Environmental exposure to combustion-derived air pollution is associated with reduced functional capacity in apparently healthy individuals

The relationship between multiple perfluoroalkyl substances and cardiorespiratory fitness in male adolescents

Exposure to perfluoroalkyl substances (PFASs) is associated with a number of adverse health outcomes. However, the relationship between mixed and individual PFAS exposure and cardiorespiratory fitness (CRF) in adolescents remains unclear. We used cross-sectional data from 491 teenagers (aged 13-19 years) from the 2003-2004 National Health and Nutrition Examination Survey (NHANES) and examined the association between mixed PFAS exposure and CRF via weighted quantile sum (WQS) regression. Maximal oxygen consumption (VO2max) was used to evaluate CRF. Multivariate linear regression was performed to investigate the relationship between each PFAS and VO2max as well as the relationship between PFAS exposure and the inflammation parameters and blood lipid content. Mediation analyses were performed to investigate possible explanations of the risk of low CRF due to PFAS exposure. The results showed that for males, mixed PFAS exposure was negatively related to VO2max (beta =  - 0.80, 95% CI: - 1.53 to - 0.10, P = 0.028) and that of the PFASs, perfluorononanoic acid (PFNA) had the greatest influence on VO2max. In the individual PFAS analysis, PFNA was negatively related to VO2max in male adolescents (beta =  - 1.49, 95% CI: - 2.65 to - 0.32, P = 0.013). Additionally, significant relationships among serum PFNA levels and total cholesterol and the white blood cell (WBC) count were found. Mediation analyses revealed that WBC count accounted for 24.18% of the variation between PFNA level and CRF. The present results provide epidemiological evidence that exposure to PFASs, mainly PFNA, is negatively associated with CRF, possibly via alterations in WBC count.

Association between elevated serum bilirubin levels with preserved lung function under conditions of exposure to air pollution

BACKGROUND

High serum bilirubin levels have been shown to be associated with an improved pulmonary function test results. Their potential ability to similarly benefit pulmonary function in an environment of polluted air has not been tested. We retrospectively analyzed data of 15,605 apparently healthy individuals in order to evaluate the effect of serum bilirubin levels on forced expiratory volume in 1 s (FEV1).

METHODS

Individuals attended the Tel-Aviv Medical Center Inflammatory Survey for a routine annual health check between February, 2002 and June, 2009 and were divided into low, medium and high serum bilirubin levels. Their FEV1 results were compared under various levels of air pollution. Air pollution and weather data were obtained from air pollution monitoring stations of the Israeli Ministry of Environmental Protection.

RESULTS

The elevated serum bilirubin concentrations on FEV1 were evaluated under moderate and high pollution levels FEV1 and were significantly higher in participants with high blood bilirubin levels compared to medium or low levels (p < 0.001 and p = 0.018, respectively). Participants with high levels of bilirubin had preserved FEV1 under exposure to high and medium pollution levels of both Nitrogen Oxide (NOx) and Carbon Monoxide (CO) pollutants (p = 0.003 and p = 0.022, respectively). The multivariate regression analysis revealed that the influence of bilirubin under conditions of air pollution remained significant even after adjustment for FEV1 confounders, but the interaction was not significant.

CONCLUSIONS

Elevated serum bilirubin concentrations are associated with preserved lung function in healthy individuals in Israel exposed to high levels of air pollution.

Higher fine particulate matter and temperature levels impair exercise capacity in cardiac patients

OBJECTIVE

Fine particulate matter (PM2.5) air pollution and variations in ambient temperature have been linked to increased cardiovascular morbidity and mortality. However, no large-scale study has assessed their effects on directly measured aerobic functional capacity among high-risk patients.

METHODS

Using a cross-sectional observational design, we evaluated the effects of ambient PM2.5 and temperature levels over 7 days on cardiopulmonary exercise test results performed among 2078 patients enrolling into a cardiac rehabilitation programme at the University of Michigan (from January 2003 to August 2011) using multiple linear regression analyses (controlling for age, sex, body mass index).

RESULTS

Peak exercise oxygen consumption was significantly decreased by approximately 14.9% per 10 μg/m(3) increase in ambient PM2.5 levels (median 10.7 μg/m(3), IQR 10.1 μg/m(3)) (lag days 6-7). Elevations in PM2.5 were also related to decreases in ventilatory threshold (lag days 5-7) and peak heart rate (lag days 2-3) and increases in peak systolic blood pressure (lag days 4-5). A 10°C increase in temperature (median 10.5°C, IQR 17.5°C) was associated with reductions in peak exercise oxygen consumption (20.6-27.3%) and ventilatory threshold (22.9-29.2%) during all 7 lag days. In models including both factors, the outcome associations with PM2.5 were attenuated whereas the effects of temperature remained significant.

CONCLUSIONS

Short-term elevations in ambient PM2.5, even at low concentrations within current air quality standards, and/or higher temperatures were associated with detrimental changes in aerobic exercise capacity, which can be linked to a worse quality of life and cardiovascular prognosis among cardiac rehabilitation patients.