Work ability and psychological distress in a working population: results from the Stockholm Public Health Cohort.

AIMS: Psychological distress is a global public health concern with individual and societal implications causing work-related disability and loss of productivity. It is less known how much work ability contributes to the development of psychological distress. This study aimed to assess the association between self-perceived physical and mental work ability in relation to job demands, and the incidence of psychological distress in a Swedish working population. METHODS: Data were obtained from three subsamples of the Stockholm Public Health Cohort with baseline in 2010 and follow-up in 2014, based on a working population in Stockholm County aged 18-60 years, with no or mild psychological distress at baseline (n=29,882). Self-perceived physical and mental work ability in relation to job demands were assessed at baseline with a subscale from the Work Ability Index. Study participants scoring 4 or more on the General Health Questionnaire 12 at follow-up were classified as having developed psychological distress during the study period. Poisson log linear regression was used to calculate crude and adjusted rate ratios with 95% confidence intervals. RESULTS: At follow-up, 2543 participants (12%) had developed psychological distress. Reporting poor physical and/or poor mental work ability in relation to job demands at baseline was associated with an almost doubled rate ratio of psychological distress at follow-up, compared to reporting good work ability (rate ratio 1.8; 95% confidence interval 1.6-2.0). CONCLUSIONS: Poor work ability is associated with a higher incidence of future psychological distress compared to good work ability.

Summarizing the effects of different exercise types in chronic neck pain - a systematic review and meta-analysis of systematic reviews.

BACKGROUND: To date, no consensus exists as to whether one exercise type is more effective than another in chronic neck pain. This systematic review and meta-analysis of systematic reviews aimed to summarize the literature on the effect of various exercise types used in chronic neck pain and to assess the certainty of the evidence. METHODS: We searched the databases Ovid MEDLINE, Embase, Cochrane Library, SportDiscus, and Web of Science (Core Collection) for systematic reviews and meta-analyses on adults between 18 and 70 years with chronic neck pain lasting ≥ 12 weeks which investigated the effects of exercises on pain and disability. The included reviews were grouped into motor control exercise (MCE), Pilates exercises, resistance training, traditional Chinese exercise (TCE), and yoga. Study quality was assessed with AMSTAR-2 and the level of certainty for the effects of the exercise through GRADE. A narrative analysis of the results was performed and in addition, meta-analyses when feasible. RESULTS: Our database search resulted in 1,794 systematic reviews. We included 25 systematic reviews and meta-analyses including 17,321 participants (overlap not accounted for). The quality of the included reviews ranged from critically low to low (n = 13) to moderate to high (n = 12). We found low to high certainty of evidence that MCE, Pilates exercises, resistance training, TCE, and yoga have short-term positive effects on pain and that all exercise types except resistance training, show positive effects on disability compared to non-exercise controls. We found low to moderate certainty of evidence for conflicting results on pain and disability when the exercise types were compared to other exercise interventions in the short-term as well as in intermediate/long-term apart for yoga, as no long-term results were available. CONCLUSION: Overall, our findings show low to high certainty of evidence for positive effects on pain and disability of the various exercise types used in chronic neck pain compared to non-exercise interventions, at least in the short-term. Based on our results, no optimal exercise intervention for patients with chronic neck pain can be recommended, since no large differences between the exercise types were shown here. Because the quality of the included systematic reviews varied greatly, future systematic reviews need to increase their methodological quality. TRIAL REGISTRATION: Prospero CRD42022336014.

Description and comparison of postoperative functioning of patients with hip fracture 2018 and 2008 at the Örebro University Hospital - a comparative cross-sectional study.

