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Association between long-term exposure to traffic-related air pollution and subclinical atherosclerosis: the REGICOR study.

Rivera M, Basagaña X, Aguilera I, Foraster M, Agis D, de Groot E, Perez L, Mendez MA, Bouso L, Targa J, Ramos R, Sala J, Marrugat J, Elosua R, Künzli N - Environ. Health Perspect. (2012)

Bottom Line: Associations with IMT and ABI were estimated using linear regression and multinomial logistic regression, respectively, controlling for sex, age, smoking status, education, marital status, and several other potential confounders or intermediates.Stronger associations were observed among those with a high level of education and in men ≥ 60 years of age.Prospective studies are needed to confirm associations and further examine differences among population subgroups.

View Article: PubMed Central - PubMed

Affiliation: Centre for Research in Environmental Epidemiology (CREAL), Barcelona, Spain. marcelaepi@gmail.com

ABSTRACT

Background: Epidemiological evidence of the effects of long-term exposure to air pollution on the chronic processes of atherogenesis is limited.

Objective: We investigated the association of long-term exposure to traffic-related air pollution with subclinical atherosclerosis, measured by carotid intima media thickness (IMT) and ankle-brachial index (ABI).

Methods: We performed a cross-sectional analysis using data collected during the reexamination (2007-2010) of 2,780 participants in the REGICOR (Registre Gironí del Cor: the Gerona Heart Register) study, a population-based prospective cohort in Girona, Spain. Long-term exposure across residences was calculated as the last 10 years' time-weighted average of residential nitrogen dioxide (NO2) estimates (based on a local-scale land-use regression model), traffic intensity in the nearest street, and traffic intensity in a 100 m buffer. Associations with IMT and ABI were estimated using linear regression and multinomial logistic regression, respectively, controlling for sex, age, smoking status, education, marital status, and several other potential confounders or intermediates.

Results: Exposure contrasts between the 5th and 95th percentiles for NO2 (25 µg/m3), traffic intensity in the nearest street (15,000 vehicles/day), and traffic load within 100 m (7,200,000 vehicle-m/day) were associated with differences of 0.56% (95% CI: -1.5, 2.6%), 2.32% (95% CI: 0.48, 4.17%), and 1.91% (95% CI: -0.24, 4.06) percent difference in IMT, respectively. Exposures were positively associated with an ABI of > 1.3, but not an ABI of < 0.9. Stronger associations were observed among those with a high level of education and in men ≥ 60 years of age.

Conclusions: Long-term traffic-related exposures were associated with subclinical markers of atherosclerosis. Prospective studies are needed to confirm associations and further examine differences among population subgroups.

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Related in: MedlinePlus

Subgroup analyses: estimates of percent differences (95% CIs) in IMTcca (left) and IMTseg (right) associated with exposure contrasts between the 5th and 95th percentiles for 10-year weighted average values of NO2 (25 µg/m3; A), traffic load within 100 m (7,200,000 vehicle-m/day; B), and traffic intensity on the nearest street (15,000 vehicles/day; C) according to sex, sex × age ≥ 60 years, education, medication treatment, and smoking status. Estimates adjusted by sex, age, sex × age interaction, smoking status, education, marital status, BMI, HDL, waist circumference, systolic and diastolic blood pressure, weekly energy expenditure in physical activity during leisure time (tertiles), adherence to Mediterranean diet, plausibility of reported diet, medication (med) treatment, and percentage of people with low education (educ) at the census-tract level. Models for traffic load were additionally adjusted for occupational status.
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f1: Subgroup analyses: estimates of percent differences (95% CIs) in IMTcca (left) and IMTseg (right) associated with exposure contrasts between the 5th and 95th percentiles for 10-year weighted average values of NO2 (25 µg/m3; A), traffic load within 100 m (7,200,000 vehicle-m/day; B), and traffic intensity on the nearest street (15,000 vehicles/day; C) according to sex, sex × age ≥ 60 years, education, medication treatment, and smoking status. Estimates adjusted by sex, age, sex × age interaction, smoking status, education, marital status, BMI, HDL, waist circumference, systolic and diastolic blood pressure, weekly energy expenditure in physical activity during leisure time (tertiles), adherence to Mediterranean diet, plausibility of reported diet, medication (med) treatment, and percentage of people with low education (educ) at the census-tract level. Models for traffic load were additionally adjusted for occupational status.

