Susan Ferry

Estimating the prevalence of low back pain in the general population. Evidence from the South Manchester Back Pain Survey.

Study Design This report gives the results of a population-based cross-sectional mailed questionnaire, with prospective follow-up of survey responders and nonresponders. Objective To determine the 1-month period prevalence of low back pain in an adult population in the United Kingdom and to estimate the effect of nonresponse bias. Summary of Background Data Previous United Kingdom population studies have reported a 1-year period prevalence of low back pain of 37%. However, the definitions of low back pain have varied, and the influence of nonresponse rarely has been reported. Methods The study population was made up of all 7669 adults (18 to 75 years old) registered with two family practices in a sociodemographically mixed suburban area. The questionnaire, including a pain drawing to identify the site of any pain, was mailed to the entire study population. Two repeat mailings were sent to nonresponders. Family practice consultations about low back pain by individuals from the study population were monitored over the following 12 months using computerized records of all surgery contacts. Results Of the study population, 4501 (59%) responded. The 1-month period prevalence of low back pain was 39% (35% in males, 42% in females). The age distribution was unimodal, with peak prevalence in those aged 45 to 59 years old. Responders to the first mailing had a small but nonsignificant increase in prevalence compared with those who responded to the second or third mailing. Nonresponders had a subsequent consultation rate for low back pain that was 22% lower than that for the survey responders. Conclusions After considering potential differences in nonresponders, the estimated 1-month prevalence of low back pain was between 35% and 37%. Prevalence figures in survey responders may overestimate the true population prevalence by a modest amount.

Psychologic distress and low back pain. Evidence from a prospective study in the general population.

Study Design The present is a prospective population-based cohort study. Objectives To determine whether psychologic distress in patients free of low back pain predicts future new episodes of such pain. Summary of Background Data An association between symptoms of depression and anxiety and low back pain has been described in cross-sectional studies. It is unclear whether this represents cause or effect or whether it is found only in chronic pain sufferers attending specialist clinics. There is a need to investigate this prospectively in the general population. Methods The study population was 4501 adults aged 18–75 years who responded to a questionnaire survey mailed to all those registered with two family practices in the United Kingdom. The survey inquired about low back pain during the previous month and included the 12-item General Health Questionnaire, a validated schedule for measuring psychologic distress in the general population. New episodes of low back pain during the 12 months after the survey were identified by two methods-continuous monitoring of all primary care consulters and a second postal survey at the end of the 12-month period to determine occurrences for which consultation had not been sought. Results Among 1638 subjects free of current low back pain in the baseline survey, the likelihood of developing a new episode of nonconsulting low back pain was higher among those with General Health Questionnaire scores in the upper third of the range compared with the lower third (adjusted odds ratio, 1.8[1.4, 2.4]). This could not be explained either by age and gender differences or by general physical health. The increased risk persisted when analysis was restricted to those who at baseline could not recall ever having had low back pain in the past and to those with full-time employment. Conclusion Symptoms of psychologic distress in individuals without back pain predict the subsequent onset of new episodes of low back pain. We calculate from these data that the proportion of new episodes of low back pain that might be attributable to such psychologic factors in the general population is 16%.

Influence of previous pain experience on the episode incidence of low back pain: results from the South Manchester Back Pain Study.

Background: A pathological cause cannot be identified for most new episodes of low back pain (LBP) presenting to the general practitioner. One important potential influence on susceptibility is previous pain experience. To accurately investigate the contribution of this phenomenon to the onset of new episodes of LBP a prospective population study is required. Aims: To determine the relationship of prior pain in the back and other musculoskeletal sites to risk of subsequent new episodes of LBP. Methods: The population studied included all 2715 adults from the South Manchester Back Pain Study who were free of LBP during the month prior to the baseline survey. At baseline a detailed musculoskeletal pain history was obtained. New episodes of LBP over the subsequent 12 months were ascertained by: (i) prospectively monitoring all primary care consultations in the study cohort (consulting episodes) and (ii) a follow‐up survey after 1 year to determine new episodes during that 12‐month period not leading to consultation (non‐consulting episodes). Results: The 12‐month cumulative incidence of new consulting episodes was 3% in males and 5% in females, and for new non‐consulting episodes 31% in males and 32% in females. Those with a history of previous LBP had twice the rate of new episodes, both consulting and non‐consulting, compared to those with no LBP in the past. Neck pain or pain in other musculoskeletal sites at baseline also doubled the risk of a subsequent new episode of LBP. Adjusting for psychological distress and the other pain variables had little influence on the findings. Conclusion: In those currently free of LBP a previous history of the symptom substantially increases the risk of a further episode, with pain in other sites an equally strong independent predictor of subsequent LBP.

The association between different patterns of hand symptoms and objective evidence of median nerve compression: A community-based survey

OBJECTIVE To examine the association between different patterns of hand symptoms and the presence of delayed nerve conduction in the general population. METHODS We performed a 2-stage screening survey involving a questionnaire on current hand symptoms, and nerve conduction testing in samples of subjects with and without symptoms. Of 648 respondents to the symptom questionnaire, 212 reported hand symptoms. In all, 155 were tested for nerve conduction of sensory and motor median nerve latencies, including 40 who had reported no symptoms. Patterns of hand symptoms were compared with nerve conduction results and associations weighted back to the general population. RESULTS The presence of any hand symptoms had only a 40% sensitivity for delayed nerve conduction on latency testing. The presence of typical symptoms of carpal tunnel syndrome had a much lower sensitivity. CONCLUSION In a community setting, the distribution of hand symptoms does not usefully correlate with the presence of delayed nerve conduction in the median nerve.