BACKGROUND: Hip fractures are a global problem, and it will probably increase. Hip fractures impair health aspects which creates demands on postoperative care. This study describes and compares patients with hip fracture in 2008 and in 2018. An increased knowledge of this group could be a basis how to optimize aftercare and dimension rehabilitation. METHODS: Using a comparative cross-sectional study to describe and compare patients with hip fracture from 2018 and 2008 at Örebro University Hospital regarding age, sex, multimorbidity, fracture type, surgical materials, surgery within 24 hours, length of stay, postoperative walking ability, physical activity level and hand grip strength. Data was collected from 76 patients with hip fracture from 2018 and 78 patients from 2008. Outcome measures considering functioning were walking ability (Functional Ambulation Categories), physical activity level (Classification system of physical activity) and hand grip strength (Jamar hand dynamometer). Statistical analyses used were hypothesis tests and regressions analysis. RESULTS: No differences in age, sex, fracture type, proportion of surgery within 24 hours or length of stay between the cohorts. The cohort 2018 had more multimorbidity in number of diagnoses and ASA-classification preoperatively. In 2018 70% of the participants were dependent in walking ability (physical human support) compared to 43% 2008 (p = 0.007). Proportion of physically inactive was 9% in 2018 compared to 21% 2008 (p = 0.047). Hand grip strength was 5.1 kg better in 2018 (p = 0.011). Adjusted for age, sex, ASA-classification (American Society of Anaesthesiologists Classification System), surgical materials and number of days between surgery and testing the cohort of 2018 had a lower odds to have independent walking ability and higher odds to be physical active. Differences in hand grip strength decreased to 4.7 kg. Participants in 2018 suffered significantly more multimorbidity. CONCLUSIONS: Study indicated differences in patients' postoperative functioning between 2018 and 2008 with more impaired walking ability, more multimorbidity, higher proportion of physically active and better hand grip strength 2018. The results are important for future reasoning regarding care needs of patients with hip fracture.

Vigorous regular leisure-time physical activity is associated with a clinically important improvement in back pain - a secondary analysis of randomized controlled trials.

BACKGROUND: Neck and back pain are musculoskeletal conditions with serious individual and societal consequences. Current evidence about the prognostic value for neck and back pain is limited and conflicting. This prospective cohort study aimed to assess the association between leisure-time physical activity (LPA) and improvement of neck and/or back pain in a working population receiving manual therapy or general care in one of two randomized controlled trials (RCTs). METHODS: Analyses of data from two RCTs evaluating the effect of manual therapies for neck and/or back pain was conducted. Participants (n = 1 464) answered questionnaires about frequency and effort level of LPA at baseline. LPA on moderate or vigorous levels was compared to no or low/irregular moderate and vigorous levels. Pain intensity was assessed with numerical scales at baseline and 3-, 6-, and 12-month follow-up. The outcome was minimal clinically important improvement in pain intensity, defined as ≥2 points improvement in mean pain intensity at follow-up. Crude- and adjusted risk ratios (RR) with 95% confidence intervals (CI) were calculated with Poisson regression analysis and stratified by pain location. RESULTS: Participants with neck and/or back pain performing vigorous LPA showed a minimal clinically important improvement after 12 months compared to the control group; RR 1.35 (95% CI; 1.06-1.73). No effect was observed at 3 or 6 months. Moderate LPA did not improve pain intensity in any follow-up. Stratified analyses revealed that the effect of vigorous LPA at 12 months in back pain was RR 1.83 (95% CI; 1.26-2.66) and neck pain RR 1.06 (95% CI; 0.75-1.49). CONCLUSIONS: Persons with neck and/or back pain receiving manual therapy or general evidence-based care have greater chance of improvement after 12 months if they prior to treatment frequently practice vigorous LPA. When analyzed separately, the effect was only present for back pain. TRIAL REGISTRATION: Registration in Current Controlled Trials (ISRCTN), Stockholm Manual Intervention Trial (MINT), ISRCTN92249294 BJORN-trial, ISRCTN56954776.

Sex and maturity status affected the validity of a submaximal cycle test in adolescents.

AIM: This study assessed the validity and reliability of the Ekblom-Bak (EB) submaximal cycle test in adolescents and identified any sex- or maturity-related factors for prediction errors. METHODS: We recruited 50 healthy subjects through a public announcement in Stockholm, Sweden, in 2016. The 27 boys and 23 girls were aged 10-15 years and in Tanner stages I-IV. They performed an EB test and incremental treadmill running test for direct measurement of maximal oxygen uptake (VO2 max). RESULTS: The estimation error of VO2 max was 0.09 L/min. The correlation (r) was 0.86, and the standard error of the estimate (SEE) was 0.29 L/min. The largest overestimation was seen in prepubertal boys (0.49 L/min). The best precision of the EB test was achieved when boys in Tanner stages I and II were re-calculated using the prediction equation developed for adult women. This yielded a mean difference of -0.05 L/min, r = 0.92 and SEE 0.23 L/min, in the entire sample. The prediction error was lowered in boys, but not girls, with increasing pubertal maturity. CONCLUSION: The EB test was reasonably valid in adolescents, seemed to be related to sex and maturity status, and our findings support its use.

