Table 1.

Demographic data for patients with disc herniation and knee patients and P-values for comparison between groups

	Patients with disc herniation		Knee patients		P-value
	n = 69	Percentage	n = 162	Percentage
Men	39	56.5	94	58.0
Women	30	43.5	68	42.0	0.833
Mean age, years	40		44		0.007
Work load
Heavy	19	27.5	37	22.8
Moderate	27	39.1	82	50.6
Light	18	26.1	41	25.3
Unemployed	5	7.2	2	1.2	0.208
Educational level
Occupations requiring university or specialist education	22	31.9	54	33.3
Occupations not requiring advanced education	45	65.2	100	61.7
Studying	2	2.9	8	4.9	0.842
Physical activity
Leisure time physical activity, yes	52	75.4	125	77.2
No. leisure time physical activity	17	24.6	36	22.2
No data	–		1	0.6	0.708
Physical activity occasionally	32	46.4	59	36.4
Physical activity once a week	9	13.0	21	13.0
Physical activity 2–5 times a week	25	36.2	71	43.8
No data	3	4.3	11	6.8	0.270
Mean time of complaints, months	18		21		0.100