Potentially traumatic events as predictors of disability pension: A 10-year follow-up study in Norway.

AIMS: Are potentially traumatic events associated with subsequent disability pension? Traumatic exposure and post-traumatic stress disorder (PTSD) may represent a disabling state with both personal and professional consequences for the affected individual. Despite this, there is a scarcity of research studying the effects of traumatic exposure on disability pension. This study examined the differences in risk for disability pension among unexposed, exposed to trauma and PTSD cases. METHODS: An ambidirectional Norwegian cohort study, consisting of 1238 individuals aged 18-66 years who were at risk of disability pension, were interviewed using the Composite International Diagnostic Interview, and linked with registry data on disability pension. Registry follow-up in the Norwegian Insurance Database lasted ten years following interview in 2000-01. The risk of disability pension after traumatic exposure, divided into accidental and premeditated, was assessed by Cox proportional hazards regression analysis. RESULTS: In 10 years, 9.5% of the cohort had been granted disability pension. Overall exposure to traumatic events did not alter the risk of disability pension. However, among women, exposure to premeditated traumas did increase the risk (HR 2.96 (95% CI 1.54-5.68)), and was an independent risk factor. Fulfilling criteria for PTSD caseness further increased the risk (HR 4.69 (95% CI 1.78-12.40)). There was no increased risk found between traumatic exposure and disability pension for men. CONCLUSIONS: Exposure to trauma, particularly premeditated trauma, seems to be an independent risk factor for disability pension in women.

The epidemiology of post-traumatic stress disorder in Norway: trauma characteristics and pre-existing psychiatric disorders.

PURPOSE: The prevalence of PTSD differs by gender. Pre-existing psychiatric disorders and different traumas experienced by men and women may explain this. The aims of this study were to assess (1) incidence and prevalence of exposure to traumatic events and PTSD, (2) the effect of pre-existing psychiatric disorders prior to trauma on the risk for PTSD, and (3) the effect the characteristics of trauma have on the risk for PTSD. All stratified by gender. METHOD: CIDI was used to obtain diagnoses at the interview stage and retrospectively for the general population N = 1634. RESULTS: The incidence for trauma was 466 and 641 per 100,000 PYs for women and men, respectively. The incidence of PTSD was 88 and 31 per 100,000 PYs. Twelve month and lifetime prevalence of PTSD was 1.7 and 4.3 %, respectively, for women, and 1.0 and 1.4 %, respectively, for men. Pre-existing psychiatric disorders were risk factors for PTSD, but only in women. Premeditated traumas were more harmful. CONCLUSION: Gender differences were observed regarding traumatic exposure and in the nature of traumas experienced and incidences of PTSD. Men experienced more traumas and less PTSD. Pre-existing psychiatric disorders were found to be risk factors for subsequent PTSD in women. However, while trauma happens to most, it only rarely leads to PTSD, and the most harmful traumas were premeditated ones. Primary prevention of PTSD is thus feasible, although secondary preventive efforts should be gender-specific.

Predicting disability pension - depression as hazard: a 10 year population-based cohort study in Norway.

Disability pension (DP) is an escalating challenge to individuals and the welfare state, with mental health problems as imminent hazard. The objective of the present paper was to determine if a diagnosis of depression increased the risk of subsequent DP, and whether the risk differed by gender. A population cohort of 1230 persons were diagnostically interviewed (Composite International Diagnostic Interview, CIDI) in a population study examining mental health, linked to the DP registry and followed for 10 years. The risk for DP following depression was estimated using Cox regression. Life-time depression, as well as current depression, increased the risk of subsequent DP for both genders. The fully adjusted [baseline health, health behavior and socio-economic status (SES)] hazard ratios (HRs) for life-time depressed men and women were 2.9 [95% confidence interval (CI) 1.5-5.8] and 1.6 (95% CI 1.0-2.5) respectively. Men were significantly older at time of DP. There are reasons to believe that depression went under-recognized and under-treated. To augment knowledge in the field, without underestimating depression as risk for DP, a deeper understanding of the nature and effects of other distress is needed.

Changes in formal help seeking for psychological distress: the OsLof study.