Protocol for identifying and characterising critical physical tasks in the military: Development and validation.

BACKGROUND: When establishing Physical Employment Standards, validity is dependent on the correct identification and characterisation of critical job tasks. OBJECTIVE: To develop and validate a standardised protocol for the identification, characterisation, and documentation of critical physical job tasks in military occupational specialities in the Swedish Armed Forces (SwAF), and propose a definition of critical physical job tasks for use in the SwAF. METHODS: A protocol was drafted with three content domains, including a preliminary definition. Protocol content validity was iteratively assessed in two consecutive stages where ten subject experts rated relevance and simplicity. A consensus panel revised the protocol after each stage. Content validity index (CVI) was calculated as item-CVI (I-CVI) per each feature and as scale average (S-CVI/Ave) per content domain. Acceptable content validity thresholds were 0.78 and 0.90, respectively. RESULTS: The validated protocol consisted of 35 items with an I-CVI≥0.90 and≥0.80 for relevance and simplicity, respectively. The S-CVI/Ave was 0.97 for relevance and 0.98 for simplicity. The protocol was language reviewed, reorganised for easy use, and approved by the consensus panel. The final protocol includes: background and aim of the protocol, the accepted generic and critical physical job task definitions, protocol instructions, subject expert-qualifications, job task source and characteristics. CONCLUSION: A standardised protocol for identification and characterisation of critical job tasks in SwAF military occupational specialties was developed. The protocol content was rated relevant and simple by experts and will be of importance in future work establishing physical requirements in the SwAF.

The influence of self-reported leisure time physical activity and the body mass index on recovery from persistent back pain among men and women: a population-based cohort study.

BACKGROUND: There is limited knowledge about leisure time physical activity and the body mass index (BMI) as prognostic factors for recovery from persistent back pain. The aim of this study was to assess the influence of leisure time physical activity and BMI on recovery from persistent back pain among men and women in a general population. METHODS: The study population (n=1836) in this longitudinal cohort study consisted of participants reporting persistent back pain in the baseline questionnaire in 2002-2003. Data on leisure time physical activity, BMI and potential confounders were also collected at baseline. Information on recovery from persistent back pain (no back pain periods ≥ 7 days during the last 5 years) was obtained from the follow-up questionnaire in 2007. Log-binomial models were applied to calculate Risk Ratios with 95 percent Confidence Intervals (CI) comparing physically active and normal weight groups versus sedentary and overweight groups. RESULTS: Compared to a sedentary leisure time, all measured levels of leisure time physical activity were associated with a greater chance of recovery from persistent back pain among women. The adjusted Risk Ratios was 1.46 (95% CI: 1.06, 2.01) for low leisure time physical activity, 1.51 (95% CI: 1.02, 2.23) for moderate leisure time physical activity, and 1.67 (95% CI: 1.08, 2.58) for high leisure time physical activity. There were no indications that leisure time physical activity influenced recovery among men, or that BMI was associated with recovery from persistent back pain either among men or among women. CONCLUSIONS: Regular leisure time physical activity seems to improve recovery from persistent back pain among women.

Prognosis of patients with whiplash-associated disorders consulting physiotherapy: development of a predictive model for recovery.

