Drivers of international variation in prevalence of disabling low back pain: Findings from the Cultural and Psychosocial Influences on Disability study.

BACKGROUND: Wide international variation in the prevalence of disabling low back pain (LBP) among working populations is not explained by known risk factors. It would be useful to know whether the drivers of this variation are specific to the spine or factors that predispose to musculoskeletal pain more generally. METHODS: Baseline information about musculoskeletal pain and risk factors was elicited from 11 710 participants aged 20-59 years, who were sampled from 45 occupational groups in 18 countries. Wider propensity to pain was characterized by the number of anatomical sites outside the low back that had been painful in the 12 months before baseline ('pain propensity index'). After a mean interval of 14 months, 9055 participants (77.3%) provided follow-up data on disabling LBP in the past month. Baseline risk factors for disabling LBP at follow-up were assessed by random intercept Poisson regression. RESULTS: After allowance for other known and suspected risk factors, pain propensity showed the strongest association with disabling LBP (prevalence rate ratios up to 2.6, 95% CI: 2.2-3.1; population attributable fraction 39.8%). Across the 45 occupational groups, the prevalence of disabling LBP varied sevenfold (much more than within-country differences between nurses and office workers), and correlated with mean pain propensity index (r = 0.58). CONCLUSIONS: Within our study, major international variation in the prevalence of disabling LBP appeared to be driven largely by factors predisposing to musculoskeletal pain at multiple anatomical sites rather than by risk factors specific to the spine. SIGNIFICANCE: Our findings indicate that differences in general propensity to musculoskeletal pain are a major driver of large international variation in the prevalence of disabling low back pain among people of working age.

Stability of symptom patterns in Australian Gulf War veterans: 10-year longitudinal study.

OBJECTIVES: Previously we established that symptoms reported by 1990-1991 Gulf War veterans were correlated and exhibited a pattern with 3 factors (psychophysiological distress, somatic distress and arthroneuromuscular distress), and this pattern was similar to that observed in a military comparison group. In this follow-up study, we examined whether the patterns of symptomatology have changed over time. METHODS: Using data on 56 symptoms that was collected in 2000-2003 (wave 1) and 2011-2012 (wave 2) from an Australian cohort of Gulf War veterans (veterans) and a military comparison group, exploratory factor analysis was conducted and Tucker's Congruence Coefficient (TCC) was used to determine factor structure similarity across study groups and waves. RESULTS: The results showed that the 3 factors observed at wave 1 were still present at wave 2, and factor structures across study groups and study waves were fairly similar, with TCC ranging 0.86-0.92. Veterans consistently reported more symptoms across all 3 factors. Veterans' symptomatology specific to psychophysiological distress increased between waves 1 and 2 (ratio of means 1.15; 95% CI 1.07 to 1.25) but psychophysiological distress symptomatology was constant in the comparison group (ratio of means 0.97; 95% CI 0.89 to 1.06). Somatic and arthroneuromuscular distress symptomatology significantly increased over time for both study groups, although at a similar rate. CONCLUSIONS: While the symptom groupings (measured by the 3 factors) remained unchanged at 10 years of follow-up, and remained comparable between Gulf War and comparison group, symptomatology continued to be elevated in Gulf War veterans than in the comparison group, and was most evident for psychophysiological distress.

Major depression and depressive symptoms in Australian Gulf War veterans 20 years after the Gulf War.

