Traffic-Related Air Pollution and Otitis Media
Traffic-Related Air Pollution and Otitis Media
Background: Otitis media is one of the most common infections in young children. Although exposure to environmental tobacco smoke is a known risk factor associated with otitis media, little information is available regarding the potential association with air pollution.
Objective: We set out to study the relationship between exposure to traffic-related air pollution and otitis media in two birth cohorts.
Methods: Individual estimates of outdoor concentrations of traffic-related air pollutants-nitrogen dioxide, fine particles [particulate matter with aerodynamic diameters ≤ 2.5 µm (PM25)], and elemental carbon-were calculated for home addresses of approximately 3,700 and 650 infants from birth cohort studies in the Netherlands and Germany, respectively. Air pollution exposure was analyzed in relation to physician diagnosis of otitis media in the first 2 years of life.
Results: Odds ratios (adjusted for known major risk factors) for otitis media indicated positive associations with traffic-related air pollutants. An increase in 3 µg/m PM2.5, 0.5 µg/m elemental carbon, and 10 µg/m NO2 was associated with odds ratios of 1.13 (95% confidence interval, 1.00-1.27), 1.10 (1.00-1.22), and 1.14 (1.03-1.27) in the Netherlands and 1.24 (0.84-1.83), 1.10 (0.86-1.41), and 1.14 (0.87-1.49) in Germany, respectively.
Conclusions: These findings indicate an association between exposure to traffic-related air pollutants and the incidence of otitis media. Given the ubiquitous nature of air pollution exposure and the importance of otitis media to children's health, these findings have significant public health implications.
Otitis media is one of the most common childhood infections in young children. Three of four children experience otitis media by 3 years of age, with most infections occurring before age 2 (Bluestone and Klein 2001). Otitis media is one of the leading causes of doctor's visits in childhood (Freid et al. 1998) and the main reason for children to consume antibiotics or undergo surgery in developed countries (Rovers et al. 2004). Otitis media with effusion (OME), in which fluid and mucus stay trapped in the ear after infection, may lead to conductive hearing loss that, if persistent, may lead to delays in the development of speech, language, and cognitive abilities (Klein 2000; Teele et al. 1990). Recurrent acute otitis media leads to decreased quality of life measurements in children and is also stressful to their caregivers (Brouwer et al. 2005). In addition, the direct and indirect costs associated with otitis media are high: In the United States, annual health care costs were estimated at $3-5 billion (Bondy et al. 2000). Indirect costs due to caregiver work loss are also substantial and may in fact exceed direct costs. In 1994, the total yearly cost for otitis media in Canada was estimated to be $611 million-60% of the total economic cost associated with all forms of diabetes (Coyte et al. 1999). Evidence also indicates a steady increase in the incidence of diagnoses (Bluestone and Klein 2001; Lanphear et al. 1997). Consequently, identification of potentially preventable risk factors for otitis media, such as air pollution exposure, would have significant implications for health care costs. Because air pollution is not typically considered a risk factor for otitis media, this illness is also not considered in air pollution health impact and cost-benefit assessments (Kunzli et al. 2000).
Of particular relevance to a possible association between air pollution exposure and otitis media is the strength of environmental tobacco smoke (ETS) exposure as a risk factor (Jinot and Bayard 1996; National Cancer Institute 1999; U.S. Department of Health and Human Services 1986). A quantitative meta-analysis published in 1998 concluded that consistent evidence of causal relationship between parental smoking in the home and acute otitis media exists (Strachan and Cook 1998). Despite this finding and the large number of studies assessing the impact of ambient air pollution exposures on upper respiratory infections, the potential relationships between episodes of otitis media and ambient air pollution exposure have not been examined in detail. Accordingly, we assessed the relationship between traffic-related air pollution and otitis media in two birth cohorts, one in the Netherlands and another in Munich, Germany.
Previous analysis of this Dutch birth cohort indicated a significant association between a combined measure of severe upper respiratory tract and ear/nose/throat infections for the 12-month period before the child's second birthday and exposure to traffic-related air pollutants (Brauer et al. 2002), but did not address otitis media specifically. This earlier analysis focused on the period between 12 and 24 months of age, whereas otitis media incidence peaks between 6 and 11 months of age (Rovers et al. 2004). Earlier analysis of the German cohort indicated associations between air pollution exposure and (nocturnal dry) cough without respiratory infections (Gehring et al. 2002). Neither of these analyses included independent assessment of otitis media episodes in relation to air pollution exposure.
