Masayuki Shima - Academia.edu (original) (raw)

Papers by Masayuki Shima

Research paper thumbnail of Acute Effects of Summer Air Pollution on Pulmonary Function and Airway Inflammation in Healthy Young Women

Journal of Epidemiology, 2014

Background: Exposure to air pollution has been reported to be associated with asthma exacerbation... more Background: Exposure to air pollution has been reported to be associated with asthma exacerbation. However, little is known about the effects of air pollutant exposure in healthy people. A panel study was conducted to evaluate the acute effects of air pollutants on pulmonary function and airway inflammation in healthy subjects. Methods: Exhaled breath condensate (EBC) pH, fractional concentration of exhaled nitric oxide (FeNO), and pulmonary function were measured in 21 healthy young women repeatedly for two weeks in the summer in Tokyo, Japan. The concentrations of air pollutants were obtained from the monitoring stations in the neighborhoods where the subjects lived. Statistical analyses were performed using generalized estimating equations. Results: EBC pH decreased significantly with a 10-ppb increase in the 4-day average ozone (O 3) concentration and a 10-µg/m 3 increase in the 4-day average suspended particulate matter (SPM) concentration (−0.07 [95% confidence interval {CI} −0.11 to −0.03] and −0.08 [95% CI −0.12 to −0.03], respectively). Subjects with a history of rhinitis showed marked decreases in EBC pH associated with increases in O 3 and SPM. The changes in forced expiratory volume in 1 second (FEV 1) were also significantly associated with a 10-µg/m 3 increase in the 3-day average concentration of SPM (−0.09 L [95% CI −0.17 to −0.01]). FeNO increased significantly in relation to the increase in O 3 and SPM among only subjects with a history of asthma. Conclusions: Over the course of the study, EBC became significantly acidic with increases in O 3 and SPM concentrations. Furthermore, higher SPM concentrations were associated with decreased FEV 1. Subjects with a history of rhinitis or asthma are considered to be more susceptible to air pollutants.

Research paper thumbnail of Effects of airborne particulate matter on respiratory morbidity in asthmatic children

Background: The effects of airborne particulate matter (PM) are a major human health concern. In ... more Background: The effects of airborne particulate matter (PM) are a major human health concern. In this panel study, we evaluated the acute effects of exposure to PM on peak expiratory flow (PEF) and wheezing in children. Methods: Daily PEF and wheezing were examined in 19 asthmatic children who were hospitalized in a suburban city in Japan for approximately 5 months. The concentrations of PM less than 2.5 µm in diameter (PM 2.5) were monitored at a monitoring station proximal to the hospital. Moreover, PM 2.5 concentrations inside and outside the hospital were measured using the dust monitor with a laser diode (PM 2.5(LD)). The changes in PEF and wheezing associated with PM concentration were analyzed. Results: The changes in PEF in the morning and evening were significantly associated with increases in the average concentration of indoor PM 2.5(LD) 24 h prior to measurement (-2.86 L/min [95%CI:-4.12,-1.61] and-3.59 L/min [95%CI:-4.99,-2.20] respectively, for 10-µg/m 3 increases). The change in PEF was also significantly associated with outdoor PM 2.5(LD) concentrations, but the changes were smaller than those observed for indoor PM 2.5(LD). Changes in PEF and concentration of stationary-site PM 2.5 were not associated. The prevalence of wheezing in the morning and evening were also significantly associated with indoor PM 2.5(LD) concentrations (odds ratios = 1.014 [95%CI: 1.006, 1.023] and 1.025 [95%CI: 1.013, 1.038] respectively, for 10-µg/m 3 increases). Wheezing in the evening was significantly associated with outdoor PM 2.5(LD) concentration. The effects of indoor and outdoor PM 2.5(LD) remained significant even after adjusting for ambient nitrogen dioxide concentrations. Conclusion: Indoor and outdoor PM 2.5(LD) concentrations were associated with PEF and wheezing among asthmatic children. Indoor PM 2.5(LD) had a more marked effect than outdoor PM 2.5(LD) or stationary-site PM 2.5 .