BACKGROUND: Data from the Norwegian HUNT suggests that only 10-13% of individuals suffering from depression and anxiety have sought professional help, fuelling concerns that only a fraction of individuals with clinically significant mental health problems receive adequate treatment in Norway. AIM: The aim of this study was to examine formal help seeking for psychological distress in two communities in Norway (one urban and one rural) over time, in relation to the prevalence of distress. In addition, the proportion with potential unmet need for professional help was examined. METHODS: A randomly drawn selection of individuals from Oslo (urban) and Lofoten (rural), the OsLof study, were interviewed about help seeking and administered the Hopkins Symptom Checklist (HSCL-25) in 1990 and 2001. RESULTS: Results showed a significant shift in help seeking over time, whereas the prevalence of distress (HSCL-25 >or= 1.75) remained stable in both communities, ranging between 13% and 16%. A significant increase occurred in the proportion seeking help from psychiatrists/psychologists, together with a significant decrease in help seeking from GPs and non-medical services. CONCLUSION: Multiple explanatory factors might account for the decline in overall formal help seeking, such as the improvement in the economical situation observed across the decade. No urban-rural difference in help seeking was observed, despite Oslo having a higher calculated man-labour year in psychiatric services. Even though potential unmet need has been decreasing among the psychologically distressed, only 40% had sought help from mental health professionals in 2001, indicating the need of the speciality health services to address this issue further.

Selection effects in psychiatric epidemiology: a 14-year prospective study of the Hopkins Symptom Check List-25 as a predictor of mortality in the Norwegian general population.

BACKGROUND: Inconsistent findings in studies examining the association between mental health problems and mortality have suggested study design as a source of discrepancy. This study investigates if selection bias is introduced by an extensive personal interview, recruiting a healthier population, and furthermore examines the association between mental distress and mortality. METHOD: The OsLof study consists of a random population-based sample of 2,014 persons above 18 years that participated in an interview in 1989, including the Hopkins Symptom Check List-25 (HSCL-25). A second material was drawn as an approximate 1% sample of the Norwegian population (N = 31.907). Both samples were followed up until 2003, emigration or death. Hazard rates were estimated by Cox regression and piecewise exponential survival regression. RESULTS: Mortality rates were similar regardless of HSCL, and lower than in the 1% population sample, in the first 2 years of follow-up. A higher mortality rate in those with HSCL > or = 1.75 appeared after 8 years of follow-up, and after 12 years the mortality rate was 1.57 times higher than in the population sample. CONCLUSION: Studies of predictors ought to have a long follow-up, as several years might pass before differences in mortality are revealed. Due to selection effects, short follow-up might lead to erroneously believing predictors to be protective. This study was consistent with other studies with long follow-up, showing higher mortality associated with mental distress.

Sensitivity analysis for unmeasured confounding in a marginal structural Cox proportional hazards model.

Sensitivity analysis for unmeasured confounding should be reported more often, especially in observational studies. In the standard Cox proportional hazards model, this requires substantial assumptions and can be computationally difficult. The marginal structural Cox proportional hazards model (Cox proportional hazards MSM) with inverse probability weighting has several advantages compared to the standard Cox model, including situations with only one assessment of exposure (point exposure) and time-independent confounders. We describe how simple computations provide sensitivity for unmeasured confounding in a Cox proportional hazards MSM with point exposure. This is achieved by translating the general framework for sensitivity analysis for MSMs by Robins and colleagues to survival time data. Instead of bias-corrected observations, we correct the hazard rate to adjust for a specified amount of unmeasured confounding. As an additional bonus, the Cox proportional hazards MSM is robust against bias from differential loss to follow-up. As an illustration, the Cox proportional hazards MSM was applied in a reanalysis of the association between smoking and depression in a population-based cohort of Norwegian adults. The association was moderately sensitive for unmeasured confounding.

Self-reported work ability of Norwegian women in relation to physical and mental health, and to the work environment.

