Table 2.

Demographic characteristics of the participants.

Variable	Treatment condition		P value
	Real  N (%)	Sham  N (%)
Age
Mean (SD)	70.6 (4.67)	76.7 (7.00)	0.01
Range	65–82	66–90
Gender
Male	4 (21%)	7 (39%)	0.24
Female	15 (79%)	11 (61%)
Race/ethnicity
White	17 (89%)	15 (83%)	0.59
Black/african american	2 (11%)	3 (17%)
Marital status∗
Currently married	10 (52%)	7 (39%)	0.86
Divorced	3 (16%)	3 (17%)
Widowed	5 (23%)	5 (28%)
Never married	1 (5%)	2 (11%)
Employment situation∗
Working (full time)	2 (11%)	2 (11%)	0.76
Working (part time)	2 (11%)	1 (5%)
Not employed	1 (5%)	3 (17%)
Retired	14 (73%)	11 (61%)
Education level∗
<8th grade	1 (5%)	0 (0%)	0.75
8th to 11th grade	0 (0%)	1 (5%)
High school	5 (26%)	4 (22%)
Technical or vocational school	1 (5%)	2 (11%)
College and graduate	12 (64%)	10 (56%)
Estimated income before taxes∗
Less than $10,000	2 (11%)	5 (28%)	0.07
$10,000 to $19,999	2 (11%)	4 (22%)
$20,000 to $39,999	7 (37%)	1 (5%)
$40,000 to $59,000	4 (21%)	1 (5%)
$60,000 to $100,000	1 (5%)	3 (17%)
More than $100,000	0 (0%)	1 (5%)
Causes of back pain
Osteoporosis	2 (11%)	4 (22%)	0.37
Osteoarthritis	7 (37%)	6 (33%)	0.72
Scoliosis	4 (21%)	3 (17%)	0.67
Disk herniation	4 (21%)	2 (11%)	0.37
Spinal stenosis	6 (32%)	9 (50%)	0.30
Spondylitis	1 (5%)	0 (0%)	0.31
Spondylosis	2 (11%)	0 (0%)	0.15
Vertebral fracture	1 (5%)	1 (5%)	1.00
Current treatment for back pain∗
Yes, currently	4 (21%)	5 (28%)
NOT currently, but past	11 (58%)	9 (50%)	0.82
Never	3 (16%)	2 (11%)
Current pain medication use
Yes	10 (53%)	7 (39%)	0.40
No	9 (47%)	11 (61%)
Current sleep medication use
Yes	3 (16%)	2 (11%)	0.68
No	16 (84%)	16 (89%)
Satisfied with current treatment∗
Yes	9 (47%)	9 (50%)	0.23
No	4 (21%)	1 (5%)

*n varies due to missing data.