Table 3. Associations between daily lifting load and mental stress after the workday and on the following morning. [LSM=least squares means; CI=confidence intervals].

Lifting load (kg)		N	Minimally adjusted a			P-value	Fully adjusted b			P-value
			LSM		LSM differences		LSM		LSM differences
			Estimates		Difference (95% CI)		Estimates		Difference (95% CI)
After work
	0–499	439	1.17		Reference		1.24		Reference
	500–1999	143	1.28		0.11 (-0.29–0.50)	0.596	1.36		0.12 (-0.27–0.52)	0.540
	2000–3499	118	1.35		0.18 (-0.30–0.66)	0.459	1.43		0.19 (-0.29–0.67)	0.439
	3500–4999	191	1.21		0.04 (-0.49–0.58)	0.875	1.27		0.03 (-0.50–0.57)	0.900
	≥5000	50	1.91		0.74 (0.10–1.37)c–f	0.024	1.96		0.72 (0.08–1.36)c–f	0.028
The following morning
	0–499	439	0.44		Reference		0.65		Reference
	500–1999	143	0.65		0.21 (-0.18–0.59)	0.289	0.88		0.23 (-0.16–0.62)	0.246
	2000–3499	118	1.05		0.60 (0.12–1.08)c,d,f,g	0.014	1.28		0.63 (0.15–1.11) c,d,f,g	0.010
	3500–4999	191	0.60		0.16 (-0.37–0.68)	0.562	0.83		0.18 (-0.35–0.71)	0.511
	≥5000	50	0.46		0.02 (-0.64–0.68)	0.955	0.69		0.04 (-0.63–0.70)	0.911

^a Minimally adjusted model: Adjusted for age, sex, job title, years of employment, daily working hours, low-back pain intensity the preceding 4 weeks prior to baseline, chronic low-back pain, and perceived stress during the two weeks prior to baseline. ^b Fully adjusted model: Minimally adjusted + BMI, leisure-time physical activity, smoking status, influence at work, access to work tools, role clarity, guidance, community and cohesion between colleagues, recognition, respectful relationship between leader and employees, and fairness. ^c Statistically significant different from 0–499 kg (reference). ^d Statistically significant different from 500–1999 kg. ^e Statistically significant different from 2000–3499 kg. ^f Statistically significant different from 3500–4999 kg. ^g Statistically significant different from ≥5000 kg.