Effectiveness of three interventions for secondary prevention of low back pain in the occupational health setting - a randomised controlled trial with a natural course control

Table 2 Baseline characteristics of the study participants. Means (SD = standard deviation) or percentages when applicable

Characteristics	Rehab (n = 43)			Physio (n = 43)			Advice (n = 40)			Control (n = 50)
Characteristics	%	mean	SD	%	mean	SD	%	mean	SD	%	mean	SD	p
Demographic features
Age, years	.	45	9	.	44	8	.	45	7	.	46	7	0.44
Male, %	65	.	.	72	.	.	68	.	.	60	.	.	0.30
High School diploma/vocational degree, %	67	.	.	56	.	.	58	.	.	70	.	.	0.23
Health related features
Duration of LBP, years	.	13	9	.	10	9	.	14	9	.	11	9	0.51
Smoking, %	31	.	.	40	.	.	40	.	.	23	.	.	0.14
Work-related features
Blue collar worker, %	74	.	.	77	.	.	90	.	.	84	.	.	0.56
Shift worker^a, %	43	.	.	28	.	.	39	.	.	32	.	.	0.68
Physical workload (1–5)^b	.	3	1	.	3	1	.	3	1	.	3	1	0.48
Mental workload (1–5)^b	.	3	1	.	3	1	.	3	1	.	3	1	0.07
Work ability (0–10)^c	.	7	2	.	7	2	.	7	2	.	7	2	0.84
Total SA days/previous year	.	16	23	.	21	28	.	19	26	.	22	49	0.62
Total SA periods/previous year	.	4	5	.	4	4	.	4	4	.	4	5	0.99
Low back specific SA days/previous year	.	6	14	.	9	25	.	9	22	.	9	41	0.92
Outcome variables at baseline
LBP intensity, LBP (0–100)	.	60	17	.	55	14	.	60	18	.	60	18	0.47
Physical impairment, PHI (0–18)	.	8	5	.	8	5	.	8	5	.	7	5	0.19
Pain related fear, FABQ (13–78)	.	38	14	.	38	12	.	37	12	.	35	12	0.26
FABQ work, FABQw (6–36)	.	18	7	.	16	7	.	16	7	.	16	7	0.61
FABQ physical activity, FABQph (4–24)	.	13	5	.	14	5	.	13	5	.	12	4	0.09

^atwo-shift or three-shift work
^bself rated workload: 1 = very heavy, 2 = moderate, 3 = intermediate, 4 = rather light, 5 = very light
^crange 0–10 from the lowest possible work ability (0) to the best possible work ability (10)
The three intervention groups were pooled for the comparison with the Control group and P denotes the p-value of the comparison. Range (when applicable) is presented after the variable name in the parenthesis
Rehab outpatient rehabilitation at the physical medicine unit, Physio progressive back-specific exercises, Advice self-care advice by an OH physician, Control Natural course control group, SA sickness absence, LBP low back pain, VAS Visual Analogue Scale, PHI physical impairment by the Roland-Morris Disability Questionnaire (0 to 18), FABQ Fear Avoidance Beliefs questionnaire, FABQw Fear Avoidance beliefs questionnaire, work subscale, FABQph Fear Avoidance beliefs questionnaire, physical activity subscale

ISSN: 1471-2458