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Yoga for Chronic Low Back Pain
A Randomized Trial
Helen E. Tilbrook, BSc, MSc; Helen Cox, BSc, MSc; Catherine E. Hewitt, BSc, MSc, PhD; Arthur Ricky Kang’ombe, BSc, MSc;
Ling-Hsiang Chuang, BSc, MSc, PhD; Shalmini Jayakody, BSc, MSc; John D. Aplin, MA, PhD; Anna Semlyen, BA, MSc;
Alison Trewhela, DBL, CSL; Ian Watt, BSc (Med Sci), MB, ChB, MPH; and David J. Torgerson, MSc, PhD
Background: Previous studies indicate that yoga may be an effec-
tive treatment for chronic or recurrent low back pain.
Objective: To compare the effectiveness of yoga and usual care for
chronic or recurrent low back pain.
Design: Parallel-group, randomized, controlled trial using computer-
generated randomization conducted from April 2007 to March
2010. Outcomes were assessed by postal questionnaire. (Inter-
national Standard Randomised Controlled Trial Number Register:
ISRCTN 81079604)
Setting: 13 non–National Health Service premises in the United
Kingdom.
Patients: 313 adults with chronic or recurrent low back pain.
Intervention: Yoga (n⫽156) or usual care (n⫽157). All partici-
pants received a back pain education booklet. The intervention
group was offered a 12-class, gradually progressing yoga program
delivered by 12 teachers over 3 months.
Measurements: Scores on the Roland–Morris Disability Question-
naire (RMDQ) at 3 (primary outcome), 6, and 12 (secondary out-
comes) months; pain, pain self-efficacy, and general health mea-
sures at 3, 6, and 12 months (secondary outcomes).
Results: 93 (60%) patients offered yoga attended at least 3 of the
first 6 sessions and at least 3 other sessions. The yoga group had
better back function at 3, 6, and 12 months than the usual care
group. The adjusted mean RMDQ score was 2.17 points (95% CI,
1.03 to 3.31 points) lower in the yoga group at 3 months, 1.48
points (CI, 0.33 to 2.62 points) lower at 6 months, and 1.57 points
(CI, 0.42 to 2.71 points) lower at 12 months. The yoga and usual
care groups had similar back pain and general health scores at 3, 6,
and 12 months, and the yoga group had higher pain self-efficacy
scores at 3 and 6 months but not at 12 months. Two of the 157
usual care participants and 12 of the 156 yoga participants reported
adverse events, mostly increased pain.
Limitation: There were missing data for the primary outcome
(yoga group, n⫽21; usual care group, n⫽18) and differential
missing data (more in the yoga group) for secondary outcomes.
Conclusion: Offering a 12-week yoga program to adults with
chronic or recurrent low back pain led to greater improvements in
back function than did usual care.
Primary Funding Source: Arthritis Research UK.
Ann Intern Med. 2011;155:569-578. www.annals.org
For author affiliations, see end of text.
Back pain is a common and costly condition (1, 2).
Exercise treatment, although widely used and recom-
mended, has only a small effect on back pain (3–5). Yoga
may offer an alternative approach to the treatment of low
back pain. The benefits of yoga may be greater than those
of exercise alone because yoga offers a combination of
physical exercise with mental focus, and patients are taught
good posture, self-awareness, and self-care along with re-
laxation. We recently conducted a literature review and
found evidence that yoga may be an effective treatment
of chronic low back pain (6–12). However, the
previous studies had limitations, including small sam-
ple sizes, a single yoga teacher delivering the program,
and short-term follow-up. We therefore conducted a trial
to determine whether offering a 12-week yoga program to
adults with chronic or recurrent low back pain led to
greater improvements in back function than usual care (13)
(https://hscisrv07.york.ac.uk/yoga/html/index.html).
METHODS
Design Overview
In this parallel-group, randomized, controlled trial,
participants were allocated in an overall ratio of 1:1 to
usual care or yoga. Participants were recruited between July
2007 and July 2008, with final follow-up in November
2009. The Leeds (East) Research Ethics Committee ap-
proved the study (reference 07/Q1206/35).
Setting and Participants
Thirty-nine general practices were recruited to the
study. Participating general medical practices searched pa-
tient databases and mailed out an invitation packet to all
individuals aged 18 to 65 years who had a visit for low
back pain in the past 18 months; database searches were
undertaken in 2 waves. In addition, during the second
wave of recruitment, advertisements were also placed in
local media. Individuals who were interested in participat-
ing were asked to return a consent form and an eligibility
See also:
Print
Editors’ Notes .............................570
Web-Only
Appendix Tables
Conversion of graphics into slides
Video supplement
Annals of Internal Medicine Original Research
© 2011 American College of Physicians 569
questionnaire containing the Roland–Morris Disability
Questionnaire (RMDQ) (14)—a 24-item questionnaire
with scores ranging from 0 (best) to 24 (worst)—to the
York Trials Unit.
Trial coordinators determined eligibility; criteria were
as follows: a score of 4 or more on the RMDQ, musculo-
skeletal pain bounded by the lowest ribs and gluteal folds,
and ability to attend 1 of the yoga venues. Patients were
excluded if they 1) did not return a baseline questionnaire
(second recruitment wave only), 2) had performed yoga in
the previous 6 months, 3) could not get off the floor un-
aided, 4) could not use stairs, 5) were pregnant, 6) had
life-threatening comorbid conditions, 7) had previously
undergone spinal surgery, 8) had severe documented psy-
chiatric problems or alcohol dependency, and 9) had indi-
cations of serious spinal neurologic abnormality (1 or more
of the following: difficulty passing urine; numbness around
their back passage, genitals, or inner thighs; numbness,
pins and needles, or weakness in both legs; or unsteadiness
on feet). Eligibility was confirmed through the partici-
pant’s general practitioner.