Mentions: Effect modification. The association of all exposure markers with IMT differed across education level (Figure 1). In persons with a higher level of education, the association of 10-year exposure to air pollution with IMT was stronger (model 2 with NO2 and IMTcca). Increases of 25 μg/m3 in NO2, 7,200,000 vehicle-m/day in traffic load in 100 m, and 15,000 vehicles/day on the nearest street were associated with 4.6% (95% CI: 0.4, 8.9), 4.8% (95% CI: 0.7, 8.9), and 3.3% (95% CI: –0.02, 6.7) differences in IMTcca, respectively, among persons with a high education level; –1.5% (95% CI: –5.1, 2.1), 1.3% (95% CI: –2.4, 5.0), 1.3% (95% CI: –1.8, 4.4) among persons with a secondary school–level education; and 0.6% (95% CI: –2.8, 2.9), 0.5% (95% CI: –2.7, 3.8), 2.4% (95% CI: –0.6, 5.6) among persons with a primary school–level education. Similar patterns were observed for the associations of exposure to air pollutants with IMT6seg. Effects estimates were also stronger in men ≥ 60 years of age compared to younger men, showing significant associations of NO2 and traffic load in 100 m with IMT (percent difference in IMTcca for NO2, traffic load, and traffic intensity were 4.3% (95% CI: 0.2, 8.4), 5.9% (95% CI: 1.6, 10.3), and 3.4% (95% CI: –0.07, 7.0), respectively, among men ≥ 60 years of age, and –1.5% (95% CI: –5.7, 2.7), –1.5% (95% CI: –5.7, 2.6), and 1.2% (95% CI: –2.7, 5.0), respectively, among men < 60 years of age. No evidence of effect modification by smoking, medication treatment (Figure 1), menopause, diabetes (results not shown), or Mediterranean diet [see Supplemental Material, Figure S3 (http://dx.doi.org/10.1289/ehp.1205146)] was observed.


Association between long-term exposure to traffic-related air pollution and subclinical atherosclerosis: the REGICOR study.

Rivera M, Basagaña X, Aguilera I, Foraster M, Agis D, de Groot E, Perez L, Mendez MA, Bouso L, Targa J, Ramos R, Sala J, Marrugat J, Elosua R, Künzli N - Environ. Health Perspect. (2012)

Subgroup analyses: estimates of percent differences (95% CIs) in IMTcca (left) and IMTseg (right) associated with exposure contrasts between the 5th and 95th percentiles for 10-year weighted average values of NO2 (25 µg/m3; A), traffic load within 100 m (7,200,000 vehicle-m/day; B), and traffic intensity on the nearest street (15,000 vehicles/day; C) according to sex, sex × age ≥ 60 years, education, medication treatment, and smoking status. Estimates adjusted by sex, age, sex × age interaction, smoking status, education, marital status, BMI, HDL, waist circumference, systolic and diastolic blood pressure, weekly energy expenditure in physical activity during leisure time (tertiles), adherence to Mediterranean diet, plausibility of reported diet, medication (med) treatment, and percentage of people with low education (educ) at the census-tract level. Models for traffic load were additionally adjusted for occupational status.
© Copyright Policy - public-domain
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3569680&req=5

