Human biomonitoring (HBM) is a technique to evaluate chemical exposure level by measuring the levels of chemicals or related substances such as their metabolites or adducts in biological samples (e.g., urine or blood). Compared with exposure assessment by an approach to estimate insecticide intake from diet or the environment, HBM can provide information more specific to an individual exposure dose and can reflect the exact body burden condition at the time of measurement. If the analytical sensitivities, completeness and cost-effectiveness of the method are improved further, HBM might be widely applicable to not only research fields such as epidemiological and occupational study but also routine analysis for effective prevention of the exposure of the human body to chemical substances. In this article, we provide an overview of HBM as a determination method for insecticide exposure markers in urine and its applications, and discuss future research perspectives in the field of environmental and occupational health.
Mercury and its compounds are classified into three main groups: metallic mercury (Hg0), inorganic mercury (Hg2+), and organic mercury (methyl mercury: CH3Hg+, etc.). Metallic mercury is the only metal that is liquid at ambient temperature and normal pressure, which readily forms an amalgam with other metals. Therefore, mercury has long been used for refining various metals, and mercury amalgam has been used for dental treatment. Mercury has also been used in measuring instruments such as thermometers, barometers and blood pressure monitors, as well as electric appliances such as lighting equipment and dry batteries. Large amounts of metallic mercury are still used in other countries as a catalyst in the production of caustic soda by electrolysis. In addition, mercury compounds have been used in various chemicals such as mercurochrome, agricultural chemicals, and mildew-proofing agents. However, the use of mercury has also caused health problems for people. Minamata disease in Japan is a typical example. Also, since mercury is highly volatile, it is discharged as a product of industrial activities or derived from volcanoes, and it has been concluded on the basis of the findings of the United Nations Environment Program (UNEP) that it is circulating globally. Therefore, with the aim of establishing an internationally legally binding treaty for the regulation of mercury use to reduce risk, an intergovernmental negotiating committee was established in 2009. Japan actively contributed to this negotiation owing to its experience with Minamata disease, which led to the Convention on the regulation of mercury use being discharged as the “Minamata Convention on Mercury” and the treaty came into force on August 16, 2017. In this review, we introduce 1) the Global Mercury Assessment by UNEP; 2) mercury kinetics, exposure assessment and toxicity of different chemical forms; 3) large-scale epidemics of methylmercury poisoning; 4) methylmercury exposure assessment and health survey in whale-eating populations; 5) elemental mercury exposure assessment and health survey of mercury mine workers in China.
Arsenic is widely distributed in nature, and humans are exposed to arsenic through air, water, beverages, and food. On the bases of previous studies of highly exposed populations, arsenic is designated as a Group 1 human carcinogen by the International Agency for Research on Cancer (IARC), and IARC has established a causal role for arsenic in cancers of the urinary bladder, lung, and skin in humans. However, there are very few epidemiological studies of the association between low–moderate arsenic exposure and cancer. In particular, there is only one study of the association between arsenic intake from food and cancer. Further epidemiological studies are needed.
Cadmium is a nonessential heavy metal and an industrial and environmental pollutant. It has been known that cadmium must enter cells to cause damage. To understand the transport systems responsible for cadmium entry into cells, it is important to determine the precise mechanisms underlying cadmium toxicity. Numerous studies have sought to unravel the exact pathways by which cadmium enters various cells and the mechanisms by which it causes toxicity in the organs of human and animals. The purpose of this review is to present the progress made regarding the mechanisms of cadmium transport in various cells and the mechanisms underlying cadmium toxicity in organs.
