Table 6.

Determinants of morphologic outcomes in multivariate backward linear regression analysis

Morphologic outcomes
Explanatory variable	c	95% CI	P	Total R2 (%)	R2 Change (%)
SDS score
Age	0.12	0.05–0.18	0.001	6	6
Prolonged occupational standing	0.80	0.22–1.38	0.007	12	6
Lifetime workload exposure	−0.00034	−0.00007 to 0.000004	0.078	17	5
Number of degenerated discs
Age	0.03	0.01–0.04	0.012	3	3
Prolonged occupational standing	0.21	0.04–0.39	0.017	8	5
Psychosocial risk factors	−0.17	−0.34 to 0.001	0.051	10	2
Family predisposition	0.50	−0.041 to 1.04	0.071	18	8
Severity of disc narrowinga
Age	0.01	0.01–0.02	<0.001	14	14
Family predisposition	0.19	0.01–0.38	0.044	17	3
Job workload category	0.06	-0.01 to 0.12	0.087	21	4
Number of herniated levels
Gender	0.73	0.21–1.25	0.007	6	6
BMI	−0.08	−0.14 to −0.01	0.020	10	4
Number of stenotic levels
Age	0.03	0.01–0.04	0.001	7	7
Job workload category	0.48	0.19–0.77	0.002	12	5
Psychosocial risk factors	0.16	0.03–0.29	0.019	13	1
Awkward occupational postures	−0.30	−0.56 to −0.04	0.026	16	3
Lifetime workload exposure	−0.00001	−0.00002 to −0.000001	0.028	20	4
Self-reported heavy workload	0.48	−0.06 to 1.03	0.082	23	3

^aSubjects with disc narrowing (n=98) were selected