Randomization and Interventions
The randomization sequence was computer generated
by an independent data manager and was stratified by par-
ticipants’ prespecified availability to attend yoga classes
from a list of classes available, with 1 block per class. Eli-
gible participants’ details were entered into a randomiza-
tion database by the trial coordinators and secretary, who
were blinded to the allocation sequence. A variable alloca-
tion ratio was used for each class to ensure that no more
than 15 participants were allocated to any 1 class. Classes
for which fewer than 15 participants expressed availability
had an allocation ratio favoring the intervention group to
ensure that there were equal numbers of participants in
each group. Seven participants were added later and were
randomly assigned individually in a 1:1 ratio.
All participants received a back pain education booklet
(The Back Book [15]) and usual care. The intervention
group was also offered a yoga program. The usual care
group was offered a 1-time session of yoga after final
follow-up.
Yoga for Healthy Lower Backs
Twenty experienced yoga teachers from 2 yoga
associations—the British Wheel of Yoga and Iyengar Yoga
(10 from each)—were recruited for the study. Teachers
attended program training sessions over 2 weekends. All
teachers taught the same form of yoga according to the
teachers’ manual class plans and the pose descriptions and
sequences contained in the students’ manual. For each
course, 2 teachers were selected: 1 to teach and 1 to serve
as back-up. Treatment fidelity was assessed on 2 sepa-
rate occasions by the back-up yoga teachers. At each
assessment, a report was completed and sent to the trial
coordinators for review. The fidelity of content was ver-
ified by this process, and no changes resulted from the
monitoring sessions.
Yoga was delivered in nonmedical centers in England
(Cornwall, North and West London, Manchester, and
York) and was delivered in twelve 75-minute classes (1
class per week). The classes ran from November 2007 to
February 2008 and from September 2008 to December
2008. At the first class, participants were given the student
manual, a mat, and a relaxation compact disc (which fea-
tured 4 narrated guided relaxations focusing on body parts,
color meditation, breath awareness, and mental positivity).
Home practice sheets were distributed in the class at 4
intervals over the 12 weeks.
The yoga program introduced participants to the
foundational elements of yoga adapted appropriately for
low back pain, including asana, pranayama, relaxation
techniques, mental focus, and philosophy. Classes con-
sisted of an introduction to the weekly theme; pain-
relieving or settling-in relaxing poses; a program of seated,
standing, prone, and supine poses; educative postural ad-
vice; and 5 to 15 minutes of relaxation. Poses targeted stiff,
weak, and uneducated areas of the whole body, with the
intention of improving mobility, strength, and posture and
reducing pain. Later classes featured postures that built on
previous weeks, with the aim of increasing confidence in
performing more daily activities. Classes sought to train
participants in using yoga in everyday life and at home.
Participants were encouraged to undertake yoga for 30
minutes daily or to practice at least 2 times per week, and
to use the compact disc.
See the Video Supplement (available at www.annals
.org) for further information.
Context
Is yoga an effective therapy for low back pain?
Contribution
In this trial, adults with chronic or recurrent low back pain
were randomly assigned to a 12-session, 3-month yoga
program (n⫽156) or usual care (n⫽157). The yoga
group had better back function but similar back pain and
general health scores at 3, 6, and 12 months compared
with the usual care group. Eight participants reported ad-
verse events, such as increased pain, that were perhaps
related to yoga.
Caution
Compliance with yoga was incomplete, and some out-
come data were missing.
Implication
Yoga can improve some outcomes in adults with chronic
low back pain.
—The Editors
Original Research Yoga for Chronic Low Back Pain
570 1 November 2011 Annals of Internal Medicine Volume 155 • Number 9 www.annals.org
Figure 1. Study flow diagram.
Included in analysis at 6 mo (n = 137)
Not assessed at 6 mo (n = 19)
Lost to follow-up at 6 mo: 6
Withdrew: 8 (did not want to continue: 4; GP
deemed ineligible after randomization: 3;
unable to attend classes: 1)
Questionnaires not returned‡: 4
Change from baseline score could not be
calculated: 1
Included in analysis at 6 mo (n = 135)
Not assessed at 6 mo (n = 22)
Lost to follow-up at 6 mo: 9
Withdrew: 4 (did not want to continue: 1; GP
deemed ineligible after randomization: 3)
Questionnaires not returned‡: 7
Change from baseline could not be
calculated: 2
Included in analysis at 3 mo (n = 135)
Not assessed at 3 mo (n = 21)
Lost to follow-up at 3 mo: 5
Withdrew: 7 (did not want to continue: 3; GP
deemed ineligible after randomization: 3;
unable to attend classes: 1)
Questionnaires not returned‡: 8
Change from baseline score could not be
calculated: 1
Excluded (n = 779)
Roland–Morris Disability Questionnaire Score <4: 19
≥1 "red flags"*: 435
Attended yoga in past 6 mo: 46
Involved in back pain trial in past 6 mo: 42
Unable to get off the floor unaided and/or unable to walk up
and down stairs: 156
Had spinal surgery: 84
Pregnant: 3
Outside of age range: 4
Could not attend any of the classes on offer: 86
Not seen GP in past 18 mo and/or withdrawn before
randomization by GP: 5
Did not return baseline questionnaire: 20
Withdrew before randomization: 3
Had upper back pain not low back pain: 1
Included in analysis at 3 mo (n = 139)
Not assessed at 3 mo (n = 18)
Lost to follow-up at 3 mo: 6
Withdrew: 4 (did not want to continue: 1; GP
deemed ineligible after randomization: 3)
Questionnaires not returned‡: 6
Change from baseline scores could not be
calculated: 2
Included in analysis at baseline (n = 152)
Not assessed at baseline (n = 4)
Lost to follow-up at baseline†: 1
Withdrew (did not want to continue): 2
Questionnaire not returned†: 1
Included in analysis at baseline (n = 147)
Not assessed at baseline (n = 10)
Lost to follow-up at baseline†: 4
Withdrew: 2 (did not want to continue: 1; GP
deemed ineligible after randomization: 1)
Questionnaires not returned‡: 4
Assigned to yoga (n = 156)
Did not attend any sessions: 23
Randomly assigned (n = 313)
From GP recruitment: 279
From media recruitment: 34
Screening forms returned (n = 1093)
From GP recruitment: 995
From media recruitment: 98
Assigned to usual care (n = 157)
Included in analysis at 12 mo (n = 135)
Not assessed at 12 mo (n = 21)
Lost to follow-up at 12 mo: 13
Withdrew: 8 (did not want to continue: 4; GP
deemed ineligible after randomization: 3;
unable to attend classes: 1)
Included in analysis at 12 mo (n = 137)
Not assessed at 12 mo (n = 20)
Lost to follow-up at 12 mo: 12
Withdrew: 5 (did not want to continue: 1; GP
deemed ineligible after randomization: 3;
death: 1)
Change from baseline could not be
calculated: 3
GP ⫽general practitioner.
