We reviewed studies on genotoxicity and carcinogenicity of cadmium (Cd). Salmonella typhimurium and Escherichia coli exposed to Cd did not show mutagenicity, whereas cultured mammalian cells exposed to Cd showed mutation, DNA strand breaks, and chromosomal aberrations. Carcinogenicity tests showed that exposure to Cd increased the occurrence of tumors in testis, lung, prostate, hematopoietic tissues, and injection sites. On the other hand, recent epidemiologic studies are not supportive of earlier observations on the association between Cd and prostate cancer. The US NIOSH data on a possible association between Cd and lung cancer may need reevaluation. No studies which show a positive relationship between oral Cd exposure and carcinogenesis have been reported. All available data suggest that Cd should be reassigned to IARC Group 2A (probably carcinogenic to humans) from the current Group 1.

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We have reviewed earlier studies on the possible involvement of cadmium in life-cycle related diseases and the reproductive toxicity of Cd including environmental disrupting actions. Experimental studies have suggested that Cd may be involved in the aggravation of life-cycle related diseases and the occurrence of reproductive toxicity. On the other hand, epidemiological studies did not necessarily support the experimental observations. Thus, we conclude that it is necessary to investigate further to determine whether Cd is responsible for the aggravation of life-cycle related diseases or has the capability to act as an environmental endocrine disrupter in humans.

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Recent interest concerning methylmercury that accumulates in the aquatic food chain appears to be directed not to the adverse effects of high-dose exposure in humans, but to the critical concentration at which methylmercury may affect the progeny of the exposed population. In epidemiological studies, however, uncertainties and limitations in estimating exposure make it difficult to quantify dose-response associations and can thereby lead to inaccuracies when deriving such concentrations. In this respect, benchmark dose calculation for quantitative outcomes may shed new light on the epidemiological procedure for estimating the critical concentration.
After the epidemic outbreaks of methylmercury poisoning in Japan and Iraq, large-scale follow-up studies were carried out in the Faroe Islands, Seychelles and New Zealand, to clarify the effects of prenatal methylmercury exposure on child neurodevelopment in the latter half of the 1980s. This article presents an overview of the outcomes obtained from the Faroe Islands Prospective Study, as well as a brief interpretation of the benchmark dose calculation. Although the Faroe and Seychelles Islands studies did not seem to differ greatly in the study setting, such as the exposure level and sample size, the former study observed some significant dose-effect relationships between methylmercury concentrations at birth and neurobehavioral end-points, but the latter failed to find any significant associations except in one test. The discrepancy between the two conclusions is also discussed.

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Objectives: The purpose of this study was to assess the effects of recent influenza epidemics on mortality in Japan.
Methods: We applied a new definition of excess mortality associated with influenza epidemics and a new estimation method (new method) proposed in our previous paper to the national vital statistics for 1975-1999 (ICD8- ICD10 had been adopted) in Japan. This new method has the advantages of removing a source of random variations in excess mortality and of being applicable to shifting trends in mortality rates from different causes of death in response to the revision of ICD. The monthly rates of death from all causes other than accidents (all causes) and some cause-specific deaths such as pneumonia, malignant neoplasm, heart disease, cerebrovascular disease (C. V. D) and diabetes (D. M.) were analyzed by total and by five age groups: 0-4 years, 5-24 years, 25-44 years, 45-64 years, and 65 years old or older.
Results: The following findings were noted:
1. For each epidemic in every other year since 1993, large-scale excess mortality of over 10, 000 deaths was observed and the effect of those epidemics could be frequently detected in mortality even among young persons, i. e., 0-4 years or 5-25 years.
2. Excess mortality associated with influenza epidemics influenced mortality by some chronic diseases such as pneumonia, heart disease, C. V. D., D. M., etc. For some epidemic years since 1978, excess mortality rates were detected even in mortality by malignant neoplasm.
Conclusions: It has been definitely shown by applying the new method to the national vital statistics for 1975-1999 in Japan that influenza epidemics in recent years exerted an influence on overall mortality, increasing the number of deaths among the elderly and the younger generation. Monitoring of the trends in excess mortality associated with influenza epidemics should be continued.

