Patterns of multisite pain and associations with risk factors.

To explore definitions for multisite pain, and compare associations with risk factors for different patterns of musculoskeletal pain, we analysed cross-sectional data from the Cultural and Psychosocial Influences on Disability (CUPID) study. The study sample comprised 12,410 adults aged 20-59 years from 47 occupational groups in 18 countries. A standardised questionnaire was used to collect information about pain in the past month at each of 10 anatomical sites, and about potential risk factors. Associations with pain outcomes were assessed by Poisson regression, and characterised by prevalence rate ratios (PRRs). Extensive pain, affecting 6-10 anatomical sites, was reported much more frequently than would be expected if the occurrence of pain at each site were independent (674 participants vs 41.9 expected). In comparison with pain involving only 1-3 sites, it showed much stronger associations (relative to no pain) with risk factors such as female sex (PRR 1.6 vs 1.1), older age (PRR 2.6 vs 1.1), somatising tendency (PRR 4.6 vs 1.3), and exposure to multiple physically stressing occupational activities (PRR 5.0 vs 1.4). After adjustment for number of sites with pain, these risk factors showed no additional association with a distribution of pain that was widespread according to the frequently used American College of Rheumatology criteria. Our analysis supports the classification of pain at multiple anatomical sites simply by the number of sites affected, and suggests that extensive pain differs importantly in its associations with risk factors from pain that is limited to only a small number of anatomical sites.

Clinical presentation of low back pain and association with risk factors according to findings on magnetic resonance imaging.

We hypothesised that the relative importance of physical and psychological risk factors for mechanical low back pain (LBP) might differ importantly according to whether there is underlying spinal pathology, psychological risk factors being more common in patients without demonstrable pathology. If so, epidemiological studies of LBP could benefit from tighter case definitions. To test the hypothesis, we used data from an earlier case-control study on patients with mechanical LBP who had undergone magnetic resonance imaging (MRI) of the lumbosacral spine. MRI scans were classified for the presence of high-intensity zone (HIZ), disc degeneration, disc herniation, and nerve root displacement/compression. Information about symptoms and risk factors was elicited by postal questionnaire. Logistic regression was used to assess associations of MRI abnormalities with symptoms and risk factors, which were characterised by odds ratios (ORs) and 95% confidence intervals (CIs). Among 354 patients (52% response), 306 (86.4%) had at least 1, and 63 (17.8%) had all 4 of the MRI abnormalities. Radiation of pain below the knee (280 patients) and weakness or numbness below the knee (257 patients) were both associated with nerve root deviation/compression (OR 2.5, 95% CI 1.4 to 4.5; and OR 1.8, 95% CI 1.1 to 3.1, respectively). However, we found no evidence for the hypothesised differences in risk factors between patients with and without demonstrable spinal pathology. This suggests that when researching the causes and primary prevention of mechanical LBP, there may be little value in distinguishing between cases according to the presence or absence of the more common forms of potentially underlying spinal pathology.

Case-control study of low-back pain referred for magnetic resonance imaging, with special focus on whole-body vibration.

OBJECTIVES: This study investigated risk factors for low-back pain among patients referred for magnetic resonance imaging (MRI), with special focus on whole-body vibration. METHODS: A case-control approach was used. The study population comprised working-aged persons from a catchment area for radiology services. The cases were those in a consecutive series referred for a lumbar MRI because of low-back pain. The controls were age- and gender-matched persons X-rayed for other reasons. Altogether, 252 cases and 820 controls were studied, including 185 professional drivers. The participants were questioned about physical factors loading the spine, psychosocial factors, driving, personal characteristics, mental health, and certain beliefs about low-back pain. Exposure to whole-body vibration was assessed by six measures, including weekly duration of professional driving, hours driven in one period, and current root mean square A(8). Associations with whole-body vibration were examined with adjustment for age, gender, and other potential confounders. RESULTS: Strong associations were found with poor mental health and belief in work as a causal factor for low-back pain, and with occupational sitting for > or =3 hours while not driving. Associations were also found for taller stature, consulting propensity, body mass index, smoking history, fear-avoidance beliefs, frequent twisting, low decision latitude, and low support at work. However, the associations with the six metrics of whole-body vibration were weak and not statistically significant, and no exposure-response relationships were found. CONCLUSIONS: Little evidence of a risk from professional driving or whole-body vibration was found. Drivers were substantially less heavily exposed to whole-body vibration than in some earlier surveys. Nonetheless, it seems that, at the population level, whole-body vibration is not an important cause of low-back pain among those referred for MRI.

In a randomized study of envelope and ink color, colored ink was found to increase the response rate to a postal questionnaire.

OBJECTIVE: To assess the effect of the colors of the envelope and ink on the response rate to a postal questionnaire in a study screening for undiagnosed parkinsonism in people aged 65 years and over in the community. STUDY DESIGN AND SETTING: A total of 2,524 people aged 65 years and over from five general practices in Aberdeen were randomized to receive a questionnaire about the symptoms of parkinsonism printed in either colored (green) or black ink, and sent out in either a brown or white envelope. RESULTS: The overall response rate was 63.5%. There was no significant interaction between envelope and ink color. The use of green ink compared to black significantly increased the response rate from 61.4% to 65.7% (OR 1.20, 95% confidence interval 1.02, 1.41). There was no overall effect of envelope color on response rate (62.3% brown and 64.8% white, OR 0.90, 95% confidence interval 0.76, 1.06) but there was significant heterogeneity between the general practices. When this general practice-envelope interaction was accounted for, brown envelopes had a significantly lower response rate than white ones (OR 0.49). CONCLUSION: This study, along with existing evidence, has shown that the use of certain ink colors in postal questionnaires is likely to increase response rates relative to black ink. The effect of envelope color was inconsistent both within this study and between previous studies.

Pilot study of the incidence and prognosis of degenerative Parkinsonian disorders in Aberdeen, United Kingdom: methods and preliminary results.

The objective of this study was to test the methods for a large study of the incidence and prognosis of Parkinson's disease and other degenerative parkinsonian disorders and provide provisional incidence figures. This was a community-based prospective study to identify patients with newly diagnosed non-drug-induced Parkinsonism (>or=2 of tremor, rigidity, bradykinesia, postural instability) from a population of 148,600 people in Aberdeen, Scotland, over 18 months. Multiple search strategies were used to identify patients, including some population screening. Incident patients and age/sex-matched controls had assessments of impairment, disability, quality of life, mood, and cognition and are being followed up yearly. Two hundred and two people with possible parkinsonian symptoms were assessed, and 82 incident patients were identified, 50 with probable Parkinson's disease. The crude incidences of probable Parkinsonism and probable Parkinson's disease were 31.4/100,000/year (95% CI: 24.5-39.7) and 22.4/100,000/year (95% CI: 16.6-29.6), respectively. The mean age of diagnosis of Parkinson's disease was 76.1 +/- 10.0 years and the incidence was greater in men. The methods were generally successful. Provisionally, we found a higher incidence of Parkinson's disease than other comparable studies, and our patients were considerably older. This may reflect better case ascertainment in the elderly. A larger study is planned.