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Modifying effect of age on the association between ambient ozone and nighttime primary care visits due to asthma attack.

Yamazaki S, Shima M, Ando M, Nitta H - J Epidemiol (2009)

Bottom Line: We also investigated the modifying effects of age on this association.There was no association between ozone and primary care visits among adults.An association was found between ozone and nighttime primary care visits for asthma attack in warmer months; the association was greater among preschool children.

View Article: PubMed Central - PubMed

Affiliation: Department of Epidemiology and Healthcare Research, Graduate School of Medicine and Public Health, Kyoto University, University, Kyoto, Japan. syam@pbh.med.kyoto-u.ac.jp

ABSTRACT

Background: We examined the association between short-term exposure to outdoor air pollution and nighttime primary care visits due to asthma attack. We also investigated the modifying effects of age on this association.

Methods: A case-crossover study was conducted at a primary care clinic in metropolitan Tokyo. The subjects were 308 children aged 0-14 years and 95 adolescents and adults aged 15-64 years. All subjects made visits to the clinic for an asthma attack at between 7 PM and 12 AM. Data on hourly concentrations of particulate matter with a 50% cut-off aerodynamic diameter < OR =2.5 microm (PM(2.5)), ozone, and nitrogen dioxide (NO(2)) were obtained. A conditional logistic regression model was used to estimate odds ratios (ORs) of primary care visits per unit increment of each air pollutant.

Results: Among children, the ORs in warmer months per 10 ppb increment of the 24-hour mean concentration of ozone were 1.16 (95% confidential interval [CI], 1.00-1.33) adjusted for temperature, and 1.29 (95% CI, 1.08-1.55) adjusted for PM(2.5), NO(2), and temperature. With respect to modification of the association by age, the ORs for 24-hour mean concentration of ozone--after adjustment for PM(2.5), NO(2) and temperature in warmer months--in children aged 0-1 years, 2-5 years, and 6-14 years were 1.06 (95% CI, 0.63-1.78), 1.37 (95% CI, 1.05-1.71), and 1.25 (95% CI, 0.87-1.82), respectively. There was no association between ozone and primary care visits among adults.

Conclusions: An association was found between ozone and nighttime primary care visits for asthma attack in warmer months; the association was greater among preschool children.

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Related in: MedlinePlus

Associations between air pollutants and nighttime primary care visits due to asthma attack in warmer months (April through September), by age. The associations are shown as odds ratios and their 95% confidence intervals per unit increment of each pollutant. The unit increments were 10 µg/m3 for PM2.5, 10 ppb for ozone, and 10 ppb for nitrogen dioxide
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fig03: Associations between air pollutants and nighttime primary care visits due to asthma attack in warmer months (April through September), by age. The associations are shown as odds ratios and their 95% confidence intervals per unit increment of each pollutant. The unit increments were 10 µg/m3 for PM2.5, 10 ppb for ozone, and 10 ppb for nitrogen dioxide

Mentions: Figure 3 shows the results of an age-stratified subgroup analysis among children in warmer months. With respect to the association between O3 and nighttime primary care visits due to asthma attack in the 2- to 5-year-old subgroup, the ORs of nighttime primary care visits due to asthma attack at time lag 6–12, lag 12–18, and lag 18–24 in the single-pollutant model were 1.08 (95% CI, 0.97–1.20), 1.16 (95% CI, 0.98–1.37), and 1.16 (95% CI, 1.01–1.34), respectively. When using the multipollutant model, the ORs were 1.20 (95% CI, 1.03–1.39), 1.34 (95% CI, 1.05–1.71), and 1.30 (95% CI, 1.02–1.64), respectively. The 24-hour mean concentration of O3 was also associated with nighttime primary care visits due to asthma attack. ORs were 1.20 (95% CI, 1.00–1.45) in the single-pollutant model and 1.37 (95% CI, 1.08–1.73) in the multipollutant model. In addition, daytime 8-hour mean concentration of O3 was also associated with nighttime primary care visits due to asthma attack. The ORs in the single-pollutant model and in the multipollutant model were 1.10 (95% CI, 0.98–1.24) and 1.22 (95% CI, 1.04–1.44), respectively. Among children aged 6 to 14 years, we noted elevated ORs for nighttime primary care visits due to asthma attack at lag 6–12 and in 24-hour mean concentration of O3, using a multipollutant model; the ORs were 1.36 (95% CI, 1.05–1.77) and 1.47 (95% CI, 1.08–2.01), respectively. No other associations were observed. For example, the ORs of nighttime primary care visits due to asthma attack for 24-hour mean concentration of O3 using a multipollutant model among children 0 to 4 years and 6 to 14 years were 1.06 (95% CI, 0.63–1.78) and 1.27 (95% CI, 0.88–1.84), respectively.


