Association between chemical components of PM2.5 and children's primary care night-time visits due to asthma attacks: A case-crossover study.

BACKGROUND: Few papers have examined the association between the chemical components of PM2.5 and health effects. The existence of an association is now under discussion. METHODS: This case-crossover study aimed to examine the association between the chemical components of PM2.5 and night-time primary care visits (PCVs) due to asthma attacks. The subjects were 1251 children aged 0-14 years who received medical care for asthma at a municipal emergency clinic. We measured daily average concentrations of hydrogen ion, sulfate ion, nitrate ion and water-soluble organic compounds (WSOCs), which are components of PM2.5. We estimated the odds ratios (ORs) of PCVs per unit increment (inter quartile ranges) in each chemical component of PM2.5 for the subgroups of warmer months and colder months separately. RESULTS: No association was seen between PCVs and PM2.5 mass concentrations the day before the PCVs in either warmer or colder months. In the warmer months, an association was seen with the concentrations of WSOCs and hydrogen ion the day before the PCVs (OR = 1.33; 95% CI: 1.00-1.76, OR = 1.18; 95% CI: 1.02-1.36, respectively). Furthermore, a negative association was seen between sulfate ion and PCVs (OR = 0.85; 95%CI: 0.74-0.98). No associations were observed in the colder months. CONCLUSIONS: We observed a positive association between PCVs and certain concentrations of WSOCs and hydrogen ions in warmer months. In contrast, sulfate ion showed a negative association.

Exposure to air pollution and meteorological factors associated with children's primary care visits at night due to asthma attack: case-crossover design for 3-year pooled patients.

OBJECTIVE: We examined the association of outdoor air pollution and meteorological parameters with primary care visits (PCVs) at night due to asthma attack. SETTING: A case-crossover study was conducted in a primary care clinic in Himeji City, Japan. PARTICIPANTS: Participants were 1447 children aged 0-14 years who visited the clinic with an asthma attack from April 2010 until March 2013. EXPOSURE: Daily concentrations of air pollutants and meteorological parameters were measured. PRIMARY OUTCOME: PCVs at night due to asthma attack. A conditional logistic regression model was used to estimate ORs of PCVs per unit increment of air pollutants or meteorological parameters (the per-unit increments of particulate matter with an aerodynamic diameter ≤2.5 µm (PM2.5) and ozone were 10 µg/m(3) and 10 ppb, respectively). Analyses took into consideration the effects of seasonality. RESULTS: We noted an association between PCVs and daily ozone levels on the day before a PCV (OR=1.17; 95% CI 1.01 to 1.35; p=0.04), as well as between PCVs and 3-day mean ozone levels before a PCV (OR=1.29; 95% CI 1.00 to 1.46; p=0.04), from April until June. We also observed an association between PCVs and daily PM2.5 levels on the day before a PCV from December until March (OR=1.16; 95% CI 1.01 to 1.33; p=0.05). Meteorological parameters, such as hours of sunshine from September until November, atmospheric pressure from April until June, and temperature from April until August, were also found to be associated with PCVs. CONCLUSIONS: The findings in the present study supported an association between ozone and PCVs and suggest that certain meteorological items may be associated with PCVs.

Intermittent and episode-driven use of pranlukast to reduce the frequency of wheezing in atopic children: a randomized, double-blind, placebo-controlled trial.

BACKGROUND: Leukotriene receptor antagonist (LTRA) therapy reduces asthma exacerbations in children older than 2 years. However, whether early intervention using LTRA in atopic smaller children aged 1 to 2 years who had experienced episodic wheezing can reduce the frequency of wheezing is unknown. METHODS: A randomized, double-blind, placebo-controlled, multi-center trial of episode-driven intermittent use of pranlukast for 12 months, one of the LTRAs, was conducted by enrolling children who had two, but not more than two, episodes of wheezing prior to entry and were allergen-specific IgE-positive (≥class 2). The primary outcome was increased episodes of wheezing more than once a month for 3 months. RESULTS: Seventy-seven children were randomly assigned to receive pranlukast (n = 37) or placebo (n = 40). The primary outcome occurred in 10 of 36 (28%) of the pranlukast group and 14 of 39 (36%) in the placebo group, which was not significantly different (P = 0.45). Even though the study period was extended to a maximum of >5 years, there was no significant difference in the Kaplan-Meier curves in the occurrence of the primary outcome between the two groups. CONCLUSIONS: These results suggest that intermittent and episode-driven use of pranlukast in small children with a prior history of wheezing and atopic sensitization may not reduce the frequency of wheezing later in life. However, the sample size was too small to make a definitive conclusion. TRIAL REGISTRATION: UMIN000000634.

