attitudes, while facility-related factor was the implementation of hand-washing evaluation.ConclusionSince the hand hygiene compliance rate is low among care staff at facilities for the elderly, it is necessary to take measures to improve hand hygiene. Educational programs for hand hygiene should be developed in view of the conditions of individual facilities.

Three year follow up study of national influenza vaccination practices in Japan.

STUDY OBJECTIVE--To evaluate new national influenza vaccination practices which were started in 1987 under a revised law in Japan. DESIGN--This was a three year, nonrandomised cohort study with information collected by questionnaire between 1989 and 1991. SETTING--Eight primary schools in the city of Yonago, Tottori, Japan. These schools were selected from 23 schools in the city. PARTICIPANTS--Altogether 4251 pupils (1355 boys and 2896 girls) in years 1-4 of the eight primary schools were included in this study, and followed up. Three years later, data for 1619 pupils (768 boys and 851 girls) were obtained and analysed. MAIN RESULTS--The one-winter seasonal incidence rates of influenza-like disease were 13.4%, 29.9%, and 10.3% in 1989, 1990, and 1991 respectively. The incidence rate of influenza-like disease in fully vaccinated pupils was significantly lower than that in unvaccinated pupils in 1990, but not in 1989 or 1991. Stepwise multiple regression analysis showed that the incidence of influenza-like disease had a statistical relationship with the frequency of vaccination and the school year (R2 was 0.0148). Standardised parameters of the frequency of vaccination and the school frequency of vaccination and the school year were -0.089 and -0.080 respectively. CONCLUSIONS--The preventive effects of influenza vaccine are not strong. There must be some unknown factors that affect the incidence of influenza. This vaccine is useful for pupils in the early school years who seem to have less resistance. All pupils should not be inoculated with the vaccine to reduce influenza transmission in the community or school.

Polymorphism of Trp64Arg in β3-adrenergic receptor gene and serum LDL-cholesterol concentrations in healthy Japanese

Background Polymorphism of Trp64Arg in the β3-adrenergic receptor (β3-AR) gene may play a critical role in lipid and lipoprotein metabolism by mediating lipolysis and thermogenesis. Since the frequency of Arg alleles of the β3-AR gene is generally low among many populations, studies on the Arg/Arg genotype in relation to lipid and lipoprotein metabolism are required in countries such as Japan which has a relatively high frequency of the Arg allele. Methods We genotyped 275 clinically healthy Japanese (male/female, 134/141, mean 45.7 years) without medication for β3-AR gene polymorphism by polymerase chain reaction–restriction fragment length polymorphism analysis, and investigated the effects of the gene polymorphism on clinical parameters including body mass index (BMI), blood pressure and serum lipid and lipoprotein concentrations. Results The genotype frequencies were: Trp/Trp, 68.0%; Try/Arg, 28.0% and Arg/Arg, 4.0%, with an allele frequency of 0.18 for Arg64. When subjects were divided into three groups according to the genotype, a significant increase of serum LDL-cholesterol (LDL-C) concentration in the Arg/Arg group (3.48 ± 1.59 mmol/L) was observed when compared with those of the Trp/Trp and Arg/Trp groups (3.15 ± 0.80, 3.25 ± 0.92 mmol/L, respectively). Genotype differences did not show any significant effect on other parameters. Spearmans rank correlation demonstrated a significant relationship between LDL-C concentrations and the number of Arg alleles, age and BMI. Multiple regression analysis, using LDL-C concentration as a criterion variable and some factors including β3-AR gene polymorphism as explanatory variables, revealed that the number of Arg alleles was a significant and independent factor for LDL-C concentrations, along with age and BMI. Conclusions These findings suggested a role of the β3-AR gene polymorphism in regulating lipid and lipoprotein metabolism, showing small but significant effects on elevated LDL-C values in subjects with Arg/Arg, but not Trp/Arg and Trp/Trp genotypes.

Survival Analysis of Patients with Interval Cancer Undergoing Gastric Cancer Screening by Endoscopy

Aims Interval cancer is a key factor that influences the effectiveness of a cancer screening program. To evaluate the impact of interval cancer on the effectiveness of endoscopic screening, the survival rates of patients with interval cancer were analyzed. Methods We performed gastric cancer-specific and all-causes survival analyses of patients with screen-detected cancer and patients with interval cancer in the endoscopic screening group and radiographic screening group using the Kaplan-Meier method. Since the screening interval was 1 year, interval cancer was defined as gastric cancer detected within 1 year after a negative result. A Cox proportional hazards model was used to investigate the risk factors associated with gastric cancer-specific and all-causes death. Results A total of 1,493 gastric cancer patients (endoscopic screening group: n = 347; radiographic screening group: n = 166; outpatient group: n = 980) were identified from the Tottori Cancer Registry from 2001 to 2008. The gastric cancer-specific survival rates were higher in the endoscopic screening group than in the radiographic screening group and the outpatients group. In the endoscopic screening group, the gastric cancer-specific survival rate of the patients with screen-detected cancer and the patients with interval cancer were nearly equal (P = 0.869). In the radiographic screening group, the gastric cancer-specific survival rate of the patients with screen-detected cancer was higher than that of the patients with interval cancer (P = 0.009). For gastric cancer-specific death, the hazard ratio of interval cancer in the endoscopic screening group was 0.216 for gastric cancer death (95%CI: 0.054-0.868) compared with the outpatient group. Conclusion The survival rate and the risk of gastric cancer death among the patients with screen-detected cancer and patients with interval cancer were not significantly different in the annual endoscopic screening. These results suggest the potential of endoscopic screening in reducing mortality from gastric cancer.

Retrospective Cohort Study of Smoking and Lung Cancer Incidence in Rural Prefecture, Japan

ObjectivesWe conducted an epidemiological study of the relationship between lung cancer incidence and smoking, with special reference to the benefits of smoking cessation for reducing lung cancer incidence, to promote a local smoking control program.MethodsThe study was a retrospective cohort study. The population studied was 16,383 male examinees of lung cancer health examinations in 1995 in Tottori Prefecture, Japan. Smoking status from the questionnaire during the health examination was used as the exposure variable. Endpoint (lung cancer incidence) was obtained from the Tottori population-based cancer registry. A multivariable analysis using the Cox proportional hazard model was adapted for statistical analysis. The average follow-up period was 4.3 years.ResultsThe hazard ratio of current smokers for the incidence of lung cancer was 4.9, whereas that of ex-smokers was 2.2. The dose-response relationship between lung cancer incidence and lifetime cigarette consumption (pack year) was determined. The ratio increased among younger subjects (under 65 years old). The hazard ratio of ex-smokers decreased with years just after quitting smoking, and reached the level of never smokers after 10–19 years from smoking cessation.ConclusionsWe reconfirmed that the magnitude of risk estimates of smoking for lung cancer incidence was similar to those of previous studies, and smoking cessation was effective for reducing lung cancer risk.