*An indicator of a more serious medical condition.
†Baseline questionnaires were sent out after randomization to the first-wave participants (n⫽165) and before randomization to the second-wave
participants (n⫽148). Participants who did not return a baseline questionnaire in the second wave were not randomly assigned.
‡Participants who did not return a questionnaire at that time point but completed questionnaires at subsequent follow-ups. Therefore, the numbers
given for “questionnaire not returned” are not cumulative. Number included in analysis refers to numbers included in the main mean Roland–Morris
Disability Questionnaire analyses.
Original ResearchYoga for Chronic Low Back Pain
www.annals.org 1 November 2011 Annals of Internal Medicine Volume 155 • Number 9 571
Outcomes and Follow-up
Questionnaires were posted with a prepaid enve-
lope. Nonresponders were initially followed up with
postal reminders and then with a telephone call by the
trial coordinators or secretary to collect the primary out-
come measure. A subset of participants was randomly
assigned to receive an electronic reminder on the day
Table 1. Baseline Characteristics of Participants With Low Back Pain Allocated to Yoga or Usual Care*
Characteristic Usual Care Group Yoga Group
Participants,
n
Data Participants,
n
Data
Age 157 156
Mean (SD) 46.3 (11.5) y 46.4 (11.3) y
Median (interquartile range) 46.4 (38.5–55.5) y 47.2 (37.6–56.0) y
Male participants 157 43 (27) 156 50 (32)
Age when participant left full-time education 146 152
ⱕ16 y 50 (34) 51 (34)
17–19 y 34 (23) 42 (28)
ⱖ20 y 59 (40) 55 (36)
Still in full-time education 3 (2) 4 (3)
Completed further education since leaving school, college, or university 140 79 (56) 141 85 (60)
Employment status 142 143
Employed part-time 33 (23) 30 (21)
Employed full-time 61 (43) 63 (44)
Unemployed 9 (6) 7 (5)
Unable to work because of poor health 10 (7) 9 (6)
At home, not looking for paid employment 11 (8) 18 (13)
Self-employed 18 (13) 16 (11)
Type of employment 140 135
Foreman/supervisor 3 (2) 14 (10)
Manager 27 (19) 27 (20)
Self-employed with employees 6 (4) 6 (4)
Self-employed without employees 18 (13) 14 (10)
Other employee 85 (61) 74 (55)
Never been in paid employment 1 (1) 0 (0)
Current back pain 143 110 (77) 152 118 (78)
Medication use 147 81 (55) 152 87 (57)
Disability
Median time that the participant has been unable to undertake usual
activities (range)
144 0 (0–28) d 150 0 (0–28) d
Median time that back pain kept the participant in bed (range) 145 0 (0–7) d 151 0 (0–14) d
Duration of back pain problems 155 153
Median (range) 72 (3–480) mo 96 (3–540) mo
Mean (SD) 113.5 (115.3) mo 130.28 (117.0) mo
Intervention preference 156 155
Yoga 95 (61) 112 (72)
Usual care 7 (4) 4 (3)
Indifferent 54 (35) 39 (25)
Belief that yoga works 157 156
Yes 81 (52) 93 (60)
No 0 (0) 1 (1)
Don’t know 76 (48) 62 (40)
Expectation that yoga works 157 156
Yes 87 (55) 89 (57)
No 0 (0) 2 (1)
Don’t know 70 (45) 65 (42)
*Unless otherwise noted, values are the numbers (percentages) of participants.
Original Research Yoga for Chronic Low Back Pain
572 1 November 2011 Annals of Internal Medicine Volume 155 • Number 9 www.annals.org
they were due to receive the 6-month questionnaire
(16). First-wave participants received £5 with the 12-
month questionnaire, and second-wave participants re-
ceived £5 with the 3-, 6-, and 12-month questionnaires.
Outcomes were measured before randomization; at
baseline; and at 3, 6, and 12 months. The prespecified
primary outcome was back function at 3 months, immedi-
ately after the yoga intervention. Back function was mea-
sured by using the RMDQ (14).
Secondary outcomes were 1) 6- and 12-month mea-
sures of the primary outcome; 2) physical and mental
health Short Form-12 (SF-12) Health Survey component
summary scores (17, 18); 3) back pain scores on the Ab-
erdeen Back Pain Scale (ABPS) (19); 4) self-efficacy scores
on the Pain Self-Efficacy Questionnaire (PSEQ) (20); 5)
EuroQol-5D health index (21) (results reported separate-
ly); 6) number of days spent in bed and number of days
with restricted activity (follow-up data reported separately);
7) economic data, including medication use over the pre-
vious 4 weeks and other health care use (reported sepa-
rately); 8) beliefs, expectations, and preferences for treat-
ment at baseline (22, 23); 9) class attendance (self-reported
and class registers); and 10) use of yoga at home. We did
not collect data on participants’ use of nonsteroidal anti-
inflammatory drugs or other physical activities.
Finally, participants were asked to call if they experi-
enced an adverse event or became pregnant. All events were
reported in accordance with National Research Ethics
guidelines. Adverse events were assigned potential causality
by 1 author (a practicing general practitioner and professor
of primary and community care) within the time frame
stated in the guidelines. There was no predefined list of
possible adverse events. An independent steering commit-
tee reviewed all adverse events.
