Table 2.

Univariate regression analyses: variables associated with back pain within 6 and 12 months of baseline

	Back pain within 6 months						Back pain within 12 months
	na	Casesa	(%)	OR	95 % CI	p-value	na	Casesa	(%)	OR	95 % CI	p-value
Individual factors
Body weight (Kg)
< 87	.	.	.	.	.	.	82	37	(45)	1.00	Reference	.
≥ 87	.	.	.	.	.	.	36	22	(61)	1.91	0.86–4.25	0.112
Body height (m)
< 1.86	90	23	(26)	1.00	Reference	.	74	30	(41)	1.00	Reference	.
≥ 1.86	47	21	(45)	2.35	1.12–4.96	0.024	44	29	(66)	2.84	1.30–6.17	0.009
Health-related factors
Previous back pain b
No	75.6	17	(22)	1.00	Reference	.	90	36	(40)	1.00	Reference	.
Yes	61.4	27	(44)	3.60	1.59–8.14	0.002	28	23	(82)	6.90	2.40–19.82	<0.001
Previous lower extremity pain b
No	104	26	(25)	1.00	Reference	.	66.6	27	(41)	1.00	Reference	.
Yes	33	18	(55)	2.71	1.29–5.68	0.008	51.4	32	(62)	2.43	1.45–5.14	0.021
Previous neck/shoulder pain b
No	.	.	.	.	.	.	83	38	(46)	1.00	Reference	.
Yes	.	.	.	.	.	.	35	21	(60)	1.78	0.80–3.96	0.160
Work-related factors
Military occupational function
Infantry (Assault)	93	26	(28)	1.00	Reference	.	81	36	(44)	1.00	Reference	.
Ranger	24	7	(29)	1.06	0.39–2.86	0.907	20	11	(55)	1.52	0.57–4.09	0.399
CBC-Crewc	20	11	(55)	3.15	1.17–8.48	0.023	17	12	(71)	3.00	0.97–9.30	0.057
Sitting work
< 1/2 work day	111	31	(28)	1.00	Reference	.	93	42	(45)	1.00	Reference	.
≥ 1/2 work day	26	13	(50)	2.58	1.08–6.18	0.033	25	17	(68)	2.58	1.01–6.57	0.047
Computer work
< 1/4 work day	112	33	(29)	1.00	Reference	.	93	43	(46)	1.00	Reference	.
≥ 1/4 work day	25	11	(44)	1.88	0.77–4.57	0.163	25	16	(64)	2.07	0.83–5.15	0.119
Vibrating floor/seat
< 1/4 work day	.	.	.	.	.	.	86.8	39.8	(46)	1.00	Reference	.
≥ 1/4 work day	.	.	.	.	.	.	31.2	19.2	(62)	1.89	0.82–4.38	0.135
Clinical test of movement control
Standing bow
Pass	.	.	.	.	.	.	76.2	42.2	(55)	1.00	Reference	.
Fail	.	.	.	.	.	.	41.8	16.8	(40)	0.54	0.24–1.20	0.129
Double leg lift-lower
Pass	76.6	30.1	(39)	1.00	Reference	.	.	.	.	.	.	.
Fail	60.4	13.9	(23)	0.46	0.21–1.01	0.054	.	.	.	.	.	.

odds ratio (OR) with corresponding 95 % confidence interval (95 % CI) and significance level (p-value) for variables associated at p <0.20 with back pain within 6 and 12 months of baseline

^aBased on pooling of 30 imputed datasets

^bPain within 6 months prior to baseline

^cCBC-Crew; Combat Craft(Boat/Hovercraft) Crew

^.Category not applicable