Associations between air pollution and cardio-respiratory physiological measures in older adults exercising outdoors.

We examined whether exercising indoors vs. outdoors reduced the cardio-respiratory effects of outdoor air pollution. Adults ≥55 were randomly assigned to exercise indoors when the Air Quality Health Index was ≥5 and outdoors on other days (intervention group, n = 37), or outdoors everyday (control group, n = 35). Both groups completed cardio-respiratory measurements before and after exercise for up to 10 weeks. Data were analyzed using linear mixed effect regression models. In the control group, an interquartile range increase in fine particulate matter (PM2.5) was associated with increases of 1.4% in heart rate (standard error (SE) = 0.7%) and 5.6% (SE = 2.6%) in malondialdehyde, and decreases of 5.6% (SE = 2.5%) to 16.5% (SE = 7.5%) in heart rate variability measures. While the hypothesized benefit of indoor vs. outdoor exercise could not be demonstrated due to an insufficient number of intervention days (n = 2), the study provides evidence of short-term effects of air pollution in older adults. ISRCTN #26552763.

Associations between blood volatile organic compounds, and changes in hematologic and biochemical profiles, in a population-based study.

OBJECTIVE: To investigate the influence of volatile organic compound (VOC) levels in blood, on hematological and serum biochemical parameters in the Canadian population. METHODS: We tested the association between seven selected VOCs and hematological profiles and serum tests reflecting liver and kidney function and glucose metabolism using a cross-sectional study design in 3950 participants of the Canadian Health Measures Survey from 2012 to 2015. We used generalized linear mixed models adjusting for age, sex, smoking, alcohol consumption, BMI, education and household income. RESULTS: An increase in blood concentration equivalent to the geometric mean for benzene, ethylbenzene, toluene, m-, p-xylenes, styrene, and total xylenes was associated with 0.68% (95% CI 0.36, 1.0) to 0.91% (95% CI 0.52, 1.3) increase in hemoglobin, and a 1.79% (95% CI 0.96, 2.62) to 4.11% (95% CI 3.11, 5.11) increase in total white blood cell count. Ethylbenzene, toluene, m-, p-xylenes and styrene were positively associated with increased platelet counts. A geometric mean increase for all VOCs was associated with decreases in creatinine. m- and p-xylenes were associated with a significant change in every measured blood cell count and liver function parameter, and in creatinine. Ethylbenzene was also positively associated with an increase in every measured hematologic parameter, two of the three liver function tests, and creatinine. Results were similar when stratified by age, but differed by smoking status and sex. CONCLUSIONS: This study provides evidence that VOCs in blood, at levels found in the Canadian population, may influence blood cell counts and indicators of liver and kidney function, including an inverse association between serum VOC and creatinine. This novel finding merits further investigation to understand the impact of VOCs on human physiology and population health.