Statistical Analysis
The United Kingdom BEAM (Back Pain Exercise and
Manipulation) trial (3) found that a change in the RMDQ
score of 1.57 points was a cost-effective difference. Assum-
ing an SD of 4 points (as in the United Kingdom BEAM
sample size), this results in an effect size of 0.39. To detect
this effect size, assuming 80% power and 20% attrition, we
required a total of 262 participants (131 per group).
The analysis plan was agreed on in advance by an
independent trial steering committee. Analyses were con-
ducted according to the original randomized treatment as-
signment regardless of adherence to protocol. Analyses
were performed by using SAS software, version 9.2 (SAS
Institute, Cary, North Carolina). The statistician was
blinded to randomized group.
Analyses were conducted by using a linear mixed
model (proc mixed in SAS) to compare changes from base-
line in RMDQ scores between the groups over time. The
linear mixed model assumed that data were missing at ran-
dom. Time was treated as a categorical variable and was
included as a fixed effect in addition to group, age, sex,
eligibility RMDQ score, class preference (stratification fac-
tor), group and time interaction, and duration of back
pain. The likelihood ratio test was used to select the best
covariance pattern. Model diagnostics showed that residu-
Figure 2. Mean RMDQ scores over time, by randomly assigned group.
Mean Change From Baseline RMDQ Score
Time of Follow-up
Usual care
Yoga
Baseline Month 12Month 6Month 3
–3
–4
–2
–1
0
1
Mean changes from baseline are all predicted means and 95% CIs, estimated from the mixed-effects models, and were adjusted by month, age, sex,
eligibility score, class availability, and duration of back pain as fixed effects and random intercepts as random effects. RMDQ ⫽Roland–Morris Disability
Questionnaire.
Original ResearchYoga for Chronic Low Back Pain
www.annals.org 1 November 2011 Annals of Internal Medicine Volume 155 • Number 9 573
als were normally distributed with constant variance, and
random intercept effects did not depart significantly from
the normal distribution (24, 25). Difference in scores be-
tween the groups at 3 (primary outcome) months and at 6
and 12 months (secondary outcomes), and 95% CIs were
estimated from the model. To explore the effect of partic-
ipant intervention preference, the above model was ex-
tended to include intervention preference and an interac-
tion term between intervention preference and group. The
Fisher exact test was also used to explore the association
between adherence and intervention preference.
To assess departures from the missing-at-random as-
sumption in the primary outcome model, a best-case and
worst-case sensitivity analysis was undertaken. Under the
best-case analysis, all yoga participants with missing data
were assigned the lowest RMDQ score from yoga partici-
pants with observed data, and all usual care participants
with missing data were assigned the highest RMDQ score
from usual care participants with observed data. Under the
worst-case analysis, all yoga participants with missing data
were assigned the highest RMDQ score from yoga partic-
ipants with observed data, and all usual care participants
with missing data were assigned the lowest RMDQ score
from usual care participants with observed data.
The ABPS, SF-12 mental and physical component
scores, and PSEQ were analyzed by using the same analysis
method as used for the primary outcome. The number of
adverse events by participant and the total number of
events by group were summarized.
Role of the Funding Source
This trial was funded by Arthritis Research UK and
sponsored by the University of York. The funding source
had no role in designing the study; collecting, analyzing,
and interpreting the data; writing the report; or deciding to
submit the manuscript for publication.
RESULTS
A total of 1093 individuals with low back pain were
screened, and 313 (28.7%) were randomly assigned from 5
centers: 156 to yoga and 157 to usual care (Figure 1).
Participants were mostly middle-aged employed women
(Table 1); the average duration of back pain was 10 years
(SD, 9.7), and 77% had current back pain. At baseline,
207 (67%) participants expressed a preference for yoga, 11
(4%) preferred usual care, and 93 (30%) had no prefer-
ence. Two participants did not express a preference.
Study Treatments
There were 16 yoga courses, and the average number
of participants allocated to each was 9.75 (SD, 3.68; me-
dian, 10 [range, 3 to 15]). The range in mean change from
baseline RMDQ scores at 3 months by class was ⫺6.5 to
0. Ninety-three (60%) participants attended at least 3 of
the first 6 classes and at least any other 3 classes (adhered);
of the remaining participants, 40 (26%) attended at least 1
class but did not meet the above criteria (mean attendance,
3.1; median attendance, 3.0 [range, 1 to 8]) and 23 (15%)
did not attend any classes. Of participants who adhered,
Table 2. Results of the Linear Mixed Model for the RMDQ Outcome Measure: Main Analysis and Sensitivity Analysis
Variable Mean
Baseline
RMDQ
Score (SD)
Mean Change in RMDQ Score From Baseline (95% CI)*
Month 3
P
Value Month 6
P
Value Month 12
P
Value
Main analysis
Yoga group 7.84 (3.96) ⫺2.14 (⫺3.00 to ⫺1.29) ⫺2.42 (⫺3.27 to ⫺1.57) ⫺2.04 (⫺2.90 to ⫺1.19)
Usual care group 7.75 (4.72) 0.03 (⫺0.89 to 0.94) ⫺0.94 (⫺1.86 to ⫺0.02) ⫺0.48 (⫺1.39 to 0.43)
Between-group difference in
means
⫺2.17 (⫺3.31 to ⫺1.03) ⬍0.001 ⫺1.48 (⫺2.62 to ⫺0.33) 0.011 ⫺1.57 (⫺2.71 to ⫺0.42) 0.007
Sensitivity analysis
Best-case analysis†
Yoga group ⫺2.90 (⫺3.89 to ⫺1.91) ⫺3.10 (⫺4.09 to ⫺2.11) ⫺2.85 (⫺3.84 to ⫺1.86)
Usual care group 0.52 (⫺0.55 to 1.58) ⫺0.10 (⫺1.16 to 0.97) ⫺0.08 (⫺1.15 to 0.98)
Between-group difference in
means
⫺3.42 (⫺4.75 to ⫺2.08) ⬍0.001 ⫺3.01 (⫺4.34 to ⫺1.67) ⬍0.001 ⫺2.77 (⫺4.11 to ⫺1.43) ⬍0.001
Worst-case analysis‡
Yoga group ⫺0.29 (⫺1.30 to 0.72) ⫺0.78 (⫺1.79 to 0.23) ⫺0.10 (⫺1.11 to 0.91)
Usual care group ⫺0.18 (⫺1.26 to 0.91) ⫺1.41 (⫺2.49 to ⫺0.33) ⫺0.93 (⫺2.01 to 0.15)
Between-group difference in
means
⫺0.11 (⫺1.47 to 1.24) 0.87 0.63 (⫺0.73 to 1.98) 0.36 0.83 (⫺0.53 to 2.19) 0.23
RMDQ ⫽Roland–Morris Disability Questionnaire.