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Objectives: Dental health status of patients with Parkinson's disease (PD) is thought to be poor due to difficulty in brushing. However, a previous study examining a small number of patients with PD indicated quite good dental health in these patients. In order to determine whether the dental status of patients with PD, a cross-sectional survey was performed for the decayed, missing, and filled teeth (DMFT) in a larger number of patients with PD and the results were analyzed for their relationship with sex, age, salivary flow, salivary pH, tooth-brushing and other eating habits.
Methods: The dental status of 31 consecutive outpatients with PD who were 60 years old and over, and who visited a university hospital in 1999, was examined. The subjects consisted of 17 males (mean age 71.1, range 61-78 years) and 14 females (70.2, 60-84). Their unstimulated saliva was collected for 5 minutes, and information concerning their tooth-brushing and eating habits was ascertained. The total number of DMFT, as well as the number of remaining teeth were calculated. Sex- and age-specific numbers of DMFT and remaining teeth were compared with the corresponding figures obtained in the National Dental Diseases Survey (NDDS) in 1993. These indices were also examined for their relationship with sex, age, salivary excretion, salivary pH, tooth-brushing and other eating habits.
Results: In total, DMFT for the PD patients was 19.3±1.5 (mean±standard error) and the number of remaining teeth was 16.5±1.7. The expected numbers from the NDDS were 24.3 for DMFT and 10.2 for remailing teeth. Both indicated a healthier than average dental condition among patients with PD. This finding was confirmed for site-specific values, and in each sex and age category, except in males aged 70 years and over. Salivary flow of the patients was 2.2±0.2ml/5min, and pH was 6.5±0.1. The proportion of the patients who brushed their teeth 3 times a day or more was 68 percent (21/31), while the expected proportion from the NDDS was 19 percent. Spearman's correlation coefficients of DMFT with probable risk factors indicated a significant correlation: r=0.54 with age, -0.39 with salivary flow, -0.39 with salivary pH, and -0.47 with the number of brushings per day. Male patients aged 70 years and over, and who had a higher DMFT, showed a lower salivary pH. A smaller proportion of them (36%) brushed their teeth three times a day or more, and a greater proportion of them (64%) had a habit of eating between meals.
Conclusion: The present results suggest that PD outpatients with mild symptoms generally keep good dental health. They were, however, still subject to conventional caries-associated factors. One of the reasons for their overall better dental status may be partly related to their better salivary characteristics and tooth-brushing habits.

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Objectives: The Lifestyle Study Group of the Life Planning Center developed the “Lifestyle Survey for Prevention of Cardiovascular Diseases (LPC Lifestyle Questionnaire) in 1982, and conducted a baseline study (questionnaire survey of lifestyle, physical measurements, blood pressure measurement and blood tests) in two cohorts residing in an agricultural/fishing village and an urban area in 1991. Based on the baseline data of 1991, the present study aimed to elucidate the effect of dietary lifestyle on changes of BMI in a cohort of a total of 173 persons residing in the agricultural/fishing village and the urban area.
Methods: Discriminant analysis was conducted using ΔBMI as a dependent variable, and the 1991 scores of six dietary lifestyle scales, age, BMI and region as independent variables. The following results were obtained.
Results: 1. When the mean scores of 6 dietary lifestyle scales, age and BMI in the 1991 survey were compared among three sub-groups classfied by the changes of BMI, significant intergroup differences were observed in sugar content score (tendency of high intake of snacks and juice), age and BMI. Compared to the -1≤ΔBMI<+1 and -5≤ΔBMI<-1 groups, the+1≤ΔBMI<+5 group had the highest sugar content score and the lowest age within group. BMI was the lowest in the group with -1≤ΔBMI<+1.
2. When discriminant analysis was conducted using ΔBMI as a dependent variable, and the scores of six dietary lifestyle scales, age, BMI in the 1991 survey and region as independent variables, the results showed that sugar content score, cooking initiative score (interest in new dishes and modifying cooking for health), age and BMI were statistically significant for the discrimination.
Conclusions: The findings suggest that even in young subjects with low BMI, if the sugar content score and cooking initiative score are high, there is a high possibility of increased BMI in the future.

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