BACKGROUND: Risk of major depression (depression) was elevated in Australia's Gulf War veterans in a 2000-2002 (baseline) study. A follow up study has measured the Gulf War-related risk factors for depression, also the current prevalence and severity of depression, use of anti-depressant medication, and persistence, remittance or incidence of depression since baseline in Gulf War veterans and a military comparison group. METHODS: Participants completed the Composite International Diagnostic Interview v.2.1, the 9-item Patient Health Questionnaire and the Military Service Experience Questionnaire, and consented to Repatriation Pharmaceutical Benefits Scheme (RPBS) and PBS linkage. RESULTS: Prevalence of depression (9.7% Gulf War veterans and 7.7% comparison group; adj RR=1.2, 95% CI 0.8-1.7), and pattern of persistence, remittance and incidence of depression since baseline, were similar in the two groups, however veterans reported slightly more severe symptoms (adj median difference 1, 95% CI 0.26-1.74) and were more likely to have been dispensed anti-depressant medication (adj RR=1.56, 95% CI 1.05-2.32). Depression amongst veterans was associated with self-reported Gulf War-related stressors in a dose-response relationship (adj RR 1.06, 95% CI 1.02-1.09). LIMITATIONS: Lower participation rates at follow up resulted in reduced statistical power compared with baseline, Gulf War related stressor data collected at baseline was at risk of recall bias, and RPBS and PBS databases do not capture all dispensed Nervous System medications. CONCLUSIONS: More than 20 years after the Gulf War, veterans are experiencing slightly more severe depressive symptoms than a military comparison group, and depression continues to be associated with Gulf War-related stressors.

A telephone survey of factors affecting willingness to participate in health research surveys.

BACKGROUND: In recent years, reduced participation has been encountered across all epidemiological study designs, both in terms of non-response as well as refusal. A low response rate may reduce the statistical power but, more importantly, results may not be generalizable to the wider community. METHODS: In a telephone survey of 1413 randomly selected members of the Australian general population and of 690 participants sourced from previous studies, we examined factors affecting people's stated willingness to participate in health research. RESULTS: The majority of participants (61 %) expressed willingness to participate in health research in general but the percentage increased when provided with more specific information about the research. People were more willing if they have personal experience of the disease under study, and if the study was funded by government or charity rather than pharmaceutical companies. Participants from previous studies, older people and women were the groups most willing to participate. Younger men preferred online surveys, older people a written questionnaire, and few participants in any age and sex groups preferred a telephone questionnaire. CONCLUSION: Despite a trend toward reduced participation rates, most participants expressed their willingness to participate in health research. However, when seeking participants, researchers should be concrete and specific about the nature of the research they want to carry out. The preferred method of recommended contact varies with the demographic characteristics.

Depression in Gulf War veterans: a systematic review and meta-analysis.

BACKGROUND: Although post-traumatic stress disorder (PTSD) has been a focus of attention in 1990/1991 Gulf War veterans, the excess risk of depression has not been clearly identified. We investigated this through a systematic review and meta-analysis of studies comparing depression in Gulf War veterans to depression in a comparison group of non-deployed military personnel. METHOD: Multiple electronic databases and grey literature were searched from 1990 to 2012. Studies were assessed for eligibility and risk of bias according to established criteria. RESULTS: Of 14 098 titles and abstracts assessed, 14 studies met the inclusion criteria. Gulf War veterans had over twice the odds of experiencing depression [odds ratio (OR) 2.28, 95% confidence interval (CI) 1.88-2.76] and dysthymia or chronic dysphoria (OR 2.39, 95% CI 2.0-2.86) compared to non-deployed military personnel. This finding was robust in sensitivity analyses, and to differences in overall risk of bias and psychological measures used. CONCLUSIONS: Despite divergent methodologies between studies, depression and dysthymia were twice as common in Gulf War veterans and are important medical conditions for clinicians and policymakers to be aware of in managing Gulf War veterans' health.

Symptoms and medical conditions in Australian veterans of the 1991 Gulf War: relation to immunisations and other Gulf War exposures.

AIMS: To investigate whether Australian Gulf War veterans have a higher than expected prevalence of recent symptoms and medical conditions that were first diagnosed in the period following the 1991 Gulf War; and if so, whether these effects were associated with exposures and experiences that occurred in the Gulf War. METHODS: Cross-sectional study of 1456 Australian Gulf War veterans and a comparison group who were in operational units at the time of the Gulf War, but were not deployed to that conflict (n = 1588). A postal questionnaire was administered and the likelihood of the diagnosis of self-reported medical conditions was assessed and rated by a medical practitioner. RESULTS: Gulf War veterans had a higher prevalence of all self-reported health symptoms than the comparison group, and more of the Gulf War veterans had severe symptoms. Increased symptom reporting was associated with several exposures, including having more than 10 immunisations, pyridostigmine bromide tablets, anti-biological warfare tablets, pesticides, insect repellents, reportedly being in a chemical weapons area, and stressful military service experiences in a strong dose-response relation. Gulf War veterans reported psychological (particularly post-traumatic stress disorder), skin, eye, and sinus conditions first diagnosed in 1991 or later more commonly than the comparison group. Over 90% of medical conditions reported by both study groups were rated by a medical practitioner as having a high likelihood of diagnosis. CONCLUSION: More than 10 years after the 1991 Gulf War, Australian veterans self-report all symptoms and some medical conditions more commonly than the comparison group. Further analysis of the severity of symptoms and likelihood of the diagnosis of medical conditions suggested that these findings are not due to over-reporting or to participation bias.

