Tazuru Tsuboi

Effects of SO2 on respiratory system of adult Miyakejima resident 2 years after returning to the island.

Effects of SO2 on Respiratory System of Adult Miyakejima Resident 2 Years after Returning to the Island: Satoko Iwasawa, et al. Department of Preventive Medicine and Public Health, School of Medicine, Keio University

Detection and intake assessment of organophosphate flame retardants in house dust in Japanese dwellings.

The demand for phosphorus flame retardants (PFRs) has recently increased as an alternative to polybrominated diphenyl ether (PBDE). PFRs have been detected in house dust, but little is known about the concentrations of PFRs in private homes and the effects on human health. We measured the levels of 10 PFRs in indoor floor dust and upper surface dust from 128 Japanese dwellings of families with children in elementary school. The median (min-max) concentrations (μg/g) of PFRs were as follows: tris(2-butoxyethyl) phosphate (TBOEP), 30.88 (<0.61-936.65); tris(2-chloro-iso-propyl) phosphate (TCIPP), 0.74 (<0.56-392.52); and triphenyl phosphate (TPHP), 0.87 (<0.80-23.35). These values exceeded 50% detection rates, and the rates are median over the LOD in floor dust. The concentrations (μg/g) of TBOEP 26.55 (<0.61-1933.24), TCIPP 2.23 (<0.56-621.23), TPHP 3.13 (<0.80-27.47), tris(2-chloroethyl) phosphate (TCEP) 1.17 (<0.65-92.22), and tributyl phosphate (TNBP) 0.74 (<0.36-60.64) exceeded 50% detection rates in the upper surface dust. A significant positive correlation (P<0.05) between the concentrations of TCIPP and TBOEP was shown in floor dust and upper surface dust (n=48). Estimated median and 95th percentile daily intake was calculated for toddlers and elementary school children and was compared with reference dose values (RfD) from the literature. For TBOEP, the estimated 95th percentile intake from floor dust was 14% of RfD for toddlers and 4% for school children. The estimated intake from upper surface dust was somewhat lower. Estimated median intake of TBOEP and median intake for the other PFRs were less than 1% of the RfD. TBOEP, TCIPP and TPHP were the main PFRs in the dust. The median levels of PFRs are well below the RfD values.

Associations of phthalate concentrations in floor dust and multi-surface dust with the interior materials in Japanese dwellings

Phthalates are widely used as plasticizers in numerous products. However, there has been some concern about the various effects they may have on human health. Thus, household phthalate levels are an important public health issue. While many studies have assessed phthalate levels in house dust, the association of these levels with building characteristics has scarcely been examined. The present study investigated phthalate levels in house dust samples collected from the living areas of homes, and examined associations between these phthalate levels and the interior materials. Dust was collected from two portions of the living area: floor dust from the entire floor surface, and multi-surface dust from objects more than 35 cm above the floor. The levels of seven phthalates were measured using gas chromatography/mass spectrometry in selective ion monitoring mode. Phthalate levels were higher in multi-surface dust than in floor dust. Among floor dust samples, those from dwellings with compressed wooden flooring had significantly higher levels of di-iso-butyl phthalate compared to those with other floor materials, while polyvinyl chloride (PVC) flooring was associated with higher di-2-ethylhexyl phthalate (DEHP) levels. Among multi-surface dust samples, higher levels of DEHP and di-iso-nonyl phthalate (DINP) were found in samples from homes with PVC wallpaper than without. The number of PVC interior materials was significantly positively correlated with the levels of DEHP and DINP in multi-surface dust. The phthalate levels in multi-surface dust were associated with the interior surface materials, and those in floor dust were directly related to the flooring materials. Our findings show that when using house dust as an exposure assessment, it is very important to note where the samples were collected from. The present report provides useful information about the association between phthalates and dust inside dwellings, which will assist with establishing public health provisions.

Exposure to phthalates in house dust and associated allergies in children aged 6-12years.

