Table 2.

Changes in concentrations of biomarkers after 1-hour exposure to SHS in cars

BiomarkerPre [C] (ng/mg creatinine)0–8 h post [C] (ng/mg creatinine)Max post [C] (ng/mg creatinine)0–8-h change (ng/mg creatinine)PMax change (ng/mg creatinine)P value
2-HPMA
 Mean (95% CI)21.6 (12.7–30.5)37.9 (12.7–63.0)49.0 (22.6–75.5)18.2 (-8.9–45.3)0.12730.0 (1.5–58.6)0.011
 Median (IQR)16.3 (13.5–23.0)22.1 (14.8–39.9)35.9 (17.1–63.6)4.6 (−3.1–19.6)9.4 (3.7–36.3)
3-HPMA
 Mean (95% CI)160.5 (101.3–219.7)160.0 (86.3–233.7)187.4 (115.7–259.2)−1.6 (−86.4–82.2)0.83926.1 (−57.8–109.9)0.414
 Median (IQR)113.7 (88.8–261.7)122.1 (103.8–162.8)150.2 (127.8–191.7)−6.4 (-56.8–46.4)31.6 (4.9–57.3)
AAMA
 Mean (95% CI)50.8 (36.2–65.3)46.5 (37.6–55.5)54.7 (42.2–67.10−2.3 (−11.6–7.0)0.8936.4 (−3.0–15.7)0.244
 Median (IQR)49.5 (39.2–57.5)46.2 (33.0–58.2)50.0 (37.4–66.1)1.2 (−8.8–8.5)5.4 (−6.2–17.5)
CNEMA
 Mean (95% CI)1.29 (0.86–1.73)2.22 (1.94–2.50)2.45 (2.11–2.79)0.92 (0.57–1.27)<0.0011.15 (0.68–1.62)<0.001
 Median (IQR)1.12 (0.77–1.71)2.31 (1.94–2.58)2.53 (2.10–2.88)0.82 (0.70–1.23)1.06 (0.75–1.36)
HEMA
 Mean (95% CI)2.73 (1.58–3.87)3.43 (2.30–4.55)3.84 (2.40–5.28)0.81 (0.21–1.40)0.0031.22 (0.30–2.14)0.001
 Median (IQR)1.91 (1.32–3.56)2.81 (1.87–4.53)2.93 (2.19–5.12)0.54 (0.38–0.81)0.59 (0.46–1.14)
HMPMA
 Mean (95% CI)110.2 (46.3–174.2)140.8 (82.0–199.6)171.4 (114.7–228.1)29.1 (−47.6–105.9)0.14761.1 (-15.2–137.3)0.048
 Median (IQR)86.3 (70.3–94.3)102.5 (83.8–156.3)154.7 (109.6–183.1)13.5 (−9.9–71.2)73.3 (7.8–100.3)
MMA
 Mean (95% CI)40.1 (19.4–60.5)65.1 (35.5–94.7)74.3 (39.2–109.5)27.2 (12.7–41.8)<0.00136.7 (17.5–55.9)<0.001
 Median (IQR)24.2 (13.2–52.1)40.8 (33.3–112.4)46.9 (33.3–121.0)19.1 (10.6–31.4)24.8 (14.0–56.5)
MHBMA-3
 Mean (95% CI)0.27 (0.10–0.47)0.58 (0.40–0.76)0.73 (0.46–0.99)0.28 (0.05–0.50)0.0090.43 (0.13–0.73)<0.001
 Median (IQR)0.19 (0.11–0.38)0.53 (0.43–0.73)0.65 (0.43–0.87)0.21 (0.10–0.39)0.33 (0.21–0.47)
PMA
 Mean (95% CI)0.23 (0.14–0.32)0.34 (0.26–0.41)0.37 (0.29–0.46)0.11 (0.02–0.20)0.0170.14 (0.04–0.25)0.011
 Median (IQR)0.22 (0.09–0.29)0.33 (0.24–0.41)0.38 (0.26–0.42)0.11 (−0.05–0.18)0.14 (0.002–0.22)

NOTE: Numbers in bold indicate statistical significance at α < 0.05.

Abbreviations: mean, arithmetic mean; IQR, interquartile range; [C], concentration; 0–8 h change, 0–8 h post [C] minus pre [C]; Max change, Max post [C] minus pre [C].