Abstract and Introduction
Abstract
Background: Otitis media is one of the most common infections in young children. Although exposure to environmental tobacco smoke is a known risk factor associated with otitis media, little information is available regarding the potential association with air pollution.
Objective: We set out to study the relationship between exposure to traffic-related air pollution and otitis media in two birth cohorts.
Methods: Individual estimates of outdoor concentrations of traffic-related air pollutants-nitrogen dioxide, fine particles [particulate matter with aerodynamic diameters ≤ 2.5 µm (PM25)], and elemental carbon-were calculated for home addresses of approximately 3,700 and 650 infants from birth cohort studies in the Netherlands and Germany, respectively. Air pollution exposure was analyzed in relation to physician diagnosis of otitis media in the first 2 years of life.
Results: Odds ratios (adjusted for known major risk factors) for otitis media indicated positive associations with traffic-related air pollutants. An increase in 3 µg/m PM2.5, 0.5 µg/m elemental carbon, and 10 µg/m NO2 was associated with odds ratios of 1.13 (95% confidence interval, 1.00-1.27), 1.10 (1.00-1.22), and 1.14 (1.03-1.27) in the Netherlands and 1.24 (0.84-1.83), 1.10 (0.86-1.41), and 1.14 (0.87-1.49) in Germany, respectively.
Conclusions: These findings indicate an association between exposure to traffic-related air pollutants and the incidence of otitis media. Given the ubiquitous nature of air pollution exposure and the importance of otitis media to children's health, these findings have significant public health implications.
Introduction
Otitis media is one of the most common childhood infections in young children. Three of four children experience otitis media by 3 years of age, with most infections occurring before age 2 (Bluestone and Klein 2001). Otitis media is one of the leading causes of doctor's visits in childhood (Freid et al. 1998) and the main reason for children to consume antibiotics or undergo surgery in developed countries (Rovers et al. 2004). Otitis media with effusion (OME), in which fluid and mucus stay trapped in the ear after infection, may lead to conductive hearing loss that, if persistent, may lead to delays in the development of speech, language, and cognitive abilities (Klein 2000; Teele et al. 1990). Recurrent acute otitis media leads to decreased quality of life measurements in children and is also stressful to their caregivers (Brouwer et al. 2005). In addition, the direct and indirect costs associated with otitis media are high: In the United States, annual health care costs were estimated at $3-5 billion (Bondy et al. 2000). Indirect costs due to caregiver work loss are also substantial and may in fact exceed direct costs. In 1994, the total yearly cost for otitis media in Canada was estimated to be $611 million-60% of the total economic cost associated with all forms of diabetes (Coyte et al. 1999). Evidence also indicates a steady increase in the incidence of diagnoses (Bluestone and Klein 2001; Lanphear et al. 1997). Consequently, identification of potentially preventable risk factors for otitis media, such as air pollution exposure, would have significant implications for health care costs. Because air pollution is not typically considered a risk factor for otitis media, this illness is also not considered in air pollution health impact and cost-benefit assessments (Kunzli et al. 2000).
Of particular relevance to a possible association between air pollution exposure and otitis media is the strength of environmental tobacco smoke (ETS) exposure as a risk factor (Jinot and Bayard 1996; National Cancer Institute 1999; U.S. Department of Health and Human Services 1986). A quantitative meta-analysis published in 1998 concluded that consistent evidence of causal relationship between parental smoking in the home and acute otitis media exists (Strachan and Cook 1998). Despite this finding and the large number of studies assessing the impact of ambient air pollution exposures on upper respiratory infections, the potential relationships between episodes of otitis media and ambient air pollution exposure have not been examined in detail. Accordingly, we assessed the relationship between traffic-related air pollution and otitis media in two birth cohorts, one in the Netherlands and another in Munich, Germany.
Previous analysis of this Dutch birth cohort indicated a significant association between a combined measure of severe upper respiratory tract and ear/nose/throat infections for the 12-month period before the child's second birthday and exposure to traffic-related air pollutants (Brauer et al. 2002), but did not address otitis media specifically. This earlier analysis focused on the period between 12 and 24 months of age, whereas otitis media incidence peaks between 6 and 11 months of age (Rovers et al. 2004). Earlier analysis of the German cohort indicated associations between air pollution exposure and (nocturnal dry) cough without respiratory infections (Gehring et al. 2002). Neither of these analyses included independent assessment of otitis media episodes in relation to air pollution exposure.
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