Research paper thumbnail of Air Pollution and Serum C-reactive Protein Concentration in Children

Journal of Epidemiology, 2007

Research paper thumbnail of Effect of outdoor and indoor nitrogen dioxide on respiratory symptoms in schoolchildren

International journal of epidemiology, 2000

Background Nitrogen dioxide (NO 2), an oxidant gas that contaminates both outdoor and indoor air,... more Background Nitrogen dioxide (NO 2), an oxidant gas that contaminates both outdoor and indoor air, is considered to be a potential risk factor for asthma. We investigated concurrently the effects of outdoor and indoor NO 2 on the prevalence and incidence of respiratory symptoms among children. Methods A cohort study was carried out over 3 years on 842 schoolchildren living in seven different communities in Japan. Indoor NO 2 concentrations over 24 hours were measured in both winter and summer in the homes of the subjects, and a 3-year average of the outdoor NO 2 concentration was determined for each community. Respiratory symptoms were evaluated every year from responses to questionnaires. Results The prevalence of bronchitis, wheeze, and asthma significantly increased with increases of indoor NO 2 concentrations among girls, but not among boys. In neither boys nor girls were there significant differences in the prevalence of respiratory symptoms among urban, suburban, and rural districts. The incidence of asthma increased among children living in areas with high concentrations of outdoor NO 2. Multiple logistic regression analysis showed that a 10 parts per billion (ppb) increase of outdoor NO 2 concentration was associated with an increased incidence of wheeze and asthma (odds ratios [OR] = 1.76, 95% CI : 1.04-3.23 and OR = 2.10, 95% CI : 1.10-4.75, respectively), but that no such associations were found with indoor NO 2 concentration (OR = 0.73, 95% CI : 0.45-1.14 and OR = 0.87, 95% CI : 0.51-1.43, respectively). Conclusions These findings suggest that outdoor NO 2 air pollution may be particularly important for the development of wheeze and asthma among children. Indoor NO 2 concentrations were associated with the prevalence of respiratory symptoms only among girls. Girls may be more susceptible to indoor air pollution than boys.

Research paper thumbnail of Acute Effects of Summer Air Pollution on Pulmonary Function and Airway Inflammation in Healthy Young Women

Journal of Epidemiology, 2014

Background: Exposure to air pollution has been reported to be associated with asthma exacerbation... more Background: Exposure to air pollution has been reported to be associated with asthma exacerbation. However, little is known about the effects of air pollutant exposure in healthy people. A panel study was conducted to evaluate the acute effects of air pollutants on pulmonary function and airway inflammation in healthy subjects. Methods: Exhaled breath condensate (EBC) pH, fractional concentration of exhaled nitric oxide (FeNO), and pulmonary function were measured in 21 healthy young women repeatedly for two weeks in the summer in Tokyo, Japan. The concentrations of air pollutants were obtained from the monitoring stations in the neighborhoods where the subjects lived. Statistical analyses were performed using generalized estimating equations. Results: EBC pH decreased significantly with a 10-ppb increase in the 4-day average ozone (O 3) concentration and a 10-µg/m 3 increase in the 4-day average suspended particulate matter (SPM) concentration (−0.07 [95% confidence interval {CI} −0.11 to −0.03] and −0.08 [95% CI −0.12 to −0.03], respectively). Subjects with a history of rhinitis showed marked decreases in EBC pH associated with increases in O 3 and SPM. The changes in forced expiratory volume in 1 second (FEV 1) were also significantly associated with a 10-µg/m 3 increase in the 3-day average concentration of SPM (−0.09 L [95% CI −0.17 to −0.01]). FeNO increased significantly in relation to the increase in O 3 and SPM among only subjects with a history of asthma. Conclusions: Over the course of the study, EBC became significantly acidic with increases in O 3 and SPM concentrations. Furthermore, higher SPM concentrations were associated with decreased FEV 1. Subjects with a history of rhinitis or asthma are considered to be more susceptible to air pollutants.