BACKGROUND: Patients with whiplash-associated disorders (WAD) have a generally favourable prognosis, yet some develop longstanding pain and disability. Predicting who will recover from WAD shortly after a traffic collision is very challenging for health care providers such as physical therapists. Therefore, we aimed to develop a prediction model for the recovery of WAD in a cohort of patients who consulted physical therapists within six weeks after the injury. METHODS: Our cohort included 680 adult patients with WAD who were injured in Saskatchewan, Canada, between 1997 and 1999. All patients had consulted a physical therapist as a result of the injury. Baseline prognostic factors were collected from an injury questionnaire administered by Saskatchewan Government Insurance. The outcome, global self-perceived recovery, was assessed by telephone interviews six weeks, three and six months later. Twenty-five possible baseline prognostic factors were considered in the analyses. A prediction model was built using Cox regression. The predictive ability of the model was estimated with concordance statistics (c-index). Internal validity was checked using bootstrapping. RESULTS: Our final prediction model included: age, number of days to reporting the collision, neck pain intensity, low back pain intensity, pain other than neck and back pain, headache before collision and recovery expectations. The model had an acceptable level of predictive ability with a c-index of 0.68 (95% CI: 0.65, 0.71). Internal validation showed that our model was robust and had a good fit. CONCLUSIONS: We developed a model predicting recovery from WAD, in a cohort of patients who consulted physical therapists. Our model has adequate predictive ability. However, to be fully incorporated in clinical practice the model needs to be validated in other populations and tested in clinical settings.

Influence of work ability and smoking on the prognosis of long-duration activity-limiting neck/back pain: a cohort study of a Swedish working population.

OBJECTIVES: Long-duration activity-limiting neck/back pain is common, but the knowledge of what work and lifestyle factors that influence the prognosis is sparse. The objective was therefore to evaluate if two factors, good self-perceived work ability and no daily smoking, are associated with a favourable prognosis of long-duration activity-limiting neck/back pain in a working population, and if these exposures have a synergistic prognostic effect. DESIGN: A prospective cohort study based on three subsamples from the Stockholm Public Health Cohort. SETTINGS: A working population in Stockholm County, Sweden. PARTICIPANTS: Individuals, 18-61 years old, reporting long-duration activity-limiting neck/back pain the previous 6 months at baseline in 2010 (n=5177). MEASURES: The exposures were: self-perceived work ability (categorised into good, moderate and poor) and daily smoking (no/yes). The outcome in 2014 was 'absence of long-duration activity-limiting neck/back pain' the previous 6 months representing a favourable prognosis of reported problems at baseline in 2010. Risk ratios (RRs) and risk differences (RDs) with 95% CI was estimated by general linear regressions, and the synergistic effect was estimated by the synergy index (SI) with 95% CI. RESULTS: Participants with moderate or good work ability, respectively, had an adjusted RR for a favourable prognosis of 1.37 (95% CI 1.11 to 1.69), and 1.80 (1.49 to 2.17) in comparison with participants with poor work ability. The corresponding adjusted RD were 0.07 (0.02 to 0.11) and 0.17 (0.12 to 0.22). Participants not smoking on daily basis had an adjusted RR of 1.21 (1.02 to 1.42), and an adjusted RD of 0.05 (0.01 to 0.10) for a favourable outcome compared with daily smokers. The adjusted SI was 0.92 (0.60 to 1.43). CONCLUSION: For participants with long-duration activity-limiting neck/back pain, moderate or good self-perceived work ability and not being a daily smoker were associated with a favourable prognosis but having both exposures seemed to have no synergistic prognostic effect.

The ability of a submaximal cycle ergometer test to detect longitudinal changes in VO2max.

