Ann Kristin Knudsen

The Health Status of Nonparticipants in a Population-based Health Study The Hordaland Health Study

The authors aimed to examine whether nonparticipation in a population-based health study was associated with poorer health status; to determine whether specific health problems were overrepresented among nonparticipants; and to explore potential consequences of participation bias on associations between exposures and outcomes. They used data from the Hordaland Health Study (HUSK), conducted in western Norway in 1997-1999. Of 29,400 persons invited, 63.1% participated in the study. Information from HUSK was linked with the Norwegian national registry of disability pensions (DPs), including information about DP diagnosis. The risk of DP receipt was almost twice as high among nonparticipants as participants (relative risk = 1.88, 95% confidence interval: 1.81, 1.95). The association was strongest for DPs received for mental disorders, with a 3-fold increased risk for nonparticipation. Substance abuse, psychotic disorders, and personality disorders were especially overrepresented among nonparticipants. The authors simulated the impact of nonparticipation on associations between exposures and outcomes by excluding HUSK participants with higher symptoms of common mental disorders (exposure) and examining the impact on DP (outcome). This selective exclusion modestly reduced associations between common mental disorders and DP. The authors conclude that nonparticipants have poorer health, but this is disorder-dependent. Participation bias is probably a greater threat to the validity of prevalence studies than to studies of associations between exposures and outcomes.

Common mental disorders and long-term sickness absence in a general working population. The Hordaland Health Study.

Objective:  To examine and compare the prospective effect of the common mental disorders (CMD) anxiety and depression on duration and recurrence of sickness absence (SA), and to investigate whether the effect of CMD on SA is detectable over time.

Common mental disorders and disability pension award: Seven year follow-up of the HUSK study

OBJECTIVE Rates of disability pension (DP) awards remain high in most developed countries. We aimed to estimate the impact of anxiety and depression on DPs awarded both for mental and for physical diagnoses and to estimate the relative contribution of sub case-level anxiety and depression compared with case-level symptom loads. METHODS Information from a large cohort study on mental and physical health in individuals aged 40-46 (N=15,288) was linked to a comprehensive national database of disability benefits. Case-level and sub case-level anxiety and depression were defined as scores on the Hospital Anxiety and Depression Scale of >or=8 and 5-7, respectively. The outcome was incident award of a DP (including ICD-10 diagnosis) during 1-7-year follow-up. RESULTS DP awards for all diagnoses were predicted both from case-level anxiety [HR 1.90 (95% CI 1.50-2.41)], case-level depression [HR 2.44 (95% CI 1.65-3.59] and comorbid anxiety and depression [HR 4.92 (95% CI 3.94-6.15)] at baseline. These effects were only partly accounted for by adjusting for baseline somatic symptoms and diagnoses. Anxiety and depression also predicted awards for physical diagnoses [HR 3.26 (95% CI 2.46-4.32)]. The population attributable fractions (PAF) of sub case-level anxiety and depression symptom loads were comparable to those from case-level symptom loads (PAF anxiety 0.07 versus 0.11, PAF depression 0.05 versus 0.06). CONCLUSION The long-term occupational impact of symptoms of anxiety and depression is currently being underestimated. Sub case-level symptom loads of anxiety and depression make an important and previously unmeasured contribution to DP awards.

Disability pension by occupational class - the impact of work-related factors: The Hordaland Health Study Cohort