OBJECTIVES: To examine the self-reported level of work ability among female employees and the relationship between work ability and demographic characteristics, physical health, mental health, and various psychosocial and organizational work environment factors. METHODS: Participants were 597 female employees with an average age of 43 years from urban and rural areas in Norway. Trained personnel performed a structured interview to measure demographic variables, physical health, and characteristics of the working environment. Mental health was assessed using the 25-item version of the Hopkins Symptoms Checklist (HSCL-25). Work ability was assessed using a question from the Graded Reduced Work Ability Scale. RESULTS: Of the 597 female employees, 8.9% reported an extremely or very reduced ability to work. Twenty-four percent reported poor physical health and 21.9% reported mental distress (>/= 1.55 HSCL-25 cut-off). Women, who reported moderately and severely reduced work ability, did not differ a lot. Moderately reduced work ability increased with age and was associated with physical and mental health. Severely reduced work ability was strongly associated only with physical health and with unskilled occupation. Of eight work environment variables, only three yielded significant associations with work ability, and these associations disappeared after adjustment in the multivariate analysis. CONCLUSION: Results indicate that ageing, in addition to poor self-reported physical health and unskilled work, were the strongest factors associated with reduced work ability among female employees. Impact of work environment in general was visible only in univariate analysis.

Overlap, comorbidity, and stability of somatoform disorders and the use of current versus lifetime criteria.

The authors examined disorder overlap, comorbidity, stability, and predictors of somatoform disorders (SDs) by "lifetime" and "current" symptom criteria in a general population sample of 421 respondents interviewed with the Composite International Diagnostic Interview in 1990 and 2001. Disorder overlap and comorbidity were considerable. "Current" SDs were four times more likely to occur among respondents with depression. Diagnostic stability was highest for "current" SDs (retrospective consistency: 42%). Young women were more prone to a stable (chronic) course over time. Previous depression and physical disease were risk factors for "current" but not for "lifetime" SDs; diagnostic criteria should therefore be based on current symptoms.

Changes in body mass index by age, gender, and socio-economic status among a cohort of Norwegian men and women (1990-2001).

BACKGROUND: Consistent with global trends, the prevalence of obesity is increasing among Norwegian adults. This study aimed to investigate individual trends in BMI (kg/m2) by age, gender, and socio-economic status over an 11-year period. METHODS: A cohort of 1169 adults (n = 581 men; n = 588 women) self-reported BMI during a general health interview twice administered in two regions in Norway. RESULTS: Average BMI increased significantly from 23.7 (SD = 3.4) to 25.4 (SD = 3.8), with equivalent increases for both genders. Proportion of obesity (BMI > or = 30) increased from 4% to 11% for women and 5% to 13% for men. Of those already classified as overweight or obese in 1990, 68% had gained additional weight 10 years later, by an average increase of 2.6 BMI units. The greatest amount of weight gain occurred for the youngest adults (aged 20-29 years). Age-adjusted general linear models revealed that in 1990, women with a lower level of education had a significantly greater BMI than more educated women. In both 1990 and 2001, rural men with the highest level of household income had a greater BMI than rural men earning less income. Weight gain occurred across all education and income brackets, with no differential associations between SES strata and changes in BMI for either gender or region. CONCLUSION: Results demonstrated significant yet gender-equivalent increases in BMI over an 11-year period within this cohort of Norwegian adults. Whereas socio-economic status exerted minimal influence on changes in BMI over time, young adulthood appeared to be a critical time period at which accelerated weight gain occurred.

Urban-rural differences in BMI, overweight and obesity in Norway (1990 and 2001).

AIM: The aim of this study was to examine body mass index and the prevalence of overweight and obesity in 1990 and 2001 in Oslo and Lofoten, Norway. METHODS: A randomly selected study population of 1,924 individuals (OsLof) underwent a structured personal interview in 1990. In 2001, 1629 individuals underwent the same interview. These samples were analysed as two cross-sectional datasets. RESULTS: Overall mean BMI in 1990 was 24.7 for men and 22.9 for women, increasing significantly in 2001 to 26.1 and 24.6, respectively. In 1990, 37% of men and 20% of women were overweight, while 5% of men and 4% of women were obese. The corresponding figures for 2001 were 48% and 27% for overweight, and 12% and 11% for obesity, respectively. DISCUSSION: The greatest increases in average BMI occurred for the youngest (18-34 years) for both genders and geographic regions. In 1990, urban-rural differences existed for mean BMI and proportion overweight for both genders, although geographic differences persisted only for women 10 years later.

Current somatoform disorders in Norway: prevalence, risk factors and comorbidity with anxiety, depression and musculoskeletal disorders.

