Environmental Health and Preventive Medicine最新文献

Background: Organic chemicals have been known to cause allergic diseases such as bronchial asthma and hypersensitivity pneumonitis; however, the possibility that they do not cause irreversible pulmonary fibrosis has not been considered. Polyacrylic acid (PAA), an organic chemical, has caused irreversible progressive pulmonary fibrosis in exposed workers, indicating its potential to induce pulmonary inflammation and fibrosis. Although intratracheal instillation studies are commonly used for evaluating lung pathology, traditional methods face challenges with chemical substances, particularly nanoparticles, which tend to aggregate in suspension and prevent uniform pulmonary distribution. Such aggregation alters the qualitative and quantitative responses to lung injury, limiting accurate assessment of lung pathology. To overcome this limitation, we developed a 'molecular dispersion method' that uses pH modification to negative charges to PAA particles, maintaining their dispersion. Using this method, we investigated the effects of PAA on pulmonary inflammation and fibrosis in a rat model.

Methods: F344 rats were intratracheally instilled with PAA using molecular dispersion (0.1 mg/rat, 1.0 mg/rat), PAA without molecular dispersion (1.0 mg/rat), and normal saline (control group). Rats were sacrificed at 3 days, 1 week, 1 month, 3 months, and 6 months after exposure to examine inflammatory and fibrotic responses.

Results: PAA caused persistent increases in neutrophil influx in the bronchoalveolar lavage fluid (BALF) from 3 days to 1 month following instillation. In histopathological findings, the group with molecular dispersion had almost no inflammatory masses in the lung tissue compared to the group without molecular dispersion, and exhibited relatively uniform dispersion.

Conclusion: Intratracheal instillation of dispersed PAA induced neutrophil inflammation and fibrosis in the rat lung, suggesting that PAA might have pulmonary inflammogenicity and fibrogenicity. Intrapulmonary dispersion of PAA particles following intratracheal instillation studies using the molecular dispersion method was similar to that following inhalation studies.

Background: This cross-sectional study examined meal patterns based on daily energy intake distribution and their associations with nutrient and food intake, diet quality, and body mass index (BMI).

Methods: Body height, weight, habitual dietary intake and the Healthy Eating Index (HEI)-2020 score by eating occasion were assessed using the validated Meal-based Diet History Questionnaire among employees (465 males and 193 females aged 20-75 years) in the Tokyo Metropolitan Area. Meal patterns were extracted based on % energy intake from breakfast, lunch, dinner, and snacks using K-means clustering by sex. Dietary intake, HEI-2020 score, and BMI were then compared between sex-specific meal patterns.

Results: The identified patterns were "large lunch and dinner" (n = 299), "three meals-balanced" (n = 97), and "large dinner" (n = 69) patterns in males and "large dinner" (n = 79); "large afternoon snack" (n = 54) and "large lunch" (n = 60) patterns in females. The HEI-2020 scores were the highest for dinner, followed by breakfast, lunch, and snacks in any meal pattern. Males with the "large dinner" pattern had lower intakes of rice, bread, carbohydrates, dietary fibre, and thiamine; higher intake of alcoholic beverages; and higher HEI-2020 scores than those with other patterns. Females with a "large dinner" pattern had a lower intake of bread, confectionery, total and saturated fats, and carbohydrates; higher intake of fish, meat, and alcoholic beverages; higher HEI-2020 scores; and lower BMI. Thus, a meal pattern with higher energy intake distribution at dinner was associated with higher diet quality among males and females and lower BMI among females in Japanese workers.

Conclusions: These findings suggest that improving the quality of the meal with the highest energy contribution could help enhance overall dietary quality and metabolism.

Background: As research progresses, there is a growing body of evidence indicating that urinary metallothionein (MT) levels may be elevated in individuals exposed to cadmium (Cd). This study aimed to investigate the potential association between urinary MT levels and causes of mortality among residents of the Kakehashi River Basin who have been exposed to Cd.

Method: The study involved a total of 1,398 men and 1,731 women were conducted between 1981 and 1982, with follow-up until November 2016. The study employed the Cox proportional-hazards model to examine the association between higher urinary MT concentrations and the risk of all-cause or cause-specific mortality within the population. Furthermore, the Fine and Gray competing risks regression model was used to evaluate the links between specific causes of death.

Results: The findings revealed that elevated urinary MT concentrations were linked to increased all-cause mortality and higher mortality rates from renal and urinary tract diseases across all participants. Specifically, in men, higher urinary MT levels were associated with elevated all-cause mortality, while in women, increased concentrations were linked to higher mortality from endocrine, nutritional, and metabolic diseases, as well as cardiovascular diseases. Even after adjusting for competing risks, higher urinary MT concentrations were associated with tumor-related mortality in men and continued to be associated with cardiovascular disease mortality in women.

Conclusions: In conclusion, the results suggest that women may face a greater risk of adverse health effects due to prolonged exposure to Cd. Urinary MT levels could potentially serve as a biomarker for mortality from these diseases in populations chronically exposed to Cd.

