Long-term Coarse Particulate Matter Exposure and Heart Rate Variability in the Multi-ethnic Study of Atherosclerosis

Indoor Air Pollution and Impaired Cardiac Autonomic Function in Chronic Obstructive Pulmonary Disease

Rationale: Indoor air pollution represents a modifiable risk factor for respiratory morbidity in chronic obstructive pulmonary disease (COPD). The effects of indoor air pollution, as well as the impact of interventions to improve indoor air quality, on cardiovascular morbidity in COPD remain unknown. Objectives: To determine the association between indoor particulate matter (PM) and heart rate variability (HRV), a measure of cardiac autonomic function tied to cardiovascular morbidity and mortality, as well as the impact of household air purifiers on HRV. Methods: Former smokers with moderate-severe COPD were recruited from a 6-month randomized controlled trial of a portable air cleaner intervention to undergo paired assessment of both in-home PM and HRV using 24-hour Holter monitoring at up to five time points. Primary outcomes were HRV measures tied to cardiovascular morbidity (standard deviation of normal-to-normal intervals [SDNN] and root mean square of successive differences between normal-to-normal intervals [RMSSD]). Measurements and Results: Eighty-five participants contributed 317 HRV measurements. A twofold increase in household PM ⩽2.5 µm in aerodynamic diameter was associated with decreases in SDNN (β, -2.98% [95% confidence interval (CI), -5.12 to -0.78]) and RMSSD (β, -4.57% [95% CI, -10.1 to -1.60]). The greatest effects were observed with ultrafine particles (<100 nm) (RMSSD; β, -16.4% [95% CI, -22.3 to -10.1]) and among obese participants. Participants randomized to the active air cleaner saw improvements in RMSSD (β, 25.2% [95% CI, 2.99 to 52.1]), but not SDNN (β, 2.65% [95% CI, -10.8 to 18.1]), compared with the placebo group. Conclusions: This is the first U.S. study to describe the association between household PM and cardiac autonomic function among individuals with COPD, as well as the potential cardiovascular health benefits of household air cleaners.

Epigenetically mediated electrocardiographic manifestations of sub-chronic exposures to ambient particulate matter air pollution in the Women's Health Initiative and Atherosclerosis Risk in Communities Study

BACKGROUND

Short-duration exposure to ambient particulate matter (PM) air pollution is associated with cardiac autonomic dysfunction and prolonged ventricular repolarization. However, associations with sub-chronic exposures to coarser particulates are relatively poorly characterized as are molecular mechanisms underlying their potential relationships with cardiovascular disease.

MATERIALS AND METHODS

We estimated associations between monthly mean concentrations of PM < 10 μm and 2.5-10 μm in diameter (PM10; PM2.5-10) with time-domain measures of heart rate variability (HRV) and QT interval duration (QT) among U.S. women and men in the Women's Health Initiative and Atherosclerosis Risk in Communities Study (nHRV = 82,107; nQT = 76,711). Then we examined mediation of the PM-HRV and PM-QT associations by DNA methylation (DNAm) at three Cytosine-phosphate-Guanine (CpG) sites (cg19004594, cg24102420, cg12124767) with known sensitivity to monthly mean PM concentrations in a subset of the participants (nHRV = 7,169; nQT = 6,895). After multiply imputing missing PM, electrocardiographic and covariable data, we estimated associations using attrition-weighted, linear, mixed, longitudinal models adjusting for sociodemographic, behavioral, meteorological, and clinical characteristics. We assessed mediation by estimating the proportions of PM-HRV and PM-QT associations mediated by DNAm.

RESULTS

We found little evidence of PM-HRV association, PM-QT association, or mediation by DNAm.

CONCLUSIONS

The findings suggest that among racially/ethnically and environmentally diverse U.S. populations, sub-chronic exposures to coarser particulates may not exert appreciable, epigenetically mediated effects on cardiac autonomic function or ventricular repolarization. Further investigation in better-powered studies is warranted, with additional focus on shorter duration exposures to finer particulates and non-electrocardiographic outcomes among relatively susceptible populations.

Particulate matter air pollution and reduced heart rate variability: How the associations vary by particle size in Shanghai, China

BACKGROUND

It remains unclear which size of particles has the strongest effects on heart rate variability (HRV).

OBJECTIVE

To explore the association between HRV parameters and daily variations of size-fractionated particle number concentrations (PNCs).

