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Serum vitamin D levels are not altered after controlled diesel exhaust exposures in healthy human subjects
Citation:
Mirowsky, J., K. Stratford, M. Madden, S. Harder, R. Devlin, AND M. Hazari. Serum vitamin D levels are not altered after controlled diesel exhaust exposures in healthy human subjects. Society of Toxicology Annual Meeting, Baltimore, MD, March 12 - 16, 2017.
Impact/Purpose:
Vitamin D deficiency can impact human health quality. There is concern over whether air pollution- the PM and/or gas phase components- can impact Vitamin D levels in exposed populations. This abstract reports findings from a controlled diesel exhaust exposed study that acute exposure to the exhaust did not alter plasma levels of the main Vitamin D metabolite in exposed healthy young individuals.
Description:
Past research has suggested that exposure to urban air pollution may be associated with vitamin D deficiency in human populations. Vitamin D is widely known for its importance in bone growth/remodeling, muscle metabolism, and its ability to promote calcium absorption in the gut; deficiency in vitamin D results in the development of rickets in children and osteomalacia in adults. In the current study, we assessed whether vitamin D levels are altered under controlled exposures to a commonly measured urban air pollutant, diesel. For this study, we exposed 12 healthy volunteers to clean air and diesel exhaust (300 μg/m3) for 2 hours while undergoing intermittent exercise. Venous blood was collected before, 0 hrs post-, and 18 hrs post-exposure, and 25-hydroxyvitamin D [25(OH)D] was measured in the serum. The average baseline value of 25(OH)D (mean ± standard error) was 22.9 ± 2.5 ng/mL. Four subject’s baseline values were vitamin D deficient (30 ng/mL). Additionally, there was no significant change in the baseline values between the clean air and diesel exposures (paired t-test, p = 0.54), suggesting minimal variability in 25(OH)D over the experiment's time course. Small inductions in 25(OH)D were found following clean air exposures (12.5 ± 4.9% and a 7.1 ± 5.0% for 0 hrs post- and 18 hrs post-exposure values compared to baseline, respectively). Minimal changes in 25(OH)D were observed following diesel exhaust exposures 0 hrs (3.5 ± 5.2%) and 18 hrs following exposures (-2.7 ± 5.0%). Notably, there was no significant change in 25(OH)D 0 hrs post (p = 0.14) or 18 hrs post (p = 0.17) between the clean air and diesel exposures. These results suggest that diesel exhaust alone does not alter the concentration of vitamin D in healthy people exposed under controlled conditions. [Does not represent EPA policy.]