Increased allostatic load associated with ambient air pollution acting as a stressor: Cross-sectional evidence from the China multi-ethnic cohort study

Outdoor air pollution, road traffic noise, and allostatic load in children aged 6-11 years: evidence from six European cohorts

Emerging evidence suggests that exposure to air pollutants and road traffic noise triggers stress responses, which mediate physiological responses in multiple organs and tissues. However, epidemiological study in children is sparse. We aimed to evaluate whether outdoor air pollution and road traffic noise are associated with physiological response measured by allostatic load in children. We studied 919 children aged 6-11 years from the HELIX (Human Early Life Exposome) cohort in 6 European countries with 19 biomarkers assessed in four physiological systems-cardiovascular, metabolic, immune/inflammation, and neuroendocrine systems. We then calculated both count-based and continuous scores for each physiological system and generated allostatic load scores (range 0-19). Exposure to air pollution (NO2, PM2.5, PM10, PM2.5absorbance) and road traffic noise (LDEN) based on participants' home, school, and commuting route addresses were estimated for the year prior to outcome assessment. Higher exposure to all air pollutants was associated with a higher allostatic load, although only the association of PM10 survived correction for multiple testing (for count-based allostatic load score: RR = 1.27, 95%CI: 1.08, 1.48; for continuous allostatic load score: β = 0.56, 95% CI: 0.27-0.84, per each 10 µg/m3 increase in PM10). Examining physiological systems separately, higher exposure to air pollution was mainly associated with higher allostatic load in the immune/inflammatory and metabolic systems. No associations between road traffic noise and allostatic load were observed. Our findings suggest that air pollution act as a chronic stressor in manifesting multi-systemic physiological dysregulation in childhood, which may be a precursor of air pollution-related diseases.

Lower risk of atrial fibrillation associated with visible greenness within community life circle: Findings from a population-based study

Existing studies have found the health implications of greenness on cardiovascular health, but largely focus on greenspace rather than visible greenness. We aimed to investigate the relationship between visible greenness within the community life circle and atrial fibrillation (AF). Our study included 11,539 permanent residents from a large prospective cohort in a megacity of southern China from 2015 to 2017. We generated 15-minute walking isochrone for each study participant as the community life circle and combined it with green view index (GVI) to estimate corresponding exposure to residential greenness. GVI was calculated utilizing street view images and a fully convolutional neural network tailored for evaluating urban environments. We combined logistic regression model and a doubly-robust approach to explore the relationship between GVI and AF. Mediation analyses were used to assess the mediating role of air pollution, body mass index (BMI) and exercise time on the relationship between GVI and AF. We found that each IQR increase in GVI exposure was associated with a 22.6 % (95 % CI: 8.7 %, 34.1 %) reduction in the risk of AF. The mediation effect of PM1 on the relationship between GVI and AF was also identified. Higher visible greenness exposure within community life circle was associated with reduced risk of AF among urban residents. Visible greenness within urban community areas should be emphasized as a solution to promote cardiovascular health.

Association of waist circumference and BMI with premature death in young and middle-aged population

Introduction

Premature death is a global health indicator, significantly impacted by obesity, especially in young and middle-aged population. Both body mass index (BMI) and waist circumference (WC) assess obesity, with WC specifically indicating central obesity and showing a stronger relationship with mortality. However, despite known associations between BMI and premature death, as well as the well-recognized correlation between WC and adverse health outcomes, the specific relationship between WC and premature death remains unclear. Therefore, focusing on young and middle-aged individuals, this study aimed to reliably estimate independent and combined associations between WC, BMI and premature death, thereby providing causal evidence to support strategies for obesity management.

Methods

This study involved 49,217 subjects aged 18-50 years in the United States from 1999 to 2018 National Health and Nutrition Examination Survey (NHANES). Independent and combined associations between WC and BMI with premature death across sex and age stratum were examined by Cox regression. Survey weighting and inverse probability weighting (IPW) were further considered to control selection and confounding bias. Robustness assessment has been conducted on both NHANES and China Health and Retirement Longitudinal Study (CHARLS) data.