Japan has laws in place that are intended to reduce health risks from environmental pollution, including air pollution. On the basis of the “polluters pay” principle, these laws are designed to support pollution victims. In Miyazaki Prefecture, people were chronically exposed to arsenic in Takachiho Town as a result of the operation of Toroku Mine. As a result of this pollution, the Miyazaki Prefectural Government has provided annual health checkups for residents since 1973. The examination consists of the following: blood test, urine test, body measurement, CT scan, respiratory test, hearing test, taste test, olfactory test, eye exam, neurological exam, internal exam, and skin exam. Test results are entered into the electronic database for chronic arsenic poisoning. In order to maintain public awareness of the danger of environmental pollution, we are engaging in a project to inform the public of our history of pollution and environmental restoration efforts. We also hope to help other Asian countries that are suffering from arsenic contamination of groundwater by providing support for trainees that are participating in JICA projects.
The Renewable energy is a key driver of generating clean energy because it continuously lower air pollution. In particular, the development of wind power energy has been remarkable, and it currently accounts for approximately one-third of renewable electricity. Germany has the largest onshore wind deployment. On the other hand, the United Kingdom is most highly expected to develop offshore wind power. Germany and Denmark have assessed the usefulness of wind turbines, and they benefited from wind energy. Execution of not only environmental impact assessment (EIA) but also health impact assessment (HIA) is an obligation in the United Kingdom, the practice of EIA and HIA is important for the successful construction of wind turbine facilities. We in Japan should learn the method of handling renewable energy systems from major European countries.
Impacts of wind power generation facilities on neighborhood residents, animals, plants, water environment and landscape are a concern. Therefore, in 2010, wind turbine facilities were targeted to be covered by the environmental impact assessment law, which was enacted in 1999, and was amended with the environmental impact statement procedure in 2013. A guidance level of noise produced by wind turbines in quiet residential areas was set in 2017. In the environmental impact statement procedure at the planning stage of targeted projects, the trust of precedent users should be obtained and consensus building should be implemented. Projects of wind turbine facilities are accepted in accordance with the environmental impact assessment law using the new guidance noise level and the procedure of the environmental impact statement.
Since the large-scale construction of wind power facilities in Japan, serious complaints have arisen from residents regarding wind turbine noise (WTN). However, there was insufficient scientific background to assess this issue. To address this situation, several research projects have been conducted by the Ministry of the Environment, Government of Japan. In this paper, we report actual WTN field measurements for these projects. The LAeq values of WTN ranged from 25 to 50 dB in residential areas. On the other hand, the residual noise levels in control areas with similar local characteristics to the wind farm areas but not affected by WTN ranged from 20 to 35 dB. Thus, there was a notable difference between WTN and residual noise. Wind power facilities are often constructed in quiet, rural districts. With regards to WTN, LAeq of noise caused by wind turbines as well as the increase in the overall noise level are important. The measurements of spectral characteristics of WTN were compared against the criterion curve to assess low-frequency noise. As a result, infrasound (frequency components below 20 Hz) for all measured WTN values in the residential (immission) areas were found to be much lower than the corresponding values on the criterion curve. In addition, amplitude modulation (AM) sound (also referred to as “swish sound”) is often associated with WTN, and can cause serious discomfort to nearby residents. The actual situation with regard to AM sound in residential areas located near wind farms was clarified by field measurements.
We investigated whether long-term exposure to low-frequency noise generated by wind power facilities is a risk factor for sleep disorders. We performed an epidemiological study of the living environment and health effects of such noise by surveying 9,000 residents (≥20 years of age) living in areas with operational wind power facilities. Sleep disorders were assessed using the Athens Insomnia Scale. To assess environmental noise in residential areas near wind turbines, infrasound and low-frequency sound exposure levels were measured at 50 community centers of a town. The prevalence of sleep disorders was significantly higher among residents who reported subjectively hearing noise (by approximately twofold) than among those who did not. Moreover, the reported prevalence of sleep disorders was significantly higher (by approximately twofold) among residents living at a distance of ≤1,500 m from the nearest wind turbine than among residents living at a distance of ≥2,000 m, suggesting a dose-response relationship. The attitudes of residents towards wind power facilities strongly affected their responses regarding sleep disorder prevalence. It is highly likely that audible noise generated by wind power facilities is a risk factor for sleep disorders. Obtaining a satisfactory consensus from local residents before installing wind power facilities is important as for more amenable their attitudes towards such facilities.
