Association of pulmonary, cardiovascular, and hematologic metrics with carbon nanotube and nanofiber exposure among U.S. workers: a cross-sectional study

Table 3 Associations of occupational exposure metrics with chest symptom and respiratory allergy development among 108 workers

	Chest symptom	Respiratory allergy
N outcome-free at start of work	63	64
N (%) reporting outcome after start of CNT/F work	13 (21%)	9 (14%)
Unadjusted OR (p-value ^a ) from logistic regression
Duration of CNT/F work (OR at 1 year)	1.07 (0.36)	1.20 (0.0081)
Presence of CNT in sputum (OR yes:no)	NA^b	0.91 (0.94)
EC – inhalable (OR at 1 μg/m³)	1.02 (0.34)	1.02 (0.040)
EC – respirable (OR at 1 μg/m³)	1.11 (0.19)	1.08 (0.096)
TEM structure count (OR at 0.1 structure/cm³)	1.03 (0.47)	1.07 (0.33)
Fine particulate counts (OR at 2000 per cm³)^c	1.07 (0.31)	0.85 (0.095)
Nanoscale particulate counts (OR at 2000 per cm³)^d	1.05 (0.63)	0.98 (0.85)
Fine particulate matter mass (OR at 10 μg/m³)^e	0.84 (0.67)	0.61 (0.31)

Abbreviations: CNT/F carbon nanotubes or nanofibers, EC elemental carbon, NA not available, OR odds ratio, TEM transmission electron microscopy
^amaximum-likelihood based
^bno sputum CNT was detected among those reporting chest symptoms since start of CNT/F work
^cmeasured with condensation particle counter (10-1000 nm diameter)
^dmeasured with electrical low-pressure impactor (23-96 nm diameter)
^emeasured with photometer (<2.5 μm diameter)

ISSN: 1743-8977