Relationship between working hours and sleep quality with consideration to effect modification by work style: a community-based cross-sectional study.

BACKGROUND: Although longer working hours are associated with lower sleep quality, it is still necessary to work a certain number of hours to make a living. In this study, we investigated the relationship between working hours and sleep quality in a community setting. We then explored how to manage work style while maintaining the sleep quality of workers without markedly reducing working hours. METHODS: 4388 day-time workers in various occupations living in Ota ward in Tokyo were included in the analysis. The relationship between working hours and sleep quality measured by the Athens Insomnia Scale was examined by ANOVA and linear regression models. Effect modification by work style (work end time, shift in working start and end time, current work from home status, change in work place) on the relationship between working hours and sleep quality was investigated by multivariate linear regression models. RESULTS: Longer working hours were significantly associated with lower sleep quality. The magnitude of the relationship between long working hours and low sleep quality was significantly larger when work end time was later (p for trend of interaction < 0.01) and when working start and end time were shifted later (vs no change, p for interaction = 0.03). The relationship was marginally greater when the proportion of work from home was increased (vs no change, p for interaction = 0.07). CONCLUSIONS: A relationship between longer working hours and lower sleep quality was observed among workers. Leaving work earlier or optimizing the work environment at home may diminish the adverse effect of long working hours on sleep quality.

Study Profile of the Tsuruoka Metabolomics Cohort Study (TMCS).

The Tsuruoka Metabolomics Cohort Study (TMCS) is an ongoing population-based cohort study being conducted in the rural area of Yamagata Prefecture, Japan. This study aimed to enhance the precision prevention of multi-factorial, complex diseases, including non-communicable and aging-associated diseases, by improving risk stratification and prediction measures. At baseline, 11,002 participants aged 35-74 years were recruited in Tsuruoka City, Yamagata Prefecture, Japan, between 2012 and 2015, with an ongoing follow-up survey. Participants underwent various measurements, examinations, tests, and questionnaires on their health, lifestyle, and social factors. This study used an integrative approach with deep molecular profiling to identify potential biomarkers linked to phenotypes that underpin disease pathophysiology and provide better mechanistic insights into social health determinants. The TMCS incorporates multi-omics data, including genetic and metabolomic analyses of 10,933 participants and comprehensive data collection ranging from physical, psychological, behavioral, and social to biological data. The metabolome is used as a phenotypic probe because it is sensitive to changes in physiological and external conditions. The TMCS focuses on collecting outcomes for cardiovascular disease, cancer incidence and mortality, disability, functional decline due to aging and disease sequelae, and the variation in health status within the body represented by omics analysis that lies between exposure and disease. It contains several sub-studies on aging, heated tobacco products, and women's health. This study is notable for its robust design, high participation rate (89%), and long-term repeated surveys. Moreover, it contributes to precision prevention in Japan and East Asia as a well-established multi-omics platform.

The Nutritional Characteristics of Usual Lunches Consumed Among Japanese Workers: Comparison Between Different Lunch-Type Groups.

OBJECTIVE: This study investigated whether the nutritional characteristics of lunches consumed by Japanese workers differ by where the meal is usually prepared or eaten. METHODS: This cross-sectional study included 620 employees (aged 20 to 75 years) from eight business offices in Tokyo, Japan. Dietary data were collected using the validated Meal-based Diet History Questionnaire. The Healthy Eating Index 2015 and dietary intakes from lunch were compared between workers classified by usual lunch type: homemade (n = 190), staff canteen (n = 77), restaurant (n = 109), and takeaway (n = 244). RESULTS: Healthy Eating Index 2015 for lunch was highest in the staff canteen group, followed by the homemade group. The staff canteen group had higher intakes of total vegetables, potatoes, fish, and several vitamins from lunch than the restaurant or takeaway groups. CONCLUSIONS: Homemade and canteen lunches are relatively healthy options for lunch for Japanese workers.

Factors affecting activities of daily living among patients with Wilson disease.