The factors contributing to the declining birthrate in Japan include the declining marriage rate, an increase in the average age of those getting married, economic burden, childcare burden, later child-bearing, and infertility. There is a gender difference in role division, with 70% of unmarried people live with their parents and continue to work while leaving the household chores to their mothers. The loss of these housekeeping services and the increase in the number of irregular workers are factors contributing to the declining marriage rate and the increase in the average age of those getting married. The expansion of the family support policy in Japan from the male breadwinner model to the earner-career model may have been delayed, but it is expected to provide economic benefits as well as actual childcare service benefits in order to reduce the economic and physical burden of childcare for married couples. It is also necessary to provide education in reproductive health to both men and women in schools and workplaces regarding late child-bearing and infertility. Furthermore, it is necessary to evaluate the cost-effectiveness analysis of improvements in fertility and disclose the relevant information in addition to sharing information on medical technology related to pregnancy/childbirth and treatment of diseases. It is urgent to prepare society for natural and healthy pregnancies/childbirths during optimal child-bearing years.
In recent years, the birthrate has been continuously declining in Japan. The main causes of the decline are social factors. On the other hand, there is increasing evidence that many environmental chemicals show endocrine disrupting properties. Thus, we hypothesized that exposure to these chemicals would also be a causal for the fertility crisis. In this review, we examined current evidence that focused on environmental chemical exposure in utero and its association with reproductive hormones in children. We have included the findings from a prospective birth cohorts, the Hokkaido Study on Environment and Children’s Health Sapporo cohort. According to the literature, environmental chemical levels in utero, such as polychlorinated biphenyl, dioxins, perfluorinated chemical substances, phthalates, and bisphenol A were somewhat associated with the levels of reproductive hormones, such as testosterone, estradiol, progesterone, inhibin B, and insulin-like factor-3 in cord blood, in early childhood and adolescence. The literature also suggests the association between exposure to these chemicals and brain-sexual differentiation or the anogenital distance, which suggests the disruption of androgen shower during the developmental stage in the fetal period. There are still knowledge gaps on whether these hormones at an early stage affect the pubertal development and reproductive functions in later life. In addition, alternative chemicals are produced after banning one type. The health effects of alternative chemicals should be evaluated. Effects of exposure to a mixture of the chemicals should also be examined in future studies. In conclusion, the prevention of environmental chemical hazards in relation to human reproductive function is important. It would be one of the countermeasures to the falling birthrate caused by fertility issues.
Although the birthrate greatly declined from the 1960s to the mid-1970s amongst many developed countries, the downturn has steadily been reversed by promoting women’s rights and reviewing family policies in some European countries such as Sweden and France. The current total fertility rate in Sweden or France is approximately around 1.9 children per woman. The favorable state can be partly explained by the active family policies of these countries. The government of Sweden has implemented a wide range of measures including tax allowances, childcare services, and other subsidies, as well as an18 month parental leave to be shared between mothers and fathers. The government of France has expanded childcare and provided incentives by increasing childcare/family benefits with each subsequent child.
In Japan, the fertility rate has changed from a downward trend to an upward trend, but only very slightly over the last decade. The legislative systems and enforcement remain totally inadequate to maintain stable a fertility rate. The Japanese government should try to change the social security/labor policies into more active and generous ones, with enhancement of economic support and promotion of work-life balance. Other attempts including removing barriers to encourage the youth to start a family are needed to overcome declining birth rates in Japan.