*Mean changes from baseline and between-group differences (yoga minus usual care) are predicted means and 95% CIs, estimated from the mixed-effects models and
adjusted by month, age, sex, eligibility score, class preference, and duration of back pain as fixed effects and random intercepts as random effects in all models. A lower score
indicates better health.
†All yoga participants with missing data were assigned the lowest RMDQ score from yoga participants with observed data, and all usual care participants with missing data
were assigned the highest RMDQ score from usual care participants with observed data.
‡All yoga participants with missing data were assigned the highest RMDQ score from yoga participants with observed data, and all usual care participants with missing data
were assigned the lowest RMDQ score from usual care participants with observed data.
Original Research Yoga for Chronic Low Back Pain
574 1 November 2011 Annals of Internal Medicine Volume 155 • Number 9 www.annals.org
72% (n⫽66) expressed a preference for yoga at baseline,
1% (n⫽1) preferred usual care, and 27% (n⫽25) had
no preference; 1 person did not express a preference. Of
participants who did not adhere, 73% (n⫽46) expressed
a preference for yoga, 5% (n⫽3) preferred usual care, and
22% (n⫽14) had no preference. There was no association
between treatment preference at baseline and adherence
(P⫽0.39, Fisher exact test).
RMDQ Scores
The yoga group had better back function at 3 (primary
outcome), 6, and 12 (secondary outcomes) months than
the usual care group (Figure 2 and Table 2). The adjusted
mean RMDQ score was 2.17 points (95% CI, 1.03 to
3.31 points) lower in the yoga group at 3 months, 1.48
points (CI, 0.33 to 2.62 points) lower at 6 months, and
1.57 points (CI, 0.42 to 2.71 points) lower at 12 months.
There was no overall association between RMDQ
score and class preference (P⫽0.119), and the effect of
treatment did not vary by baseline intervention preference
(Pfor interaction ⫽0.39) or whether the participant had
current back pain at baseline (Pfor interaction ⫽0.27).
Sensitivity Analyses
Under the best-case analysis, participants in the yoga
group continued to have better back function at 3, 6, and
12 months than participants in the usual care group, with
larger treatment effect estimates (Table 2). Conversely, un-
der the worst-case analysis, there was no evidence of a
difference in back function between the yoga and usual
care groups.
Secondary Outcome Measures
The yoga and usual care groups had similar back pain
and general health scores at 3, 6, and 12 months; the yoga
group had higher pain self-efficacy scores at 3 and 6
months but not at 12 months (Table 3). There was no
association at all time points between pain and general
health and treatment (ABPS, P⫽0.136; SF-12 physical
component score, P⫽0.21; SF-12 mental component
score, P⫽0.145), and the results did not vary by month
of follow-up (Pfor interaction for ABPS ⫽0.39; for SF-12
physical component score ⫽0.82; for SF-12 mental com-
ponent score ⫽0.24). There was an association over all
time points between the PSEQ score and treatment
(P⫽0.022), and the effect of treatment did not vary by
month of follow-up (Pfor interaction ⫽0.36).
For all secondary outcome measures, there were dif-
ferential rates of missing outcome data between the 2
groups. The rates of missing data ranged from 17% to
Table 3. Results of the Linear Mixed Model for the Secondary Outcome Measures*
Outcome Measure Mean
Baseline
Value (SD)
Mean Change From Baseline (95% CI)
Month 3
P
Value
Month 6
P
Value
Month 12
P
Value
ABPS†
Yoga group 25.36 (10.59) ⫺3.62 (⫺5.56 to ⫺1.69) ⫺3.98 (⫺5.95 to ⫺2.01) ⫺3.23 (⫺5.20 to ⫺1.27)
Usual care group 26.69 (10.87) ⫺1.20 (⫺3.23 to 0.83) ⫺2.24 (⫺4.28 to ⫺0.20) 2.51 (⫺4.54 to ⫺0.48)
Between-group difference
in means
⫺2.42 (⫺4.97 to 0.12) 0.062 ⫺1.74 (⫺4.32 to 0.84) 0.186 ⫺0.73 (⫺3.30 to 1.84) 0.58
SF-12 PCS‡
Yoga group 44.41 (9.13) 2.65 (1.07 to 4.23) 2.89 (1.28 to 4.50) 2.99 (1.39 to 4.59)
Usual care group 44.04 (9.45) 1.29 (⫺0.35 to 2.94) 1.64 (⫺0.01 to 3.29) 2.20 (0.55 to 3.84)
Between-group difference
in means
1.36 (⫺0.70 to 3.41) 0.20 1.24 (⫺0.83 to 3.33) 0.24 0.80 (⫺1.28 to 2.87) 0.45
SF-12 MCS‡
Yoga group 45.04 (10.90) 1.94 (0.14 to 3.73) 1.64 (⫺0.18 to 3.46) 0.83 (⫺0.98 to 2.65)
Usual care group 45.02 (10.66) ⫺0.08 (⫺1.94 to 1.78) ⫺0.37 (1.50 to ⫺2.24) 0.41 (⫺1.45 to 2.27)
Between-group difference
in means
2.02 (⫺0.31 to 4.35) 0.090 2.02 (⫺0.34 to 4.37) 0.093 0.42 (⫺1.92 to 2.77) 0.72
PSEQ‡
Yoga group 44.04 (10.71) 3.85 (1.85 to 5.84) 4.29 (2.27 to 6.32) 3.35 (1.33 to 5.37)
Usual care group 43.78 (11.76) 0.88 (⫺1.22 to 2.99) 0.97 (⫺1.15 to 3.08) 1.60 (⫺0.50 to 3.70)
Between-group difference
in means
2.96 (0.35 to 5.58) 0.027 3.33 (0.68 to 5.97) 0.014 1.75 (⫺0.87 to 4.38) 0.190
ABPS ⫽Aberdeen Back Pain Scale; PSEQ ⫽Pain Self-Efficacy Questionnaire; SF-12 MCS ⫽Short Form-12, mental component score; SF-12 PCS ⫽Short Form-12,
physical component score.