Wilson disease (WD) is a congenital copper metabolism disorder with various manifestations and can be treated with oral medication. This study examined the factors related to decline in activities of daily living (ADL) in patients with WD as research in this area remains limited. We enrolled 308 patients with WD, including patients who participated in a national survey and those who sought cares at the Department of Pediatrics, Toho University Ohashi Medical Center, from 2016 to 2017. We analyzed the association between ADL decline and factors including age at diagnosis, period from diagnosis to survey, hepatic symptoms, neurological signs, and psychiatric presentation at diagnosis. The relative risks (RRs) for ADL decline were estimated for each factor using multivariate modified Poisson regression analysis. Overall, 97 out of 308 (31.5%) patients experienced ADL decline. After adjusting for explanatory variables, regression analysis revealed that factors significantly associated with ADL decline were a period of ≥20 years from diagnosis to survey (adjusted RR = 2.34, 95% confidence interval [CI]: 1.47-3.74), hepatic symptoms with splenomegaly (adjusted RR = 2.57, 95% CI: 1.26-5.24), mild neurological signs (adjusted RR = 3.20, 95% CI: 1.96-5.23), and severe neurological signs (adjusted RR = 3.63, 95% CI: 2.28-5.77). Neurological signs, hepatic symptoms with splenomegaly, and a period of 20 years from diagnosis to survey are associated with ADL decline. Thus, careful assessment of patients for these factors is necessary, and these findings may guide future efforts to improve patient prognosis.

Misreporting of height and weight by primary school children in Japan: a cross-sectional study on individual and environmental determinants.

BACKGROUND: Appropriate body constitution during childhood is important for future health. However, it has been suggested that thinness is increasing among adolescent girls and boys in Japan. Since misreporting of height/weight may be a possible reflection of the child's ideal body image, we investigated the magnitude and direction of height/weight misreporting and its determinants among Japanese young adolescents. METHODS: A total of 1019 children in public primary schools were included in the analysis. Both measured and self-reported values of height/weight were obtained. Misreporting of height/weight was calculated by subtracting the measured value from the self-reported value. The association between misreporting and several variables such as the BMI z-score of individuals and body constitution of surrounding children was explored by multivariate linear mixed models. RESULTS: As BMI z-score increased, 'overreporting' of height by boys and 'underreporting' of height by girls became larger (p = 0.06 in boys, p = 0.02 in girls). Both boys and girls with a larger body size tended to underreport their weight (p < 0.01 in boys, p < 0.01 in girls). Boys who belonged to a school with a larger average BMI z-score were more likely to overreport their weight. This tendency was not observed for girls. CONCLUSIONS: Self-reported height/weight was generally accurate in Japanese primary school children. However, even primary school children misreported their height/weight intentionally like adults, possibly due to social pressure to lose weight or that not to stand out. Thus, health education about appropriate body constitution should be provided from the beginning of adolescence, particularly for girls.

Current status and future prospects of the Japanese orthopaedic association national registry (JOANR), Japan's first national registry of orthopaedic surgery.

The Japanese Orthopaedic Association National Registry (JOANR) is Japan's first national registry of orthopaedic surgery, which has been developed after having been selected for the Project for Developing a Database of Clinical Outcome approved by the Health Policy Bureau of the Ministry of Health, Labour and Welfare. Its architecture has two levels of registration, one being the basic items of surgical procedure, disease, information on surgeons, surgery-related information, and outcome, and the other being detailed items in the affiliated registries of partner medical associations. It has a number of features, including the facts that, because it handles medical data, which constitute special care-required personal information, data processing is conducted entirely in a cloud environment with the imposition of high-level data security measures; registration of the implant data required to assess implant performance has been automated via a bar code reader app; and the system structure enables flexible collaboration with the registries of partner associations. JOANR registration is a requirement for accreditation as a core institution or partner institution under the board certification system, and the total number of cases registered during the first year of operation (2020) was 899,421 registered by 2,247 institutions, providing real-world evidence concerning orthopaedic surgery.

Smoking and drinking habits relating to development of ulcerative colitis in Japanese: A multicenter case-control study.