BACKGROUND: The purpose of the present study was to examine the ability of a submaximal cycling test to detect longitudinal changes in maximal oxygen uptake (VO2max) and examine the conformity between changes in measured and estimated VO2max over a time span of 5-8 years. METHODS: A total of 35 participants (21 men and 14 women), aged 29 to 63 years, performed the Ekblom-Bak (EB) submaximal cycle test for estimation of VO2max and a maximal treadmill running test for direct measurement of VO2max. The baseline tests were conducted between 2009 and 2012, and the follow-up tests were completed 5 to 8 years later. Pearson's coefficient of correlation (r) and paired sample t-test were used to analyse the association between change in measured and estimated VO2max. Random and systematic errors between the measured and estimated VO2max were evaluated using Bland-Altman plots. Repeated measures ANOVA were used to test differences between changes over time. RESULTS: There was no significant change in mean measured VO2max between baseline and follow-up (p = 0.91), however large individual variations were noted (- 0.78 to 0.61 L/min). The correlation between individual change in measured and estimated VO2max was r = 0.75 (p < 0.05), and the unstandardised B-coefficient from linear regression modelling was 0.88 (95% CI 0.61 to 1.15), i.e., for each litre of change in estimated VO2max, the measured value had changed 0.88 L. The correlation between baseline and follow-up errors (the difference between estimated-measured VO2max at each occasion) was r = 0.84 (p < 0.05). With regard to the testing procedure, repeated measures ANOVA revealed that there was no significant difference between the group who exercised at the same work rates at baseline and follow-up (n = 25), and those who required a change in work rate (n = 10). CONCLUSIONS: The EB test detected a change in VO2max with reasonably good precision over a time span of 5-8 years. Further studies are needed to evaluate if the test can be used in clinical populations and in subjects with different medications.

Non-Preferred Work and the Incidence of Spinal Pain and Psychological Distress-A Prospective Cohort Study.

Mental illness and psychological distress are global concerns. This study aimed to investigate the association between having non-preferred work and the incidence of spinal pain, psychological distress, and spinal pain with concurrent psychological distress, and if associations are modified by sleep disturbance. A prospective study of 4285 participants 23-62 years old was conducted, from years 2007 to 2010. Participants reported their work situation as preferred/non-preferred regarding profession/workplace with a high/low possibility to change. Psychological distress was measured with the General Health Questionnaire 12 and spinal pain with questions about neck/back pain. Binominal regression analyses calculated relative risk (RR) with 95% confidence interval (CI). Non-preferred work with a low possibility to change was associated with a higher incidence of spinal pain (RR 1.8; 95% CI 1.2-2.6) and psychological distress (RR 1.8; 95% CI 1.4-2.4) compared to preferred work. The RR was 1.4 (95% CI 0.9-2.1) for spinal pain and 1.3 (95% CI 1.0-1.7) for psychological distress among those with a high possibility to change. Non-preferred work yielded a higher incidence of spinal pain with concurrent psychological distress (RR 1.9; 95% CI 1.0-3.7). Sleep disturbance did not modify associations. A replication based on newer data is needed to confirm the results. In conclusion, non-preferred work is associated with a higher incidence of spinal pain and psychological distress, especially if the possibility to change job is low.

The long-term effects of naprapathic manual therapy on back and neck pain - results from a pragmatic randomized controlled trial.

BACKGROUND: Back and neck pain are very common, disabling and recurrent disorders in the general population and the knowledge of long-term effect of treatments are sparse. The aim of this study was to compare the long-term effects (up to one year) of naprapathic manual therapy and evidence-based advice on staying active regarding non-specific back and/or neck pain. Naprapathy, a health profession mainly practiced in Sweden, Finland, Norway and in the USA, is characterized by a combination of manual musculoskeletal manipulations, aiming to decrease pain and disability in the neuromusculoskeletal system. METHODS: Subjects with non-specific pain/disability in the back and/or neck lasting for at least two weeks (n = 409), recruited at public companies in Sweden, were included in this pragmatic randomized controlled trial. The two interventions compared were naprapathic manual therapy such as spinal manipulation/mobilization, massage and stretching, (Index Group), and advice to stay active and on how to cope with pain, provided by a physician (Control Group). Pain intensity, disability and health status were measured by questionnaires. RESULTS: 89% completed the 26-week follow-up and 85% the 52-week follow-up. A higher proportion in the Index Group had a clinically important decrease in pain (risk difference (RD) = 21%, 95% CI: 10-30) and disability (RD = 11%, 95% CI: 4-22) at 26-week, as well as at 52-week follow-ups (pain: RD = 17%, 95% CI: 7-27 and disability: RD = 17%, 95% CI: 5-28). The differences between the groups in pain and disability considered over one year were statistically significant favoring naprapathy (p < or = 0.005). There were also significant differences in improvement in bodily pain and social function (subscales of SF-36 health status) favoring the Index Group. CONCLUSIONS: Combined manual therapy, like naprapathy, is effective in the short and in the long term, and might be considered for patients with non-specific back and/or neck pain. TRIAL REGISTRATION: Current Controlled Trials ISRCTN56954776.