Research into reproductive toxicology may lead to one of the countermeasures to the declining birth rate observed in industrialized countries. Some chemicals can pose risks to human reproduction that is a multistage process starting from the development of male and female germ cells to childbirth and the subsequent growth and development of the child. In Japan, the government has amended law enforcement, i.e., the Regulations on Labor Standards for Women, recently to improve protection for pregnant women against reproductive chemical hazards in workplaces. Male workers may also be protected against such hazards if appropriate risk assessment and the following management are performed as required by the Industrial Safety and Health Law. However, it remains a concern that an unexpected adverse outcome due to an unknown reproduction hazard may occur owing to the use of chemicals not listed in the regulations. This is because the toxicity of a large number of chemicals has not been entirely revealed. Moreover, it is often difficult to determine from a Safety Data Sheet for a product of interest whether the chemicals contained in the product do not have reproductive toxicity or the toxicity data are just not available because of lack of pertinent studies. Thus, researchers in the field of occupational and environmental health need to make effort to fill in such data gaps and to raise the awareness among the public the importance of experimental and epidemiological studies. Study designs for investigating subclinical effects, mechanisms of reproductive toxicity, exposure levels, and dose-response relationships to determine environmental standards are also required.
Objectives: In this study, we aimed to (1) determine the effects of age, period, and cohort on mortality rate trends between 1958 and 2012 in Japan and (2) assess gender differences in projected life expectancy (LE) for the 2023–2047 period.
Methods: A time trend study was conducted using age-period-cohort (APC) analysis. A Bayesian APC model was fitted to describe mortality rate trends for the 1958–2012 period and to project mortality rates for 2023–2047. LE was predicted by Chiang’s method using projected mortality rates.
Results: Age, period, and cohort effects showed similar patterns between males and females. As time passes, gender differences in projected LE were larger among individuals over 65 years than among those under 65 years. Time series change rates of the extension of projected LE after excluding specific causes of death showed the following: smaller extension of projected LE in males in terms of mortality risk from malignant neoplasms, heart diseases, pneumonia, and accidents (under 65 years) and in females in terms of mortality risk from heart diseases, cerebrovascular diseases, and suicide (over 65 years).
Conclusions: Gender differences in projected LE are expected to be smaller before middle age and to be larger among seniors. These projected gender differences stem in part from the lower mortality risk among men than among women from malignant neoplasms, heart diseases, pneumonia, and accidents (under 65 years), and among women compared to men from heart disease, cerebrovascular disease, and suicide (over 65 years).
Objectives: The aims of this study were to clarify the conditions of food consumption related to salt intake in women aged 40–59 years and to determine the characteristics of working mothers.
Methods: Among all guardians in a medical university, 247 (effective response rate, 32.2%) mothers of 40–59 years of age participated in this study.
Results: Factors related to salt intake were the frequency of consuming Japanese dishes (stewed foods, Japanese style rice, pickles, miso soup, noodles, vinegared dishes, marinated foods) and dietary habit (use of low-sodium seasoning when cooking, the amount of broth left unconsumed when eating noodle soup, the use of seasoning at the table). In comparison with the nonworking mothers, a greater number of the working mothers purchased smaller amount of fresh food and prepared meals for dinner in less than 30 minutes. Furthermore, the frequency of consuming Japanese dishes was also lower in the working mothers. This was not related to their state of mind or knowledge about salt consumption in relation to health and conscious effort to eat less salt, but rather to their longer work hours and shorter meal preparation time. Dietary habits are related to the state of mind, flavor, and knowledge and efforts to eat less salt. Working mothers, as well as nonworking mothers had dietary habits.
Conclusion: For women in this age group, to reduce salt consumption, adopting ways to eat less salt at the table, which are feasible for everyone, are effective.
Objectives: In this study, we examined whether a combined regimen of a short-term nap and a light physical exercise is effective in improving sleep among elderly individuals with mild-to-moderate dementia in communal living group homes.
Methods: Twenty-three female residents (aged 87.4±5.6 years) living in two group homes for the elderly with dementia were included in the present study. After undergoing an assessment for eligibility, they were randomly allocated to either the study group (N=11), who participated in the regimen of a short-term nap (<30 min) and light physical exercise for four weeks, or the control group (N=12), who received the usual nursing care without participating in the nap and exercise regimen. The lengths of sleep time and wake time were measured using a sleep monitor with a radiofrequency motion sensor. The frequencies of nocturnal behavioral and psychological symptoms associated with dementia including excitement, violence, night delirium, wandering, and unhygienic behavior were investigated throughout the study period.
