During the latter half of the 1990s, Japanese healthcare professionals and policy-makers recognized the value of an "evidence-based" approach. At the same time, an increased social awareness of the need to protect research participants and personal information began to appear. Recognition of an evidence-based approach further promoted epidemiologic research while regulations on personal information protection imposed certain limitations on this same research. In April 2000, as a solution to this conflict, a working group funded by Japan's Ministry of Health and Welfare (MHW; currently the Ministry of Health, Labour and Welfare: MHLW) proposed a first draft of ethical guidelines for epidemiologic research. Over the next two years, the collection of domestic and foreign data by working groups and governmental ad hoc committees, questions raised by the mass media, and public statements made by organizations, such as the Science Council of Japan and the Japan Epidemiologic Association (JEA), led to a collaborative effort between the Ministry of Education, Culture, Sports, Science and Technology and the MHLW. This effort led to the creation of the Ethical Guidelines for Epidemiologic Research in June 2002, which was revised in 2004. Furthermore, JEA also announced the Ethical Guidelines for Conducting of Epidemiologic Research in October 2002. While the development of these ethical guidelines has been a challenge for Japanese epidemiologists, it has also allowed the epidemiologic community to understand their role in society. This review aims to provide insight into the interaction between the epidemiologic community and society by assessing historically the developmental process of these ethical guidelines. J Epidemiol 2005;15:107-112.
BACKGROUND: The Global Initiative for Chronic Obstructive Lung Disease guidelines recommended a forced expiratory volume at one second per forced vital capacity as a standard diagnostic criterion of chronic obstructive pulmonary disease (COPD). A few reports on the risk factors of COPD have used the standard diagnostic criteria. In our study, the effects of age and smoking on COPD in Japan under the standard diagnosis criteria were evaluated. METHODS: Subjects were 11,460 participants aged 25-74 years during health check-ups including spirometry at the Toyota Community Medical Center in Japan. Logistic regression analyses with or without COPD as a dependent variable and age as an independent variable were conducted among non-smokers. The ratio of the observed number of COPD cases in former and current smokers to the number expected for non-smokers with the same distribution of age (O/E) was calculated. RESULTS: The proportion of males incurring COPD significantly increased with age, and the O/E for former and current male smokers was significantly higher than one, i.e., O/E (95% confidence interval) for current smokers with a Brinkman Index of <400, 400-799, and 800+ were 3.10 (2.00-4.81), 2.78 (2.05-3.73), and 4.76 (3.65-6.19), respectively. Among females, the O/E for current smokers with a Brinkman Index of <400, and 400-799 were significantly higher than one. CONCLUSION: Age and smoking were shown to constitute strong risk factors for COPD under the standard diagnostic criteria. J Epidemiol 2005; 15:113- 117.
BACKGROUND: Although laboratory experiments suggest protective effects of green tea against colorectal cancer, few prospective cohort studies have been conducted. METHODS: We conducted a pooled analysis of two prospective cohort studies among residents in Miyagi Prefecture in rural northern Japan. The first study started in 1984 and included 26,311 subjects. The second study started in 1990 and included 39,604 subjects. The subjects responded to a selfadministered questionnaire including an item on green tea consumption. With 7 to 9 years of follow-up, 305 colon and 211 rectal cancers were identified in the two cohorts through record linkage to a regional cancer registry. We used Cox regression to estimate the hazard ratio (HR) of colorectal cancer according to the consumption of green tea with adjustment for potential confounders, and pooled the estimates obtained from each cohort by general variance-based method. RESULTS: Multivariate pooled HRs for colon cancer associated with drinking 1-2, 3-4, and 5 or more cups of green tea per day, as compared with less than 1 cup per day, were 1.06 (95% confidence interval [CI] = 0.74-1.52), 1.10 (0.78-1.55), 0.97 (0.70-1.35), respectively (trend p = 0.81). Corresponding HRs for rectal cancer were 0.85 (95% CI = 0.56-1.29), 0.70 (0.45-1.08), 0.85 (0.58-1.23), respectively (trend p = 0.31). CONCLUSIONS: Consumption of green tea was not associated with lower risk of colorectal cancer. J Epidemiol 2005; 15:118-124.
