Are neck flexion, neck rotation, and sitting at work risk factors for neck pain?
From: Occup. Environ. Med. 2001;58;200-207
Objective: To study the relation between neck pain and work related neck flexion, neck rotation, and sitting.
Methods: A prospective cohort study was performed with a follow up of 3 years among 1334 workers from 34 companies. Work related physical load was assessed by analysing objectively measured exposure data of neck flexion, neck rotation, and sitting posture. Neck pain was assessed by a questionnaire. Adjustments were made for various physical factors that were related or not related to work, psychosocial factors, and individual characteristics.
Results: significant positive relation was found between the percentage of the working time in a sitting position and neck pain, implying an increased risk of neck pain for workers who were sitting for more than 95% of the working time. A trend for a positive relation between neck flexion and neck pain was found, suggesting an increased risk of neck pain for people working with the neck at aminimum of 20° of flexion for more than 70% of the working time. No clear relation was found between neck rotation and neck pain.
Conclusion: Sitting at work for more than 95% of the working time seems to be a risk factor for neck pain and there is a trend for a positive relation between neck flexion and neck pain. No clear relation was found between neck rotation and neck pain.
Neck pain is a major health problem in modern society. Prevalence data have shown that in a general population the 1 year prevalence of neck pain can be as high as 40%, the prevalence for women being slightly higher. One year prevalences in occupational settings showed values varying between 6% and 76%, also with higher values for female workers.
Neck pain is assumed to be of multifactorial origin, implying that several risk factors can contribute to its development. Most studies which are reported in the literature focus on only one or a few risk factors. Moreover, most studies on risk factors for neck pain are of cross sectional design, which makes it difficult to formulate any conclusion about the temporal relation between risk factors and neck pain.
Among the many different putative risk factors for neck pain, work related physical risk factors may play a major part. Most studies on work related physical risk factors have collected information on exposure by questionnaires which are filled in by the workers. However, to validly measure the physical load at work, the duration and frequency of certain postures need to be assessed objectively.
There seems to be consensus that potentially the main physical risk factors for neck pain are static postures and repetitive movements of the neck (neck flexion), static posture and repetitive or forceful movements of the arm, and a sitting posture at work.
The purpose of this study is to assess the longitudinal relation between neck pain and three physical risk factors related to work, neck flexion, neck rotation, and sitting posture. To our knowledge this is the first prospective cohort study in which this relation has been assessed on the basis of objectively measured exposure data, and in which the potential confounding effect of various psychosocial factors, physical factors not related to work, and individual characteristics has been taken into account.
Main Points
- There is a significant positive association between prolonged sitting at work and neck pain, implying that there is an increased risk of neck pain for people who are working almost all day in a sitting position (more than 95% of the working time). Due to the prospective study design and thorough adjustment for confounding, it can be concluded that this relation between sitting posture and neck pain is probably a causal relation.
- There is a positive trend for an association between neck pain and neck flexion at work, although not significant, suggesting that there is an increased risk of neck pain for people who are working with the neck flexed more than 20° for a major part of their working day. A low endurance time of the neck muscles seems to play an important part in the development of neck pain due to neck flexion at work.
- No clear relation was found between neck rotation at work and neck pain.
- Based on the results of this study, prevention of neck pain should focus on the reduction of time spent working in a sitting position and the promotion of more dynamic working postures.
