Oliveira C.B.1, Franco M.R.1, Demarchi S.J.1, Morelhão P.K.1, Hisamatsu T.M.1, Teixeira R.D.J.1, Pinto R.Z.1
1São Paulo State University (UNESP), Physical Therapy Department, Presidente Prudente, Brazil
Background: Low back pain (LBP) is a prevalent musculoskeletal condition that imposes an enormous economic burden for general society and causes functional impairment for people. Sedentary behavior may be a risk factor for developing LBP. In addition, the sedentary behavior increases the risk of cardiovascular diseases and depression in adults. Sitting time is considered a sedentary activity that increases intradiscal load and weakened lumbar structures, however no previous study investigated the association of this behavior with pain and disability in patients with non-specific chronic LBP.
Purpose: To investigate the association of sitting time with pain and disability in patients with non-specific chronic LBP.
Methods: One-hundred-fifty patients with chronic non-specific LBP were included. Participants aged from 18 to 60 years and report moderate intensity LBP or interference with function as measured by items 7 or 8 of the 36-Item Short Form Health Survey were considered eligible. At the baseline assessment, the following information were collected: demographic and anthropometric data, symptoms duration, pain intensity (11-point numerical rating scale), disability (Roland Morris Disability Questionnaire) and sitting time (hours per week-days and hours per weekend-days - questions 5a and 5b from International Physical Activity Questionnaire). In a subsample of 100 participants, the sitting time showed good to excellent reliability (Intraclass Correlation Coefficient2,1= 0.79 95% Confidence Interval(CI): 0.71 to 0.85). Univariate and multivariable linear regression analyses were conducted separately with pain and disability as dependent variables, sitting time as independent variable, and sex, age and BMI as covariates in the multivariable models. Potential candidate variables for multivariable models were identify using p≤0.25 as criterion in the univariate models. P value of 0.05 was set as criterion for the final multivariable models.
Results: The sample with 150 patients with chronic LBP was nearly two thirds female and had a mean (standard deviation) of 39 (11.5) years with median [interquartile range] symptom duration of 42 [6 to 48] months. Univariate analyses demonstrated that sex and age were associated with pain and age, BMI and sitting time on week-days (β= -0.005, 95% CI: -0.008 to -0.001, p = 0.01) were associated with disability. Variables associated with the dependent variables were included in the multivariate models. In the final model for pain and disability as dependent variable, only age remained explaining 3% and 11% of the variance, respectively, after elimination of non-significant variables.
Conclusion(s): Weekday hours on sitting time was negatively associated with disability, but not with pain. However, sitting time did not remained in the multivariable model. Future studies should be conducted using objective measures to quantify sedentary time.
Implications: Our study showed that sitting time was not cross-sectionally associated with the clinical outcomes, suggesting that pain intensity and disability levels do not alter the sedentary lifestyle of patients with chronic LBP. Further longitudinal studies should be conducted investigating the prognostic role of sitting time for pain and disability in patients with chronic LBP.
Funding acknowledgements: Supported by the São Paulo Research Foundation (grant nos. 2016/03826-5, 2015/17093-7, 2015/07704-9, 2015/02744-2, and 2014/14077-8).
Topic: Musculoskeletal: spine
Ethics approval: This study was approved by the Ethics Committee of the São Paulo State University, Brazil (CAAE36332514.0.0000.5402).
All authors, affiliations and abstracts have been published as submitted.