Background and Aim: The number of patients with ulcerative colitis (UC) has been increasing in Japan. To elucidate the risk factors for developing UC in Japan, a hospital-based case-control study was conducted. This study examined the association between smoking/drinking habits and UC onset in detail. Methods: Cases comprised 132 Japanese patients who had been newly diagnosed with UC between 2008 and 2014 at 38 collaborating hospitals in Japan, and controls comprised 167 patients without UC. Detailed data on smoking and drinking habits were collected using a self-administered questionnaire. Results: Ex-smokers showed an increasing odds ratio (OR) for UC development compared with never smokers (OR 2.42, 95% confidence interval 1.24-4.72). The ORs of ex-smokers were particularly high among subjects aged less than 40 years, subjects who had smoked more than 10 pack-years, and subjects who were within 13 years of quitting smoking. Regarding drinking habits, ex-drinkers also showed a more than twofold higher OR for UC compared to never drinkers. Ex-drinkers 40 years or older, ex-drinkers who had consumed more than 364 drink-years, and subjects who were less than 6 years after quitting drinking showed increased ORs for UC. Conclusion: These findings suggest the need for careful attention for UC onset among heavy smokers who quit smoking before 40 years of age and heavy drinkers who quit drinking at ≥40 years of age.

Guardianship dietary and other behavioural factors associated with skipping breakfast in Japanese primary school children: A child-guardian dyad study.

BACKGROUND AND OBJECTIVES: Regular breakfast consumption is widely considered an important component of healthy dietary habits. In this study, we assessed differences in nutrient/food intake between breakfast consumers and skippers. We also investigated behavioural factors related with breakfast skipping utilizing data collected from both children and their guardians. METHODS AND STUDY DESIGN: This cross-sectional study was conducted in 14 public primary schools in Japan. Two questionnaires were distributed: a behavioural questionnaire and a brieftype, self-administered diet history questionnaire. In total, 1816 child (10-12 y/o)-guardian dyads were included in the analysis. Intakes of nutrients and foods were compared between breakfast consumers and skippers by the ttest. The relationship between breakfast skipping and behavioural factors was investigated by logistic regression analysis by child sex. RESULTS: The proportion of breakfast skippers in the children was 9.8%. Daily intakes of nutrients/foods were better in the breakfast consumers. Later bedtime, lower nutrition knowledge level, and frequent incomplete consumption of home meals was significantly or marginally associated with breakfast skipping. Guardians' breakfast skipping was also associated with children's breakfast skipping. Some relationships between behavioural factors and breakfast skipping differed between boys and girls. CONCLUSIONS: Breakfast consumers had a more nutritious meal quality. To increase breakfast consumption, morning time schedules may need to be rearranged to avoid time pressure. Nutritional knowledge and dietary behaviour appear relevant. Guardians played a major role in coping with breakfast avoidance, in part as role models.

Maternal Exposure to Fine Particulate Matter and Its Chemical Components Increasing the Occurrence of Gestational Diabetes Mellitus in Pregnant Japanese Women.

Introduction: PM2.5 exposure is a suspected risk factor for diabetes. It is hypothesized that maternal PM2.5 exposure contributes to the development of gestational diabetes mellitus (GDM). The association between PM2.5 exposure and GDM is controversial and limited evidence is available for the exposure to PM2.5 chemical components. We investigated the association between maternal exposure to total PM2.5 mass and its components, particularly over the first trimester (early placentation period), and GDM. Methods: Data were obtained from the Japan Perinatal Registry Network database, which includes all live births and stillbirths after 22 weeks of gestation at 39 cooperating hospitals in 23 Tokyo wards (2013-2015). At one fixed monitoring site, we performed daily filter sampling of fine particles and measured daily concentrations of carbon and ion components. The average concentrations of total PM2.5 and its components over the 3 months before pregnancy and the first (0-13 gestational weeks) and second (14-27 gestational weeks) trimesters were calculated and assigned to each woman. We estimated the odds ratios (ORs) of GDM in a multilevel logistic regression model. Results: Among 82,773 women (mean age at delivery = 33.7 years) who delivered singleton births, 3,953 (4.8%) had GDM. In the multiexposure period model, an association between total PM2.5 exposure and GDM was observed for exposure over the first trimester (OR per interquartile range (IQR = 3.63 µg/m3) increase = 1.09; 95% confidence interval (CI) = 1.02-1.16), but not for the 3 months before pregnancy or the second trimester. For PM2.5 components, only organic carbon exposure over the first trimester was positively associated with GDM (OR per IQR (0.51 µg/m3) increase = 1.10; 1.00-1.21). Conclusions: This is the first evidence that exposure to total PM2.5 and one of its components, organic carbon, over the first trimester increases GDM occurrence in Japan.

