To examine prevalence of hepatitis C virus (HCV) infection and liver dysfunction in hemodialysis units, we surveyed markers for HCV infection and serum alanine aminotransferase (ALT) in hemodialysis patients. 204 hemodialysis patients (111 men and 93 women; mean age, 53 12 years) in four hemodialysis units in Fukuoka, Japan were investigated. All serum samples were tested for antibody to HCV (anti-HCV) by second-generation enzyme-linked immunosorbant assay (ELISA). HCV RNA was detected to identify present HCV infection in the anti-HCV- positive patients by polymerase chain reaction (PCR) using primers deduced from the 5'- noncoding region. Liver dysfunction was defined as an elevated concentration of serum ALT (above 36 IU/liter) tested by a multiple autoanalyser. 105 patients (51.5 percent) were initially positive for anti-HCV, 95 (90.5 percent) of whom were also positive for HCV RNA. Ten became positive for anti-HCV in hemodialysis units during the observation, eight (80 percent) of whom had sustained HCV viremia. The route of transmission of HCV was not clear, but two of these patients had received blood transfusions. Of 95 patients with HCV viremia, 43 (45.3 percent) had had liver dysfunction at least once. In conclusion, HCV infection continues to occur in hemodialysis units not through blood transfusion and many of them become HCV carriers. Liver dysfunction was found in about a half of HCV-infected hemodialysis patients during the observation. J Epidemiol, 1996 ; 6 : 166-171.
The effect of hyperlipidemia on the progression of chronic renal failure was investigated in 104 chronic renal failure patients, aged 39.3±2.9 years. The follow up period was 4.1±2.9 years. The serum creatinine level was 2.1±1.1 (mean SD) mg/dl at the beginning of study and increased to 8.7±4.4 mg/dl at the end of the study. The reciprocal serum creatinine concentration (1/Cr) was plotted against the observation time. and the slope was calculated. The absolute value of the slope was used as the progression rate of renal impairment. The progression rate was positively related to total cholesterol level or urinary protein score, while it was negatively related to total protein level. Without the influence of urinary protein score, the progression rate correlated with total cholesterol level. The result suggests that hypercholesterolemia may be an independent aggravating factor in the progression of renal dysfunction in chronic renal failure patients. J Epidemiol, 1996 ; 6 : 172-177.
The present study investigated longitudinal change in serum cholesterols of isolated hypertriglyceridemic cases(54 males, 34 females) and age-matched controls(115 males, 98 females) based on a 4-year longitudinal observation . At the baseline, the level of triglyceride was significantly higher in hypertriglyceridemic cases(329±133mg/dl in males, 274±76mg/dl in females) than in the controls (81±18 mg/dl in males, 73±16mg/dl in females). Further, body mass index (BMI) was also significantly higher than that of the controls. There were no statistical differences in total cholesterol(TC) between the cases (197±23mg/dl males, 211± 30mg/dl females) and the controls (189±19mg/dl males, 202±18mg/dl females). In hypertriglyceridemic cases, both TC and low density lipoprotein plus very low density lipoprotein cholesterols significantly increased between the baseline and the four years later (TC: 197±23mg/dl to 205± 26mg/dl in males, p<0.05. 211±30mg/dl to 227±44mg/dl in females, p<0.01), whereas no change was observed in the controls. The BMI of the cases and the controls were unchanged throughout the study period. The present study shows that isolated hypertriglyceridemia with normocholesterolemia proceeds to hypercholesterolemia, which is compatible with endogenous lipoprotein metabolism. J Epidemiol, 1996 ; 6 : 178-183.
The Okinawa Islands located in the southern-most part of Japan were under U.S.administration from 1945 to 1972. During that time, fluoride was added to the drinking water supplies in most regions. The relationship between fluoride concentration in drinking water and uterine cancer mortality rate was studied in 20 municipalities of Okinawa and the data were analyzed using correlation and multivariate statistics. The main findings were as follows. (1) A significant positive correlation was found between fluoride concentration in drinking water and uterine cancer mortality in 20 municipalities (r=0.626, p<0.005). (2) Even after adjusting for the potential confounding variables, such as tap water diffusion rate, primary industry population ratio, income gap, stillbirth rate, divorce rate, this association was considerably significant. (3) Furthermore, the time trends in the uterine cancer mortality rate appear to be related to changes in water fluoridation practices. J Epidemiol, 1996 ; 6 : 184-191.
To compare the feasibility of response scales with different numbers of steps for measuring health status, we assessed the ease of completing 4, 5, and 7- point scales and a visual analog scale. Four forms of the questionnaire, each of which consisted of the same ten questions about health status, but with a different type of scale among the four above mentioned, were given to 48 patients with a variety of conditions and diagnoses. The forms were attached together and the order in which they were presented was systematically varied considering permutations of forms. Respondents were asked to complete the forms following the order of the sheets. The 5-point scale form was most commonly chosen as the easiest to complete, and item omission was least frequent with this form.Similar high- reliability results in terms of Cronbach's alpha were achieved for each of the four forms. An additional survey among 153 patients confirmed the results of the first survey.The selection of the easiest scale to complete varied by sex (men preferred the 7- point scale), but was not affected by the conditions or diagnoses of the patients. The study suggests that the 5-point scale is most useful for measuring health status. J Epidemiol, 1996 ; 6 : 192-197.
To assess the contemporary rate of hepatitis C virus (HCV) propagation in Japanese community, we conducted a sentinel study on three groups of people: company employees, long-term inpatients, and blood donors. A total of 3079 company employees negative for anti- HCV were followed thereafter, and seroconversion to anti-HCV was found in 5 per 5786 person- years. None of them was positive for HCV RNA. In the group of 703 long-term inpatients (25 of whom were initially positive for anti-HCV), none showed seroconversion to anti-HCV per 2712 person-years. As for 114266 repeated blood donors who were initially antibody-negative, 227 became anti-HCV positive later. Of these seroconverted donors, 83 were found to have anti-HCV with titers of 26 or greater. HCV RNA was positive in only 3 of them. Thus, the incidence rates of acquired HCV viremia in these three groups were 0 for both company employees and long-term inpatients, and 1.78 (95% C.l.: 0.37-5.19) per 100000 person-years in blood donors. These results suggest that community-acquired HCV infection is now rare in Japan, and that even if it occurred it hardly leads to persistent viremia. J Epidemiol, 1996 ; 6 : 198-203.
The aim of this study was to determine the actual prevalence of diabetes mellitus and to investigate the contribution of various risk factors to the diabetes mellitus among the population in a methyl mercury polluted area. The study was a population based cross sectional mass screening survey. A case-control study was designed to estimate the role of various risk factors including methyl mercury exposure for diabetes mellitus. The study was confined to a small rural town 10km north of Minamata City; 1, 087 persons older than 40 years were examined. Measurement of glucose metabolism was made on the basis of urine and haematological examinations. Data on risk factors were collected by questionnaire, and by measurement of body height and weight (obesity). The prevalence rate of the diabetes mellitus was 8.4% in males and 5.3% in females. The odds ratio of family history was significantly higher, 4.63. The odds ratio of residential history in a methyl mercury high polluted area was 0.58. The prevalence of the diabetes mellitus in this methyl mercury polluted area was not increased, contrary to what was expected based on the pathological findings. J Epidemiol, 1996; 6 : 204-208.