f1: Subgroup analyses: estimates of percent differences (95% CIs) in IMTcca (left) and IMTseg (right) associated with exposure contrasts between the 5th and 95th percentiles for 10-year weighted average values of NO2 (25 µg/m3; A), traffic load within 100 m (7,200,000 vehicle-m/day; B), and traffic intensity on the nearest street (15,000 vehicles/day; C) according to sex, sex × age ≥ 60 years, education, medication treatment, and smoking status. Estimates adjusted by sex, age, sex × age interaction, smoking status, education, marital status, BMI, HDL, waist circumference, systolic and diastolic blood pressure, weekly energy expenditure in physical activity during leisure time (tertiles), adherence to Mediterranean diet, plausibility of reported diet, medication (med) treatment, and percentage of people with low education (educ) at the census-tract level. Models for traffic load were additionally adjusted for occupational status.
Mentions: Effect modification. The association of all exposure markers with IMT differed across education level (Figure 1). In persons with a higher level of education, the association of 10-year exposure to air pollution with IMT was stronger (model 2 with NO2 and IMTcca). Increases of 25 μg/m3 in NO2, 7,200,000 vehicle-m/day in traffic load in 100 m, and 15,000 vehicles/day on the nearest street were associated with 4.6% (95% CI: 0.4, 8.9), 4.8% (95% CI: 0.7, 8.9), and 3.3% (95% CI: –0.02, 6.7) differences in IMTcca, respectively, among persons with a high education level; –1.5% (95% CI: –5.1, 2.1), 1.3% (95% CI: –2.4, 5.0), 1.3% (95% CI: –1.8, 4.4) among persons with a secondary school–level education; and 0.6% (95% CI: –2.8, 2.9), 0.5% (95% CI: –2.7, 3.8), 2.4% (95% CI: –0.6, 5.6) among persons with a primary school–level education. Similar patterns were observed for the associations of exposure to air pollutants with IMT6seg. Effects estimates were also stronger in men ≥ 60 years of age compared to younger men, showing significant associations of NO2 and traffic load in 100 m with IMT (percent difference in IMTcca for NO2, traffic load, and traffic intensity were 4.3% (95% CI: 0.2, 8.4), 5.9% (95% CI: 1.6, 10.3), and 3.4% (95% CI: –0.07, 7.0), respectively, among men ≥ 60 years of age, and –1.5% (95% CI: –5.7, 2.7), –1.5% (95% CI: –5.7, 2.6), and 1.2% (95% CI: –2.7, 5.0), respectively, among men < 60 years of age. No evidence of effect modification by smoking, medication treatment (Figure 1), menopause, diabetes (results not shown), or Mediterranean diet [see Supplemental Material, Figure S3 (http://dx.doi.org/10.1289/ehp.1205146)] was observed.

Bottom Line: Associations with IMT and ABI were estimated using linear regression and multinomial logistic regression, respectively, controlling for sex, age, smoking status, education, marital status, and several other potential confounders or intermediates.Stronger associations were observed among those with a high level of education and in men ≥ 60 years of age.Prospective studies are needed to confirm associations and further examine differences among population subgroups.

View Article: PubMed Central - PubMed

Affiliation: Centre for Research in Environmental Epidemiology (CREAL), Barcelona, Spain. marcelaepi@gmail.com

ABSTRACT

Background: Epidemiological evidence of the effects of long-term exposure to air pollution on the chronic processes of atherogenesis is limited.

Objective: We investigated the association of long-term exposure to traffic-related air pollution with subclinical atherosclerosis, measured by carotid intima media thickness (IMT) and ankle-brachial index (ABI).

Methods: We performed a cross-sectional analysis using data collected during the reexamination (2007-2010) of 2,780 participants in the REGICOR (Registre Gironí del Cor: the Gerona Heart Register) study, a population-based prospective cohort in Girona, Spain. Long-term exposure across residences was calculated as the last 10 years' time-weighted average of residential nitrogen dioxide (NO2) estimates (based on a local-scale land-use regression model), traffic intensity in the nearest street, and traffic intensity in a 100 m buffer. Associations with IMT and ABI were estimated using linear regression and multinomial logistic regression, respectively, controlling for sex, age, smoking status, education, marital status, and several other potential confounders or intermediates.

Results: Exposure contrasts between the 5th and 95th percentiles for NO2 (25 µg/m3), traffic intensity in the nearest street (15,000 vehicles/day), and traffic load within 100 m (7,200,000 vehicle-m/day) were associated with differences of 0.56% (95% CI: -1.5, 2.6%), 2.32% (95% CI: 0.48, 4.17%), and 1.91% (95% CI: -0.24, 4.06) percent difference in IMT, respectively. Exposures were positively associated with an ABI of > 1.3, but not an ABI of < 0.9. Stronger associations were observed among those with a high level of education and in men ≥ 60 years of age.

Conclusions: Long-term traffic-related exposures were associated with subclinical markers of atherosclerosis. Prospective studies are needed to confirm associations and further examine differences among population subgroups.

Show MeSH
Related in: MedlinePlus