This paper primarily aimed to overview the rationale for initiating the Japan Collaborative Cohort Study for Evaluation of Cancer Risk Sponsored by Monbusho (Ministry of Education, Science, Sports and Culture of Japan) (JACC Study), by comparing socio-demographic and nutritional changes that were witnessed between 1965 and 1990 in Japan, and also to describe the study design, the follow-up conditions as of the end of 1997, and the frameworks for analyzing the data of the lung, stomach, pancreas and gallbladder/bile duct, based on the approximately 8-year follow-up data. For other major sites such as cancers of the large intestine and liver, an analysis will be started in the fiscal year of 2002. This paper secondarily aimed to be cited as the basic information on the JACC Study when several publications are to be based on. J Epidemiol, 2001 ; 11 : 144-150
The mortality data on lung cancer in Japan from 1960 to 1995 was analysed based on an age-period-cohort (APC) model. Though the APC model has an 'identifiable problem' caused by the relationship of age, period and cohort parameters, non-linear components of them revealed their original (separated) effects. They were: (1) non-linear age effects had a peak in 55-59 and 60-64 years old in males and 50-54 in females, (2) non-linear period effects were very small in both genders, (3) non-linear age and period effects were small enough to neglect compared with their linear effects, and (4) there were five parts of trends in Japanese lung cancer mortality in both genders in the non-linear birth cohort effects. The 1961-65 birth cohort effect seemed to increase differently from previous birth years. This trend should be monitored carefully. J Epidemiol, 2001 ; 11 : 151-159
While universal insurance coverage should eliminate or substantially reduce financial and certain structural barriers to medical care, inequity in utilization of care may continue to exist. We conducted a questionnaire survey of a national random sample of 4500 Japanese age16 or over in October, 1995. Separate analyses were conducted to predict the physician visit rates for the entire respondents (N=3395) and for those with chronic conditions (N=777). Forty-three percent of the total subjects reported an ambulatory physician visit within the past three months. About 17% of subjects with one chronic condition and 14% of those with two or more chronic conditions did not have any physician visits within recent three months. The regression model demonstrated that having a home doctor, as well as comorbidity and perceived health status, is significantly associated with outpatient visit both among all subjects (p< 0.0001) and among those with chronic conditions (p< 0.01). The Japanese health system still has unevenness in outpatient resource utilization. This mainly pertains to whether they have their own regular physician. The failure of some persons with chronic diseases to be seen requires further investigation. J Epidemiol, 2001 ; 11 : 160-169
Age-specific and age-standardized rates (ASR) of registered cancers for nine communities in the U.S.A. (21.8 million inhabitants, mainly white) were obtained from IARC data (1978-82, 1983-87, 1988-92). The percentage of people supplied with "optimally" fluoridated drinking water (FD) obtained from the Fluoridation Census 1985, U.S.A. were used for regression analysis of incidence rates of cancers at thirty six sites (ICD-WHO, 1957). About two-thirds of sites of the body (ICD) were associated positively with FD, but negative associations were noted for lip cancer, melanoma of the skin, and cancers of the prostate and thyroid gland. In digestive organs the stomach showed only limited and small intestine no significant link. However, cancers of the oral cavity and pharynx, colon and rectum, hepato-biliary and urinary organs were positively associated with FD. This was also the case for bone cancers in male, in line with results of rat experiments. Brain tumors and T-cell system Hodgkin's disease, Non-Hodgkin lymphoma, multiple myeloma, melanoma of the skin and monocytic leukaemia were also correlated with FD. Of the 36 sites, 23 were positively significant (63.9%), 9 not significant (25.0%) and 4 negatively significant (11.1%). This may indicate a complexity of mechanisms of action of fluoride in the body, especially in view of the coexising positive and negative correlations with the fluoridation index. The likelihood of fluoride acting as a genetic cause of cancer requires consideration.
An eleven-year follow-up study was carried out to elucidate the changes in the level of environmental exposure to cadmium (Cd) from rice after soil replacement of polluted paddy fields and these effects on urinary excretion of Cd in male inhabitants of a Cd-polluted area in Toyama, Japan. In addition, the prevalence of renal tubular dysfunction (RTD) was examined to clarify the progress of Cd-induced RTD. One hundred and twenty-seven male inhabitants born between 1914 and 1929 in 11 districts of the Cd-polluted Jinzu River basin and 31 reference subjects in 2 adjacent districts were examined twice in 1985-86 and 1996-97. The geometric means of Cd concentrations in polished rice (Cd-R) in the Cd-polluted areas were 0.18 ppm in 1985 and 0.21 ppm in 1986; these values were significantly higher than those of the reference areas (0.13 ppm in 1985 and 0.12 ppm in 1986). After 11 years, the Cd-R levels were significantly decreased to approximately half (0.08 ppm in 1996, 0.12 ppm in 1997) due to soil replacement of polluted paddy fields, which has been carried out since 1980. The mean Cd levels in urine (Cd-U) were significantly reduced from 7.9 and 9.5*g/g creatinine in the initial study to 6.9 and 6.8*g/g creatinine in the follow-up study. However, the prevalence of RTD, which was determined by urinary *2-microglobulin exceeding 1 mg/g creatinine and urinary glucose exceeding 150 mg/g creatinine, increased from 18 and 23% in the 1985-86 study to 25 and 32% in the 1996-97 study, and a total of 12 new cases (12%) of RTD were found. Whereas, only one subject (4%) in the reference control areas was identified as RTD. Cd-induced RTD was prevalent, progressive and irreversible for male inhabitants of the Cd-polluted Jinzu River basin, although the environmental exposure to Cd through rice was significantly reduced by soil replacement of polluted paddy fields. J Epidemiol, 2001 ; 11 : 180-189
The effects of long-term blood pressure (BP) levels on cerebrovascular changes were analyzed in a community-based healthy elderly population. Cranial computed tomography (CT) was performed for 300 residents aged 69 years and older. Long-term BP during the ten years prior to CT was assessed, and the cerebrovascular changes were compared among different patterns of long-term blood pressure variability. White matter lesions (WML) and/or silent infarctions (SI) were found in 73 subjects (23.6%). Multiple logistic regression analysis showed that subjects with long-term diastolic hypertension (DHT) had the highest risk of cerebrovascular changes (adjusted odds ratio (OR), 95% confidence interval (CI); 7.1, 2.4-21.6, for WML; 7.2, 2.7-19.4, for SI), and that long-term isolated systolic hypertension (ISHT) was significantly associated with SI (adjusted OR, 95%Cl, 2.3, 1.1-4.9), but not with WML (adjusted OR, 95%CI, 1.3, 0.5-3.3). Efforts to prevent both DHT and ISHT would be beneficial, though different underlying mechanisms for WML and SI were suggested. J Epidemiol, 2001 ; 11 : 190-198
By and large, biomedical research is not a priority sector in Asian countries due to many factors. Lack of resources and trained manpower are certainly among these factors. We investigated the factors related to biomedical research productivity in Asian countries based on Medline data. The number of biomedical articles published in the indexed journals from each country of Asia and Oceania during 1990-1998 was used as a surrogate of total biomedical research productivity. Multiple regression analysis revealed that low gross national product per capita (p<0.013), insufficient number of physicians (p<0.047), and inadequate public spending on the health sector (p<0.049) were responsible for the meager number of biomedical publications in Asian countries. J Epidemiol, 2001 ; 11 : 199-202