The health of Australian veterans of the 1991 Gulf War: factor analysis of self-reported symptoms.

BACKGROUND: A recent report showed that Australian veterans of the 1991 Gulf War displayed a greater prevalence of a multitude of self-reported symptoms than a randomly sampled comparison group of military personnel who were eligible for deployment but were not deployed to the Gulf. AIMS: To investigate whether the pattern, rather than frequency, of symptom reporting in these Australian Gulf War veterans differed from that of the comparison group personnel. METHODS: Factor analysis was used to determine whether the co-occurrence of 62 symptoms in 1322 male Gulf War veterans can be explained by a number of underlying dimensions, called factors. The methodology was also applied to 1459 male comparison group subjects and the factor solutions of the two groups were compared. RESULTS: For the Gulf War veterans, a three factor solution displayed replicability and construct validity. The three factors were labelled as psycho-physiological distress, somatic distress, and arthro-neuromuscular distress, and were broadly similar to those described in previous studies of Gulf War veterans. A concordant three factor solution was also found for the comparison group subjects, with strong convergence of the factor loadings and factor scores across the two groups being displayed. CONCLUSION: Results did not display evidence of a unique pattern of self-reported symptoms among Gulf War veterans. Results also indicated that the differences between the groups lie in the degrees of expression of the three underlying factors, consistent with the well documented evidence of increased self-reported symptom prevalence in Gulf War veterans.

Respiratory health status of Australian veterans of the 1991 Gulf War and the effects of exposure to oil fire smoke and dust storms.

BACKGROUND: Since the 1991 Gulf War concerns have been raised about the effects on veterans' health of exposures to Kuwaiti oil fire smoke and to dust storms. METHODS: A cross sectional study compared 1456 Australian Gulf War veterans with a randomly sampled military comparison group (n = 1588). A postal questionnaire asked about respiratory conditions, exposures, medications, tobacco use, demographic characteristics, and military service details. During a medical assessment, spirometric tests and a physical examination were performed and a respiratory questionnaire was administered. RESULTS: The response rate for the Gulf War veteran group was 80.5% and for the comparison group 56.8%. Australian Gulf War veterans had a higher than expected prevalence of respiratory symptoms and respiratory conditions suggesting asthma (OR 1.4; 95% CI 1.1 to 1.9) and bronchitis first diagnosed since the Gulf War (OR 1.9; 95% CI 1.2 to 3.1) but did not have poorer lung function or more ventilatory abnormalities than the comparison group. Veterans who reported exposure to oil fire smoke had slightly poorer forced vital capacity (difference between means -0.10 l; 95% CI -0.18 to -0.03) and those exposed to dust storms had a slightly better peak expiratory flow rate (difference between means 12.0 l/min; 95% CI 0.6 to 23.4) than veterans who did not report exposure. Veterans who were in the Gulf at or after the start of the oil fires had more respiratory conditions suggesting asthma (OR 1.7; 95% CI 1.0 to 2.9) than those who completed their deployment before this time. CONCLUSIONS: Increased self-reporting of respiratory symptoms, asthma, and bronchitis by veterans was not reflected in poorer lung function. The findings do not suggest major long term sequelae of exposure to oil fire smoke or dust storms.

Psychological health of Australian veterans of the 1991 Gulf War: an assessment using the SF-12, GHQ-12 and PCL-S.

