Appendix 1. CENTRAL Search Strategy

#1    MeSH descriptor Neck Pain explode all trees
#2    neck pain
#3    (#1 OR #2)
#4    MeSH descriptor Workplace explode all trees
#5    workplace
#6    worksite
#7    MeSH descriptor Sick Leave explode all trees
#8    sick leave
#9    (#4 OR #5 OR #6 OR #7 OR #8)

Appendix 2. MEDLINE Search Strategy

1    randomized controlled trial.pt.
2    controlled clinical trial.pt.
3    randomized.ab.
4    placebo.ab,ti.
5    drug therapy.fs.
6    randomly.ab,ti.
7    trial.ab,ti.
8    groups.ab,ti.
9    or/1‐8
10  (animals not (humans and animals)).sh.
11  9 not 10
12  neck muscles.sh.
13  exp Neck/
14  exp neck pain/
15  whiplash injuries.sh.
16  neck.ti,ab.
17  exp Musculoskeletal System/
18  musculoskeletal disorder$.mp.
19  or/12‐18
20  11 and 19
21  exp Workplace/
22  exp Sick Leave/
23  exp Work/
24  or/21‐23
25  24 and 20

Appendix 3. EMBASE Search Strategy

1    Clinical Article/
2    exp Clinical Study/
3    Clinical Trial/
4    Controlled Study/
5    Randomized Controlled Trial/
6    Major Clinical Study/
7    Double Blind Procedure/
8    Multicenter Study/
9    Single Blind Procedure/
10  Phase 3 Clinical Trial/
11  Phase 4 Clinical Trial/
12  crossover procedure/
13  placebo/
14  or/1‐13
15  allocat$.mp.
16  assign$.mp.
17  blind$.mp.
18  (clinic$ adj25 (study or trial)).mp.
19  compar$.mp.
20  control$.mp.
21  cross?over.mp.
22  factorial$.mp.
23  follow?up.mp.
24  placebo$.mp.
25  prospectiv$.mp.
26  random$.mp.
27  ((singl$ or doubl$ or trebl$ or tripl$) adj25 (blind$ or mask$)).mp.
28  trial.mp.
29  (versus or vs).mp.
30  or/15‐29
31  14 and 30
32  human/
33  Nonhuman/
34  exp ANIMAL/
35  Animal Experiment/
36  33 or 34 or 35
37  32 not 36
38  31 not 36
39  37 and 38
40  38 or 39
41  neck muscles.mp.
42  exp NECK/
43  whiplash injuries.mp.
44  neck.mp.
45  exp neck pain/
46  exp neck muscle/
47  musculoskeletal disorder$.mp.
48  or/41‐47
49  40 and 48
50  exp workplace/
51  worksite.mp.
52  sick leave.mp. or exp medical leave/
53  or/50‐52
54  53 and 49

Appendix 4. CINAHL Search Strategy

S37 S31 and S36
S36 S32 or S33 or S34 or S35
S35 (MH "Sick Leave")
S34 (MH "Work Environment+")
S33 "worksite"
S32 "workplace"
S31 S23 and S30
S30 S24 or S25 or S26 or S27 or S28 or S29
S29 "musculoskeletal disorder*"
S28 (MH "Whiplash Injuries")
S27 (MH "Cervical Vertebrae")
S26 (MH "Neck Pain")
S25 (MH "Neck")
S24 ("neck muscles") or (MH "Neck Muscles+")
S23 S21 not S22
S22 (MH "Animals+")
S21 S20 or S19 or S18 or S17 or S16 or S15 or S14 or S13 or S12 or S11 or S10 or S9 or S8 or S7 or S6 or S5 or S4 or S3 or S2 or S1
S20 "volunteer*"
S19 prospectiv*
S18 "control*"
S17 "follow‐up stud*"
S16 (MH "Prospective Studies+")
S15 (MH "Evaluation Research+")
S14 (MH "Comparative Studies")
S13 "latin square"
S12 (MH "Study Design+")
S11 (MH "Random Sample+")
S10 "random*"
S9    "placebo*"
S8    (MH "Placebos")
S7    (MH "Placebo Effect")
S6    "triple‐blind"
S5    "single‐blind"
S4    "double‐blind"
S3    ""clinical W8 trial""
S2    "randomi?ed controlled trial*"
S1    (MH "Clinical Trials+") 

Appendix 5. PsycInfo Search Strategy

((KW=(Randomi?ed controlled trial*) OR KW=(clinical trial*) OR KW=(clin* near trail*) OR KW= (sing* near blind*) OR KW=(sing* near mask*) OR (doub* near blind*) OR KW=(doubl* NEAR mask*) OR KW=(trebl* near mask*) OR KW=(trebl* near mask*) OR KW=(tripl* near blind*) OR KW=(tripl* near mask*) OR KW=(placebo*) OR KW=(random*) OR DE=(research design) OR KW=(Latin square) OR KW=(comparative stud*) OR KW=(evaluation stud*) OR KW=(follow up stud*) OR DE=(prospective stud*)OR KW=(control*) OR KW=(prospective*) OR KW=(volunteer*)) AND DE=(neck)) and (KW=(workplace or worksite or (sick leave)))

Appendix 6. ISI Web of Science Search Strategy

# 23     #22 AND #17
# 22     #21 OR #20 OR #19 OR #18
# 21     Topic=(sickness absence)
# 20     Topic=(sick leave)
# 19     Topic=(worksite)
# 18     Topic=(workplace)
# 17     #16 AND #12
# 16     #15 OR #14 OR #13
# 15     Topic=(neck* pain)
# 14     Topic=(musculosk* disorder*)
# 13     Topic=(musculosk* syst*)
# 12     #11 OR #10 OR #9 OR #8 OR #7 OR #6 OR #5 OR #4 OR #3 OR #2 OR #1
# 11     Topic=(prospective stud*)
# 10     Topic=(follow up stud*)
# 9       Topic=(controlled trial)
# 8       Topic=(comparative stud*)
# 7       Topic=(research design)
# 6       Topic=(controlled clinical trial)
# 5       Topic=(random*)
# 4       Topic=(placebo*)
# 3       Topic=(clinical trial*)
# 2       Topic=(double blind*)
# 1       Topic=(single blind*)