Estimated Glomerular Filtration Rate and Hearing Impairment in Japan: A Longitudinal Analysis Using Large-Scale Occupational Health Check-Up Data.

Several longitudinal studies have examined associations between renal dysfunction and hearing impairment. Here, we explored the longitudinal association between estimated glomerular filtration rate (eGFR) and hearing impairment among the working-age population in Japan. Participants were 88,425 males and 38,722 females aged 20-59 years, without hearing impairment at baseline (2013), who attended Japanese occupational annual health check-ups from 2013 to 2020 fiscal year. eGFR was categorized into four groups (eGFR upper half of ≥90, lower half of ≥90 (reference), 60-89, and <60 mL/min/1.73 m2). Low- and high-frequency hearing impairment were assessed using data from pure-tone audiometric testing. A Cox proportional hazards model was applied to estimate hazard ratio (HR) values for hearing impairment. Low eGFR did not increase the risk of low- or high-frequency hearing impairment. For males, multivariable-adjusted HR of high-frequency hearing impairment was 1.16 (95% confidence interval, 1.01-1.34) for the upper half of the ≥90 mL/min/1.73 m2; however, this positive association between high eGFR and high-frequency hearing impairment did not appear to be robust in a number of sensitivity analyses. We conclude that, among the Japanese working-age population, eGFR was not generally associated with hearing impairment in people of either sex.

Changes in cross-sectional areas of posterior extensor muscles in thoracic spine: a 10-year longitudinal MRI study.

Age-related changes in the posterior extensor muscles of the cervical and lumbar spine have been reported in some studies; however, longitudinal changes in the thoracic spine of healthy subjects are rarely reported. Therefore, this study aimed to evaluate changes in the cross-sectional areas (CSAs) of posterior extensor muscles in the thoracic spine over 10 years and identify related factors. The subjects of this study were 85 volunteers (mean age: 44.7 ± 11.5) and the average follow-up period was about 10 years. The CSAs of the transversospinalis muscles, erector spinae muscles, and total CSAs of the extensor muscles from T1/2 to T11/12 were measured on magnetic resonance imaging. The extent of muscle fat infiltration was assessed by the signal intensity (luminance) of the extensor muscles' total cross-section compared to a section of pure muscle. We applied a Poisson regression model, which is included in the generalized linear model, and first examined the univariate (crude) association between each relevant factor (age, sex, body mass index, lifestyle, back pain, neck pain, neck stiffness, and intervertebral disc degeneration) and CSA changes. Then, we constructed a multivariate model, which included age, sex, and related factors in the univariate analysis. The mean CSAs of the transversospinalis muscles, erector spinae muscles, and total CSAs of the extensor muscles significantly increased over 10 years. Exercise habit was associated with increased CSAs of the erector spinae muscles and the total area of the extensor muscles. The cross-section mean luminance significantly increased from baseline, indicating a significant increase of fat infiltration in the posterior extensor muscles. Progression of disc degeneration was inversely associated with increased fat infiltration in the total extensor muscles.

A Case-Crossover Analysis of the Association between Exposure to Total PM2.5 and Its Chemical Components and Emergency Ambulance Dispatches in Tokyo.

A limited number of studies have investigated the association between short-term exposure to PM2.5 components and morbidity. The present case-crossover study explored the association between exposure to total PM2.5 and its components and emergency ambulance dispatches, which is one of the indicators of morbidity, in the 23 Tokyo wards. Between 2016 and 2018 (mean mass concentrations of total PM2.5 13.5 µg/m3), we obtained data, from the Tokyo Fire Department, on the daily cases of ambulance dispatches. Fine particles were collected at a fixed monitoring site and were analyzed to estimate the daily mean concentrations of carbons and ions. We analyzed 1038301 cases of health-based all-cause ambulance dispatches by using a conditional logistic regression model. The average concentrations of total PM2.5 over one and the previous day were positively associated with the number of ambulance dispatches. In terms of PM2.5 components, the percentage increase per interquartile range (IQR) increase was 0.8% for elemental carbon (IQR = 0.8 µg/m3; 95% CI = 0.3-1.3%), 0.9% for sulfate (2.1 µg/m3; 0.5-1.4%), and 1.1% for ammonium (1.3 µg/m3; 0.4-1.8%) in the PM2.5-adjusted models. This is the first study to find an association between some specific components in PM2.5 and ambulance dispatches.

