Table 4.

Continuous relationships of 12-month low-back pain (LBP) outcomes to alternative measures of cumulative lifetime vibration dose among professional drivers (N=537, observations=854). Changes in odds ratio (OR) for a change in 10ⁿ dose units are shown, (see table 2 for the definitions of the measures of cumulative lifetime vibration dose). [CI=confidence interval.]

Measures of vibration dose	LBP			Chronic LBP			Sciatic pain
	OR (95% CI) a,b	Wald test (P-value)	QIC (Δ) c	OR (95% CI) a,b	Wald test (P-value)	QIC (Δ) c	OR (95% CI) a,b	Wald test (P-value)	QIC (Δ) c
∑[awz2t] (107 m2s-3)	1.09 (0.98–1.22)	2.47 (0.12)	756 (0)	1.13 (0.99–1.29)	3.42 (0.064)	533 (0)	1.15 (1.02–1.29)	5.48 (0.019)	998 (0)
∑[A(8)z2t] (103 m2s-4)	1.51 (1.05–2.16)	4.91 (0.027)	753 (-3)	1.65 (1.08–2.51)	5.45 (0.020)	530 (-3)	1.69 (1.17–2.44)	7.75 (0.005)	994 (-4)
∑[Ftotal,rms2t] (1011 N2s)	1.77 (1.21–2.59)	8.68 (0.003)	744 (-12)	2.03 (1.35–3.07)	11.5 (0.0007)	521 (-12)	1.96 (1.41–2.72)	15.9 (0.0001)	981 (-17)
∑[Ftotal,rmst] (109 Ns)	1.25 (1.07–1.45)	8.06 (0.0045)	744 (-12)	1.34 (1.12–1.60)	10.5 (0.0012)	520 (-13)	1.29 (1.13–1.47)	14.9 (0.0001)	982 (-16)
∑[Fd,total,peak t1/6] (103 N)	1.53 (1.02–2.27)	4.31 (0.038)	749 (-7)	1.67 (1.01–2.76)	3.99 (0.046)	528 (-5)	1.65 (1.21–2.25)	9.92 (0.0016)	989 (-9)
∑[Sedpeak t1/6] (MPa)	2.04 (1.06–3.95)	4.53 (0.033)	749 (-7)	2.54 (1.09–5.88)	4.71 (0.030)	527 (-6)	2.46 (1.46–4.17)	11.3 (0.0008)	987 (-11)

^a∑[a_wz²t], ∑[A(8)_z²t]: OR adjusted by age-at-entry, body mass index, physical work load, psychosocial work environment, and follow up time.

^b∑[F_total,rms²t] to ∑[Sed_peak t^1/6]: OR adjusted by age-at-entry, physical work load, psychosocial work environment, and follow up time.

^cQIC is the quasi-likelihood information criterion for the comparison between models. QIC difference (Δ) is calculated as the difference between the QIC value for a specific exposure model and the model including ∑[a_wz²t] calculated according to a second power time dependency