Appendix 7. OTseeker (Occupational Therapy Systematic review of Evidence)

Keywords: work OR worksite OR workplace
Diagnosis/Subdiscipline: Musculoskeletal or connective tissue injuries/ disorders/ procedures
Method: Clinical Trial

Appendix 8. PEDro (The Physiotherapy Evidence database)

Abstract & Title: work
Body Part: head or neck
Subdiscipline: musculoskeletal
Method: clinical trial
Match all search terms (AND)

Appendix 9. Criteria for risk of bias assessment for RCTs

1. Was the method of randomisation adequate? A random (unpredictable) assignment sequence. Examples of adequate methods are coin toss (for studies with two groups), rolling a dice (for studies with two or more groups), drawing of balls of different colours, drawing of ballots with the study group labels from a dark bag, computer‐generated random sequence, pre‐ordered sealed envelops, sequentially‐ordered vials, telephone call to a central office, and pre‐ordered list of treatment assignments

Examples of inadequate methods are: alternation, birth date, social insurance/security number, date in which they are invited to participate in the study, and hospital registration number

2. Was the treatment allocation concealed? Assignment generated by an independent person not responsible for determining the eligibility of the patients. This person has no information about the persons included in the trial and has no influence on the assignment sequence or on the decision about eligibility of the patient.

Was knowledge of the allocated interventions adequately prevented during the study?
3. Was the patient blinded to the intervention?
This item should be scored “yes” if the index and control groups are indistinguishable for the patients or if the success of blinding was tested among the patients and it was successful. 

4. Was the care provider blinded to the intervention? This item should be scored “yes” if the index and control groups are indistinguishable for the care providers or if the success of blinding was tested among the care providers and it was successful 

5. Was the outcome assessor blinded to the intervention? Adequacy of blinding should be assessed for the primary outcomes.  This item should be scored  “yes” if the success of blinding was tested among the outcome assessors and it was successful or:

• for patient‐reported outcomes in which the patient is the outcome assessor (e.g., pain, disability): the blinding procedure is adequate for outcome assessors if participant blinding is scored “yes”

• for outcome criteria assessed during scheduled visit and that supposes a contact between participants and outcome assessors (e.g., clinical examination): the blinding procedure is adequate if patients are blinded, and the treatment or adverse effects of the treatment cannot be noticed during clinical examination

• for outcome criteria that do not suppose a contact with participants (e.g., radiography, magnetic resonance imaging): the blinding procedure is adequate if the treatment or adverse effects of the treatment cannot be noticed when assessing the main outcome

• for outcome criteria that are clinical or therapeutic events that will be determined by the interaction between patients and care providers (e.g., co‐interventions, hospitalisation length, treatment failure), in which the care provider is the outcome assessor: the blinding procedure is adequate for outcome assessors if item “4” is scored “yes”

• for outcome criteria that are assessed from data of the medical forms: the blinding procedure is adequate if the treatment or adverse effects of the treatment cannot be noticed on the extracted data

Were incomplete outcome data adequately addressed?
6. Was the drop‐out rate described and acceptable? The number of participants who were included in the study but did not complete the observation period or were not included in the analysis must be described and reasons given. If the percentage of withdrawals and drop‐outs does not exceed 20% for short‐term follow‐up and 30% for long‐term follow‐up and does not lead to substantial bias a 'yes' is scored. (N.B. these percentages are arbitrary, not supported by literature).

7. Were all randomised participants analysed in the group to which they were allocated? All randomised patients are reported/analysed in the group they were allocated to by randomisation for the most important moments of effect measurement (minus missing values) irrespective of non‐compliance and co‐interventions.   

8. Are reports of the study free of suggestion of selective outcome reporting? In order to receive a ‘yes’, the review author determines if all the results from all pre‐specified outcomes have been adequately reported in the published report of the trial.  This information is either obtained by comparing the protocol and the report, or in the absence of the protocol, assessing that the published report includes enough information to make this judgment.

Other sources of potential bias:
9.  Were the groups similar at baseline regarding the most important prognostic indicators? In order to receive a “yes”, groups have to be similar at baseline regarding demographic factors, duration and severity of complaints, percentage of patients with neurological symptoms, and value of main outcome measure(s).

10. Were co‐interventions avoided or similar? This item should be scored “yes” if there were no co‐interventions or they were similar between the index and control groups.

11. Was the compliance acceptable in all groups? The reviewer determines if the compliance with the interventions is acceptable, based on the reported intensity, duration, number and frequency of sessions for both the index intervention and control intervention(s). For example, physiotherapy treatment is usually administered over several sessions; therefore it is necessary to assess how many sessions each patient attended. For single‐session interventions (for ex: surgery), this item is irrelevant.

12. Was the timing of the outcome assessment similar in all groups? Timing of outcome assessment should be identical for all intervention groups and for all important outcome assessments.

Appendix 10. Questions to determine clinical relevance

1. Are the patients described in detail so that you can decide whether they are comparable to those that you see in your practice?

2. Are the interventions and treatment settings described well enough so that you can provide the same for your patients?

3. Were all clinically relevant outcomes measured and reported?

4. Is the size of the effect clinically important?

5. Are the likely treatment benefits worth the potential harms?