Modifying effect of age on the association between ambient ozone and nighttime primary care visits due to asthma attack.

Yamazaki S, Shima M, Ando M, Nitta H - J Epidemiol (2009)

Associations between air pollutants and nighttime primary care visits due to asthma attack in warmer months (April through September), by age. The associations are shown as odds ratios and their 95% confidence intervals per unit increment of each pollutant. The unit increments were 10 µg/m3 for PM2.5, 10 ppb for ozone, and 10 ppb for nitrogen dioxide
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3924139&req=5

fig03: Associations between air pollutants and nighttime primary care visits due to asthma attack in warmer months (April through September), by age. The associations are shown as odds ratios and their 95% confidence intervals per unit increment of each pollutant. The unit increments were 10 µg/m3 for PM2.5, 10 ppb for ozone, and 10 ppb for nitrogen dioxide
Mentions: Figure 3 shows the results of an age-stratified subgroup analysis among children in warmer months. With respect to the association between O3 and nighttime primary care visits due to asthma attack in the 2- to 5-year-old subgroup, the ORs of nighttime primary care visits due to asthma attack at time lag 6–12, lag 12–18, and lag 18–24 in the single-pollutant model were 1.08 (95% CI, 0.97–1.20), 1.16 (95% CI, 0.98–1.37), and 1.16 (95% CI, 1.01–1.34), respectively. When using the multipollutant model, the ORs were 1.20 (95% CI, 1.03–1.39), 1.34 (95% CI, 1.05–1.71), and 1.30 (95% CI, 1.02–1.64), respectively. The 24-hour mean concentration of O3 was also associated with nighttime primary care visits due to asthma attack. ORs were 1.20 (95% CI, 1.00–1.45) in the single-pollutant model and 1.37 (95% CI, 1.08–1.73) in the multipollutant model. In addition, daytime 8-hour mean concentration of O3 was also associated with nighttime primary care visits due to asthma attack. The ORs in the single-pollutant model and in the multipollutant model were 1.10 (95% CI, 0.98–1.24) and 1.22 (95% CI, 1.04–1.44), respectively. Among children aged 6 to 14 years, we noted elevated ORs for nighttime primary care visits due to asthma attack at lag 6–12 and in 24-hour mean concentration of O3, using a multipollutant model; the ORs were 1.36 (95% CI, 1.05–1.77) and 1.47 (95% CI, 1.08–2.01), respectively. No other associations were observed. For example, the ORs of nighttime primary care visits due to asthma attack for 24-hour mean concentration of O3 using a multipollutant model among children 0 to 4 years and 6 to 14 years were 1.06 (95% CI, 0.63–1.78) and 1.27 (95% CI, 0.88–1.84), respectively.

Bottom Line: We also investigated the modifying effects of age on this association.There was no association between ozone and primary care visits among adults.An association was found between ozone and nighttime primary care visits for asthma attack in warmer months; the association was greater among preschool children.

View Article: PubMed Central - PubMed

Affiliation: Department of Epidemiology and Healthcare Research, Graduate School of Medicine and Public Health, Kyoto University, University, Kyoto, Japan. syam@pbh.med.kyoto-u.ac.jp

ABSTRACT

Background: We examined the association between short-term exposure to outdoor air pollution and nighttime primary care visits due to asthma attack. We also investigated the modifying effects of age on this association.

Methods: A case-crossover study was conducted at a primary care clinic in metropolitan Tokyo. The subjects were 308 children aged 0-14 years and 95 adolescents and adults aged 15-64 years. All subjects made visits to the clinic for an asthma attack at between 7 PM and 12 AM. Data on hourly concentrations of particulate matter with a 50% cut-off aerodynamic diameter < OR =2.5 microm (PM(2.5)), ozone, and nitrogen dioxide (NO(2)) were obtained. A conditional logistic regression model was used to estimate odds ratios (ORs) of primary care visits per unit increment of each air pollutant.

Results: Among children, the ORs in warmer months per 10 ppb increment of the 24-hour mean concentration of ozone were 1.16 (95% confidential interval [CI], 1.00-1.33) adjusted for temperature, and 1.29 (95% CI, 1.08-1.55) adjusted for PM(2.5), NO(2), and temperature. With respect to modification of the association by age, the ORs for 24-hour mean concentration of ozone--after adjustment for PM(2.5), NO(2) and temperature in warmer months--in children aged 0-1 years, 2-5 years, and 6-14 years were 1.06 (95% CI, 0.63-1.78), 1.37 (95% CI, 1.05-1.71), and 1.25 (95% CI, 0.87-1.82), respectively. There was no association between ozone and primary care visits among adults.

Conclusions: An association was found between ozone and nighttime primary care visits for asthma attack in warmer months; the association was greater among preschool children.

Show MeSH
Related in: MedlinePlus