Association between PM2.5 and primary care visits due to asthma attack in Japan: relation to Beijing's air pollution episode in January 2013.

AIM: In January 2013, extremely high concentrations of fine particles (PM2.5) were observed around Beijing, China. In Japan, the health effects of transboundary air pollution have been a matter of concern. We examined the association between the levels of outdoor PM2.5 and other air pollutants with primary care visits (PCVs) at night due to asthma attack in Himeji City, western Japan. METHODS: A case-crossover study was conducted in a primary care clinic in Himeji City, Japan, involving 112 subjects aged 0-80 years who visited the clinic due to an asthma attack between 9 p.m. and 6 a.m. during the period January-March, 2013. Daily concentrations of particulate matter, ozone, nitrogen dioxide, and some meteorological elements were measured, and a conditional logistic regression model was used to estimate the odds ratios (OR) of PCVs per unit increment in air pollutants or meteorological elements. RESULTS: Of the 112 subjects, 76 (68 %) were aged <15 years. We did not note any association between daily PM2.5 levels and PCVs due to asthma attack at night. A positive relation between ozone and PCVs due to asthma attack was detected. The OR per 10 ppb increment in daily mean ozone the day before the visit was 2.31 (95 % confidence interval 1.16-4.61). CONCLUSION: These findings do not support an association between daily mean concentration of PM2.5 and PCVs at night. However, we did find evidence suggesting that ozone is associated with PCVs.

Association of ambient air pollution and meteorological factors with primary care visits at night due to asthma attack.

AIM: The association of outdoor air pollution and meteorological elements with primary care visits at night due to asthma attack was studied. METHODS: A case-crossover study was conducted in a primary care clinic in Himeji City, Japan. The subjects were 956 children aged 0-14 years who visited the clinic with an asthma attack between the hours of 9 p.m. and 6 a.m. Daily concentrations of particulate matter, ozone, nitrogen dioxide, and a number of meteorological elements were measured, and a conditional logistic regression model was used to estimate odds ratios (ORs) of primary care visits per unit increment of air pollutants or meteorological elements. The analyses took into consideration the effects of seasonality. RESULTS: Of the 956 children, 73 (7.6 %) were aged <2 years and 417 (43.6 %) were aged 2-5 years. No association between daily ozone levels and primary care visits due to asthma attack at night in the spring or summer was found. An inverse relation between suspended particulate matter and primary care visits due to asthma attack was detected in the winter. ORs in the summer per degree increment in daily mean temperature was 1.31 [95 % confidential interval (CI) 1.09-1.56], and ORs in the autumn per hourly increment in daily hours of sunshine was 0.94 (95 % CI 0.90-0.99). CONCLUSION: The findings of our study fail to support any association between daily mean concentration of air pollutant and primary care visits at night. However, we did find evidence indicating that certain meteorological elements may be associated with primary care visits.

Genome-wide association study identifies HLA-DP as a susceptibility gene for pediatric asthma in Asian populations.

Asthma is a complex phenotype influenced by genetic and environmental factors. We conducted a genome-wide association study (GWAS) with 938 Japanese pediatric asthma patients and 2,376 controls. Single-nucleotide polymorphisms (SNPs) showing strong associations (P<1×10(-8)) in GWAS were further genotyped in an independent Japanese samples (818 cases and 1,032 controls) and in Korean samples (835 cases and 421 controls). SNP rs987870, located between HLA-DPA1 and HLA-DPB1, was consistently associated with pediatric asthma in 3 independent populations (P(combined) = 2.3×10(-10), odds ratio [OR] = 1.40). HLA-DP allele analysis showed that DPA1*0201 and DPB1*0901, which were in strong linkage disequilibrium, were strongly associated with pediatric asthma (DPA1*0201: P = 5.5×10(-10), OR = 1.52, and DPB1*0901: P = 2.0×10(-7), OR = 1.49). Our findings show that genetic variants in the HLA-DP locus are associated with the risk of pediatric asthma in Asian populations.

Risk factors for wheezing, eczema and rhinoconjunctivitis in the previous 12 months among six-year-old children in Himeji City, Japan: food allergy, older siblings, day-care attendance and parental allergy history.