Risk of transition from occasional neck/back pain to long-duration activity limiting neck/back pain: a cohort study on the influence of poor work ability and sleep disturbances in the working population in Stockholm County.

OBJECTIVES: The prevalence of neck/back pain (NBP) is high worldwide. Limited number of studies have investigated workers with occasional NBP regarding the risk of developing long-duration activity limiting NBP (LNBP). The objectives were to assess (1) the effect of poor work ability and sleep disturbances in persons with occasional NBP on the risk of LNBP, and (2) the interaction effect of these exposures. DESIGN: Cohort study based on three subsamples from the Stockholm Public Health Cohort. SETTINGS: The working population in Stockholm County. PARTICIPANTS: Persons aged 18-60 years, reporting occasional NBP the past 6 months at baseline year 2010 (n=16 460). MEASURES: Work ability was assessed with items from the Work Ability Index, perceived mental and/or physical work ability. Sleep disturbances were self-reported current mild/severe disturbances. The outcome in year 2014 was reporting NBP the previous 6 months, occurring ≥couple of days per week and resulting in decreased work ability/restricted other daily activities. The additive effect of having both poor work ability and sleep disturbances was modelled with a dummy variable, including both exposures. Poisson log-linear regression was used to calculate risk ratios (RRs) and 95% CIs. RESULTS: At follow-up, 9% had developed LNBP. Poor work ability and sleep disturbances were independent risk factors for LNBP; adjusted RR 1.7 (95% CI: 1.4 to 2.0) and 1.4 (95% CI: 1.2 to 1.5), respectively. No additive interaction was observed. CONCLUSION: Workers with occasional NBP who have poor work ability and/or sleep disturbances are at risk of developing LNBP. Having both conditions does not exceed additive risk.

Predictive models for short-term and long-term improvement in women under physiotherapy for chronic disabling neck pain: a longitudinal cohort study.

OBJECTIVES: To develop predictive models for short-term and long-term clinically important improvement in women with non-specific chronic disabling neck pain during the clinical course of physiotherapy. DESIGN: Longitudinal cohort study based on data from a randomised controlled trial evaluating short-term and long-term effects on sensorimotor function over 11 weeks of physiotherapy. PARTICIPANTS AND SETTINGS: Eighty-nine women aged 31-65 years with non-specific chronic disabling neck pain from Gävle, Sweden. MEASURES: The outcome, clinically important improvement, was measured with the Patient Global Impression of Change Scale (PGICS) and the Neck Disability Index (NDI), assessed by self-administered questionnaires at 3, 9 and 15 months from the start of the interventions (baseline). Twelve baseline prognostic factors were considered in the analyses. The predictive models were built using random-effects logistic regression. The predictive ability of the models was measured by the area under the receiver operating characteristic curve (AUC). Internal validity was assessed with cross-validation using the bootstrap resampling technique. RESULTS: Factors included in the final PGICS model were neck disability and age, and in the NDI model, neck disability, depression and catastrophising. In both models, the odds for short-term and long-term improvement increased with higher baseline neck disability, while the odds decreased with increasing age (PGICS model), and with increasing level of depression (NDI model). In the NDI model, higher baseline levels of catastrophising indicated increased odds for short-term improvement and decreased odds for long-term improvement. Both models showed acceptable predictive validity with an AUC of 0.64 (95% CI 0.55 to 0.73) and 0.67 (95% CI 0.59 to 0.75), respectively. CONCLUSION: Age, neck disability and psychological factors seem to be important predictors of improvement, and may inform clinical decisions about physiotherapy in women with chronic neck pain. Before using the developed predictive models in clinical practice, however, they should be validated in other populations and tested in clinical settings.

Healthy lifestyle behaviour and risk of long-duration troublesome neck pain among men and women with occasional neck pain: results from the Stockholm public health cohort.

