The objective of this paper is to describe a method of estimating the prevalence of non-insulin dependent diabetes mellitus (NIDDM) in a community. We first counted subjects with previously diagnosed NIDDM and those newly diagnosed by use of the 75-gram oral glucose tolerance test (OGTT). We then used the OGTT data to predict the prevalence of NIDDM at different levels of fasting plasm glucose (FPG) among the subjects who did not undergo the OGTT. Data were derived from 3, 614 residents aged 20 years and older in a rural area where population-based screening for NIDDM was performed using FPG or post-prandial plasma glucose(PG). Of the 318 participants who underwent an OGTT in 1992, 35 (11.0%) were judged to have NIDDM by the 2-hour PG criterion. We applied the above-described method to the 1, 179 subjects who had an FPG but failed to undergo the OGTT. The estimated prevalence of NIDDM, which included the previously diagnosed group, the newly diagnosed group and the expected group, was calculated. The estimated prevalence of diabetes in this population aged 20 years and older turned out to be 6.1% (95% Cl: 5.3-6.9). As a validation study, the same method was applied to 220 subjects who did not undergo the OGTT in 1992 but did so in 1994. The actual prevalence of NIDDM among these subjects was compared to the prevalence expected from the 1992 data by our method. The actual value was within the 95% confidence interval of the expected value. J Epidemiol, 1996 ; 6 : 114-119.
Clinical tests, a questionnaire on life style and mental health, and physical fitness tests were conducted on 3, 132 individuals (1, 796 men and 1, 336 women) to find the relationships between physical fitness level and life style, mental health, or cardiovascular risk factors among Japanese. Individuals with an advanced physical fitness level also exhibited optimum mental health: the odds ratio (OR) and 95% confidence interval (CI) for their sensation of fatigue (fast recovery) was 1.16 (95% Cl = 1.00 to 1.35) and that for mood recovery (fast) was 1.29 (95% Cl = 1.12 to 1.49). Among those with an advanced physical fitness level, the following were rare (OR): daily smoking [0.78]; obesity (over 120%) [0.73 (95% Cl = 0.62 to 0.87)]; thick subcutaneous fat (over 20 mm on the back) [0.77 (95% Cl = 0.66 to 0.90)]; high blood sugar level [0.64 (95% Cl = 0.50 to 0.82)]; and hypertension [0.67 (95% Cl = 0.49 to 0.91)]. These are risks for circulatory diseases. These data show that risk factors associated with cardiovascular disease are more common in those with a low physical fitness level. J Epidemiol, 1996 ; 6 : 120-127.
Animal experiments have shown a hypocholesterolemic effect of green tea extracts. Only few epidemiological studies have addressed the relation between green tea consumption and serum total cholesterol (TC) and low density lipoprotein cholesterol (LDL-C). This paper examined the relation of green tea consumption to serum lipids and lipoproteins in 2, 062 male self-defense officials in Japan, aged 49-55 years, who received a preretirement health examination at three hospitals of the Self-Defense Forces in 1991-1992. A self-administered questionnaire queried the consumption of green tea and a limited number of other dietary items as well as lifestyle characteristics. After adjustment for body mass index, waist-hip ratio, smoking, alcohol use, exercise, rank, and hospital, green tea consumption was inversely associated with serum levels of TC and LDL-C, but not with either high density lipoprotein cholesterol or triglycerides. Rice consumption was positively correlated with green tea consumption, and also was associated independently with lower levels of TC and LDL-C. Additional adjustment for rice, however, did not change the results. Daily drinking of 10 cups of green tea was associated with differences of 6.2 mg/dl in TC (95% confidence interval [Cl] 0.4-12.1) and 6.2 mg/dl in LDL-C (95% CI 0.7-11.7). These findings of association of green tea with blood cholesterol hint at a possible causal relationship, which requires confirmation by further studies in humans using different methods. J Epidemiol, 1996 ; 6 : 128-133.
