Table 4. Baseline predictors of persistence of disabling low back pain.

Analysis was restricted to the 191 subjects with disabling LBP at baseline

Predictor	Persistence of disabling low back pain
	na	%b	PRR	(95% CI)c	PRR	(95% CI)d
Occupation
Office workers	20	35.7	1.0		1.0
Nurses	57	42.2	1.2	(0.8-1.8)	1.4	(1.0-2.0)
Occupational lifting e	49	40.5	0.8	(0.5-1.3)	0.9	(0.7-1.1)
Adverse beliefs about LBP
Physical activity	33	40.2	1.0	(0.7-1.4)	0.9	(0.7-1.2)
Work relatedness	67	42.4	1.3	(0.8-2.3)	1.0	(0.7-1.6)
Prognosis	44	42.3	1.2	(0.9-1.7)	1.1	(0.9-1.3)
Mental health
Good	14	30.4	1		1
Intermediate	16	30.8	1.1	(0.6-1.9)	1.2	(0.7-2.1)
Poor	47	50.5	1.7	(1.1-2.7)	1.7	(1.0-2.7)
Number of distressing somatic symptoms in past week
0	33	34.7	1		1
1	22	44.9	1.3	(0.9-1.9)	1.3	(0.9-1.8)
≥2	22	46.8	1.3	(0.9-1.9)	1.3	(0.9-1.8)
Smoking
Never	31	40.3	1		1
Former smoker	15	31.9	0.8	(0.5-1.4)	0.7	(0.5-1.1)
Current smoker	31	46.3	1.3	(0.9-1.9)	1.1	(0.8-1.4)
LBP in past 12 months,
≤1 month in total	20	28.6	1		1
>1 month in total	57	47.1	1.6	(1.1-2.4)	1.6	(1.1-2.4)

^aNumber of subjects with outcome

^bPercentage of subjects with outcome

^cEach risk factor analysed in a separate regression model that included sex, age (in four ten-year bands) and occupation

^dAll risk factors analysed in a single regression model that also included sex and age (in four ten-year bands)

^eLifting weights >25kg by hand in an average working day