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KSR Number: KSRA14808

Leisure-time physical activity and sciatica: a systematic review and meta-analysis

Risk of Bias Assessment

Overall summary: Risk of bias unclear

Bottom Line

The available evidence suggests that a moderate to high level of leisure-time physical activity reduces the risk of developing lumbar radicular pain. Appropriate efforts were not made to minimise errors in the study selection process. The authors did not state whether the data extraction was undertaken in duplicate, so reviewer error and bias could not be ruled out. The results should be interpreted cautiously due to high heterogeneity between the studies.

Risk of Bias Assessment

Overall summary Risk of bias unclear

Unclear

The authors had acknowledged that the selection of studies was carried out by a single reviewer and heterogeneity of clinical outcomes. No information was provided regarding the number of authors involved in the data extraction process.

A. Did the interpretation of findings address all of the concerns identified in Domains 1 to 4? No information
B. Was the relevance of identified studies to the review's research question appropriately considered? Probably yes
C. Did the reviewers avoid emphasizing results on the basis of their statistical significance? Probably yes
Risk of bias in the review Unclear

Details of Review

Number of studies 18
Number of participants 101,420
Last search date August 2015
Review type Aetiological
Objective To evaluate the association of moderate and high levels of leisure-time physical activity with lumbar radicular pain and clinically verified sciatica.
Population General population, nurses, former elite athletes (a member of the national team, various sports), and eligible men for military service.

Cases: patients with lumbar disc herniation and hospitalised due to sciatica .

Controls: patients participated in routine health examination or inpatients.
Outcome Lumbar radicular pain (low back pain radiating down the lower limb) and clinically verified sciatica (lumbar radicular pain that is accompanied by physical signs or radiographic evidence of herniated disc or nerve root impingement).
Study design Cross-sectional studies, case control studies (both population-based and hospital-based) and cohort studies.
Exposure Physically active (at least once a week), moderate level of physical activity (one to three times a week) or high level of physical activity (four to seven times per week).

Results

The pooled analysis of cross-sectional studies reported that a higher prevalence of lumbar radicular pain or sciatica was observed in participants who exercised at least once a week (prevalence ratio (PR) = 1.29, 95% confidence interval (CI) 1.09 to 1.53; four studies, n = 10,046 participants), or who exercised one to three times a week (moderate) (PR = 1.34, 95% CI 1.02 to 1.77; two studies, n = 7,631 participants) when compared to inactive participants. Four case control studies showed a non-significant association between leisure-time physical activity for at least once a week and clinically verified sciatica (pooled odds ratio = 0.80, 95% CI 0.58 to 1.08, n = 9,350 participants).

A meta-analysis of two cross-sectional studies showed a higher prevalence of lumbar radicular pain or sciatica in moderately active participants compared with inactive. Whereas a meta-analysis of six prospective cohort studies showed an inverse, but non-significant association between moderate level of physical activity and lumbar radicular pain or sciatica. Similar results were observed in a subgroup analysis of six studies

Meta-analysis of two cross-sectional studies indicated a higher prevalence of lumbar radicular pain or sciatica, but non-significant in highly active participants than in inactive participants. Whereas meta-analysis of seven prospective cohort studies reported that high level of leisure-time physical activity (≥four times per week) was inversely associated with lumbar radicular pain or sciatica compared to no regular physical activity (risk ratio (RR) = 0.88, 95% CI 0.78 to 0.99, n = 78,065 participants).

The association of leisure-time physical activity for at least once a week (RR = 0.99, 95% CI 0.86 to 1.13, nine cohort studies, n = 73,008 participants) or leisure-time physical activity for one to three times a week (RR = 0.93, CI 0.82–1.05; six cohort studies, n = 69,049 participants) was non-significant with lumbar radicular pain or sciatica compared to inactive participants.

Full Risk of Bias Assessment

The eligibility criteria were well described and appeared appropriate to address the present review question. No restriction was reported based on study characteristics and sources of information.

1.1 Did the review adhere to pre-defined objectives and eligibility criteria? Probably yes
1.2 Were the eligibility criteria appropriate for the review question? Probably yes
1.3 Were eligibility criteria unambiguous? Probably yes
1.4 Were all restrictions in eligibility criteria based on study characteristics appropriate (e.g. date, sample size, study quality, outcomes measured)? Probably yes
1.5 Were any restrictions in eligibility criteria based on sources of information appropriate (e.g. publication status or format, language, availability of data)? Probably yes
Concerns regarding specification of study eligibility criteria Low

MEDLINE, EMBASE, Scopus, Web of Science, Google Scholar and ResearchGate databases (1964 to August 2015) were searched for relevant studies. The reference lists of included articles were searched for additional reports. The search strategy was reported in full and appeared to be adequate. The searches were not restricted to date, publication format or language. Only one reviewer was involved in the study selection process.

2.1 Did the search include an appropriate range of databases/electronic sources for published and unpublished reports? Probably yes
2.2 Were methods additional to database searching used to identify relevant reports? Probably yes
2.3 Were the terms and structure of the search strategy likely to retrieve as many eligible studies as possible? Probably yes
2.4 Were restrictions based on date, publication format, or language appropriate? Probably yes
2.5 Were efforts made to minimise error in selection of studies? Probably no
Concerns regarding methods used to identify and/or select studies High

No information was provided regarding the number of authors involved in the data extraction process. Sufficient study characteristics appear to have been extracted to allow interpretation of the results. Details of the confounders adjusted were provided. The study results were appropriately collected for the synthesis. Methodological quality of the included studies was assessed using appropriate criteria. Two reviewers were independently involved in the risk of bias assessment.

3.1 Were efforts made to minimise error in data collection? No information
3.2 Were sufficient study characteristics considered for both review authors and readers to be able to interpret the results? Probably yes
3.3 Were all relevant study results collected for use in the synthesis? Probably yes
3.4 Was risk of bias (or methodological quality) formally assessed using appropriate criteria? Probably yes
3.5 Were efforts made to minimise error in risk of bias assessment? Yes
Concerns regarding methods used to collect data and appraise studies Unclear

The synthesis included all eligible studies. The method of analysis was explained and appeared appropriate. There was significant evidence of heterogeneity among the studies. Residual heterogeneity existed even after performing the subgroup analysis. Publication bias was assessed using the funnel plots, Egger’s test and the trim-and-fill method. The quality of individual studies was considered in the synthesis.

4.1 Did the synthesis include all studies that it should? Probably yes
4.2 Were all pre-defined analyses reported or departures explained? Probably yes
4.3 Was the synthesis appropriate given the degree of similarity in the research questions, study designs and outcomes across included studies? Probably no
4.4 Was between-study variation minimal or addressed in the synthesis? Probably no
4.5 Were the findings robust, e.g. as demonstrated through funnel plot or sensitivity analyses? Probably yes
4.6 Were biases in primary studies minimal or addressed in the synthesis? Probably yes
Concerns regarding synthesis and findings High

Keywords

  • leisure
  • physical activity
  • sciatica