We report here a historical cohort study on cancer mortality among Minamata disease (MD) patients (n=1, 351) in Kagoshima and Kumamoto Prefectures of Japan. Taking into account their living area, sex, age and fish eating habits, the residents (n=5, 667; 40 years of age or over at 1966) living in coastal areas of Kagoshima, who consumed fish daily, were selected as a reference group from the six-prefecture cohort study conducted by Hirayama et al. The observation periods of the MD patients and of the reference group were from 1973 to 1984 and from 1970 to 1981, respectively. Survival analysis using the Poisson regression model was applied for comparison of mortality between the MD patients and the reference group. No excess of relative risk (RR) adjusted for attained age, sex and follow-up period was observed for mortality from all causes, all cancers, and non-cancers combined. Analysis of site-specific cancers showed a statistically significant decrease in mortality from stomach cancer among MD patients (RR, 0.49; 95 % confidence interval, 0.26-0.94). In addition, a statistically significant eight-fold excess risk, based on 5 observed deaths, was noted for mortality from leukemia (RR, 8.35; 95 % confidence interval, 1.61-43.3). It is, however, unlikely for these observed risks to be derived from methylmercury exposure only. Further studies are needed to understand the mechanisms involved in the observed risks among MD patients. J Epidemiol, 1996 ; 6 : 134-138.
To analyze the risk factors of thyroid cancer among Japanese women who generally consume much more iodine than Europeans, we conducted a hospital-based case-referent study at Aichi Cancer Center Hospital (ACCH) in Nagoya, Japan. Ninety-four female patients aged between 20- 79 years with papillary or follicular carcinoma of the thyroid, and 22, 666 female outpatients without cancer were used. Past history of benign thyroid mass or goiter (odds ratio: OR=13.9) and hyperthyroidism (OR=5.0) showed increased ORs of thyroid cancer. Thyroid cancer cases consumed coffee less frequently (OR=0.5) and had had more experience of delivery than referents (?3 times; OR=2.5). Western style breakfast (OR=0.5) also decreased the OR. For the multivariate analysis, past history of thyroid diseases (OR=4.3) was positively associated with the risk of thyroid cancer and everyday coffee consumption (OR=0.6) tended to decrease the risk. These results suggest that thyroid hormone-related factors may be involved in the risk of thyroid cancer in Japan, too. To clarify the risk involved in Japanese food, another comparative study including detailed information on iodine intake between countries and individuals is required. J Epidemiol, 1996 ; 6 : 140-147.
Objective. The objective of this article is to describe the epidemiologic pictures of Kawasaki disease(KD) in Japan during the 2-year period of 1993 and 1994 based on the data obtained by the thirteenth nationwide epidemiologic survey of KD which was conducted by the Japan Kawasaki Disease Research Committee. Methods. A survey form and diagnostic criteria of KD were sent to all hospital pediatric departments (2, 640) throughout Japan with 100 or more beds. The patients to be reported in this surveys were all the incident KD cases who satisfied the diagnostic criteria. Results.(1) A total of 1, 730 (65.5%) hospitals responded, reporting 11, 458(5, 389 in 1993 and 6, 069 in 1994; 6, 729 males and 4, 729 females; male/female ratio=1.42) with an incidence rate of 95.1 per 100, 000 children of age <5 years.(2) The monthly number of patients was higher in winter and summer, although the monthly difference was not marked. (3) Age specific incidence rates showed a uni-modal peak at one year of age. (4) The proportion of patients with family history of KD in sibling was 1 %. (5) The proportion of recurrent patients was 3%. (6) The proportion of patients with cardiac sequelae in one month after disease onset was 13%. (7) Number of fatal patients reported was 9, which conforms to 0.08 % of total patients. J Epidemiol, 1996 ; 6 : 148-157.
This article discusses the possibility of implementing partner notification program as a part of HIV prevention strategy in Japan. Relevant factors, like HIV seroprevalence, general population attitudes toward HIV, legislation, resources, barriers, behavioral changes, cost and effectiveness are analyzed in Japanese perspectives. Effectiveness of this program is also predicted based on the two informal contact tracing program in Japan. At the same time a review was made on the global perspectives of partner notification program and operational procedures are also outlined. Published literatures were investigated regarding prevalence of new HIV infection among the partners who underwent testing (11-39%), cost per new HIV positive case found (US $810- 3, 205), and secondary infection rate (11-20%) in Japan. Having considered all relevant factors we recommend that the partner notification program be implemented, initially in a limited area, then all over Japan. Further analysis on cost-benefit of this program remains to be done. J Epidemiol, 1996 ; 6:158-165.