Results: The subjects participating in the nap and physical exercise regimen showed a significant increase in sleep efficacy as well as a reduction in the total nocturnal wake time, whereas no clear change was observed in the control subjects. The frequencies of nocturnal episodes of urination in the study group also decreased during the course of the study. However, there was no significant decrease in the frequencies of nocturnal behavioral or psychological symptoms associated with dementia.
Conclusions: The findings of this study suggest that a short-term nap and a light physical exercise may be effective in adjusting the sleep-wake biorhythm in elderly patients with mild-to-moderate dementia and may improve sleep among these individuals.
Objectives: The purposes of this study were to clarify the microbial growth when drinking a beverage directly from its plastic bottle using models under consumption conditions characteristic for nursing students in a university and their awareness about microbial contamination in unfinished beverages in bottles.
Methods: Three types of bottled beverages were tested: mineral water, Japanese green tea with catechin, and a lactic acid beverage. The ways of drinking were putting the entire lip of a bottle into the mouth (type A) and holding half of the lip out of the mouth (type B). The bottles were kept at room temperature for 8 hours. Samples from unfinished beverages were cultured to detect viable bacteria. An anonymous questionnaire was sent to 324 nursing students of a university, among which 279 responded.
Results: The number of viable bacterial cells was larger in type A of drinking than in type B. It increased in mineral water until 2 hours, after which it remained the same. It decreased in Japanese green tea with catechin and the lactic acid beverage. However, even the smallest number exceeded the standard number for drinking beverages. Among the nursing students, 62.7% were aware of microbial contamination in unfinished beverages, but despite this awareness, they did not consume their beverages as soon as possible.
Conclusion: It is necessary to provide the nursing students with health education on the safety of partially consumed bottled beverages with respect to food hygiene, even if microorganisms do not grow in some types of beverages.
Objectives: The purposes of this research were to investigate the hazardous effects of heat-not-burn tobacco and to clarify the health effects accompanying the transition from cigarettes to heat-not-burn tobacco.
Methods: The concentrations of carbon monoxide, ammonia, formaldehyde, acetaldehyde, and dust (hazardous substances) were measured in the smoke of heat-not-burn tobacco. Twenty-nine smokers were used as the subjects. The concentrations of hazardous substances were measured in exhalation of heat-not-burn tobacco. The concentration of cotinine in saliva was also measured after the transition. A questionnaire survey was performed before and after the transition to evaluate nicotine dependence, nicotine withdrawal symptoms, and smoking behaviors.
Results: In the mainstream smoke, all hazardous substances investigated were detected. Carbon monoxide and dust were detected in the exhalation of heat-not-burn tobacco. The concentration of cotinine in the saliva of heat-not-burn tobacco users corresponded to that of cigarette smokers. Cigarette smoking was significantly positively related to the score of Fagerström Test for Nicotine Dependence (FTND). Heat-not-burn tobacco was significantly positively related to FTND and Minnesota Nicotine Withdrawal Scale (MNWS) scores. The group in which the number of heat-not-burn tobacco sticks consumed increased after transition showed a smaller number of cigarettes consumed and a higher MNWS score before transition than the group in which it decreased after transition. These two factors were significantly related to the difference between the numbers of cigarettes and heat-not-burn tobacco sticks in multiple linear regression analysis.
Conclusions: The mainstream smoke of heat-not-burn tobacco contains harmful substances. There were the possibilities that nicotine dependence and nicotine withdrawal symptoms appear after transition and that the number of heat-not-burn tobacco sticks consumed increases.
Objectives: To clarify the association between job stress and the number of physical symptoms among newly certified female nurses.
Methods: In this cross-sectional self-administered survey, we investigated 313 female nurses working at three medical-university-affiliated hospitals in February 2016. We investigated working conditions including numbers of working and on-call hours, work-life balance, Job Content Questionnaire (JCQ) scores, and 16 physical symptoms perceived more often than once a week.
