This paper reviews descriptive features of stomach cancer and current evidence for postulated etiological factors. Stomach cancer displays distinct patterns in its distribution: wide international variation, remarkable worldwide decline, and large differences in risk among populations of the same origin but living in different countries. All these descriptive features indicate that dietary factors play an important role in the causation of stomach cancer. Among reported associations with various foods, an inverse association with fresh vegetables and fruits and a positive one with salted foods are the most consistent. Those associations are in part supported by experimental studies. Much evidence from laboratory studies indicates that dietary vitamin C and beta-carotene are protective. A positive relation between Helicobacter pylori infection and stomach cancer risk has been consistently observed, but ubiquitousness of the infection weakens its causal implication. Further case-control studies on diet are unlikely to reveal new findings ; exception may be possible protective effects of green tea and garlic. On the basis of current available evidence, it appears desirable to consume less high-salt foods and to eat more fresh fruits and vegetables in order to prevent the occurrence of stomach cancer. J Epidemiol, 1994; 4 : 1-11.
To get information about secular trend of age-specific incidence rate, cumulative incidence up to 5 years of age, and whether there is a cohort effect of incidence rate of Kawasaki disease, we analyzed the data of nationwide incidence surveys of the disease in Japan from 1970 through 1990. The age-specific incidence rate increased gradually except for three nationwide epidemic years. Cumulative incidence from birth through 4 years of age also increased, and was about 0.5% for males and 0.4% for females who were born in early and middle 1980's. Although some birth cohort showed a high relative risk of incidence rate with statistical significance, there was no meaningful cohort effect on Kawasaki disease. J Epidemiol, 1994; 4 : 13-16.
Patients undergoing routine blood tests at clinics or hospitals on Iki Island, Japan were tested for antibody to hepatitis C virus (anti-HCV), hepatitis B surface antigen (HBsAg), and antibody to human T-lymphotropic virus type-1 (anti-HTLV-1). Anti-HCV accounted for 17.5%, HBsAg for 2.9%, and anti-HTLV-1 for 30.3%. Anti-HCV was present in 60.2% of the patients with liver disease and in 13. 5% of those without liver disease. A history of blood transfusion was a statistically significant risk factor for both HCV and HTLV-I infections, as was a history of acupuncture in case of HCV infection. Of the people surveyed, 7.5% had both anti-HCV and anti-HTLV-I, and anti-HTLV-|-positive persons had a significantly higher prevalence of anti-HCV than did anti-HTLV-I-negative persons (24.8% vs 14.3%, p<0.05). These data suggest that Iki Island is highly endemic for both hepatitis C virus (HCV) and for human T-lymphotropic virus type-I (HTLV-I). Blood transfusion may have been the common route in the spread for both HCV and HTLV-I. Acupuncture also may have facilitated the spread of HCV infection, in this area. J Epidemiol, 1994; 4 : 17-23.
A case-control study was conducted to evaluate the relation between several factors and the risk of non-insulin-dependent diabetes mellitus in a rural population of the island of Ojika, in the Goto islands, Nagasaki prefecture Japan. We selected 62 diabetes mellitus (DM) and 70 impaired glucose tolerance (IGT) cases and 168 normal controls for the study. They were diagnosed by WHO criteria using 75 gram glucose tolerance test applied to inhabitants of the island in June 1991. Obesity, expressed as body mass index (BMI, weight (kg)/height (cm)') at the time of diagnosis and BMI at the time when they had heaviest weight, was associated with increased risk for DM (odds ratio for one unit difference (OR)=1.15, 95% confidence interval (CI)=1.04-1.27 and OR=1.13, 95% 01=1.02-1.25, respectively). Occupational experience of rice growing, vegetable growing and breeding of cattle were inversely associated with the risk (OR=0.36 ; CI=0.17-0.76, OR=0.44 ; CI=0.21-0.93, OR=0.43 ; CI=0.21-0.93, respectively). The DM history of father was associated with the significantly high risk (OR=10.94 ; CI=1.18-101.14), but that of mother did not (OR=1.49 ; CI=0.13-17.17). The sample size of this study was not large enough to get the narrow odds ratio confidence intervals. To increase the reliability of the relative risk estimation, further intensive studies are necessary. J Epidemiol, 1994; 4 : 25-29.
In the Hohara area of Nansei-cho, one of the foci of motor neuron disease (MND) on the Kii peninsula, the death rates of MND and of leading causes of death were surveyed to obtain a clue to the etiology of MND in the Western Pacific. The crude annual death rate of MND in the Hohara area was 47.6 per 100, 000 population (for 1961-1990), and the standardized mortality ratio of MND was 5403. The death rate survey showed that the mortality of nonischemic heart disease was higher and that of diabetes mellitus was lower in Hohara as compared with the whole Japanese population. The mortality of MND has a positive correlation with the mortality of cerebrovascular diseases, and also with that of nephritis and nephrotic syndrome in Nansei-cho. These death rate data may suggest that etiological factors of MND in this focus could also influence the mortality of some other diseases. J Epidemiol, 1994; 4 : 31-35.
Our previous studies on mortality and cancer incidence showed a change in disease pattern among Japanese Brazilian in Sao Paulo, Brazil from that among Japanese in Japan. To clarify the cause of this change, a cross-sectional study was conducted for evaluating lifestyle and healthrelated factors among a representative sample of Japanese residents in Sao Paulo. The results obtained were compared with those from a cross-sectional study in five areas of Japan in which the similar protocol had been used. A questionnaire on lifestyle, anthropometric and blood pressure measurements, and blood and urine collections was administered to 411 randomly selected Japanese firstand second-generation residents aged 40 to 69 years in the city of Sao Paulo. A total of 251 (61%) subjects, 118 men and 133 women, 90 firstand 161 second-generation, participated in the study. Smoking and drinking habit, anthropometric measures and blood pressure level, and serum biochemical parameters were examined according to sex and age group. The level of total cholesterol, triglycerides and uric acid in sera, body weight and body mass index, and both systolic and diastolic blood pressures revealed a significantly higher value when compared with five Japanese groups in Japan, while serum HDL cholesterol and the percentage of smokers and drinkers were lower. These differences of lifestyle and health-related factors were discussed in relation to ischemic heart and cerebrovascular diseases and some types of cancer. J Epidemiol, 1994; 4 : 37-46.
The relationship of percent body fat (%BF) and body mass index (BMI) to blood pressure, serum lipids, hypertension and self-reported diagnosis of diabetes mellitus was examined in a crosssectional study of 1, 174 male employees at a railway company. The %BF was measured by using the near infra-red (NIR) method. Because of high collinearity between %BF and BMI (r=0.72), we categorized %BF into two groups at median within each quartile of BMI, and performed analysis of covariance on serum cholesterol (TC), serum triglycerides (TG), systolic blood pressure (SBP), and diastolic blood pressure (DBP). Age-adjusted means of TC, TG, SBP, and DBP were almost progressively increased with increasing levels of BMI regardless of %BF, but there were nearly significant or significant interactions of %BF and BMI on TC, TG, and DBP ; serum lipid levels were higher in the upper %BF group than in the lower %BF group at lower levels of BMI while the difference in DBP was more evident at higher levels of BMI. There was also a significant interaction between %BF and BMI on the prevalence of hypertension (p=0.03) ; the prevalence was much higher in the upper %BF group than in the lower %BF group at the highest BMI level. Diabetes mellitus was not measurably associated with either BMI or %BF. These findings suggest that the measurement of %BF in addition to BMI provides useful information in the evaluation and management of individual's health. J Epidemiol, 1994 ; 4: 47-50.