BACKGROUND: Icaridin and DEET are common insect repellents widely used on human skin and clothing (skin-insect repellents [skin-IR]) to repel common pests, such as mosquitoes and biting flies. Novel analytical methods for urinary skin-IR exposure biomarkers that can be effectively applied in epidemiological studies and provide strong evidence related to risk assessment associated with daily exposure are required. In this study, we aimed to develop a method for analyzing the concentrations of icaridin, DEET, and two DEET metabolites N,N-diethyl-3-(hydroxymethyl) benzamide and 3-(diethylcarbamoyl) benzoic acid in human urine. METHODS: In this analysis, after formic acid-induced acidification of the urine sample, exposure biomarkers were extracted using solid-phase extraction composed of a modified polystyrenedivinylbenzene polymer for reversed phase (hydrophobic) retention. Subsequently, high-performance liquid chromatography-tandem mass spectrometry was performed within 10 min for a separation analysis. The present method was applied to five Japanese adults (aged 20-43 years) who used icaridin or DEET-containing products within a week. RESULTS: Limits of detection were 0.06-0.11 µg/L. Extraction recoveries were 74%-88%. The intraday and interday variations were 1.5-17.5 and 0.9-15.8% relative standard deviation, respectively. All exposure biomarkers were successfully detected in all five adults. Urinary concentrations of exposure biomarkers reached their maximum values within 15 h after starting to use skin-IR. CONCLUSIONS This method was successful in measuring urinary exposure biomarkers of skin-IR, including icaridin and DEET. Moreover, this study presents the first application of biomonitoring of urinary icaridin concentrations after using a commercial product.
Humans ; Solid Phase Extraction/methods* ; Tandem Mass Spectrometry/methods* ; Adult ; Insect Repellents/urine* ; DEET/urine* ; Young Adult ; Male ; Japan ; Female ; Chromatography, Liquid ; Biomarkers/urine* ; Chromatography, High Pressure Liquid ; East Asian People

BACKGROUND: The effects of prenatal exposure to toxic elements on birth outcomes and child development have been an area of concern. This study aimed to assess the profile of prenatal exposure to toxic elements, arsenic (As), bismuth (Bi), cadmium (Cd), mercury (total mercury (THg), methylmercury (MHg), inorganic mercury (IHg)), lead (Pb), antimony (Sb) and tin (Sn), and essential trace elements, copper (Cu), selenium (Se) and zinc (Zn), using the maternal blood, cord blood and placenta in the Tohoku Study of Child Development of Japan (N = 594-650). METHODS: Inductively coupled plasma mass spectrometry was used to determine the concentrations of these elements (except mercury). Levels of THg and MeHg were measured using cold vapour atomic absorption spectrophotometry and a gas chromatograph-electron capture detector, respectively. RESULTS: Median concentrations (25th-75th) of As, Cd, Pb, Sb, Sn and THg in the maternal blood were 4.06 (2.68-6.81), 1.18 (0.74-1.79), 10.8 (8.65-13.5), 0.2 (0.06-0.40) and 0.2 (0.1-0.38) ng mL and 5.42 (3.89-7.59) ng g, respectively. Median concentrations (25th-75th) of As, Cd, Pb, Sb, Sn and THg in the cord blood were 3.68 (2.58-5.25), 0.53 (0.10-1.25), 9.89 (8.02-12.5), 0.39 (0.06-0.92) and 0.2 (0.2-0.38) ng mL and 9.96 (7.05-13.8) ng g, respectively. CONCLUSIONS THg and Sb levels in the cord blood were twofold higher than those in the maternal blood. Cord blood to maternal blood ratios for As, Cd and Sb widely varied between individuals. To understand the effects of prenatal exposure, further research regarding the variations of placental transfer of elements is necessary.
Adult ; Female ; Fetal Blood ; chemistry ; Humans ; Japan ; Maternal Exposure ; statistics & numerical data ; Maternal-Fetal Exchange ; Metals ; blood ; Placenta ; chemistry ; Pregnancy ; blood ; Trace Elements ; blood ; Urban Health

In 1952, the Japanese Society for Hygiene had once passed a resolution at its 22nd symposium on population control, recommending the suppression of population growth based on the idea of cultivating a healthier population in the area of eugenics. Over half a century has now passed since this recommendation; Japan is witnessing an aging of the population (it is estimated that over 65-year-olds made up 27.7% of the population in 2017) and a decline in the birth rate (total fertility rate 1.43 births per woman in 2017) at a rate that is unparalleled in the world; Japan is faced with a "super-aging" society with low birth rate. In 2017, the Society passed a resolution to encourage all scientists to engage in academic researches to address the issue of the declining birth rate that Japan is currently facing. In this commentary, the Society hereby declares that the entire text of the 1952 proposal is revoked and the ideas relating to eugenics is rejected. Since the Society has set up a working group on the issue in 2016, there have been three symposiums, and working group committee members began publishing a series of articles in the Society's Japanese language journal. This commentary primarily provides an overview of the findings from the published articles, which will form the scientific basis for the Society's declaration. The areas we covered here included the following: (1) improving the social and work environment to balance between the personal and professional life; (2) proactive education on reproductive health; (3) children's health begins with nutritional management in women of reproductive age; (4) workplace environment and occupational health; (5) workplace measures to counter the declining birth rate; (6) research into the effect of environmental chemicals on sexual maturity, reproductive function, and the children of next generation; and (7) comprehensive research into the relationship among contemporary society, parental stress, and healthy child-rearing. Based on the seven topics, we will set out a declaration to address Japan's aging society with low birth rate.
Aging ; Birth Rate ; trends ; Child ; Child Health ; Environmental Exposure ; adverse effects ; prevention & control ; Female ; Health Planning Guidelines ; Humans ; Japan ; epidemiology ; Male ; Occupational Health ; Reproductive Health ; education ; Research Design ; standards ; Societies, Scientific ; organization & administration ; Stress, Psychological ; prevention & control ; Women's Health