Dietary Patterns and Their Associations with Intermediate Age-Related Macular Degeneration in a Japanese Population.

This population-based cross-sectional study investigated the influence of dietary patterns on age-related macular degeneration (AMD) in a Japanese population. The Tsuruoka Metabolomics Cohort Study enrolled a general population aged 35-74 years from among participants in annual health check-up programs in Tsuruoka City, Japan. Eating habits were assessed using a food frequency questionnaire. Principal component analysis was used to identify dietary patterns among food items. The association between quartiles of scores for each dietary pattern and intermediate AMD was assessed using multivariate logistic regression models. Of 3433 participants, 415 had intermediate AMD. We identified four principal components comprising the Vegetable-rich pattern, Varied staple food pattern, Animal-rich pattern, and Seafood-rich pattern. After adjusting for potential confounders, higher Varied staple food diet scores were associated with a lower prevalence of intermediate AMD (fourth vs. first quartile) (OR, 0.63; 95% confidence interval [CI], 0.46-0.86). A significant trend of decreasing ORs for intermediate AMD associated with increasing Varied staple food diet scores was noted (p for trend = 0.002). There was no significant association between the other dietary patterns and intermediate AMD. In a Japanese population, individuals with a dietary pattern score high in the Varied staple food pattern had a lower prevalence of intermediate AMD.

Maternal exposure to fine particulate matter over the first trimester and umbilical cord insertion abnormalities.

BACKGROUND: Our hypothesis was that exposure to fine particulate matter (PM2.5) is related to abnormal cord insertion, which is categorized as a form of placental implantation abnormality. We investigated the association between exposure to total PM2.5 and its chemical components over the first trimester and abnormal cord insertion, which contributes to the occurrence of adverse birth outcomes. METHODS: From the Japan Perinatal Registry Network database, we used data on 83 708 women who delivered singleton births at 39 cooperating hospitals in 23 Tokyo wards (2013-2015). We collected PM2.5 on a filter and measured daily concentrations of carbon and ion components. Then, we calculated the average concentrations over the first trimester (0-13 weeks of gestation) for each woman. A multilevel logistic-regression model with the hospital as a random effect was used to estimate the odds ratios (ORs) of abnormal cord insertion. RESULTS: Among the 83 708 women (mean age at delivery = 33.7 years), the frequency of abnormal cord insertion was 4.5%, the median concentration [interquartile range (IQR)] of total PM2.5 was 16.1 (3.61) µg/m3 and the OR per IQR for total PM2.5 was 1.14 (95% confidence interval = 1.06-1.23). In the total PM2.5-adjusted models, total carbon, organic carbon, nitrate, ammonium and chloride were positively associated with abnormal insertion. Organic carbon was consistently, and nitrate tended to be, associated with specific types of abnormal insertion (marginal or velamentous cord insertion). CONCLUSIONS: Exposure to total PM2.5 and some of its components over the first trimester increased the likelihood of abnormal cord insertion.

Tracking Pattern of Total Cholesterol Levels from Childhood to Adolescence in Japan.

AIMS: This study aimed to evaluate the tracking pattern of serum total cholesterol (TC) levels among Japanese children using data collected continuously for 9 years and examine the relationship between childhood and adulthood TC levels. METHODS: TC levels of 2,608 first grade primary school children enrolled during 1981-2014 from two Japanese towns were measured during annual health check-ups. Nine-year trajectories of estimated TC levels stratified by TC quartiles in the first grade were analyzed using a mixed effects model. Adulthood TC levels were measured in participants who underwent health check-ups in the same area. RESULTS: Overall, 1,322 boys and 1,286 girls in the first grade of a primary school were followed for 9 years. Trajectories of TC levels during the period stratified by TC quartiles in the first grade differed significantly and did not cross each other for both sexes. Childhood data of 242 adult participants were linked with their adulthood data; the mean of age was late 20s for both sexes. The average TC levels in adulthood increased from the first to the fourth quartile in the first grade. Additionally, trajectories of TC levels differed between boys and girls. The later the admission year, the more elevated the TC levels in girls. CONCLUSION: Among Japanese children, TC levels were strongly tracked from childhood to adolescence for 9 years, and elevated TC levels in childhood were related to elevated TC levels in adulthood. Maintaining appropriate TC levels during childhood may be important to prevent future coronary artery diseases.