BACKGROUND: The future existence of somatoform disorders (SDs) has recently been debated. The objectives of this study were to investigate the prevalence of current SDs (defined as the presence of multisomatoform disorder [MSD] or somatoform disorders not otherwise specified [SDnos], without psychosocial impairment) and severe current SDs (MSD or SDnos with psychosocial impairment) in Norway. Differences in markers of severe current SDs, anxiety/depression and self-reported musculoskeletal disorders were explored. In addition, psychological distress and utilization of healthcare in subclasses (defined according to comorbidity with anxiety, depression and musculoskeletal disorders) of severe current SDs were examined. METHODS: We interviewed 1,247 respondents using the Composite International Diagnostic Interview (CIDI) in the Oslo-Lofoten general population survey in 2000-2001. Six-month prevalence rates (%) and 95% confidence intervals (CIs) for current SDs were investigated by gender and age. Risk factors of disorders, psychological distress, healthcare utilization and use of medication were explored using logistic regression analyses. RESULTS: The overall prevalence rate for severe current SDs was 10.2%. When psychosocial impairment was excluded as a criterion, the rate increased to 24.6%. Anxiety was strongly correlated with severe current SDs. Comorbidity of severe current SDs with anxiety/depression was 45%, and with musculoskeletal disorders, 43%. Analysis of healthcare utilization and use of medication showed that the presence of a comorbid psychiatric condition was more important than the presence of somatoform disorders alone. CONCLUSION: Somatoform symptoms alone (with no psychiatric comorbidity) should not be considered a psychiatric disorder.

Structure analysis of Antonovsky's sense of coherence from an epidemiological mental health survey with a brief nine-item sense of coherence scale.

Antonovsky has proposed the sense of coherence (SOC) as a crucial factor that protects against symptoms of mental disease. A central issue in research on the SOC construct is whether this is most appropriately considered as one-dimensional or three-dimensional with comprehensibility (C), manageability (Ma) and meaningfulness (Me) as separate dimensions. In this paper we address this issue by means of confirmatory factor analysis of a shortened nine-item version of Antonovsky's original 29- and 13-items Sense of Coherence Scale (SOCS-29), using epidemiological data from a mental health survey of adults in local communities (N = 1,062). In addition to analysing the internal structure of the SOC items, we examine the association between estimated factor scores and variables expected to be statistically related to SOC. Goodness-of-fit indices were very good for the three-factor model but acceptable even for the one-factor model. In the three-factor model, however, the factors were found to be very highly or, with regard to Ma and C, even perfectly correlated. Moreover, the factor scores had very similar correlations with measures of psychological wellbeing, depression and anxiety and they are also very similarly related to age (and none of them are related to gender). We therefore conclude in favour of a one-factor model.

Course and predictors of medically unexplained pain symptoms in the general population.

OBJECTIVE: The objective of this study was to explore the course and the predictors of clinically significant medically unexplained pain symptoms (MUS-pain) within the 6 months preceding the interviews at baseline and on follow-up in the general population. METHODS: A Norwegian general population study of 605 persons interviewed with the Composite International Diagnostic Interview Somatoform Section was conducted in 1989/1990 (baseline), and 421 persons (69.6% response rate; 242 women and 179 men) were reinterviewed in 2000/2001 (follow-up). Cases of recent MUS-pain compared with those at baseline were assessed on follow-up. Four blockwise logistic regression analyses were undertaken to find predictors (such as stressful life events, living alone, depression and anxiety, and physical morbidity) for recent MUS-pain in 2001. RESULTS: A small "stable" group of recent MUS-pain sufferers (8% of all reinterviewed and 33.6% of those with recent MUS-pain at baseline) was evident. In this group almost all were women. In addition to female gender being a significant (P<.05) marker of recent MUS-pain (which gives a twofold-higher risk compared with men), only depression--not the occurrence of prior recent MUS-pain--remained a significant (P<.05) predictor in the final model, increasing the likelihood of having recent MUS-pain by threefold. CONCLUSION: The prognosis of MUS-pain is relatively good, except for a small group (mainly women) that is prone to chronicity. Clinicians should examine for depression when confronted with MUS-pain patients and should be aware of the twofold-higher risk in women for persistent MUS-pain over a long time.