BackgroundThe social gradient in disability pension is well recognized, however mechanisms accounting for the gradient are largely unknown. The aim of this study was to examine the association between occupational class and subsequent disability pension among middle-aged men and women, and to what extent work-related factors accounted for the association.MethodsA subsample (N = 7031) of the population-based Hordaland Health Study (HUSK) conducted in 1997-99, provided self-reported information on health and work-related factors, and were grouped in four strata by Erikson, Goldthorpe and Portocareros occupational class scheme. The authors obtained follow-up data on disability pension by linking the health survey to national registries of benefit (FD-trygd). They employed Cox regression analysis and adjusted for gender, health (medical conditions, mental health, self-perceived health, somatic symptoms) and work-related factors (working hours, years in current occupation, physical demands, job demands, job control).ResultsA strong gradient in disability pension by occupational class was found. In the fully adjusted model the risk (hazard ratio) ranged from 1.41 (95% CI 0.84 to 2.33) in the routine non-manual class, 1.87 (95% CI 1.07 to 3.27) in the skilled manual class and 2.12 (95% CI 1.14 to 3.95) in the unskilled manual class, employing the administrator and professional class as reference. In the gender and health-adjusted model work-related factors mediated the impact of occupational class on subsequent disability pension with 5% in the routine non-manual class, 26% in the skilled manual class and 24% in the unskilled manual class. The impact of job control and physical demands was modest, and mainly seen among skilled and unskilled manual workers.ConclusionsWorkers in the skilled and unskilled manual classes had a substantial unexplained risk of disability pension. Work-related factors only had a moderate impact on the disability risk. Literature indicates an accumulation of hazards in the manual classes. This should be taken into account when interpreting the gradient in disability pension.

Health problems account for a small part of the association between socioeconomic status and disability pension award. Results from the Hordaland Health Study

BackgroundLow socioeconomic status is a known risk factor for disability pension, and is also associated with health problems. To what degree health problems can explain the increased risk of disability pension award associated with low socioeconomic status is not known.MethodsInformation on 15,067 participants in the Hordaland Health Study was linked to a comprehensive national registry on disability pension awards. Level of education was used as a proxy for socioeconomic status. Logistic regression analyses were employed to examine the association between socioeconomic status and rates of disability pension award, before and after adjusting for a wide range of somatic and mental health factors. The proportion of the difference in disability pension between socioeconomic groups explained by health was then calculated.ResultsUnadjusted odds ratios for disability pension was 4.60 (95% CI: 3.34-6.33) for the group with elementary school only (9 years of education) and 2.03 (95% CI 1.49-2.77) for the group with high school (12 years of education) when compared to the group with higher education (more than 12 years). When adjusting for somatic and mental health, odds ratios were reduced to 3.87 (2.73-5.47) and 1.81 (1.31-2.52). This corresponds to health explaining only a marginal proportion of the increased level of disability pension in the groups with lower socioeconomic status.ConclusionThere is a socioeconomic gradient in disability pension similar to the well known socioeconomic gradient in health. However, health accounts for little of the socioeconomic gradient in disability pension. Future studies of socioeconomic gradients in disability pension should focus on explanatory factors beyond health.

Widespread pain and medically certified disability pension in the Hordaland Health Study

Widespread pain (WSP) is common in the general population and is associated with poor outcomes. The aim of this study was to quantify the risk for medically certified disability pension from WSP. We further studied how other common physical symptoms, common mental disorders and functional limitations influenced this risk. A prospective cohort design was established by linking the large population based Hordaland Health Study (n > 18000 individuals aged 40–46) with an administrative registry on disability pension awards. We modelled hazard ratios for later all‐cause and diagnosis specific disability pensioning from WSP, adjusted for potential confounders and examined the impact of other co‐occurring health problems and functional limitations. WSP was common (12.4%) and associated with a range of mental health, and non‐specific and non‐musculoskeletal symptoms. As expected, WSP was a strong predictor for disability pension award. Hazard ratios (HR) adjusted for socio‐economic status, health behaviours and comorbid medical diagnoses indicated WSP was strongest in predicting pensioning for musculoskeletal diagnoses (HR = 5.91, 95% CI 4.64–7.54), but also predicted pensioning for mental disorder (HR = 3.13, 95% CI 2.20–4.46) and other diagnoses (HR = 1.81, 95% CI 1.30–2.51). Further adjustments for other common symptoms, including mental illness, reduced, but did not abolish these risks. WSP is a major risk factor for disability pensions, and not only pensions for musculoskeletal disorders. The global impact of WSP, and its close association to other symptoms, suggests prevention of the severe occupational outcomes for this group must have a broad focus and move beyond symptom directed approaches.