*Number of participants with missing data: ABPS—baseline (yoga, 4; usual care, 10), month 3 (yoga, 26; usual care, 21), month 6 (yoga, 30; usual care, 25), month 12
(yoga, 29; usual care, 22); SF-12 PCS and SF-12 MCS—baseline (yoga, 5; usual care, 10), month 3 (yoga, 28; usual care, 21), month 6 (yoga, 32; usual care, 24), month
12 (yoga, 32; usual care, 21); PSEQ—baseline (yoga, 4; usual care, 10), month 3 (yoga, 26; usual care, 22), month 6 (yoga, 30; usual care, 26), month 12 (yoga, 29; usual
care, 21). Mean changes from baseline and between-group differences (yoga minus usual care) are predicted means and 95% CIs, estimated from the mixed-effects models,
and adjusted by month, age, sex, eligibility score, class preference, and duration of back pain as fixed effects and random intercepts as random effects.
†A lower score indicates better health.
‡A higher score indicates better health.
Original ResearchYoga for Chronic Low Back Pain
www.annals.org 1 November 2011 Annals of Internal Medicine Volume 155 • Number 9 575
21% in the yoga group and 13% to 17% in the usual
care group.
Adverse Events
Twelve of 156 (8%) yoga participants and 2 of 157
(1%) usual care participants reported adverse events (Table
4). In the yoga group, 1 adverse event was classified as
serious and possibly or probably related to yoga (the par-
ticipant experienced severe pain but had a history of severe
pain after any physical activity); the remaining 11 were
classified as nonserious and mostly related to increased
pain. In the usual care group, 2 serious adverse events
occurred.
DISCUSSION
This trial found that offering a 12-week yoga program
to adults with chronic or recurrent low back pain led to
greater improvements in back function than usual care.
The improvements in back function were observed across
the 12-month follow-up period but were more pronounced
at 3 months, immediately after the intervention. Although
there was no evidence of pain reduction at 12 months,
confidence in performing normal activities despite pain im-
proved more in the yoga group than usual care group at 3
and 6 months. We found little change in back pain and
general health scores at 3, 6, and 12 months. Yoga seemed
to be a safe form of activity, with only 8 participants re-
porting adverse events that were possibly or probably re-
lated to yoga.
Although there is no consensus, a change of 1.1 to 2.5
on the RMDQ has been recommended as clinically impor-
tant (26, 27). In this trial, we found that individuals of-
fered yoga benefited from, on average, 2.17 fewer limited
activities at 3 months and by 1.57 fewer limited activities
at 12 months. The activities measured by the RMDQ in-
clude, for example, walking more slowly than usual, stand-
ing for only short periods, and not doing any of the usual
jobs around the house. The fact that the benefits dimin-
Table 4. Adverse Events
Adverse Event Usual Care Group
(
n
ⴝ157)
Yoga Group
(
n
ⴝ156)
Serious adverse events,
n
Accident/injury* 1 0
Increased back pain possibly or
probably related to yoga
01
Increased back pain unrelated to
yoga
00
Other pain probably related to yoga† 0 0
Death 1 0
Nonserious adverse events,
n
Accident/injury* 0 1
Increased back pain possibly or
probably related to yoga
04
Increased back pain unrelated to
yoga
03
Other pain probably related to yoga† 0 3
*Unrelated to intervention.
†All patients had a history of other pain.
Figure 3. Forest plot comparing yoga with other interventions for low back pain evaluated in high-quality randomized,
controlled trials.
Study, Year
UK BEAM, 2004 (3)
Exercise
Manipulation
Manipulation + exercise
Little et al, 2008 (26)
Alexander technique (6 sessions)
Alexander technique (24 sessions)
Lamb et al, 2010 (27)
Cognitive behavioral treatment
Yoga
Mean Difference
(95% CI)
1.36 (0.63–2.10)
1.57 (0.82–2.32)
1.87 (1.15–2.60)
1.71 (0.47–2.98)
2.91 (1.66–4.16)
1.10 (0.38–1.71)
2.17 (1.03–3.31)
–5 –4 –3 –2 –1 0 1 2 3 4 5
Mean Difference in RMDQ Scores at 3 mo
Favors Control Favors Intervention
RMDQ ⫽Roland–Morris Disability Questionnaire; UK BEAM ⫽United Kingdom Back Pain Exercise and Manipulation.
Original Research Yoga for Chronic Low Back Pain
576 1 November 2011 Annals of Internal Medicine Volume 155 • Number 9 www.annals.org
ished over time, after the classes had finished, may indicate
that additional classes would be required to maintain the
improvement in back function.
Some participants in the yoga group reported that they
attended other yoga classes after the 12-week program had
finished, and others reported that they continued with
home practice (Appendix Tables 1 and 2, available at www
.annals.org). The frequency of home practice was 82% in
the first 3 months and then decreased to 65% at 6 months
and 60% at 12 months; however, 13% of the yoga group
did not provide home practice data at any of the follow-up
points. The reported figures of home practice may explain
why we observed some improvement in back function in
the long term. Of note, some participants who did not
adhere to the yoga program still reported home practice at
12 months.