BACKGROUND: The aim of this study was to clarify whether some environmental and genetic factors (food allergy, older siblings, early day-care attendance and parents' allergy history) are related to the development of allergic symptoms (wheezing in the previous 12 months [WP], eczema symptoms in the previous 12 months [EP], and rhinoconjunctivitis symptoms in the previous 12 months [RP]) in Japanese children. METHODS: Using the modified version of the International Study on Asthma and Allergies in Childhood (ISSAC) questionnaire, we studied the prevalence of WP, EP and RP among six-year-old children attending 72 primary schools throughout Himeji City, Japan, during the two years from 2005 to 2006. RESULTS: Food allergy and parents' history of allergy showed a significant relationship with the prevalence of WP, EP and RP. Day-care attendance in the first two years of life and presence of older siblings showed a significant inverse relationship with the prevalence of RP. However, neither day-care attendance nor presence of older siblings was related to the development of W and ER. CONCLUSIONS: Among Japanese children, food allergy and parents' history of allergy are risk factors for WP, ES or RS. However, early day-care attendance and presence of older siblings might be protective factors against RS. Infections in early life may affect the prevalence of rhinoconjunctivitis in six-year-old children.

Comparison of the bronchodilative effects of salbutamol delivered via three mesh nebulizers in children with bronchial asthma.

BACKGROUND: We compared the bronchodilative effects of salbutamol delivered via 3 different mesh nebulizers, Aeroneb-go(R)(AE), Omron-NE-U22(R)(OM) and Pari-eMotion(R)(PA). METHODS: We enrolled 36 children with asthma who visited the Kurosaka Pediatrics and Allergy Clinic, randomly assigned to 3 groups for treatment with AE, OM or PA. The dose of salbutamol in the solution was 0.15mgx body weight (kg)(minimum 2.5mg, maximum 5mg). FEV(1), PEFR and V(50) were measured in these patients before treatment, and at 15 and 30 minutes after salbutamol inhalation using one of the 3 mesh nebulizers. RESULTS: All groups showed a significant improvement of FEV(1), PEFR and V(50) at 30 minutes after salbutamol inhalation. The AE group did not show a significant improvement in PEFR at 15 minutes after inhalation, whereas a significant improvement in FEV(1) and V(50) was evident at the same time point. The OM group showed no significant improvement in V(50) at 15 minutes after inhalation, whereas this group clearly showed a significant improvement in PEFR and FEV(1) at the same time point. CONCLUSIONS: Overall, all 3 mesh nebulizers were useful devices in treating bronchial asthma, although some differences in lung function improvement were evident. The limitation of this study is that subjects did not include patients with severe asthma attacks.

Internet survey of childhood asthma and use of inhaled therapy in the home in Japan.

BACKGROUND: The aim of the present study is to undertake a survey of childhood asthma and details of the use of inhaled therapy from mothers with asthmatic children

Current cat ownership may be associated with the lower prevalence of atopic dermatitis, allergic rhinitis, and Japanese cedar pollinosis in schoolchildren in Himeji, Japan.

The aim of the study was to clarify the relationship between current pet ownership, passive smoking, and allergic diseases among the Japanese children. From 1995 to 2001, we distributed the Japanese edition of the questionnaire of the American Thoracic Society and the Division of Lung Diseases (ATS-DLD) to survey allergic diseases among 35,552 6-yr-old children at primary school in the city of Himeji, Japan. We analyzed the data by multiple logistic regression and calculated adjusted odds ratios for environmental factors, including passive smoking and pet (dog and/or cat) ownership. There were no significant relationships between the prevalence of asthma and current pet ownership and passive smoking. However, current cat ownership was related to a significantly lower prevalence of atopic dermatitis [adjusted odds ratio (aOR) 0.79, 95% confidence interval (CI) 0.67-0.93], allergic rhinitis (aOR: 0.71, 95% CI 0.57-0.89) and Japanese cedar pollinosis (aOR 0.57, 95% CI 0.44-0.75). Strikingly, passive smoking was also related to a significantly lower prevalence of allergic rhinitis (aOR 0.83, 95% CI 0.77-0.89) and Japanese cedar pollinosis (aOR 0.81, 95% CI 0.74-0.88). Current cat ownership was associated with a lower prevalence of atopic dermatitis, allergic rhinitis, and Japanese cedar pollinosis. In addition, passive smoking was also associated with a lower prevalence of allergic rhinitis and Japanese cedar pollinosis.