Phthalates are widely used as plasticizers in household products. Several studies have reported an association between phthalate exposure and an increased risk of allergies. The present study estimated phthalate exposure in children aged 6-12years and assessed potential correlations with allergies. House dust samples were collected from floors and multi-surface objects >35cm above the floor. Urine samples were collected from the first morning void of the day. Daily phthalate intake (DIdust and DI) was estimated using both house dust and urinary metabolite concentrations. Exposure to di-2-ethylhexyl phthalate (DEHP) in floor dust was associated with parental-reported rhino-conjunctivitis. After stratification by gender, this trend was found to only occur in boys. Furthermore, urinary mono-isobutyl phthalate was inversely associated with parental-reported wheeze in boys. DIdust of benzyl butyl phthalate (BBzP) and DEHP were significantly correlated with DI_BBzP and DI_DEHP, respectively. These correlations were stronger with floor than with multi-surface dust. Our results suggest that, among Japanese children, house dust from low surfaces, such as living room floors, might play a meaningful role in the indoor environmental exposure pathway for BBzP and DEHP.

Influence of sulfur dioxide on the respiratory system of Miyakejima adult residents 6 years after returning to the island

Mount Oyama, on the Japanese island of Miyakejima, began erupting in June 2000, necessitating the evacuation of 3,000 island residents. Volcanic gas emissions, primarily consisting of sulfur dioxide (SO2), gradually decreased and residents returned to the island after the evacuation order was lifted in February 2005.

1153 Effects of sulfur dioxide on fractional exhaled nitric oxide concentration in the child residents of miyakejima island

Introduction In 2000, all residents were forced to evacuate the island of Miyakejima in Japan, due to a volcanic eruption following massive amounts of volcanic gas emission including sulfur dioxide (SO2). As a high concentration of SO2 continuously emitted, annual health checkups focusing on the respiratory system were performed from February 2006. Since 2008 health checkups, a fractional exhaled nitric oxide concentration (FeNO) was measured. The present study aims to investigate the relationship between SO2 exposure and FeNO by comparing FeNO of the Miyakejima students with FeNO of reference students in another island in Japan, where SO2 concentration is far lower than the Japanese Environmental Standards. Methods All subjects aged 13–14 years. Total number of Miyakejima and reference students were 83 and 31. From SO2 concentration measured at the fixed-point monitoring stations, we calculated the average SO2 concentration (ppb) during the 3 month periods prior to the health checkups. Based on the clinical practice guidelines of the Official American Thoracic Society, 35 ppb was used as a cutoff point of FeNO. Results The average SO2 concentrations from 2008 to 2014 were 17.6, 17.5, 9.6, 7.3, 8.4, 4.2, and 5.0, respectively. The prevalence (%) of Miyakejima students with abnormal FeNO at 2008 to 2014 health checkups 50.0, 27.3, 18.2, 57.1, 46.2, 32 38.5, and 50.0, respectively. These prevalence were not statistically higher than the prevalence of the reference students (41.9%). Discussion No clear dose-response relationship was observed in this study. In addition to this study, we also examined the medical records of patients at the Chuo-Clinic between 2005 and 2010. Totally 4586 medical records were examined. Of these, 2594 patients developed a disease potentially caused by SO2 concentration. Therefore, further studies with regards to the relationship between the incidence of disease and SO2 should be conducted.

Association of filaggrin gene mutations and childhood eczema and wheeze with phthalates and phosphorus flame retardants in house dust: The Hokkaido study on Environment and Children's Health

BACKGROUND AND AIM Exposure to phthalates and phosphorus flame retardants (PFRs) is considered to be a risk factor for asthma and allergies. However, little is known about the contribution of loss-of-function mutations in the gene encoding filaggrin (FLG) gene, which are considered to be predisposing factors for eczema and asthma, to these associations. We investigated the associations between exposure to phthalates and PFRs in dust and eczema/wheeze among Japanese children, taking into consideration loss-of-function mutations in FLG. METHODS This study was part of the Hokkaido study on Environment and Childrens Health. Seven phthalates and 11 PFRs in household dust were measured by gas chromatography-mass spectrometry. Eczema and wheeze were assessed in children aged 7 years using the International Study of Asthma and Allergies in Childhood questionnaire. Eight FLG mutations previously identified in the Japanese population were extracted from cord blood samples. Children with one or more FLG mutations were considered to be positive for FLG mutations. The study included 296 children who had complete data (birth records, FLG mutations, first trimester and 7 years questionnaires, and phthalate/PFR levels). Odds ratios (ORs) and 95% confidential intervals (CIs) of eczema and wheeze were calculated for log-transformed phthalate/PFR levels by logistic regression. We also performed stratified analyses based on FLG mutations. RESULTS The prevalence rates of eczema and wheeze were 20.6% and 13.9%, respectively. Among children without any FLG mutations, tris (1, 3-dichloro-2-propyl) phosphate (TDCIPP) increased the OR of wheeze, (OR: 1.22, CI: 1.00-1.48). Significant p values for trends were found between tris (2-butoxyethyl) phosphate (TBOEP) and eczema and di-iso-nonyl phthalate (DiNP) and eczema among children without any FLG mutations, respectively. CONCLUSIONS Despite our limited sample size and cross-sectional study design, the effects of indoor environmental factors on childhood eczema and wheeze were clearer in children without loss-of-function mutations in FLG than in children with mutations. Children with FLG mutations might already be cared for differently in terms of medication or parental lifestyle. Further studies in larger populations are warranted so that severity of symptoms and combinations of FLG mutations can be investigated.