METHODS

We conducted a longitudinal repeated-measure study among 78 participants with a 24-h continuous ambulatory Holter electrocardiographic recorder in Shanghai, China, from January 2015 to June 2019. Linear mixed-effects models were employed to evaluate the changes of HRV parameters associated with PNCs of 7 size ranges from 0.01 to 10 μm after controlling for environmental and individual confounders.

RESULTS

On the concurrent day, decreased HRV parameters were associated with increased PNCs of 0.01-0.3 μm, and smaller particles showed greater effects. For an interquartile range increase in ultrafine particles (UFP, those < 0.1 μm, 2453 particles/cm³), the declines in very-low-frequency power, low-frequency power, high-frequency power, standard deviation of normal R-R intervals, root mean square of the successive differences between R-R intervals and percentage of adjacent normal R-R intervals with a difference ≥ 50 ms were 5.06% [95% confidence interval (CI): 2.09%, 7.94%], 7.65% (95%CI: 2.73%, 12.32%), 9.49% (95%CI: 4.64%, 14.09%), 5.10% (95%CI: 2.21%, 7.91%), 8.09% (95%CI: 4.39%, 11.65%) and 24.98% (95%CI: 14.70%, 34.02%), respectively. These results were robust to the adjustment of criteria air pollutants, temperature at different lags, and the status of heart medication.

CONCLUSIONS

Particles less than 0.3 μm (especially UFP) may dominate the acute effects of particulate air pollution on cardiac autonomic dysfunction.

Short-term PM10 and emergency department admissions for selective cardiovascular and respiratory diseases in Beijing, China

BACKGROUND

Few studies have explored PM₁₀'s connection with specific respiratory and cardiovascular emergency department admissions (EDAs). This study aimed to examine the overall effects of PM₁₀ on EDAs for cardiovascular and respiratory diseases, including specifically, cerebrovascular events (CVE), ischemic heart disease (IHD), arrhythmia, heart failure (HF), upper respiratory tract infection (URTI), lower respiratory tract infection (LRTI), chronic obstructive pulmonary disease (COPD) and asthma.

METHODS

We collected daily data for EDAs from the 10 largest hospitals in Beijing, between January 2013 and December 2013 as well as daily measurements of PM₁₀ from 17 stations in Beijing. The generalized-additive model was utilized to evaluate the associations between daily PM₁₀ and cardio-pulmonary disease admissions. Differences in gender, age, and season groups were also examined by models. Relative risks (RR) with 95% confidence interval (CI) were calculated based on subtype, age, gender and seasonal groups. In all, there were approximately 56,212 cardiovascular and 92,464 respiratory emergency admissions presented in this study.

RESULTS

The largest estimate effects in EDAs of total cardiovascular disease, CVE, IHD, total respiratory diseases, URTI, LRTI and COPD were found for PM₁₀ at day 4 (accumulative) moving average, were 0.29% (95% CI:0.12%, 0.46%), 0.36% (95% CI:0.11%, 0.61%), 0.68% (95% CI:0.25%, 1.10%), 0.34% (95% CI:0.22%, 0.47%), 0.35% (95% CI:0.18%, 0.51%), 0.34% (95% CI:0.14%, 0.55%), 2.75% (95% CI:1.38%, 4.12%) respectively. In two-pollutant models and full-pollutant model modified confounding factors, the positive correlation remained unchanged. The elderly (age ≥ 65 years) and male subjects were more susceptible to specific respiratory diseases. PM₁₀'s impact on EDAs for HF was found higher during the hot season however, EDAs for COPD peaked during the cold season.

CONCLUSION

The study markedly informed that PM₁₀ pollution was strongly associated with EDAs for cardio-pulmonary diseases. The effects of PM₁₀ pollution on COPD and heart failure EDAs were clearly determined by seasonal-temperatures.

Advances in Understanding Air Pollution and CVD

The MESA Air (Multi-Ethnic Study of Atherosclerosis and Air Pollution) leveraged the platform of the MESA cohort into a prospective longitudinal study of relationships between air pollution and cardiovascular health. MESA Air researchers developed fine-scale, state-of-the-art air pollution exposure models for the MESA Air communities, creating individual exposure estimates for each participant. These models combine cohort-specific exposure monitoring, existing monitoring systems, and an extensive database of geographic and meteorological information. Together with extensive phenotyping in MESA-and adding participants and health measurements to the cohort-MESA Air investigated environmental exposures on a wide range of outcomes. Advances by the MESA Air team included not only a new approach to exposure modeling, but also biostatistical advances in addressing exposure measurement error and temporal confounding. The MESA Air study advanced our understanding of the impact of air pollutants on cardiovascular disease and provided a research platform for advances in environmental epidemiology.