OBJECTIVES: The effect of a healthy lifestyle on the prognosis of neck pain is unknown. This study aimed to investigate if a healthy lifestyle behaviour influences the risk of long-duration troublesome neck pain among men and women with occasional neck pain. DESIGN: Longitudinal cohort study. SETTINGS: General population, and a subsample of the working population, in Stockholm County, Sweden. PARTICIPANTS: This study involved 5342 men and 7298 women, age 18 to 84, from the Stockholm Public Health Cohort, reporting occasional neck pain at baseline in 2006. MEASURES: Baseline information about leisure physical activity, smoking, alcohol consumption and consumption of fruits and vegetables were dichotomised into recommendations for healthy/not healthy behaviour. The exposure, a healthy lifestyle behaviour, was categorised into four levels according to the number of healthy behaviours (HB) met. Generalised linear models were applied to assess the exposure on the outcome long-duration troublesome neck pain (activity-limiting neck pain ≥2 days/week during the past 6 months), at follow-up in 2010. RESULTS: The adjusted risk of long-duration troublesome neck pain decreased with increasing adherence to a healthy lifestyle behaviour among both men and women (trend test: p<0.05). Compared with the reference category, none or one HB, the risk decreased by 24% (risk ratio 0.76, 95% CI 0.58 to 0.98) among men and by 34% (0.66, 0.54 to 0.81) among women, with three or four HBs. The same comparison showed an absolute reduction of the outcome by 3% in men (risk difference -0.03, 95% CI -0.05 to -0.01) and 5% in women (-0.05,-0.08 to -0.03). Similar results were found in the working population subsample. CONCLUSION: Adhering to a healthy lifestyle behaviour decreased the risk of long-duration troublesome neck pain among men and women with occasional neck pain. The results add to previous research and supports the importance of promoting a healthy lifestyle behaviour.

Concurrent validity of an isokinetic lift test used for admission to the Swedish Armed Forces.

The aim of this study was to assess the concurrent validity of the IsoKai isokinetic lift test peak force (IsoKaiPeak) in comparison to a submaximal 5-10RM deadlift test (5-10RMDL), and to develop an equation for converting the IsoKaiPeak in Newton (N) to an estimated 1RM (1RMest) deadlift load in kilograms (kg). The participants included 28 males and 16 female employees in the Swedish Armed Forces (20-59 years). Each participant conducted the IsoKai lift test, followed by the 5-10RMDL test at one occasion. The Pearson's correlation coefficient, with a 95% confidence interval was calculated to evaluate the validity between the IsoKaiPeak and the 1RMest deadlift load derived from the 5-10RMDL test. Univariate and multivariable linear regressions were used to derive the equation for calculating the 1RMest deadlift load based on the IsoKaiPeak. The IsoKaiPeak showed good- to-excellent correlation with the 1RMest deadlift weight with a correlation coefficient of 0.84 (0.72-0.91) for the total sample, and 0.65 (0.37-0.83) and 0.81 (0.53-0.93) in males and females, respectively. The final equation, 1RMest deadlift weight (kg) = -51.63 + (0.08 x IsoKaiPeak) + (2.28 x BMI), explained 72% (adjusted R2 = 0.72) of the total variance in the 1RMest, and had a standard error of the estimate (SEE) of 16.57 kg. In conclusion, the IsoKai isokinetic lift test could be considered a highly valid measure of maximal dynamic muscular strength in comparison to the 5-10RMDL. The equation can be used to convert the IsoKai lift test (N) results to an 1RMest deadlift load (kg), but with consideration of the relative large SEE.

Reliability and agreement of the IsoKai isokinetic lift test - A test used for admission to the Swedish Armed Forces.