Emotional distress as a predictor for low back disability: a prospective 12-year population-based study.

STUDY DESIGN: A population-based, prospective cohort. OBJECTIVE: To study associations between emotional distress and long-term low back disability in a general population. SUMMARY OF BACKGROUND DATA: In primary and hospital care studies, emotional, cognitive, and personality factors have been associated with low back disability, while the association between distress and novel back pain episodes has been uncertain. METHODS: A randomly drawn cohort of 1152 occupationally active persons aged 20-55 years was interviewed with a comprehensive psychosocial questionnaire in 1990, and was followed for 12 years in national registers over sickness, rehabilitation, and disability benefits. Data on emotional distress, earlier low back pain (LBP), education, life style, psychosocial, and work-related factors were collected at baseline. RESULTS: Long-term benefits due to low back disability were granted to 131 persons (11.4%) in the follow-up period. In multivariate analysis, earlier LBP, emotional distress, low grade of education, and high physical job stress were associated with low back disability. Persons with both emotional distress and earlier back pain were most at risk for disability (hazard ratio 2.91, 95% confidence interval 1.60-5.29). Persons with emotional distress but no earlier episodes of LBP had no increased risk for low back disability (hazard ratio 0.71, 95% confidence interval 0.34-1.45). CONCLUSIONS: Emotional distress is a predictor for low back disability in persons with earlier LBP, but not in persons without. To prevent low back disability, emotional distress should be considered and treated in persons with LBP.

Return of depressed men: changes in distribution of depression and symptom cases in Norway between 1990 and 2001.

BACKGROUND: Women's elevated risk of depression compared to men is a common finding in psychiatric epidemiology. Studies conducted in the 1950s and 1970s, however, documented approximately equal prevalence of sex rates. AIM: This study investigated changes in depression rates between 1990 and 2001 in Norway. Further, differences in severity were examined between men and women. METHOD: A study population (later to be called OsLof) was established in 1990, supplemented in 2001, and analysed as two cross-sectional datasets to compare sex and age differences in ICD-10 diagnoses and HSCL-25> or =1.75 caseness. Organic depression and the DSM-IV Major Depressive Episode were also examined in 2001. RESULTS: There was no significant change in the prevalence of depression or HSCL-25 caseness from 1990 to 2001. However, a major shift in prevalence occurred over time within the 18-34 year old age category with significantly higher rates among younger men (1% to 10%) and lowered rates among younger women (10% to 4%). Among persons depressed, no significant differences were found for severity between the sexes. LIMITATIONS: A selection of healthier participants than found in the source population might have resulted in lower prevalence than real. CONCLUSION: There was no indication of an overall increase in depression from 1990 to 2001, neither by diagnosis nor by symptom checklist scores. However, a major shift in prevalence occurred within the 18-34 year old age category with significantly higher rates among younger men and lowered rates among younger women. No sex differences existed in terms of severity of depression.

The impact of psychosocial and organizational working conditions on the mental health of female cleaning personnel in Norway.

BACKGROUND: This study examined the association between psychosocial and organizational work conditions and mental health among women employed in the cleaning profession in Norway. METHODS: Self-report questionnaires were mailed to 661 cleaning staff personnel from seven cleaning organizations in seven different cities across Norway. The response rate was 64%, of which 374 (88%) respondents were women. The questionnaires assessed socio-demographic information and employment history, work organization, and psychosocial working conditions. The Hopkins Symptoms Checklist (HSCL-25) was included to assess mental health. RESULTS: On average, respondents were 43 years old and reported 10.8 years of experience working in the cleaning industry. The proportion of women scoring a HSCL-25 equal to or above 1.75 was 17.5%, which was higher than the average prevalence of mental health problems among working Norwegian women (8.4%). A factor analysis of the questions specific to the psychosocial work environment identified the following four underlying dimensions: leadership, co-workers, time pressure/control, and information/knowledge. Two of these, poor satisfaction with leadership (OR = 3.6) and poor satisfaction with co-workers (OR = 2.3), were significantly related to mental health. In addition, having contact with colleagues less than once a day (OR = 2.4) and not being ethnically Norwegian (OR = 3.0) increased the risk for mental health problems. CONCLUSION: Mental health problems are frequent among female cleaning professionals in Norway. Our results indicate that quality of leadership, collaboration with co-workers, and ethnicity were significantly associated with mental health.

