Background and aims
The prevalence of chronic pain is about 20% in general populations. One of the most common pain sites is chronic low back pain (CLBP).
Our aim was to investigate whether CLBP is most prevalent as a localized pain or as part of chronic widespread pain (CWP), and to determine whether an association to pain spread explains the burden of CLBP. 
Methods
This study uses the cross-sectional (year 2016) material from a Swedish population cohort, started in 1996. It includes 1184 respondents to a questionnaire, regarding pain, Quality of life (SF-36), medication, healthcare consumption and sick leave.
Results
The prevalence of CLBP as local pain was 10% (95% CI: 8.6 ; 12.0), and 15% as part of CWP (95% CI: 12.8 ; 16.9). That is, of those having CLBP 60% also had widespread pain.
Low physical status (SF-36) and high drug use was associated both with having CLBP and with increasing number of pain site. Low mental statues (SF-36) and high health care use were only associated with increasing number of pain site. Those with CLBP and those without were close in these measures. 
Conclusion
Chronic low back pain was prevalent both as a local pain and in connection with widespread pain. Both the spread of pain and the presence of chronic low back pain explained low physical function and drug use. However, low mental statues and high health care use was explained by the spread of pain, and not by the presence of chronic low back pain.

IS THE HIGH BURDEN IN CHRONIC LOW BACK PAIN IN FACT RELATED TO PRESENCE OF CHRONIC WIDESPREAD PAIN?