Results

A linear and positive relationship between WC and all-cause premature death was found in both males and females, with adjusted HRs of 1.019 (95%CI = 1.004-1.034) and 1.065 (95%CI = 1.039-1.091), respectively. Nonlinear relationships were found with respect to BMI and all-cause premature death. For females aged 36-50 with a BMI below 28.6 kg/m2, the risk of premature death decreased as BMI increased, indicated by adjusted HRs of 0.856 (95%CI = 0.790-0.927). Joint analysis showed among people living with obesity, a larger WC increased premature death risk (HR = 1.924, 95%CI = 1.444-2.564).

Discussion

WC and BMI exhibited prominent associations with premature death in young and middle-aged population. Maintaining an appropriate WC and BMI bears significant implications for preventing premature death.

Could the association between ozone and arterial stiffness be modified by fish oil supplementation?

BACKGROUND

Arterial stiffness (AS) is an important predicting factor for cardiovascular disease. However, no epidemiological studies have ever explored the mediating role of biomarkers in the association between ozone and AS, nor weather fish oil modified such association.

METHODS

Study participants were drawn from the UK biobank, and a total of 95,699 middle-aged and older adults were included in this study. Ozone was obtained from Community Multiscale Air Quality (CMAQ) model matched to residential addresses, fish oil from self-reported intake, and arterial stiffness was based on device measurements. First, we applied a double robust approach to explore the association between ozone or fish oil intake and arterial stiffness, adjusting for potential confounders at the individual and regional levels. Then, how triglycerides, apolipoprotein B (Apo B)/apolipoprotein A (ApoA) and non-high-density lipoprotein cholesterol (Non-HDL-C) mediate the relationship between ozone and AS. Last, the modifying role of fish oil was further explored by stratified analysis.

RESULTS

The mean age of participants was 55 years; annual average ozone exposure was associated with ASI (beta:0.189 [95%CI: 0.146 to 0.233], P < 0.001), and compared to participants who did not consume fish oil, fish oil users had a lower ASI (beta: 0.061 [95%CI: -0.111 to -0.010], P = 0.016). The relationship between ozone exposure and AS was mediated by triglycerides, ApoB/ApoA, and Non-HDL-C with mediation proportions ranging from 10.90% to 18.30%. Stratified analysis showed lower estimates on the ozone-AS relationship in fish oil users (P = 0.011).

CONCLUSION

Ozone exposure was associated with higher levels of arterial stiffness, in contrast to fish oil consumption, which showed a protective association. The association between ozone exposure and arterial stiffness was partially mediated by some biomarkers. In the general population, fish oil consumption might provide protection against ozone-related AS.

Understanding the Cardiovascular and Metabolic Health Effects of Air Pollution in the Context of Cumulative Exposomic Impacts

Poor air quality accounts for more than 9 million deaths a year globally according to recent estimates. A large portion of these deaths are attributable to cardiovascular causes, with evidence indicating that air pollution may also play an important role in the genesis of key cardiometabolic risk factors. Air pollution is not experienced in isolation but is part of a complex system, influenced by a host of other external environmental exposures, and interacting with intrinsic biologic factors and susceptibility to ultimately determine cardiovascular and metabolic outcomes. Given that the same fossil fuel emission sources that cause climate change also result in air pollution, there is a need for robust approaches that can not only limit climate change but also eliminate air pollution health effects, with an emphasis of protecting the most susceptible but also targeting interventions at the most vulnerable populations. In this review, we summarize the current state of epidemiologic and mechanistic evidence underpinning the association of air pollution with cardiometabolic disease and how complex interactions with other exposures and individual characteristics may modify these associations. We identify gaps in the current literature and suggest emerging approaches for policy makers to holistically approach cardiometabolic health risk and impact assessment.