Associations Between Sub-Clinical Markers of Cardiometabolic Risk and Exposure to Residential Indoor Air Pollutants in Healthy Adults in Perth, Western Australia: A Study Protocol

Exposure to ambient air pollution and lipid levels and blood pressure in an adult, Danish cohort

BACKGROUND

Air pollution is a well-recognized risk factor for cardiovascular disease. However, the mechanistic pathways underlying the association are not completely understood. Hence, further studies are required to shed light on potential mechanisms, through which air pollution may affect the development from subclinical to clinical cardiovascular disease.

OBJECTIVES

To investigate associations between short-term exposure to air pollution and high-density lipoprotein (HDL), non-high density lipoprotein (non-HDL), systolic and diastolic blood pressure.

METHODS

The study was conducted among 32,851 Danes from the Diet, Cancer and Health - Next Generations cohort, who had a blood sample taken and blood pressure measured. We measured HDL and non-HDL in the blood samples. We modelled exposure to fine particulate matter (PM_2.5), ultrafine particles (UFP), elemental carbon (EC) and nitrogen dioxide (NO₂) in time-windows from 24 h up to 90 days before blood sampling. Pollutants were modelled as total air pollution from all sources, and apportioned into contributions from non-traffic and traffic sources. We analyzed data using linear and logistic regression, with adjustment for socio-economic and lifestyle factors.

RESULTS

Air pollution exposure over 24 h to 30 days was generally adversely associated with lipid profile and blood pressure, e.g. for 30-day UFP-exposure, adjusted β-estimates were: -0.025 (-0.043; -0.006) for HDL, 0.086 (0.042; 0.130) for non-HDL, 2.45 (1.70; 3.11) for systolic and 1.56 (1.07; 20.4) for diastolic blood pressure, per 10,000 particles/cm³. The strongest associations were found for the non-traffic components of air pollution, and among those who were overweight/obese.

DISCUSSION

In this large study of air pollution and lipid levels and blood pressure, we found that 24-h to 30-day PM_2.5, UFP, EC and NO₂ concentrations were generally adversely associated with lipid profile and blood pressure, two important cardiovascular risk factors. The study suggests potential pathways, through which air pollution could affect the development of cardiovascular disease.

Household air pollution, adherence to a healthy lifestyle, and risk of cardiometabolic multimorbidity: Results from the China health and retirement longitudinal study

BACKGROUND

The adverse health effects of household air pollution have been widely explored, but few studies have evaluated the effects of household air pollution on the risk of cardiometabolic multimorbidity (CMM), a pressing public health concern worldwide. Thus, we aimed to investigate whether exposure to household use of polluting fuels is associated with morbid CMM and, if so, whether a healthy lifestyle could mitigate this association.

METHODS

In this prospective, nationwide representative cohort of the China Health and Retirement Longitudinal Study (CHARLS), participants free of CMM (defined as the coexistence of 2 or more of the following: heart disease, stroke, and diabetes or high blood sugar) were included in 2011-2012 and followed for CMM incidence until 2018. Household air pollution was measured as the use of solid fuels for cooking and heating. The healthy lifestyle score was determined by six factors, physical activity, smoking, body mass index, total cholesterol, blood glucose, and blood pressure, and categorized into three groups (unhealthy, 0-1 factors; intermediate, 2-4; and healthy, 5-6). Cox proportional hazards models investigated associations between household air pollution and incident CMM. The potential modifier effect of a healthy lifestyle score was tested through stratified analyses.

RESULTS

Among 7125 eligible participants, 239 incident cases of CMM were identified over a median follow-up of 7.0 years. After adjustment for potential confounders, the use of solid household fuels for heating was associated with more significant hazards of CMM (adjusted hazard ratio [HR] 1.71, 95 % confidence interval [CI] 1.28 to 2.28), while use for cooking (HR, 1.14; 95 % CI, 0.85 to 1.52) was not. Compared with participants in the unhealthy group, those in the healthy and intermediate groups had considerably lower CMM risk, with adjusted HRs (95 % CI) of 0.17 (0.09 to 0.31) and 0.39 (0.29 to 0.53), respectively, regardless of the household air pollution category. Importantly, when participants adhered to a healthy lifestyle, exposure to household air pollution was no longer significantly associated with a higher risk of CMM (adjusted HR 1.77, 95 % CI 0.51 to 6.12; P = 0.369).

CONCLUSIONS

Household usage of polluting fuels was significantly associated with a higher risk of CMM, and adherence to a healthy lifestyle may mitigate this adverse effect. From a broader perspective, our findings underscore the importance of public health policies and interventions targeting multiple exposures (air pollution, physical activity, smoking, etc.) in enhancing the prevention of detrimental cardiometabolic health effect.

The Association between Exposure to Residential Indoor Volatile Organic Compounds and Measures of Central Arterial Stiffness in Healthy Middle-Aged Men and Women

It is well reported that individuals spend up to 90% of their daily time indoors, with between 60% to 90% of this time being spent in the home. Using a cross-sectional study design in a population of 111 healthy adults (mean age: 52.3 ± 9.9 years; 65% women), we investigated the association between exposure to total volatile organic compounds (VOCs) in indoor residential environments and measures of central arterial stiffness, known to be related to cardiovascular risk. Indoor VOC concentrations were measured along with ambulatory measures of pulse pressure (cPP), augmentation index (cAIx) and cAIx normalized for heart rate (cAIx₇₅), over a continuous 24-h period. Pulse wave velocity (cfPWV) was determined during clinical assessment. Multiple regression analysis was performed to examine the relationship between measures of arterial stiffness and VOCs after adjusting for covariates. Higher 24-h, daytime and night-time cAIx was associated with an interquartile range increase in VOCs. Similar effects were shown with cAIx₇₅. No significant effects were observed between exposure to VOCs and cPP or cfPWV. After stratifying for sex and age (≤50 years; >50 years), effect estimates were observed to be greater and significant for 24-h and daytime cAIx in men, when compared to women. No significant effect differences were seen between age groups with any measure of arterial stiffness. In this study, we demonstrated that residential indoor VOCs exposure was adversely associated with some measures of central arterial stiffness, and effects were different between men and women. Although mechanistic pathways remain unclear, these findings provide a possible link between domestic VOCs exposure and unfavourable impacts on individual-level cardiovascular disease risk.