Associations between allergic symptoms and phosphate flame retardants in dust and their urinary metabolites among school children

BACKGROUND Phosphate flame retardants (PFRs) are ubiquitously detected in indoor environments. Despite increasing health concerns pertaining to PFR exposure, few epidemiological studies have examined PFR exposure and its effect on childrens allergies. OBJECTIVES To investigate the association between PFRs in house dust, their metabolites in urine, and symptoms of wheeze and allergies among school-aged children. METHODS A total of 128 elementary school-aged children were enrolled. House dust samples were collected from upper-surface objects. Urine samples were collected from the first morning void. Levels of 11 PFRs in dust and 14 PFR metabolites in urine were measured. Parent-reported symptoms of wheeze, rhinoconjunctivitis, and eczema were evaluated using the International Study of Asthma and Allergies in Childhood questionnaire. The odds ratios (ORs) of the Ln transformed PFR concentrations and categorical values were calculated using a logistic regression model adjusted for sex, grade, dampness index, annual house income, and creatinine level (for PFR metabolites only). RESULTS The prevalence rates of wheeze, rhinoconjunctivitis, and eczema were 22.7%, 36.7%, and 28.1%, respectively. A significant association between tris(1,3-dichloroisopropyl) phosphate (TDCIPP) in dust and eczema was observed: OR (95% confidence interval), 1.44 (1.13-1.82) (>limit of detection (LOD) vs <LOD). The ORs for rhinoconjunctivitis (OR = 5.01 [1.53-16.5]) and for at least one symptom of allergy (OR = 3.87 [1.22-12.3]) in the 4th quartile of Σtris(2-chloro-isopropyl) phosphate (TCIPP) metabolites was significantly higher than those in the 1st quartile, with significant p-values for trend (Ptrend) (0.013 and 0.024, respectively). A high OR of 2.86 (1.04-7.85) (>LOD vs <LOD) was found for hydroxy tris(2-butoxyethyl) phosphate (TBOEP)-OH and eczema. OR of the 3rd tertile of bis (1,3-dichloro-2-propyl) phosphate (BDCIPP) was higher than the 1st tertile as a reference for at least one symptom (OR = 3.91 [1.25-12.3]), with a significant Ptrend = 0.020. CONCLUSIONS We found that TDCIPP in house dust, and metabolites of TDCIPP, TBOEP and TCIPP were associated with childrens allergic symptoms. Despite some limitations of this study, these results indicate that childrens exposure to PFR may impact their allergic symptoms.

Respiratory symptoms and effects of SO2: 4-year follow up of Miyakejima residents after returning to the island

Objectives Mount Oyama on Miyakejima Island, Tokyo, erupted in June, 2000. All Miyake village citizens were forced to evacuate from the island in September, 2000, due to continuous eruptions and emissions of unsafe amounts of volcanic gas, mainly SO2. From February, 2005, residents started to return to the island despite the fact that volcanic gas was still being emitted. This study examines changes in respiratory function over 4 years from autumn 2004 to November 2008. Methods The study population comprised 276 adults (122 male, 154 female) who each underwent an examination for respiratory health just before returning to the island (2004) and another examination 4 years after their return (2008). Exposure was approximated by monitoring data across 7 monitoring stations. Mean SO2 concentration from February 2005 to November 2008 was 0.022 ppm. Effects were evaluated by spirometry. Results Study subjects showed no reduction in lung function between 2004 and 2008. Conclusions No change was observed in respiratory function in adult Miyakejima residents due to 4 years of residence in an environment with an average SO2 concentration of 0.022 ppm. However, to truly shed light on the effects of SO2 on respiratory function in adults, it is important to continue this study and conduct further analysis.