Risk and Prognostic Factors of Low Back Pain: Repeated Population-based Cohort Study in Sweden

Study Design. Prospective longitudinal cohort study. Objective. To determine the associations for workload and health-related factors with incident and recurrent low back pain (LBP), and to determine the mediating role of health-related factors in associations between physical workload factors and incident LBP. Summary of Background Data. It is not known whether the risk factors for the development of LBP are also prognostic factors for recurrence of LBP and whether the associations between physical workload and incident LBP are mediated by health-related factors. We used data from the Swedish Longitudinal Occupational Survey of Health study. Those responding to any two subsequent surveys in 2010 to 2016 were included for the main analyses (N = 17,962). Information on occupational lifting, working in twisted positions, weight/height, smoking, physical activity, depressive symptoms, and sleep problems were self-reported. Incident LBP was defined as pain limiting daily activities in the preceding three months in participants free from LBP at baseline. Recurrent LBP was defined as having LBP both at baseline and follow-up. For the mediation analyses, those responding to three subsequent surveys were included (N = 3516). Methods. Main associations were determined using generalized estimating equation models for repeated measures data. Mediation was examined with counterfactual mediation analysis. Results. All risk factors at baseline but smoking and physical activity were associated with incident LBP after adjustment for confounders. The strongest associations were observed for working in twisted positions (risk ratio = 1.52, 95% CI 1.37, 1.70) and occupational lifting (risk ratio = 1.52, 95% CI 1.32, 1.74). These associations were not mediated by health-related factors. The studied factors did not have meaningful effects on recurrent LBP. Conclusion. The findings suggest that workload and health-related factors have stronger effects on the development than on the recurrence or progression of LBP, and that health-related factors do not mediate associations between workload factors and incident LBP.Peer reviewe

Wave function engineering in quantum dot-ring nanostructures

Modern nanotechnology allows producing, depending on application, various quantum nanostructures with the desired properties. These properties are strongly influenced by the confinement potential which can be modified, e.g., by electrical gating. In this paper we analyze a nanostructure composed of a quantum dot surrounded by a quantum ring. We show that depending on the details of the confining potential the electron wave functions can be located in different parts of the structure. Since the properties of such a nanostructure strongly depend on the distribution of the wave functions, varying the applied gate voltage one can easily control them. In particular, we illustrate the high controllability of the nanostructure by demonstrating how its coherent, optical, and conducting properties can be drastically changed by a small modification of the confining potential.Comment: 8 pages, 10 figures, 2 tables, revte

Changes in drinking as predictors of changes in sickness absence : a case-crossover study

Background We investigated whether changes in alcohol use predict changes in the risk of sickness absence in a case-crossover design. Methods Finnish public sector employees were surveyed in 2000, 2004 and 2008 on alcohol use and covariates. Heavy drinking was defined as either a weekly intake that exceeded recommendations (12 units for women; 23 for men) or having an extreme drinking session. The responses were linked to national sickness absence registers. We analysed the within-person relative risk of change in the risk of sickness absence in relation to change in drinking. Case period refers to being sickness absent within 1 year of the survey and control period refers to not being sickness absent within 1 year of the survey. Results Periods of heavy drinking were associated with increased odds of self-certified short-term (1-3 days) sickness absence (multivariable-adjusted OR 1.21, 95% CI 1.07 to 1.38 for all participants; 1.62, 95% CI 1.19 to 2.21 for men and 1.15, 95% CI 1.00 to 1.33 for women). A higher risk of short-term sickness absence was also observed after increase in drinking (OR=1.27, 95% CI 1.07 to 1.52) and a lower risk was observed after decrease in drinking (OR=0.83, 95% CI 0.69 to 1.00). Both increase (OR=1.38, 95% CI 1.21 to 1.57) and decrease (OR=1.27, 95% CI 1.19 to 1.43) in drinking were associated with increased risk of long-term (> 9 days) medically certified all-cause sickness absence. Conclusion Increase in drinking was related to increases in short-term and long-term sickness absences. Men and employees with a low socioeconomic position in particular seemed to be at risk.Peer reviewe

Changes in Smoking During Retirement Transition : A Longitudinal Cohort Study

Aims: We examined the effect of retirement transition on changes in smoking, identified trajectories of smoking around the retirement transition, and investigated factors predicting the membership in the trajectories. Methods: This longitudinal cohort study included 1,432 current or former smokers who entered into statutory retirement in 2000-2011 and who filled out two to four questionnaires sent at four-year intervals. Effect of retirement on smoking was analysed as a non-randomized pseudo-trial in which we compared the likelihood of quitting and relapsing smoking between two subsequent survey waves among those who retired and did not retire. We used latent class analysis to identify trajectories of smoking status and smoking intensity (low: 10 cigarettes/day), and multinomial logistic regression models to assess pre-retirement factors associated with smoking trajectories. Results: Retirement transition was associated with 1.7-fold odds of quitting smoking (95% confidence intervals 1.3-2.2) compared with no retirement transition. We identified three smoking status trajectories: 'sustained non-smoking' (61% of the participants), 'sustained smoking' (23%) and 'decreasing smoking' (16%). For 489 baseline smokers, we identified three smoking intensity trajectories: 'sustained high intensity smoking' (32% of the participants), 'sustained low intensity smoking' (32%) and 'decreasing high intensity smoking' (35%). Living outside an inner urban area predicted membership in the 'decreasing smoking' versus 'sustained smoking' trajectory. Conclusions: Smokers are more likely to quit smoking during transition to retirement than before or after it. Characteristics of the smoking environment may affect smoking behaviour around retirement.Peer reviewe

Change in neighborhood disadvantage and change in smoking behaviors in adults: a longitudinal, within-individual study