Background: High visceral fat mass (FM) is associated with a high risk of cardiometabolic morbidity. Meanwhile, loss of skeletal muscle (lean mass, LM) has been suggested to contribute to metabolic diseases.

Methods: We investigated associations between cardiometabolic diseases and dual energy X-ray absorptiometry (DXA)-measured body composition indices, including the FM index (FM/height²), percent body fat, trunk-to-appendicular fat ratio (TAR), trunk-to-leg fat ratio (TLR), LM index (LM/height²) and FM-to-LM ratio in 595 community-dwelling elderly Japanese men (mean age, 74 years; standard deviation, 6; range, 65 to 94). Hypertension was identified as high blood pressure and/or the use of antihypertensive drugs. Diabetes was identified as high hemoglobin A1c and/or the use of antidiabetic drugs. The ability of DXA-based indices to discriminate between the presence and absence of cardiometabolic diseases was evaluated using area under the curve (AUC) calculated by receiver operating characteristic curve analysis.

Results: Body mass index, FM index, percent body fat, TAR, TLR and FM-to-LM ratio were significantly associated with hypertension (P < 0.05). TAR and TLR, but not body mass index, FM index, percent body fat, LM index and FM-to-LM ratio, showed significant positive associations with diabetes. The AUC for the LM index was significantly lower than those for the FM index, percent body fat and FM-to-LM ratio. No associations were observed between the LM index and hypertension, dyslipidemia and diabetes.

Conclusion: The association between cardiometabolic function and LM, which includes skeletal muscle, may not be as pronounced or stronger than associations between cardiometabolic function and FM. Further detailed studies are needed to clarify how skeletal muscle contributes to cardiometabolic disease.

Background: Quick accomplishment and responsiveness are behaviors related to time management by perceived control of time, such as a positive feeling of using one's time well. In recent years, positive psychological states have been associated with a lower risk of cardiovascular disease (CVD). Thus, we investigated the associations of quick accomplishment and responsiveness with CVD mortality in a large cohort study.

Methods: The study participants were 75,049 (30,901 men and 44,148 women) aged 40-79 between 1988 and 1990 and followed until the end of 2009. Hazard ratios (HRs) and 95% confidence intervals (CIs) of mortality from CVD according to quick accomplishment, responsiveness, and their combination were calculated after adjustment for potential confounding factors using the Cox proportional hazard model.

Results: Quick accomplishment was associated with a lower risk of CVD mortality in women; a similar but marginally significant association was observed in men; the respective multivariable HR (95%CI) was 0.91 (0.83-0.99) and 0.93 (0.86-1.01). The presence of both quick accomplishment and responsiveness was associated with lower risk in men, which was confined to men aged 60-79; the respective multivariable HR (95%CI) was 0.88 (0.78-0.99) and 0.83 (0.72-0.96).

Conclusions: Quick accomplishment was associated with a lower risk of CVD mortality. Quick accomplishment and responsiveness combined were inversely associated with CVD mortality risk among older men.

Background: SARS-CoV-2 (COVID-19) is transmitted via infectious respiratory particles. Infectious respiratory particles are released when an infected person breathes, coughs, or speaks. Several studies have measured respiratory particle concentrations through focusing on activities such as breathing, coughing, and short speech. However, few studies have investigated the effect of speech duration.

Methods: This study aimed to clarify the effects of speech duration and volume on the respiratory particle concentration. Study participants were requested to speak at three voice volumes across five speech durations, generating 15 speech patterns. Participants spoke inside a clean booth where particle concentrations and voice volumes were measured and analyzed during speech.

Results: Our findings suggest that as speech duration increased, the aerosol number concentration also increased. Through focusing on individual differences, we considered there might be super-emitters who emit more aerosol particles than the average human. Two participants were identified as statistical outliers (aerosol number concentration, n = 1; mass concentration, n = 1).

Conclusions: Considering speech duration may improve our understanding of respiratory particle concentration dynamics. Two participants were identified as potential super-emitters.

Background: Technological innovations in the public transport sector are increasingly leveraged to support the goals of environmental sustainability and public health. Eco-driving assistance (EDA) systems represent one such intervention, aimed at reducing fuel consumption, emissions, and operating costs while improving passenger comfort. However, the potential unintended impacts of EDA technologies on driver health and well-being remain understudied. The EDA Trial, part of the EU-funded INTERCAMBIO project, seeks to evaluate whether the use of EDA systems may introduce new psychosocial stressors for professional drivers, with implications for occupational and public health.

Methods: The EDA tested in this trial is called "NAVIG". Buses will be assigned randomly. Operating EDA-equipped vehicle will be considered as intervention condition, operating vehicle without EDA as control. Each participant will be monitored for 10 working days maximum to accumulate at least 5 intervention shifts during the trial. Heart rate variability (HRV) will be continuously recorded during working hours to assess autonomous stress responses. The root mean square of successive differences (RMSSD) will be averaged over intervention and control shifts to enable within-subject comparisons between intervention and control conditions. Subjective stress levels will be evaluated using the self-report instruments: Cohen's perceived stress scale at baseline and visual analogous scale at baseline and daily. Moreover, neuroendocrine stress biomarkers (salivary cortisol and cortisone) will be collected repeatedly across shifts, as additional outcomes. Mixed-effects models with participant's ID as a random effect variable will be used to compare stress outcomes between EDA and non-EDA driving conditions. Models will be adjusted for potential confounders.

