Table 4.

Association between particle mass exposure (log PM₂₅₀ and log PM_Resp) and difference in baseline pulse amplitude (ΔBPA) and reactive hyperemia index (ΔRHI) between workday and day off among 48 metal smelter workers, using a fixed-effects linear regression model, adjusted for ΔS-caffeine and Δ(time since last meal)

	ΔBPA				ΔRHI
	Coeff	95% CI		p		Coeff	95% CI		p
log PM250
All	15	− 59	90	0.68	All	− 0.02	− 0.11	0.08	0.74
Plant A	− 17	− 252	218	0.88	Plant A	0.10	− 0.13	0.33	0.39
Plant B	77	− 256	410	0.63	Plant B	0.15	− 0.36	0.66	0.55
Age < 34	− 8	− 98	83	0.86	Age < 34	0.03	− 0.11	0.17	0.67
Age ≥ 34	152	43	260	0.009	Age ≥ 34	0.04	− 0.10	0.18	0.52
log PMResp
All	15	− 65	95	0.71	All	− 0.02	− 0.11	0.08	0.74
Plant A	− 65	− 350	219	0.64	Plant A	0.07	− 0.21	0.35	0.60
Plant B	61	− 238	360	0.67	Plant B	0.18	− 0.28	0.63	0.42
Age < 34	− 3.0	− 103	97	0.95	Age < 34	0.04	− 0.11	0.20	0.58
Age ≥ 34	178	62	294	0.004	Age ≥ 34	0.05	− 0.10	0.20	0.48

Due to missing covariate data, 11 subjects were excluded from the analyses

CI confidence interval, PM(₂₅₀or_Resp) particulate matter (< 250 nm or respirable aerosol fraction, respectively)