Effects of long-term air pollution exposure on ankle-brachial index and cardio-ankle vascular index: A longitudinal cohort study using data from the Electricity Generating Authority of Thailand study

Int J Hyg Environ Health. 2021 Jun 14;236:113790. doi: 10.1016/j.ijheh.2021.113790. Online ahead of print.

ABSTRACT

BACKGROUND: Ankle-brachial index (ABI) and cardio-ankle vascular index (CAVI) are surrogate measures of atherosclerosis based on the functional performance of vessels, and are highly related to cardiovascular events. However, only a few longitudinal studies have been conducted on their associations with long-term air pollution exposure.

OBJECTIVE: This study aimed to examine whether long-term air pollution exposure is associated with ABI and CAVI in workers of the Electricity Generating Authority of Thailand (EGAT) in the Bangkok Metropolitan Region (BMR).

METHODS: This longitudinal study included 1261 participants (age range, 57-76 years as of 2007) of the EGAT study (2007-2017). ABI and CAVI were measured in 2007, 2012, and 2017. Annual mean concentrations of particulate matter ≤10 μm in diameter (PM₁₀), sulfur dioxide (SO₂), nitrogen dioxide (NO₂), ozone (O₃), and carbon monoxide (CO) were estimated by ordinary kriging using data from 22 background and 7 traffic monitoring stations in BMR between 2002 and 2017. Linear mixed-effects models were used to assess associations between air pollution (expressed as 1-year, 3-year, and 5-year average concentration) and ABI and CAVI (expressed as percent changes per interquartile range (IQR) increase in PM₁₀, O₃, NO₂, SO_2, and CO). We also applied the mixed-effect ordinal logistic models to calculate odds ratios (ORs) of having high or moderate CAVI per an IQR increase in air pollution.

RESULTS: After controlling for potential confounders, 1-year average CO was negatively associated with ABI, but not significantly (-0.48%, 95% CI: -1.03, 0.07). Three-year average NO₂ was positively associated with CAVI (6.67%, 95% CI: 0.21, 13.1). In contrast, 1-year average PM₁₀ was inversely associated with CAVI although the association was not significant. Although not significantly, 1-year average NO₂ and CO were positively associated with prevalence of high or moderate CAVI.

CONCLUSIONS: Although not statistically significant, long-term NO₂ and CO exposure was associated with ABI and CAVI in the participants of the EGAT study.

PMID:34139634 | DOI:10.1016/j.ijheh.2021.113790