BACKGROUND: Electrocardiogram (ECG) is one of the most popular tools for daily clinics and health checkup, and has been used for the National Survey on Circulatory Disorders to assess the health status in Japanese people. The meaningfulness to predict mortality from all causes among people with ECG abnormality is to be clarified using national samples. METHODS: ECG findings recorded among 9,638 subjects for National Survey on Circulatory Disorders 1980 in Japan, were classified using the Minnesota Codes (mc). Their relationships to all cause mortality over 19 years were examined using Cox proportional hazard models adjusting for sex, age, systolic blood pressure, blood glucose, and smoking habits. RESULTS: Subjects with abnormal Q-QS findings showed significantly high hazard ratios ( 3.71(mc1-1) and 1.57 (mc1-3)) for mortality to the subjects who were free from any major ECG findings. Hazard ratios were 1.37 (mc2-1) to 4.16 (mc2-5) for axis deviation, and 1.34 (mc3-1) to 1.35 (mc3-3) for left high R waves. Those were 1.63 (mc4-3) to 2.59 (mc4-1) for ST depression, and 1.54 (mc5-3) to 2.33 (mc5-1) for T abnormality. The lower the second number of the Minnesota Codes was, the higher hazard ratio was observed in the Q-QS, ST, T codes. The hazard ratios of junction-type ST depression (mc4-4), and low T waves (mc5-4, 5-5) were not significant. CONCLUSIONS: ECG findings defined by the Minnesota Codes were useful to predict the risk for mortality from all causes even after adjusting for the other major risk factors, and the results supported a usefulness of the ECG for health check-ups. J Epidemiol 2005;15:125-134.
BACKGROUND: Validation studies on brief food frequency questionnaires (FFQs) for measuring consumption of macro- and micro-nutrients for the general populace are not fully executed in Japan. METHODS: Two hundred and two middle-aged Japanese (73 males and 129 females) in Aichi Prefecture, Japan completed an FFQ and 3day-weighed diet records (3d-WDRs) in February 2004. We compared intakes of energy and 26 nutrients computed with the FFQ against those with the 3d-WDRs as a reference. RESULTS: Mean daily intakes of selected nutrients determined with the FFQ were generally less than those with 3d-WDRs. The ratios assessed with the FFQ vs. 3d-WDRs (minimum - median - maximum) were distributed from 0.57 - 0.79 - 1.09 for males, and 0.61 - 0.86 - 1.04 for females. De-attenuated, log-transformed and energy-adjusted Pearson's correlation coefficients between intakes of selected nutrients quantified with both devices were distributed from 0.12 - 0.45 - 0.86 and energy-adjusted Spearman's rank correlation coefficients were from 0.13 - 0.35 - 0.76, for males. The respective values for females were 0.10 - 0.38 - 0.66, and 0.11 - 0.34 - 0.47. Median percentages for exact agreement, agreement within adjacent categories, and disagreement according to quartile classification of the energy-adjusted nutrient intakes measured with both methods were 33, 74, and 5 for males, and 35, 76, and 7 for females, respectively. CONCLUSION: Satisfactorily high relative validity indices of most nutrient intakes computed with the FFQ were attained against those with the 3d-WDRs. The questionnaire therefore appears applicable for categorizing individuals according to consumption of energy and selected nutrients in dietary studies of middle-aged Japanese. J Epidemiol 2005;15:135-145.
BACKGROUND: Proteinuria has been considered to be a prognostic marker for persons with diabetes mellitus, but only a limited number of studies about the relationship between proteinuria and mortality among general population has been available. METHODS: The subjects were 10,897 individuals who participated in the National Cardiovascular Survey conducted in 1980 and who were aged 30 years or older living in 300 districts that had been randomly selected throughout Japan. The vital records were confirmed in 1999 and 7,203 subjects (3,180 males and 4,023 females) without a history of hypertension, stroke, heart disease, renal disease, or diabetes mellitus at the start of the study were investigated. RESULTS: There were 126,825 person-years of follow-up. During the observed period of time, 371 died of cardiovascular causes, including 171 stroke deaths and 74 coronary deaths. The risk of proteinuria for cardiovascular mortality was greater than unity for those with a normal serum creatinine level, after adjusting for age and other cardiovascular disease risk factors. CONCLUSIONS: When contrasted with other cardiovascular disease risk factors, urinary protein is an independent risk factor for cardiovascular death among the Japanese population. J Epidemiol 2005; 15:146-153.