BACKGROUND: Over the past few decades, the Japanese Ministry of the Environment has been biomonitoring dioxins in the general Japanese population and, in response to public concerns, has taken measures to reduce dioxin exposure. The objectives of this study were to assess the current dioxin dietary intake and corresponding body burden in the Japanese and compare Japanese dioxin data from 2011 to 2016 and 2002-2010 surveys. We also examined the relationship between blood dioxins and health parameters/clinical biomarkers. METHODS: From 2011 to 2016, cross-sectional dioxin surveys were conducted on 490 Japanese (242 males and 248 females, aged 49.9 ± 7.6 years) from 15 Japanese prefectures. Blood (n = 490) and food samples (n = 90) were measured for 29 dioxin congeners including polychlorinated dibenzo-para-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and coplanar polychlorinated biphenyls (Co-PCBs) using gas chromatography coupled with high-resolution mass spectrometry. Using the 2006 World Health Organization toxic equivalence factors, the toxic equivalents (TEQs) were calculated. Clinical biomarkers and anthropometric parameters were also measured and information on lifestyle behaviours collected. Data imputations were applied to account for blood dioxins below the detection limit. RESULTS: The median (95% confidence interval or CI) blood levels and dioxin dietary intake was respectively 9.4 (8.8-9.9) pg TEQ/g lipid and 0.3 (0.2-0.4) pg TEQ/kg body weight/day. The median blood dioxin level in the 2011-2016 survey was found to have decreased by 41.3% compared to the 2002-2010 surveys. Participants who were older were found to be more likely to have higher dioxin levels. Blood dioxins were also significantly associated with body mass index, triglycerides, docosahexaenoic acid, eicosapentaenoic acid, and dihomo-gamma-linoleic acid levels in blood. Furthermore, associations between blood dioxin and dietary dioxin intake were evident in the unadjusted models. However, after adjusting for confounders, blood dioxins were not found to be associated with dietary dioxin intake. CONCLUSIONS Blood dioxin levels declined over the past decade. This study showed that the measures and actions undertaken in Japan have possibly contributed to these reductions in the body burden of dioxins in the Japanese population.
Adult ; Aged ; Analysis of Variance ; Biomarkers ; blood ; Body Mass Index ; Cross-Sectional Studies ; Diet ; Dioxins ; analysis ; Environmental Exposure ; analysis ; Environmental Monitoring ; methods ; Female ; Food ; Food Analysis ; Food Contamination ; analysis ; Gas Chromatography-Mass Spectrometry ; Humans ; Japan ; Male ; Middle Aged ; Surveys and Questionnaires ; Young Adult

BACKGROUND: The Japan Environment and Children's Study (JECS) is a nation-wide birth cohort study investigating environmental effects on children's health and development. In this study, the exposure characteristics of the JECS participating mothers were summarized using two questionnaires administered during pregnancy. METHODS: Women were recruited during the early period of their pregnancy. We intended to administer the questionnaire during the first trimester (MT1) and the second/third trimester (MT2). The total number of registered pregnancies was 103,099. RESULTS: The response rates of the MT1 and MT2 questionnaires were 96.8% and 95.1%, respectively. The mean gestational ages (SDs) at the time of the MT1 and MT2 questionnaire responses were 16.4 (8.0) and 27.9 (6.5) weeks, respectively. The frequency of participants who reported "lifting something weighing more than 20 kg" during pregnancy was 5.3% for MT1 and 3.9% for MT2. The Cohen kappa scores ranged from 0.07 to 0.54 (median 0.31) about the occupational chemical use between MT1 and MT2 questionnaires. Most of the participants (80%) lived in either wooden detached houses or steel-frame collective housing. More than half of the questionnaire respondents answered that they had "mold growing somewhere in the house". Insect repellents and insecticides were used widely in households: about 60% used "moth repellent for clothes in the closet," whereas 32% applied "spray insecticide indoors" or "mosquito coil or an electric mosquito repellent mat." CONCLUSIONS We summarized the exposure characteristics of the JECS participants using two maternal questionnaires during pregnancy.
Adult ; Child Health ; Cohort Studies ; Female ; Gestational Age ; Humans ; Japan ; Maternal Exposure ; statistics & numerical data ; Mothers ; statistics & numerical data ; Pregnancy ; Surveys and Questionnaires ; Young Adult