Table 1.

Patient characteristics

Variable	Patients with chronic low back pain n = 101	Matched controls n = 97	P
Age (years) mean, SD	43.7 (10.3) n = 97	43.3 (10.6) n = 92	NS
Sex (% F)	60.2% (59/98)	65.3% (62/95)	NS
Weight (kg) mean, SD	73.3 (14.5) n = 95	64.2 (11.4) n = 92	0.0214
Height (cm) mean, SD	170.1 (7.8) n = 94	168.3 (7.7) n = 92	NS
Occupational status
Working	49% (47/96)	88.4% (84/95)	<0.004
On sick leave	32.3% (31/96)	–
Not in work	14.6% (14/96)	10.5% (10/95)
On disability allowance	4.2% (4/96)	1% (1/95)
Coffee intake (cups/day) mean, SD	2.9 (2.7) n = 92	3.1 (2.5) n = 95	NS
Tea intake (cups/day) mean, SD	0.84 (1.6) n = 84	0.56 (1.3) n = 76	NS
Cola intake (glasses/day) mean, SD	0.4 (1.2) n = 79	0.4 (1.1) n = 68	NS