Association of mechanical ventilation and flue use in heaters with asthma symptoms in Japanese schoolchildren: a cross-sectional study in Sapporo, Japan.

BACKGROUND: Use of fuel heaters is associated with childhood asthma. However, no studies have evaluated the associations of flue use and mechanical ventilation (ventilation) with asthma symptoms in schoolchildren. METHODS: This cross-sectional study investigated schoolchildren in grades 1 through 6 (age 6-12 years) in Sapporo, Japan. From November 2008 through January 2009, parents completed questionnaires regarding their home environment and their children's asthma symptoms. RESULTS: In total, 4445 (69.5%) parents of 6393 children returned the questionnaire. After excluding incomplete responses, data on 3874 children (60.6%) were analyzed. The prevalence of current asthma symptoms and ever asthma symptoms were 12.8% and 30.9%, respectively. As compared with electric heaters, current asthma symptoms was associated with use of flued heaters without ventilation (OR = 1.62; 95% CI, 1.03-2.64) and unflued heaters with ventilation (OR = 1.77; 95% CI, 1.09-2.95) or without ventilation (OR = 2.23; 95% CI, 1.31-3.85). Regardless of dampness, unflued heaters were significantly associated with current asthma symptoms in the presence and absence of ventilation. CONCLUSIONS: Use of unflued heaters was associated with current asthma symptoms, regardless of dampness. In particular, the prevalence of current asthma symptoms was higher in the absence of ventilation than in the presence of ventilation. Ever asthma symptoms was only associated with use of unflued heaters without ventilation. Consequently, use of fuel heaters, especially those that have no flue or ventilation, deserves attention, as their use might be associated with childhood asthma symptoms.

Dose-response relationship of blood flow restriction training on isometric muscle strength, maximum strength and lower limb extensor strength: A meta-analysis.

Objective: To perform a meta-analysis on the efficacy and dose-response relationship of blood flow restriction training on muscle strength reported worldwide. Methods: Thirty-four eligible articles with a total sample size of 549 participants were included in the meta-analysis. This study was performed using the method recommended by the Cochrane Handbook (https://training.cochrane.org/handbook), and the effect size was estimated using the standardized mean difference (SMD) and using RevMan 5.3 software (The Nordic Cochrane Centre, The Cochrane Collaboration, Copenhagen, 2014). Results: The meta-analysis showed that blood flow restriction training increased the lower limb extensor muscle strength [SMD = 0.72, 95%; confidence interval (CI): 0.43 to 1.00, p < 0.01], knee extensor isokinetic torque SMD = 0.48 [95% CI: 0.24 to 0.73, p < 0.01], knee flexor isokinetic torque SMD = 0.39 [95% CI: 0.11 to 0.67, p < 0.01], and squat one-repetition maximum [SMD = 0.28, 95% CI: 0.01 to 0.55, p < 0.01]. There was no publication bias. Evaluation of dose-response relationship showed that the training load, mode, frequency, duration, and maximum cuff pressure affected the muscle function. Conclusion: blood flow restriction training. 16 significantly improved lower limb muscle strength, and the optimal training conditions consisted of a weight load smaller or equal to 30% of one-repetition maximum, training duration longer than 4 weeks, frequency of more than 3 times/week, and maximum cuff pressure lower than 200 mmHg. Systematic Review Registration: website, identifier registration number.

Neutron depth profiling system at CARR.

A neutron depth profiling (NDP) device was developed on China advanced research reactor (CARR) of China Institute of Atomic Energy (CIAE). The CARR-NDP device uses cold neutron beams transmitted by a neutron guide from the cold neutron source of CARR, and it is composed of a neutron beam collimator, and a vacuum target chamber containing a beam stopper and a detection system. The neutron flux at 1 m from the end of neutron guide is about 4.8 × 108 n cm-2 s-1 under operating power of 15 MW. A standard reference material SRM-2137 sample and a multilayer film sample were utilized to verify the performances of the CARR-NDP device.

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.

Comparisons of urinary phthalate metabolites and daily phthalate intakes among Japanese families.

We measured urinary phthalate metabolites, including di-n-butyl phthalate (DnBP), di-isobutyl phthalate, benzyl butyl phthalate (BBzP), and di(2-ethylhexyl) phthalate (DEHP), from 178 school-aged children and their 284 family members using gas chromatography-mass spectrometry, and we calculated daily phthalate intakes. The highest median levels of phthalate metabolites were for mono-isobutyl phthalate in all participants except schoolchildren, where the highest levels were for mono-(2-ethyl-5-oxohexyl) phthalate (MEOHP). Comparing the schoolchildren with their parents, the schoolchildren had significantly higher urinary metabolites for MEOHP, mono-(2-ethyl-5-carboxypentyl) phthalate, and ΣDEHP. Regarding daily intakes, the schoolchildren had significantly higher daily intakes of DnBP, BBzP, and ΣDEHP. All phthalate metabolite and sums of metabolite levels in the schoolchildren were positively correlated with their mothers' levels, except for MEHP, whereas fathers were less correlated with their children. The DEHP intake in this study was higher than that of most other studies. Moreover, 10% of the children and 3% of the adults exceeded the Reference Dose (RfD) value (20µg/kg/day) of the U.S. Environmental Protection Agency, which indicates that it is important to focus on children's DEHP exposure because the children exceeded the RfD more than adults among the same families who shared similar exposure sources. Our results will contribute to considerations of the regulations for some phthalates and the actual phthalate exposure levels in the Japanese population.

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.