Sixty percent of participants offered yoga adhered to
the program: Of the remaining participants, 26% attended
at least 1 class but did not fully adhere, and 15% did not
attend any classes. Reasons for nonattendance varied: with-
drawal by physician, work commitments, child care, and
other health problems. For 21 of the 40 participants who
partially adhered, we could not ascertain reasons for non-
attendance. There were missing data for all outcomes, and
differential rates of missing data were observed for second-
ary outcome measures. Hence, it is possible that such im-
balances may have biased the results.
When departures from the missing-at-random as-
sumption were assessed in the primary outcome model, the
results were consistent with those of our primary analysis
under the best-case scenario but were inconsistent under
the worst-case scenario. These analyses are useful because
they demonstrate the largest and smallest effect estimates
compatible with the observed data; however, they are both
unlikely scenarios. Unfortunately, the implications of miss-
ing data for the analysis depend on the missing-value
mechanism, and this is rarely known.
Ours was a large randomized trial with long-term
follow-up, including multiple teachers (n⫽12) deliver-
ing classes in 5 geographic areas. The program was ac-
ceptable to and taught by teachers from 2 yoga associations.
Checks were made to ensure fidelity to the program. A recent
review identified 7 other randomized, controlled trials eval-
uating yoga for low back pain (6–12), but all had design
limitations, including small sample sizes, a single yoga
teacher delivering the program, and short-term follow-up.
Most of the studies found differences in favor of yoga, and
our results are consistent with their findings.
Other interventions for low back pain that have been
evaluated in high-quality randomized, controlled trials in-
clude exercise and manipulation (3), the Alexander tech-
nique (26), and cognitive behavioral treatment (27).
Comparing the findings of this study with these other in-
terventions suggests that group yoga may improve back
function (as measured by the RMDQ) more than exercise
and manipulation, cognitive behavioral treatment, and 6
sessions of 1-to-1 Alexander technique but not as much as
24 sessions (Figure 3). However, we must be cautious
about overanalyzing these results because the comparisons
are indirect. Future research should compare yoga directly
with these other treatments.
In summary, we found that offering a 12-week yoga
program to adults with chronic or recurrent low back pain
led to greater improvements in back function than usual
care for up to 12 months. Yoga seems to be a safe and
effective activity that clinicians could consider recommend-
ing for patients with a history of low back pain.
From the University of York, Heslington, York, United Kingdom; Uni-
versity of Manchester, St. Mary’s Hospital, Manchester, United King-
dom; Yoga in York, York, United Kingdom; and SBRCP-Yoga Walsing-
ham Clinic, Truro, Cornwall, United Kingdom.
Grant Support: By Arthritis Research UK.
Acknowledgment: The authors thank Jennifer Klaber-Moffett for her
contribution to the development of the original trial protocol and con-
tribution of her expertise in low back pain during the early phase of the
trial. They also thank all the yoga teachers who participated in delivering
and assessing the intervention.
Potential Conflicts of Interest: Disclosures can be viewed at www.acponline
.org/authors/icmje/ConflictOfInterestForms.do?msNum⫽M10-2577.
Reproducible Research Statement: Study protocol: Available at Cox H,
Tilbrook H, Aplin J, et al. A pragmatic multi-centred randomised con-
trolled trial of yoga for chronic low back pain: trial protocol. Comple-
ment Ther Clin Pract. 2010;16:76-80. Statistical code and data set: Avail-
ability of certain portions of the analytic data set and statistical code to
approved individuals through written agreements with Dr. Torgerson
(e-mail, david.torgerson@york.ac.uk).
Requests for Single Reprints: Helen E. Tilbrook, BSc, MSc, York
Trials Unit, Department of Health Sciences, Lower Ground Floor,
ARRC Building, University of York, Heslington, York YO10 5DD,
United Kingdom; e-mail, helen.tilbrook@york.ac.uk.
Current author addresses and author contributions are available at www
.annals.org.
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Original Research Yoga for Chronic Low Back Pain
578 1 November 2011 Annals of Internal Medicine Volume 155 • Number 9 www.annals.org
Current Author Addresses: Ms. Tilbrook, Ms. Cox, Dr. Hewitt, Mr.
Kang’ombe, Dr. Chuang, and Ms. Jayakody: University of York, Hes-
lington, York YO10 5DD, United Kingdom.
Dr. Aplin: Manchester Academic Health Science Centre, University of
Manchester, St. Mary’s Hospital, Manchester M13 9WL, United
Kingdom.
Ms. Semlyen: Yoga in York, 24 Grange Street, York YO10 4BH, United
Kingdom.
Ms. Trewhela: SBRCP-Yoga Walsingham Clinic, 2 Walsingham Place,
Truro, Cornwall TR1 2RP, United Kingdom.
Dr. Watt: Department of Health Sciences, University of York, Area 2,
Seebohm Rowntree Building, Heslington, York YO10 5DD, United
Kingdom.
Dr. Torgerson: Hull York Medical School, York Trials Unit, Lower
Ground Floor, ARRC Building, Department of Health Sciences, Uni-
versity of York, Heslington, York YO10 5DD, United Kingdom.
Author Contributions: Conception and design: H.E. Tilbrook, H. Cox,
J.D. Aplin, A. Semlyen, A. Trewhela, I. Watt, D.J. Torgerson.
Analysis and interpretation of the data: H.E. Tilbrook, C.E. Hewitt, A.R.
Kang’ombe, J.D. Aplin, A. Semlyen, A. Trewhela, I. Watt, D.J. Torgerson.
Drafting of the article: H.E. Tilbrook, C.E. Hewitt, A.R. Kang’ombe, I.
Watt, D.J. Torgerson.
Critical revision of the article for important intellectual content: C.E.
Hewitt, L.H. Chuang, J.D. Aplin, A. Semlyen, A. Trewhela, I. Watt,
D.J. Torgerson.
Final approval of the article: H.E. Tilbrook, H. Cox, C.E. Hewitt, A.R.
Kang’ombe, J.D. Aplin, A. Semlyen, A. Trewhela, I. Watt, D.J. Torgerson.