Results: Among the 313 participants (mean age, 31.9), 57% were aged 21–29 years and 70% were single. Of the 16 physical symptoms investigated, fatigability was the most frequent complaint (66.1%), followed by lower back pain (44.7%). Univariate analysis showed that significant factors related to physical symptoms are job demands (p<0.001) and social support (p<0.001) in JCQ, binary index of supports (p<0.001), and total working hours per day (p =0.025). Multivariable-adjusted logistic regression analyses demonstrated that the likelihood of reporting a greater number (n≥3) of physical symptoms increased by 7% [95% confidence interval (CI), 2–13%] with a one-unit increase in job demand degree, and decreased by 16% (95% CI, 10–22%) in social support degree. When binary JCQ indexes were assessed, the high-support group [odds ratio (OR) 0.36; 95% CI, 0.23–0.59] was protectively associated with a greater number of physical symptoms while long working hours was significantly associated with a higher risk (OR 18%, 95% CI, 1–38%).
Conclusions: Reporting a greater number of physical symptoms may be a good indicator of job stress perceived by a nurse in a university hospital setting.
Objectives: The aim of this cross-sectional study of students was to analyze nutritional intake factors and their contribution to preventing noncommunicable diseases (NCDs) in youth.
Methods: This study was based on the results of the Eating Behavior and Health Awareness survey conducted among university, college, and vocational school students throughout the main island of Japan (1,256 valid responders).
Results: The results of the logistic regression analysis are given below. Variables with significant positive regression coefficients, in the order from higher to lower odds ratios, were as follows: “household living arrangement”, “skipping breakfast”, and “cooking techniques” were the variables shown in men; “household living arrangement”, “instant food intake”, “skipping breakfast”, “eating out”, “stages of change in healthy eating”, were the variables shown in women. In contrast, the variable “body mass index (BMI)” exhibited a significant negative regression coefficient in women. Students with low BMI showed a higher probability of exhibiting high nutritional intake.
Conclusion: The variables “household living arrangement” and “skipping breakfast” may be associated with nutritional imbalance in both genders. Future prospective studies on diet and lifestyle factors are needed to clarify this issue further.
Introduction: From 2007, competitive bidding for procurement became widely employed by the Japanese Government, and health check providers for government workers are selected every year by this method. Deterioration of health check quality due to excessive price competition is a serious concern. The National Federation of Industrial Health Organization (Zeneiren) conducted an investigative research on the contracting of health check providers and occupational physicians in workplaces in 2015–2016 in an effort to prevent low-cost but low-quality health checks. The report of the research is available on the homepage of Zeneiren. In this paper, we provide a brief overview of the report, and deterioration of health check quality due to dumping by and switching of health check providers is discussed from economic and legal viewpoints.
Method: Information was obtained from articles in print and on the Internet.
Results: A questionnaire survey of health check providers revealed that excessive discounts due to both competitive bidding and demand from companies commissioning health checks occurred on a routine basis, and some providers were concerned about worsening business conditions in the future. In a separate questionnaire survey of occupational physicians, it was discovered that they were able to evaluate the quality of health checks, whereas administrative officials responsible for selecting the providers were seldom able to adequately evaluate the health check quality, resulting in contracting providers of questionable quality, which in turn caused considerable dissatisfaction on the part of occupational physicians. Moreover, when health check providers were switched, the reporting format of health check results changed. The physicians did not favor such a change because of the considerably increased workload involved in coordinating past and current data and the risk of decreased occupational health service quality.
Discussion: Dumping makes the management of health check providers very difficult and is a cause of loss of social capital. If health check providers of good quality withdraw from the market, the supply of high-quality health checks decreases. This corresponds to external diseconomy caused by dumping on the part of the health check providers and loss of social surplus (economic surplus).
Conclusions: To avoid deterioration of occupational health service due to low-quality health checks and changes in the reporting format, occupational physicians must actively engage in the selection of health check providers of good quality.