Motoaki Adachi

Effects of Air Pollution on the Prevalence and Incidence of Asthma in Children

Abstract The effects of air pollution on asthmatic symptoms were assessed in a prospective cohort study of 3,049 schoolchildren in 8 different communities in Japan. Respiratory symptoms in these children were evaluated by questionnaires every year from the 1st through the 6th grades. The prevalence of asthma among the 1st graders was strongly associated with a history of allergic or respiratory diseases, but it was not associated with concentrations of air pollution. During the follow-up period, incidence rates of asthma were associated significantly with atmospheric concentrations of nitrogen dioxide. Particulate matter less than 10 μm in diameter (PM10) was also associated with a higher incidence of asthma, although the association was not significant. These findings suggest that air pollution, including nitrogen dioxide, may be an important factor in the development of asthma among children in urban districts.

Long term effects of exposure to automobile exhaust on the pulmonary function of female adults in Tokyo, Japan

Aims: To investigate the chronic effects of air pollution caused mainly by automobiles in healthy adult females. Methods: Respiratory symptoms were investigated in 5682 adult females who had lived in the Tokyo metropolitan area for three years or more in 1987; 733 of them were subjected to pulmonary function tests over eight years from 1987 to 1994. The subjects were divided into three groups by the level of air pollution they were exposed to during the study period. The concentrations of nitrogen dioxide and suspended particulate matter were the highest in group 1, and the lowest in group 3. Results: The prevalence rates of respiratory symptoms in group 1 were higher than those in groups 2 and 3, except for wheezing. Multiple logistic regression analysis showed significant differences in persistent phlegm and breathlessness. The subjects selected for the analysis of pulmonary function were 94, 210, and 102 females in groups 1, 2, and 3, respectively. The annual mean change of FEV1 in group 1 was the largest (−0.020 l/y), followed by that in group 2 (−0.015 l/y), and that in group 3 (−0.009 l/y). Testing for trends showed a significant larger decrease of FEV1 with the increase in the level of air pollution. Conclusions: The subjects living in areas with high levels of air pollution showed higher prevalence rates of respiratory symptoms and a larger decrease of FEV1 compared with those living in areas with low levels of air pollution. Since the traffic density is larger in areas with high air pollution, the differences among the groups may reflect the effect of air pollution attributable to particulate matter found in automobile exhaust.

The role of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and regulated on activation, normal T-cell expressed and secreted (RANTES) in the relationship between air pollution and asthma among children.

Abstract To evaluate the role of adhesion molecules and chemokines in the relationship between air pollution and asthma, the authors determined the following in 230 children who lived in 4 communities in Japan that had different levels of air pollution: serum concentrations of soluble intercellular adhesion molecule-1 (sICAM-1); soluble vascular cell adhesion molecule-1 (sVCAM-1); regulated on activation, normal T-cell expressed and secreted (RANTES); and total immunoglobulin E (IgE). Children with asthma or who exhibited wheezing (n = 115) and nonasthmatic children (n = 115) were studied. Serum concentrations of sICAM-1, sVCAM-1, and RANTES were increased significantly in asthmatic children, compared with nonasthmatic children. Nonasthmatic children with serum IgE levels that were greater than or equal to 250 IU/ml had significantly lower concentrations of sICAM-1 and sVCAM-1 than the other children. The geometric means of sICAM-1 increased as air pollution increased. The results of this study suggest that adhesion molecules or chemokines are associated with asthma and that ICAM-1 may play an important role in the relationship between air pollution and the occurrence of asthma.

Indoor nitrogen dioxide in homes along trunk roads with heavy traffic.

OBJECTIVES: To assess the distribution of indoor nitrogen dioxide (NO2) concentrations in homes located in differing environments, and to investigate the influence of factors such as automobile exhaust on the indoor environment. METHODS: The concentrations of indoor NO2 over 24 hours were measured in both the heating and non-heating periods in homes of pupils from nine elementary schools in Chiba, Japan. Information on factors that could influence indoor environments was collected by questionnaire. RESULTS: Indoor NO2 concentrations during the heating period were higher in homes with unvented heaters than in homes with vented heaters, although the concentrations varied greatly among homes primarily because of the type of heating device used. During the non-heating period, indoor NO2 concentrations were significantly higher in homes adjacent to trunk roads than in homes located in other areas. Multiple regression analysis showed that indoor NO2 concentrations were associated with atmospheric NO2 in homes with vented heaters during the heating period, and in homes in areas other than on the roadside during the non-heating period. In areas other than the roadside, cigarette smoking in indoor environments also significantly contributed to indoor NO2. The average concentrations of indoor NO2 in the homes of pupils attending each school were significantly related to the atmospheric NO2 in areas other than the roadside. However, the relation between indoor and atmospheric NO2 concentrations was not significant in roadside areas. CONCLUSIONS: These findings suggest that indoor NO2 concentrations are related to the atmospheric NO2 and type of heating appliances, and are also affected by automobile exhaust in homes located in roadside areas.