Provision of study materials or patients: A. Semlyen, A. Trewhela.
Statistical expertise: C.E. Hewitt, A.R. Kang’ombe.
Obtaining of funding: J.D. Aplin, A. Semlyen, I. Watt, D.J. Torgerson.
Administrative, technical, or logistic support: H. Cox, J.D. Aplin, A.
Semlyen.
Collection and assembly of data: H.E. Tilbrook, H. Cox, D.J. Torger-
son.
Appendix Table 1. Summary Data on Whether Participants Practiced Yoga at Home and How Often They Practiced Over Time
Variable Yoga Group,
n
/
n (%)
Usual Care Group
(
n
ⴝ157),
n
/
n (%)
Offered Yoga
(
n
ⴝ156)*
Adherent
(
n
ⴝ93)*
Partial Attenders
(
n
ⴝ40)*
Nonattenders
(
n
ⴝ23)*
Month 3
Practicing yoga at home 102/125 (82) 83/89 (93) 15/27 (56) 4 (50) 3/19 (16)
Not practicing yoga at home 23/125 (18) 6/89 (7) 12/27 (44) 4 (50) 16/19 (84)
Missing data on use of yoga at home 31/156 (20) 4/93 (4) 13/40 (33) 15/23 (65) 138/157 (88)
How often practicing yoga at home?
Daily 9/101 (9) 7/82 (9) 2/15 (13) – 1/3 (33)
Every other day 21/101 (21) 17/82 (21) 2/15 (13) 2/4 (50) –
Twice a week 40/101 (40) 35/82 (43) 5/15 (33) – –
Once a week 23/101 (23) 18/82 (22) 3/15 (20) 2/4 (50) 1/3 (33)
Less than once a week 8/101 (8) 5/82 (6) 3/15 (20) – 1/3 (33)
Missing (did not provide frequency of yoga
home use)
1/102 (1) 1/83 (1) – – –
Month 6
Practicing yoga at home 82/126 (65) 72/88 (82) 7/26 (27) 3 (27) 17/128 (13)
Not practicing yoga at home 44/126 (35) 16/88 (18) 19/26 (73) 8 (73) 111/128 (87)
Missing data on use of yoga at home 30/156 (19) 5/93 (5) 14/40 (35) 10/23 (43) 29/157 (19)
How often practicing yoga at home?
Daily 6/82 (7) 6/72 (8) – – 1/7 (6)
Every other day 10/82 (12) 9/72 (13) 1/7 (14) – 3/7 (18)
Twice a week 25/82 (31) 21/72 (29) 2/7 (29) 2/3 (67) 6/7 (35)
Once a week 21/82 (26) 16/72 (22) 4/7 (57) 1/3 (33) 4/7 (24)
Less than once a week 20/82 (24) 20/72 (28) – – 3/7 (18)
Missing (did not provide frequency of yoga
home use)
–––– –
Month 12
Practicing yoga at home 76/126 (60) 61/89 (69) 10/25 (40) 4 (36) 16/136 (12)
Not practicing yoga at home 50/126 (40) 28/89 (31) 15/25 (60) 7 (64) 120/136 (88)
Missing data on use of yoga at home 30/156 (19) 4/89 (4) 15/40 (38) 12/23 (52) 21/157 (13)
How often practicing yoga at home?
Daily 5/76 (7) 5/62 (8) – – –
Every other day 8/76 (11) 7/62 (11) 1/10 (10) – 3/16 (18)
Twice a week 28/76 (37) 21/62 (34) 6/10 (60) – 3/16 (18)
Once a week 17/76 (22) 12/62 (19) 2/10 (20) 1/4 (25) 5/16 (31)
Less than once a week 18/76 (24) 17/62 (27) 1/10 (10) 3/4 (75) 5/16 (31)
Missing (did not provide frequency of yoga
home use)
–––– –
*Total number in each group. Offered yoga: all participants randomly assigned to yoga; adherent: participants who attended at least 3 of the first 6 classes and at least 3 other
classes; partial attenders: participants who attended at least 1 class but did not meet the definition of adherent; nonattenders: participants who did not attend any of the yoga
classes offered.
Annals of Internal Medicine
W-166 1 November 2011 Annals of Internal Medicine Volume 155 • Number 9 www.annals.org
Appendix Table 2. Summary Data on Whether Participants Regularly Attended Yoga Classes After the Intervention*
Variable Yoga Group Usual Care Group
Month 3
Attending a regular yoga class, n/n (%) 1/17 (6) 4/132 (3)
Not attending a regular yoga class, n/n (%) 16/17 (94) 128/132 (97)
Mean classes attended over past 12 wk (SD), n7.14 (3.70) 3.50 (3.89)
Median classes attended over past 12 wk (range), n7.50 (1.00–12.00) 3.00 (0.00–8.00)
Missing (did not provide attendance data at 3 mo), n† 119 9
Month 6
Attending a regular yoga class, n/n (%) 19/125 (15) 5/134 (4)
Not attending a regular yoga class, n/n (%) 106/125 (85) 129/134 (96)
Mean classes attended over past 12 wk (SD), n5.52 (4.17) 3.80 (5.90)
Median classes attended over past 12 wk (range), n5.00 (0.00–12.00) 1.50 (0.00–18.00)
Missing (did not provide attendance data at 6 mo), n†13 3
Month 12
Attending a regular yoga class, n/n (%) 11/126 (9) 7/136 (5)
Not attending a regular yoga class, n/n (%) 115/126 (91) 129/136 (95)
Mean classes attended over past 12 wk (SD), n9.89 (10.24) 5.53 (7.23)
Median classes attended over past 12 wk (range), n10.00 (0.00–30.00) 1.00 (0.00–20.00)
Missing (did not provide attendance data at 12 mo), n†9 4
*Only self-reported postintervention class attendance is summarized.
†These participants completed the questionnaires but did not provide the attendance data; 36, 38, and 38 participants did not complete the 3-, 6-, and 12-month
questionnaires, respectively.
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