This study was performed to evaluate the reliability and agreement of the IsoKai isokinetic lift test as it is currently administered in admission to the Swedish Armed Forces. The study included an intrarater (n = 534) and interrater reliability sample (n = 137), of Swedish male conscripts who performed the test on two test occasions about two hours apart. Two-to-four lifts were performed at each occasion, and the highest mean (IsoKaiMF) and peak force (IsoKaiPF) produced (N) were used for evaluation. All intraclass coefficients showed excellent reliability. The interrater analyses resulted in intraclass coefficients of 0.942 (95% CI; 0.920-0.959) and 0.858 (95% CI; 0.806-0.896) for the IsoKaiMF and IsoKaiPF, respectively, while the corresponding coefficients for the intrarater analyses were 0.935 (95% CI; 0.923-0.946) and 0.865 (95% CI; 0.842-0.886). Agreement, the capability of a test to detect changes, was assessed by the standard error of measurement (SEM/SEM%) and the smallest real difference (SRD/SRD%). These estimate indicated that it is possible to achieve measurements relevant to use in real practice with the IsoKai isokinetic lift test. Bland and Altman analyses revealed no systematic errors in either sample. Based on these findings, the IsoKai isokinetic lift test is suggested to be a highly reliable test for maximal dynamic muscular strength. The test could be of use in selection procedures in order to accurately evaluate maximal dynamic muscular strength, and for evaluating longitudinal changes in strength.

Healthy lifestyle behavior and risk of long duration troublesome neck pain or low back pain among men and women: results from the Stockholm Public Health Cohort.

BACKGROUND: The role of healthy lifestyle behavior (HLB) in terms of physical activity, alcohol intake, smoking, and diet put together has not yet been explored for the risk of low back pain (LBP) and neck pain (NP). Our aim was to study if an HLB is protective against the onset of long duration troublesome LBP and NP in men and women. METHODS: Two cohorts from the Stockholm Public Health Cohort, free from LBP (n=12,483) and NP (n=10,539), respectively, in 2006, were surveyed with questionnaires. Baseline information about physical activity, alcohol intake, diet, and smoking were dichotomized into being healthy/not healthy and combined in a categorical variable according to the number of healthy behaviors present. Binomial regression analyses were used to evaluate the role of HLB for the outcomes 4 years later. RESULTS: When men with three or four healthy lifestyles were compared to men with none or one, the risk ratio (RR) of LBP was 0.63 (95% confidence interval [CI]: 0.39-1.02). The corresponding RR for LBP in women was 0.86 (95% CI: 0.56-1.32). When men with three or four healthy lifestyles were compared to men with none or one, the RR for NP was 1.13 (95% CI: 0.74-1.71). The corresponding RR for NP in women was 0.52 (95% CI: 0.35-0.77). CONCLUSION: An HLB seems to be protective for long duration troublesome LBP in men, and for long duration troublesome NP in women.

Does a healthy lifestyle behaviour influence the prognosis of low back pain among men and women in a general population? A population-based cohort study.

OBJECTIVES: To study the influence of healthy lifestyle behaviour on the prognosis of occasional low back pain among men and women in a general population. DESIGN: Cohort study with a 4-year follow-up. SETTINGS: General population in Stockholm County, Sweden. PARTICIPANTS: The study sample comprised 3938 men and 5056 women aged 18-84 from the Stockholm Public Health Cohort reporting occasional low back pain in the baseline questionnaire 2006. MEASURES: Lifestyle factors and potential confounders were assessed at baseline. The lifestyle factors smoking habits, alcohol consumption, leisure physical activity and consumption of fruit and vegetables were dichotomised using recommendations for a health-enhancing lifestyle and combined to form the exposure variable 'healthy lifestyle behaviour'. The exposure was categorised into five levels according to the number of healthy lifestyle factors met. The follow-up questionnaire in 2010 gave information about the outcome, long duration troublesome low back pain. Crude and adjusted binomial regression models were applied to estimate the association between the exposure and the outcome analysing men and women separately. RESULTS: The risk of developing long duration troublesome low back pain among women with occasional low back pain decreased with increasing healthy lifestyle behaviour (trend test: p=0.006). 21% (28/131) among women with no healthy lifestyle factor (reference) experienced the outcome compared to 9% (36/420) among women with all four factors. Compared to the reference group, the risk was reduced by 35% (RR 0.65, 95% CI 0.44 to 0.96) for women with one healthy lifestyle factor and 52% (RR 0.48, 95% CI 0.31 to 0.77) for women with all four healthy lifestyle factors. There were no clear associations found among men. CONCLUSIONS: Healthy lifestyle behaviour seems to decrease the risk of developing long duration troublesome low back pain among women with occasional low back pain and may be recommended to improve the prognosis.