Subclinical responses in healthy cyclists briefly exposed to traffic-related air pollution: an intervention study

Table 4 Percent change (pre/post-cycling) in endpoints per exposure scenario (road test or clean room)

Endpoint	Road test		Clean room		p-value for interaction
	Percent change (95%CI)	p-value	Percent change (95%CI)	p-value	Exposure scenario*	UFP^†	PM_2.5 ^‡
Exhaled NO,	-4.4% (-8.3% to -0.37%)	0.04	-1.3% (-6.5% to 4.1%)	0.63	0.38	0.63	0.50
PFA closure time	6.5% (-1.0% to 14.5%)	0.10	5.1% (-1.0% to 11.6%)	0.11	0.76	0.60	0.59
Plasma IL-6	17.4% (-6.7% to 47.9%)	0.18	-2.9% (-19.0% to 16.4%)	0.75	0.21	0.38	0.40
Clara cell protein	1.6% (-10.8% to 15.8%)	0.82	-0.27% (-11.7% to 12.7%)	0.97	0.90	0.91	0.80
Blood leukocyte counts	1.3% (-2.0% to 4.6%)	0.44	2.5% (-1.1% to 6.0%)	0.19	0.75	0.97	0.71
Blood neutrophil counts	4.6% (0.48% to 8.7%)	0.04	2.4% (-2.3% to 7.2%)	0.32	0.36	0.35	0.20
Percentage blood neutrophils	3.9% (1.5% to 6.2%)	0.003	0.22% (-1.8% to 2.2%)	0.83	0.004	0.02	0.01

Analysis adjusted for temperature, relative humidity and heart rate
*p-value for the interaction between pre/post-cycling measurements and exposure scenario (road test or clean room)
^†p-value for the interaction between pre/post-cycling measurements and UFP concentrations
^‡p-value for the interaction between pre/post-cycling measurements and PM_2.5 concentrations

ISSN: 1476-069X