Serum immunoglobulin E and hyaluronate levels in children living along major roads

To assess the effects of automobile exhaust on human health, we determined serum concentrations of total immunoglobulin E and hyaluronate in 185 schoolchildren who lived in a district that contained major roads. Serum immunoglobulin E levels were elevated in children who had asthma or wheezing, but levels did not differ with respect to distance of their homes from the major roads. Serum hyaluronate levels were higher in children who lived less than 50 m from the roadside, compared with children who resided a greater distance from roads. The difference, however, was significant only in a subgroup of children in whom immunoglobulin E levels exceeded 250 IU/ml. Our results suggest that serum hyaluronate levels in children reflect the effects of traffic-related air pollution. Children with high immunoglobulin E levels appeared to be particularly susceptible to the effects of automobile exhaust.

Acute effects of ozone exposure on lung function in mice sensitized to ovalbumin

Pulmonary responses to ozone exposure (1.0 ppm) were investigated in mice sensitized to ovalbumin compared with control mice receiving saline. Pulmonary function parameters were measured by pneumotachography. Arterial blood gases and the concentrations of soluble intercellular adhesion molecule-1 (sICAM-1) and tumor necrosis factor-alpha (TNF-alpha) in bronchoalveolar lavage fluid were analyzed. Ozone exposure, when compared with filtered air exposure, caused significantly larger decreases in dynamic compliance (P<0.05) and minute ventilation (P<0.05) in ovalbumin-sensitized mice but not in control mice. Moreover, the decrease in minute ventilation in response to ozone exposure was significantly greater (P<0.01) in ovalbumin-sensitized mice than in control mice. Ozone exposure caused a significant decrease in PaO2 in ovalbumin-sensitized mice but not in control mice. PaO2 after ozone exposure tended to be smaller in ovalbumin-sensitized mice than in control mice. The concentration of sICAM-1 in bronchoalveolar lavage fluid increased in ovalbumin-sensitized mice, but effects of ozone exposure were not observed. These results indicated that sensitization of the immune system to ovalbumin might be a risk factor which aggravates the effects of ozone exposure on the respiratory system.

Serum Complement Levels in Children in Communities with Different Levels of Air Pollution in Japan

To investigate the effects of air pollution on human health, we determined serum concentrations of complement components C3c and C4 in 1037 children who lived in 4 communities with different levels of air pollution in Japan. Serum levels of C3c and C4 were higher in children who lived in Osaka, which had a high level of air pollution, than in children who lived in areas of low air pollution. In boys, both C3c and C4 levels were increased significantly as concentrations of air pollution increased in the communities. In girls, however, the relationship was not significant. Serum levels of C3c and C4 did not differ with respect to asthma or wheezing. These findings suggest that serum C3c and C4 levels in children reflect the effects of exposure to air pollutants in urban districts. Boys appeared to be more susceptible to the effects of air pollution than girls.

Effect of air pollution and environmental tobacco smoke on serum hyaluronate concentrations in school children.

Objectives: To evaluate serum hyaluronate concentrations relative to air pollution, environmental tobacco smoke (ETS), and respiratory health in Japanese school children. Methods: Respiratory symptoms and serum IgE concentrations were examined in 1037 school children living in four communities in Japan with differing levels of air pollution. Serum hyaluronate concentrations were assayed in 230 children, consisting of all the children who had symptoms of either asthma or wheeze (65 and 50 subjects, respectively) and normal controls adjusted for sex, school grade, and school without these symptoms (115 subjects). Results: Although serum hyaluronate concentrations did not differ for either asthma or wheeze, the concentrations were significantly higher in children living in communities with higher levels of air pollution. Children with asthma or wheeze and those with serum IgE concentrations of 250 IU/ml or above showed differences in hyaluronate concentrations that related to the degree of air pollution in the communities. In children with higher serum IgE concentrations, the hyaluronate concentrations among subjects exposed to ETS were significantly higher than among those without exposure to ETS. Conclusions: The present results suggest that serum hyaluronate concentration is related to the degree of air pollution and exposure to ETS. Children with asthma or wheeze and children with higher IgE concentrations are considered to be more susceptible to environmental factors.