The correlation of duration of cervical flexion per day with  neck disability index scores in office workers: a cross sectional study

Abstract Background: An increasing number of office workers complain of neck pain after extended smart phone use. We conducted this study to examine the correlation between the duration of cervical flexion per day (DCF) during smart phone use and neck disability index scores (NDI) scores of office workers in China.Methods: In this cross-sectional study, 1791 individuals responded to an on line questionnaire. For our study, we included responses of 498 [27.8%] office workers. Excluded from the study were 1293 [72.9%] individuals including building workers, students, non-office workers, and those who did not complete the questionnaire. Participants completed an online questionnaire survey from May 29, 2019 to April 10, 2020. The NDI scores were used to evaluate cervical symptoms. Liner regression, threshold saturation effect analysis, t-test, and Pearson’s chi-square tests were used to analyze the data. Results: We analyzed questionnaire results of the 498 office workers. The t-test showed no significant differences among the gender groups for age, working age, and NDI scores (P>0.05).] while low back pain had a strong correlation with NDI scores [β (95%CI):2.40 (1.49, 3.31), P <0.0001]. When adjusting for age, working age, and low back pain covariates, DCF had a positive correlation with NDI scores. In addition, DCF had a curve line correlation with NDI scores-a monotone increasing relationship; the fold point was 6 (P<0.05).Conclusions: DCF had a positive curve line correlation with the NDI scores suggesting that office workers should limit DCF to a maximum of 6 hours to decrease NDI scores.