Exposure to chemical components of fine particulate matter and ozone, and placenta-mediated pregnancy complications in Tokyo: a register-based study.

BACKGROUND: Maternal exposure to fine particulate matter (PM2.5) was associated with pregnancy complications. However, we still lack comprehensive evidence regarding which specific chemical components of PM2.5 are more harmful for maternal and foetal health. OBJECTIVE: We focused on exposure over the first trimester (0-13 weeks of gestation), which includes the early placentation period, and investigated whether PM2.5 and its components were associated with placenta-mediated pregnancy complications (combined outcome of small for gestational age, preeclampsia, placental abruption, and stillbirth). METHODS: From 2013 to 2015, we obtained information, from the Japan Perinatal Registry Network database, on 83,454 women who delivered singleton infants within 23 Tokyo wards (≈627 km2). Using daily filter sampling of PM2.5 at one monitoring location, we analysed carbon and ion components, and assigned the first trimester average of the respective pollutant concentrations to each woman. RESULTS: The ORs of placenta-mediated pregnancy complications were 1.14 (95% CI = 1.08-1.22) per 0.51 µg/m3 (interquartile range) increase of organic carbon and 1.11 (1.03-1.18) per 0.06 µg/m3 increase of sodium. Organic carbon was also associated with four individual complications. There was no association between ozone and outcome. SIGNIFICANCE: There were specific components of PM2.5 that have adverse effects on maternal and foetal health.

A school-based nutrition education program involving children and their guardians in Japan: facilitation of guardian-child communication and reduction of nutrition knowledge disparity.

BACKGROUND: Since the risk of noncommunicable diseases is closely associated with dietary intake, it is important to establish healthy dietary habits in childhood. Although several dietary education programs for children have been attempted, their implementation at school was often difficult due to overcrowded study curricula. We developed a new program which included homework for children and guardians, and evaluated its effect. Determinants of the effect were also investigated. METHODS: The school-based nutrition education program including a 45-min lecture, a series of homework assignments involving children and guardians, and two handouts was implemented in 14 public primary schools in Japan. Seven schools each underwent the intervention in an alternating manner. Nutrition knowledge (percentage (%) of correct answers in the nutrition knowledge questionnaire) and attitude/behavior toward diet was evaluated three times (May (baseline), October, February) as outcomes. These factors and their changes following the intervention were assessed by linear mixed models to adjust for individual factors, with consideration to clustering of the participants and repeated measurements. RESULTS: In total, 2227 children aged 10-12 years and their guardians participated. All schools completed the program. Children's nutrition knowledge level was significantly increased (8.7%, 95% confidence interval [7.7-9.7]) following the intervention. Communication between children and their guardians, which was positively related with nutrition knowledge, was facilitated by the intervention. The increase in nutrition knowledge was greater among children with a lower knowledge level at baseline. CONCLUSIONS: This school-based nutrition education program was effective and feasible. Appropriate teaching materials for homework can reduce the burden on schools and facilitate communication between children and guardians. Public schools can be crucial venues for decreasing disparities in nutrition knowledge. TRIAL REGISTRATION: This study was registered as an intervention study in the UMIN Clinical Trials Registry (trial ID: UMIN000029252 ) on Sep 22, 2017.

Respiratory function declines in children with asthma associated with chemical species of fine particulate matter (PM2.5) in Nagasaki, Japan.