Results: A sample size of 26-40 participants was estimated to provide 80% power (α = 0.05) to detect differences of 12-15% between conditions. Ethical approval was obtained from the Swissethics (CER-VD 2024-01573), and participant recruitment is ongoing, with 27 drivers enrolled as of June 2025.

Conclusions: This study will provide empirical evidence on the potential health trade-offs associated with implementing eco-driving technologies in real-world settings. By assessing physiological and psychological stress responses to EDA, the trial supports a more integrated approach to environmental technology evaluation-one that considers not only energy efficiency but also the health and sustainability of the workforce.

Trial registration: The trial was registered in the ClinicalTrials.gov database (NCT06688721).

Background: The creatinine (Cre) concentration in urine is used as an adjustment factor in chemical exposure and nutritional intake assessments. Because Cre excretion varies by sex, age, race, and anthropometric measurements such as height and weight, developing a method suitable for estimating one-day Cre excretion is necessary. Accordingly, this study aimed to develop a predictive equation for individual one-day Cre excretion in Japanese school children.

Methods: Urine samples were collected from 113 boys and 91 girls (aged 6-12 years) from the Aichi Prefecture, Japan, who were free from diseases affecting the renal, muscle, or nervous systems. Urinary concentrations and one-day excreted amounts of Cre were measured and compared with the values obtained using previously reported equations or a fixed value, totaling 11 methods. Subsequently, we developed a new equation using machine learning and multiple regression analyses. Additionally, the estimated one-day sodium excretion value calculated using this equation was compared with the measured value.

Results: Among the 11 methods to predict Cre excretion, 7 overestimated-5 of which showed a positive trend bias with larger differences at higher average concentrations-and 3 underestimated-2 of which showed a negative trend bias with larger differences at lower average concentrations. A new machine learning model using sex, age, and body surface area (calculated from height and weight) yielded the most accurate prediction. Multiple regression analysis, which demonstrated the most accurate prediction, used sex, age, and body surface area as independent variables with or without the first void Cre concentration divided by urination duration from the previous night's urination to the first void. Moreover, the difference in one-day sodium excretion from first-void urine predicted using our newly developed Cre equation increased as the measured values increased.

Conclusions: Our study suggests that the estimation of one-day Cre excretion based on sex, age, and body surface area is most appropriate for Japanese schoolchildren, particularly in assessing their chemical exposure and dietary nutrient intake.

Trial registration: Trial registration is not applicable as this observational study did not involve any intervention or randomization requiring registration in a clinical trials registry.

Background: A comprehensive understanding of the epidemiology of pediatric out-of-hospital cardiac arrest (OHCA) occurring under school supervision is lacking. We aimed to comprehensively describe the characteristics and outcomes of OHCA among students in elementary schools, junior high schools, high schools, and technical colleges in Japan.

Methods: OHCA data from 2008-2021 were obtained from the SPIRITS study, which provides a nationwide database of OHCAs occurring under school supervision across Japan. We included cases in which resuscitation was attempted by emergency medical service personnel or bystanders. The cases were classified into three groups based on their etiology: cardiac, non-cardiac, and traumatic origin. The primary outcome was one-month survival with favorable neurological outcomes, defined as a Glasgow-Pittsburgh cerebral performance category of 1 or 2. The demographic characteristics, event details, and outcomes were compared across the three groups by using χ² tests for categorical variables and one-way analyses of variance for continuous variables.

Results: During the 14-year study period, 602 OHCA cases were confirmed, with 430 (71.4%) classified as cardiac, 91 (15.1%) as non-cardiac, and 81 (13.5%) as traumatic origin. Non-cardiac and traumatic cases were less likely to be witnessed at the time of arrest (46.2% and 42.0%, respectively) than cardiac cases (82.6%; p < 0.001). Initiation of cardiopulmonary resuscitation by bystanders was less common in non-cardiac and traumatic cases (62.6% and 42.0%, respectively) than that in cardiac cases (82.8%; p < 0.001). The delivery of defibrillation using public-access automated external defibrillators was also significantly less frequent in non-cardiac (3.3%) and traumatic cases (6.2%) than that in cardiac cases (59.8%; p < 0.001). Ventricular fibrillation (VF) as the first documented rhythm was observed in 77.9% of cardiac cases but was much less common in non-cardiac (5.5%) and traumatic cases (8.6%; p < 0.001). One-month survival with favorable neurological outcomes was significantly lower in non-cardiac (6.6%) and traumatic cases (0%) than that in cardiac cases (50.2%; p < 0.001).

Conclusions: OHCAs of cardiac origin were more frequently associated with VF and had relatively good prognoses. In contrast, OHCAs of non-cardiac and traumatic origins consistently resulted in poor outcomes, highlighting the critical importance of prevention strategies to reduce the occurrence of these incidents.