BACKGROUND: Evidence for an association between neighborhood disadvantage and smoking is mixed and mainly based on cross-sectional studies. To shed light on the causality of this association we examined whether change in neighborhood socioeconomic disadvantage is associated with within-individual change in smoking behaviors. METHODS: The study population comprised participants of the Finnish Public Sector study who reported a change in their smoking behavior between surveys in 2008/09 and 2012/13. We linked participants' residential addresses to a total population database on neighborhood disadvantage with 250 × 250m resolution. The outcome variables were changes in smoking status (being a smoker vs. not) as well as the intensity (heavy/moderate vs. light smoker). We used longitudinal case-crossover design, a method that accounts for time-invariant confounders by design. We adjusted models for time-varying covariates. RESULTS: Of the 3443 participants, 1714 quit while 967 began to smoke between surveys. Smoking intensity increased among 398 and decreased among 364 participants. The level of neighborhood disadvantage changed for 1078 participants because they moved residence. Increased disadvantage was associated with increased odds of being a smoker (odds ratio (OR) of taking up smoking 1.23 (95% CI 1.04-1.47) per 1 standard deviation (SD) increase in standardized national disadvantage score). OR for being a heavy/moderate (vs. light) smoker was 1.14 (95% CI 0.85-1.52) when disadvantage increased by 1 SD. CONCLUSIONS: These within-individual results link an increase in neighborhood socioeconomic disadvantage, due to move in residence, with subsequent smoking behaviors

Mental health by gender-specific occupational groups : Profiles, risks and dominance of predictors

Background: We defined gender-specific profiles of mental ill-health for the main occupational groups using three outcomes; antidepressant use, sickness absence (SA) due to depression, and suicides. We also examined which occupational groups had the highest risk of the outcomes, and compared the importance of their predictors. Methods: From a random register cohort of Finnish working age population, individuals in the six largest occupational groups in 2004 for men and women were included (N = 414 357). We used register data to define the first antidepressant purchase (i.e. use), the first long-term SA spell for depression, and suicide between Jan 1st 2005 and Dec 31st 2014. We assessed the risk of each outcome by occupational group with logistic regression models, and used dominance analysis to compare the relative importance of predictors. Results: In all six occupational groups for women, the prevalence of antidepressant use and SA for depression was higher than in the men's occupational groups. The opposite was observed for suicides. The risk of antidepressant use was lower, but the risk of suicide was 2-times higher among men in low vs. high-skilled occupations. Among women, a lower skill-level was associated with a higher risk of SA due to depression. Gender was the most important predictor of all outcomes. Limitations: We lacked information on history of medication use or health problems prior to follow-up. Conclusions: Gendered occupational status was an underlying factor explaining distinctive mental health profiles in the working population. Occupational class-dependent behavioural patterns related to mental health existed among men.Peer reviewe

Effectiveness of legislative changes obligating notification of prolonged sickness absence and assessment of remaining work ability on return to work and work participation : a natural experiment in Finland

Objectives Policies have been introduced to reduce sickness absence, but their effectiveness is largely unknown. In a natural experiment, we examined effects of legislative changes on return to work and work participation. Methods The source population consisted of up to 72164 Finnish public sector employees with a permanent job contract in 2008-2011 (before) and in 2013-2014 (after). We used employees with a continuous sickness absence of at least 30 calendar-days (n=5708-6393), 60 compensated days (n=1481-1655) and 90 compensated days (n=766-932). We examined sustainable return to work (a minimum of 28 consecutive working days) with survival analysis as well as monthly work participation after a sickness absence, and annual gain in work participation after the intervention, using trajectory analyses. Results Sustainable return to work after 60days of sickness absence occurred earlier after the legislative changes (p value 0.017), although the effect reduced towards the end of the follow-up. There were no differences in return to work after a 30 or 90days of sickness absence. The largest annual gain, postintervention versus preintervention, in monthly work participation was observed among employees with 60days of sickness absence and was 230.9 person-years/10000 employees. The corresponding annual gains among those with 30days and 90days of sickness absence were 51.8 and 39.6, respectively. Conclusions Our findings suggest that the legislative changes, obligating early notification of prolonged sickness absences as well as assessment of remaining work ability and possibilities to continue working, may enhance sustainable return to work in the short term. Other measures will be needed to enhance work participation, especially in the long term.Peer reviewe

Distinctive use of newer and older antidepressants in major geographical areas : A nationally representative register-based study

Background It is unknown whether newer, mainly selective serotonin reuptake inhibitors, and older tricyclic antidepressants are used similarly regardless of the geographical area of residence and education. Methods We included four randomly sampled cohorts of the Finnish working aged population (n = 998,540–1,033,135). The sampling (Dec 31st in 1995, 2000, 2004 and 2010) resulted in non-overlapping time windows where each participant was followed up for four years for the first antidepressant use. Using Cox proportional hazards models, we examined whether the hazard of antidepressant use differed between the capital area and three other areas (Southern, Western and Northern/Eastern Finland). Educational differences were examined using four sub-groups: capital area/high education (reference category); other areas/high education; capital area/low education; and other areas/low education. Results Hazard ratios for the use of newer antidepressants were significantly lower in all other areas compared to the capital area after adjustment for age, sex, marital status, employment status, education, income, and area-level unemployment. Findings remained consistent in all time windows, differences increasing slightly. In the sub-group analysis those with low education had the lowest level of use in all areas, also within the capital area. The results were opposite for older antidepressants in all but the last time window. Limitations Some degree of unmeasured confounding and exposure misclassification is likely to exist. Conclusions Newer antidepressants were more commonly used in the capital than in the other areas, and among those with high versus low education. These differences in antidepressant use suggest socioeconomic inequalities in the mental health treatment quality.Peer reviewe