BACKGROUND: The differential effects of PM2.5 fractions on children's lung function remain inconclusive. This study aimed to examine whether lung function in asthmatic children was associated with increased PM2.5 fractions in urban areas in Nagasaki prefecture, Japan, where the air pollution level is relatively low but influenced by transboundary air pollution. METHODS: We conducted a multiyear panel study of 73 asthmatic children (boys, 60.3%; mean age, 8.2 years) spanning spring 2014-2016 in two cities. We collected self-measured peak expiratory flow (PEF) twice a day and daily time-series data for PM2.5 total mass and its chemical species. We fitted a linear mixed effects model to examine short-term associations between PEF and PM2.5, adjusting for individual and time-varying confounders. A generalized linear mixed effects model was also used to estimate the association for worsening asthma defined by severe PEF decline. Back-trajectory and cluster analyses were used to investigate the long-range transboundary PM2.5 in the study areas. RESULTS: We found that morning PEFs were adversely associated with higher levels of sulfate (- 1.61 L/min; 95% CI: - 3.07, - 0.15) in Nagasaki city and organic carbon (OC) (- 1.02 L/min; 95% CI: - 1.94, - 0.09) in Isahaya city, per interquartile range (IQR) increase at lag1. In addition, we observed consistent findings for worsening asthma, with higher odds of severe PEF decline in the morning for sulfate (odds ratio (OR) = 2.31; 95% CI: 1.12, 4.77) and ammonium (OR = 1.73; 95% CI: 1.06, 2.84) in Nagasaki city and OC (OR = 1.51; 95% CI: 1.06, 2.15) in Isahaya city, per IQR increase at lag1. The significant chemical species were higher on days that could be largely attributed to the path of Northeast China origin (for sulfate and ammonium) or both the same path and local sources (for OC) than by other clusters. CONCLUSIONS: This study provides evidence of the differential effects of PM2.5 fractions on lung function among asthmatic children in urban areas, where the Japanese national standards of air quality have been nearly met. Continuous efforts to promote mitigation actions and public awareness of hazardous transboundary air pollution are needed to protect susceptible children with asthma.

Relationship between maternal employment status and children's food intake in Japan.

BACKGROUND: Although long maternal working hours are reported to have a negative effect on children's dietary habits, few studies have investigated this issue in Japan. Healthy dietary habits in childhood are important because they may reduce the risk of future disease. Here, we examined the relationship between maternal employment status and children's dietary intake in 1693 pairs of Japanese primary school 5th and 6th graders and their mothers. METHODS: The survey was conducted using two questionnaires, a brief-type self-administered diet history questionnaire and a lifestyle questionnaire. The analysis also considered mothers' and children's nutrition knowledge, attitudes toward diet, and some aspects of family environment. RESULTS: Longer maternal working hours were associated with children's higher intake of white rice (g/1000kcal) (ß 11.4, 95%CI [1.0, 21.9]; working ≥8h vs. not working), lower intake of confectioneries (g/1000kcal) (ß -4.0 [-7.6, -0.4]), and higher body mass index (BMI) (kg/m2) (ß 0.62 [0.2, 1.0]). Although maternal employment status was not significantly associated with lower intake of healthy food (e.g., vegetables) or higher intake of unhealthy food (e.g., sweetened beverages) in the children, in contrast with previous studies, it may have affected children's energy intake through their higher intake of white rice. Further, children's nutrition knowledge and attitudes toward diet, mothers' food intake, and some family environment factors were significantly associated with intakes of vegetables and sweetened beverages in the children. CONCLUSIONS: Longer maternal working hours were significantly associated with higher intake of white rice and lower intake of confectioneries, as well as higher BMI among children. Even when a mother works, however, it may be possible to improve her child's dietary intake by other means such as nutrition education for children or enhancement of food environment.

Trimester-Specific Association of Maternal Exposure to Fine Particulate Matter and its Components With Birth and Placental Weight in Japan.

OBJECTIVE: We investigated which trimester of exposure to PM2.5 and its components was associated with birth and placental weight, and the fetoplacental weight ratio. METHODS: The study included 63,990 women who delivered singleton term births within 23 Tokyo wards between 2013 and 2015. Each day, we collected fine particles on a filter, and analyzed their chemical constituents, including carbons and ions. Trimester-specific exposure to each pollutant was estimated based on the average daily concentrations. RESULTS: Over the third trimester, sulfate exposure tended to be inversely associated with birth weight, and decreased placental weight (difference for highest vs lowest quintile groups = -6.7 g, 95% confidence interval = -12.5 to -0.9). For fetoplacental weight ratio, there was no relationship. CONCLUSIONS: Sulfate exposure over the third trimester may reduce birth weight, particularly placental weight.