BACKGROUND: Elevated rates of psychological morbidity and symptomatology have been widely reported in 1991 Gulf War veterans. The present study used brief self-report instruments to compare the psychological health of Australian Gulf War veterans with that of a randomly sampled military comparison group. METHOD: The 12-item Short Form Health Survey (SF-12), 12-item General Health Questionnaire (GHQ-12), Posttraumatic Stress Disorder Checklist--Specific (PCL-S) and Military Service Experience (MSE) questionnaire were administered to 1424 male Australian Gulf War veterans and 1548 male Australian Defence Force members who were operational at the time of the Gulf War conflict, but were not deployed there. RESULTS: The Gulf War veterans exhibited poorer psychological health, as measured by the above three instruments, than the comparison group members. For Gulf War veterans, the number of stressful experiences, as measured by the MSE questionnaire, was correlated with scores on the three instruments. SF-12 mental health component summary scores and PCL-S caseness, but not GHQ-12 caseness, differed significantly between Gulf War veterans and comparison group members who had been on at least one active deployment. CONCLUSIONS: More than a decade after the 1991 Gulf War, Australian Gulf War veterans are exhibiting higher levels of current (past month) psychological ill-health, as measured using the GHQ-12 and PCL-S, as well as lower mental health status, as measured by the SF-12, than the comparison group. Although not a replacement for formal psychiatric diagnosis, instruments such as those above may aid in the assessment of veterans' psychological health.

Skin irritation in users of brominated pools.

This study investigated adverse skin and eye effects in swimmers using pools with three different disinfection systems (chlorine, chlorine/ozone and bromine/ozone) and monitored water quality parameters that may be related to adverse health effects. A cross-sectional study of 770 children swimming in three school pools was carried out over a 4 week period in November 1994 using a postal questionnaire. Physico-chemical and bacteriological parameters of water quality were monitored on a weekly basis. Responses were obtained for 385 swimmers. Skin rashes with an onset less than 24 h after swimming in the school pool were reported by 4-8% of swimmers. Compared with the bromine/ozone pool, the odds ratio (OR) of having a rash that started less than 24 h after pool use was 1.91 (CI 0.71-5.10) for the chlorine pool and 1.88 (CI 0.61-5.81) for the chlorine/ozone pool. Adjustment for possible confounders made no significant differences to these results. Eye redness, itch or irritation was reported by 23-33% of swimmers and 24% of non-swimmers, and wearing swimming goggles had a protective effect (OR 0.40; CI 0.24, 0.65). Disinfectant levels were more consistently maintained in the pools with automatically controlled systems. The bromine disinfection system was not associated with a greater risk of the development of skin rashes than other disinfection systems, but the numbers were small, and need to be interpreted with caution.

The effectiveness of ski bindings and their professional adjustment for preventing alpine skiing injuries.

This article presents a critical review of the extent to which alpine ski bindings and their adjustment have been formally demonstrated to prevent injuries. It considers a range of evidence, from anecdotal evidence and informed opinion to biomechanical studies, testing of equipment, epidemiological studies and controlled field evaluations. A total of 15 published studies examining the effectiveness of bindings and their adjustment were identified. All of these included anecdotal or informed opinion, and all but one focused on equipment design. Seven studies involved the testing of bindings or binding prototypes, 2 studies presented biomechanical models of the forces involved in binding operation, 6 reported an epidemiological evaluation of ski bindings and 2 considered skiers' behaviours towards binding adjustment. Some of the reviewed articles relate to the study of the biomechanics of ski bindings and their release in response to various loads and loading patterns. Other studies examined the contribution of bindings and binding-release to lower extremity, equipment-related injuries, the effect of various methods of binding adjustment on injury risk and the determinants of skiers' behaviour relating to professional binding adjustment. Most of the evidence suggests that currently used bindings are insufficient for the multidirectional release required to reduce the risk of injury to the lower limb, especially at the knee. This evidence suggests that further technical developments and innovations are required. The standard of the manufacture of bindings and boots also needs to be considered. The optimal adjustment of bindings using a testing device has been shown to be associated with a reduced risk of lower extremity injury. Generally, however, the adjustment of bindings has been shown to be inadequate, especially for children's bindings. Recommendations for further research, development and implementation with respect to ski binding and their adjustment are given in this article.