Lost Working Years Due to Mental Disorders: An Analysis of the Norwegian Disability Pension Registry

Objectives Mental disorders are prevalent diagnoses in disability benefit statistics, with awards often granted at younger age than for other diagnoses. We aimed to compare the number of lost working years following disability benefit award for mental disorders versus other diagnostic groups. Methods Data from the complete Norwegian official registry over disability benefit incidence, including primary diagnoses, were analyzed for the period 2001 to 2003 (N = 77,067), a time-period without any reform in the disability benefit scheme. Lost working years due to disability benefit award before scheduled age retirement at age 67 were calculated. Results Musculoskeletal disorders were the commonest reason for disability benefit awards (36.3%) with mental disorders in second place (24.0%). However, mental disorders were responsible for the most working years lost (33.8%) compared with musculoskeletal disorders (29.4%). Individuals awarded disability benefit for a mental disorder were on average 8.9 years younger (46.1 years) than individuals awarded for a musculoskeletal disorder (55.0 years), and 6.9 years younger than individuals awarded for any other somatic disorder (53.0 years). Anxiety and depressive disorders were the largest contributors to lost working years within mental disorders. Conclusion Age at award is highly relevant when the total burden of different diagnoses on disability benefits is considered. There is great disparity in total number of lost working years due to disability benefit award for different diagnostic groups. The high number of lost working years from mental disorders has serious consequences for both the individual and for the wider society and economy.

Psychometric properties and concurrent validity of the CRAFFT among Norwegian adolescents. Ung@hordaland, a population-based study.

The aim of the study was to examine the psychometric properties of the CRAFFT-questionnaire, and its concurrent validity with self-reported measures of alcohol consumption and illicit drug use ever among Norwegian adolescents. This study employs data from the ung@hordaland survey (N=9680). The concurrent validity of the CRAFFT-questionnaire was examined both as a case-finder with different cut-offs, but also as an ordinal scale. The ordinal scale was constructed by counting the number of affirmative responses from 0 to 6. Current self-reported excessive alcohol consumption, frequent binge drinking and any illicit drug use ever were employed as concurrent validity measures. The internal reliability of CRAFFT was adequate, and there was a linear relationship between CRAFFT-score and excessive alcohol consumption, frequent binge drinking and illicit drug use ever for both genders. Overall, this study shows a good concurrent validity and adequate psychometric properties of the CRAFFT-questionnaire. There results indicate, however, that the use of CRAFFT as a case-finder needs further research, as a suitable cut-point was difficult to determine. The authors conclude that in a clinical setting one positive answer is enough to warrant further investigation, and for research purposes the use of the questionnaire as an ordinal scale or using a cut-point of 2 might be preferable.

Long-term sickness absence among patients with chronic fatigue syndrome

Chronic fatigue syndrome is associated with high levels of occupational disability. Consecutive out-patients at a chronic fatigue syndrome treatment service were studied for associations between occupational status, symptom severity and cognitive and behavioural responses to symptoms. All patients had high symptom levels; however, those on long-term sickness absence had significantly more physical fatigue (β = 0.098, P<0.05) and worse sleep (β = 0.075, P<0.05). Patients with long-term sickness absence also demonstrated more embarrassment avoidance cognitions (β = 0.086, P<0.05) and avoidance resting behavioural responses (β = 0.078, P<0.05). Identifying and addressing avoidance behaviours and cognitions regarding embarrassment in interventions may enhance the chances of individuals returning to work.

An overview of cognitive mechanisms in pathological gambling

This paper presents an overview of the literature published on “cognitive biases” and gambling from 1960 till the present day. Typical cognitive biases are an individual’s irrational beliefs, cognitive distortions and erroneous perceptions about his or her ability to influence, control or predict the outcome of a chance event; these appear to be important for the maintenance of gambling related behaviour. Overall, the research suggests that cognitive factors are important in developing gambling addiction, but may be less important when gambling becomes habitual or regulated by automatic processes. Regardless of whether the behaviour is explained by reinforcement, needs or cognitive theories, it is still unclear why some individuals gamble more than others.