Methodological issues concerning lifetime medically unexplained and medically explained symptoms of the Composite International Diagnostic Interview: a prospective 11-year follow-up study.

OBJECTIVE: The objectives of this study were (a) to elucidate the methodological problems arising when examining lifetime symptom data by exploring the accuracy of recall of medically unexplained symptoms (MUS) and medically explained symptoms (MES) in the general population, based on interviews using the Composite International Diagnostic Interview (CIDI) Somatoform Section C, in 1990 and 2001, and (b) to find predictors for failure at follow-up to recall symptoms reported previously at baseline (i.e., symptoms "lost"). METHODS: Four hundred twenty-one persons (response rate, 69.6%; 242 women and 179 men) were reinterviewed in 2001 from a baseline population of 605. Thirty-eight clinically significant MUS and MES were assessed. Linear multiple regression analyses with the numbers of MUS-lost (medically unexplained symptoms lost to recall) and MES-lost (medically explained symptoms lost to recall) as dependent variables were undertaken to find factors affecting symptom loss. RESULTS: A wide range of individual symptoms (22-100%) were lost to recall at follow-up, indicating a large degree of measurement error, mainly due to faulty recall. The number of symptoms recalled when they were grouped was better (approximately 50% for "1-3" symptoms). Recall variability and MUS/MES transition over time undermined the credibility of this distinction. Gender and age emerged as significant (P<.01) predictors for MUS-lost, and a decrease in physical morbidity for MES-lost. Men tended to forget more symptoms than women, and younger respondents with high levels of baseline MUS remembered slightly better at follow-up. CONCLUSION: Lifetime symptom data elicited in community surveys by such instruments as the CIDI should be viewed with caution. Methodological errors weakening data credibility could lead to false impressions of true change over time. A MUS/MES distinction is difficult to maintain.

Cigarette smoking and incidence of first depressive episode: an 11-year, population-based follow-up study.

Smoking has been found to be associated with depression. Biologic hypotheses support causation in both directions. This study examined the association between cigarette smoking and a subsequent first depression. In 1990, 2,014 adults in Norway were interviewed about their lifestyle and mental health. A 2001 reinterview by trained interviewers defined the study cohort of 1,190 participants. The cases were those who experienced a first depression whose onset was estimated to occur during the follow-up period, based on retrospective assessment by the Composite International Diagnostic Interview (International Classification of Diseases, Tenth Revision). Cox regression was used to estimate the hazard rate of depression during follow-up. Alternative explanations for a direct causal influence from smoking on subsequent depression were assessed, and a sensitivity analysis was performed. The risk of depression was four times as high for heavy smokers compared with never smokers. A dose-response relation with an increasing hazard for past smokers and for an increasing number of cigarettes smoked per day for current smokers was found. Similarly, increasing smoking time was associated with increasing risk. Failure of other plausible alternatives to explain the observed association between smoking and depression might reflect a direct causal influence of smoking on depression.

Is women's mental health more susceptible than men's to the influence of surrounding stress?

BACKGROUND: Most epidemiological population studies have demonstrated that women suffer more anxiety and depression than men. A higher level of stress, greater vulnerability to stress, and a non-additive effect of private/domestic and occupational obligations on women have been suggested as an explanation. OBJECTIVE: The objective of this study was to examine if women's mental health is more susceptible than men's to the influence of surrounding stress. MATERIAL AND METHOD: A cross-sectional, random sample of the population resulted in 651 men and 626 women, all of whom were employed, participating in the study. Participants were interviewed using face-to-face standardized questionnaires. RESULTS: Younger women experienced more stressful relationship events, illness events and network events than men of the same age. Relationship events were more important for men as they grew older, and interacted with other stress to increase anxiety and depression symptoms. Stressful illness events were more strongly related to anxiety/depression symptoms in women over 40 than in men of the same age, and interacted with work stress to increase symptom scores. CONCLUSION: Stress was more strongly related to symptoms in women, suggesting that they may have a greater susceptibility to surrounding stress, and to somatic illness stress. This might contribute to the sex difference in psychiatric illness.