Research paper thumbnail of Effects of airborne particulate matter on respiratory morbidity in asthmatic children

Background: The effects of airborne particulate matter (PM) are a major human health concern. In ... more Background: The effects of airborne particulate matter (PM) are a major human health concern. In this panel study, we evaluated the acute effects of exposure to PM on peak expiratory flow (PEF) and wheezing in children. Methods: Daily PEF and wheezing were examined in 19 asthmatic children who were hospitalized in a suburban city in Japan for approximately 5 months. The concentrations of PM less than 2.5 µm in diameter (PM 2.5) were monitored at a monitoring station proximal to the hospital. Moreover, PM 2.5 concentrations inside and outside the hospital were measured using the dust monitor with a laser diode (PM 2.5(LD)). The changes in PEF and wheezing associated with PM concentration were analyzed. Results: The changes in PEF in the morning and evening were significantly associated with increases in the average concentration of indoor PM 2.5(LD) 24 h prior to measurement (-2.86 L/min [95%CI:-4.12,-1.61] and-3.59 L/min [95%CI:-4.99,-2.20] respectively, for 10-µg/m 3 increases). The change in PEF was also significantly associated with outdoor PM 2.5(LD) concentrations, but the changes were smaller than those observed for indoor PM 2.5(LD). Changes in PEF and concentration of stationary-site PM 2.5 were not associated. The prevalence of wheezing in the morning and evening were also significantly associated with indoor PM 2.5(LD) concentrations (odds ratios = 1.014 [95%CI: 1.006, 1.023] and 1.025 [95%CI: 1.013, 1.038] respectively, for 10-µg/m 3 increases). Wheezing in the evening was significantly associated with outdoor PM 2.5(LD) concentration. The effects of indoor and outdoor PM 2.5(LD) remained significant even after adjusting for ambient nitrogen dioxide concentrations. Conclusion: Indoor and outdoor PM 2.5(LD) concentrations were associated with PEF and wheezing among asthmatic children. Indoor PM 2.5(LD) had a more marked effect than outdoor PM 2.5(LD) or stationary-site PM 2.5 .

Research paper thumbnail of Air Pollution and Serum C-reactive Protein Concentration in Children

Journal of Epidemiology, 2007

Research paper thumbnail of Effect of outdoor and indoor nitrogen dioxide on respiratory symptoms in schoolchildren

International journal of epidemiology, 2000

Background Nitrogen dioxide (NO 2), an oxidant gas that contaminates both outdoor and indoor air,... more Background Nitrogen dioxide (NO 2), an oxidant gas that contaminates both outdoor and indoor air, is considered to be a potential risk factor for asthma. We investigated concurrently the effects of outdoor and indoor NO 2 on the prevalence and incidence of respiratory symptoms among children. Methods A cohort study was carried out over 3 years on 842 schoolchildren living in seven different communities in Japan. Indoor NO 2 concentrations over 24 hours were measured in both winter and summer in the homes of the subjects, and a 3-year average of the outdoor NO 2 concentration was determined for each community. Respiratory symptoms were evaluated every year from responses to questionnaires. Results The prevalence of bronchitis, wheeze, and asthma significantly increased with increases of indoor NO 2 concentrations among girls, but not among boys. In neither boys nor girls were there significant differences in the prevalence of respiratory symptoms among urban, suburban, and rural districts. The incidence of asthma increased among children living in areas with high concentrations of outdoor NO 2. Multiple logistic regression analysis showed that a 10 parts per billion (ppb) increase of outdoor NO 2 concentration was associated with an increased incidence of wheeze and asthma (odds ratios [OR] = 1.76, 95% CI : 1.04-3.23 and OR = 2.10, 95% CI : 1.10-4.75, respectively), but that no such associations were found with indoor NO 2 concentration (OR = 0.73, 95% CI : 0.45-1.14 and OR = 0.87, 95% CI : 0.51-1.43, respectively). Conclusions These findings suggest that outdoor NO 2 air pollution may be particularly important for the development of wheeze and asthma among children. Indoor NO 2 concentrations were associated with the prevalence of respiratory symptoms only among girls. Girls may be more susceptible to indoor air pollution than boys.