Longitudinal Register-based Cohort Study Research Articles

Having paid work 1 year after disability claim in different types of mental and behavioural disorders

Abstract Background The majority of claimants diagnosed with a mental and/or behavioral disorder have residual work capacity, however, the chance of actual (return to) work after a disability claim assessment may differ within this diagnosis group depending on the specific type of disease. The aim of this study is to examine the associations of different mental and behavioural diseases with having paid employment one year after the claim assessment. Methods This longitudinal register based cohort study included all work disability applicants with mental and behavioural disorders assessed with residual work capacity in the Netherlands in 2016. Data were derived from the Dutch Social Security Institute (UWV) and were linked to register data on paid employment. ICD codes were used to categorize 11 disease groups (mental retardation, autism spectrum disorders, ADHD, somatoform disorders, adjustment disorders, PTSS, anxiety, personality disorders, mood affective disorders, addictions and delusional disorders. Multivariable logistic regression analyses were conducted separately for applicants who work and not work at time of the claim assessment. Results A total of 8544 claimants (mean age 45, 56% female; n = 1915 work at baseline) were included. In the working group being diagnosed with ADHD (OR 3.05, CI 1.08-8.61) or PTSS (OR 1.45, CI 1.04-2.02) was associated with paid work, and adjustment disorder was negatively associated (OR 0.74, CI 0.56-0.97). In the not-working group, autism spectrum disorder (OR 1.51, CI 1.02-2.22), personality disorder (OR 1.36, CI 1.02-1.81) and addiction (OR 1.94, CI 1.32-2.86) was associated with return to work, and somatoform (OR 0.51, CI 0.31-0.84) disorders and mood affective disorders (OR 0.83, CI 0.70-0.99) were negatively associated. Conclusions The findings of this study show different associations between type of mental and behavioural disease groups and paid employment one year after the claim assessment. Key messages • The association of either remaining at work or return to work is different among mental and behavioural diagnosis groups, therefore a different approach is indicated. • Active interventions to facilitate return to or remain at work might be indicated in specific diagnosis groups.

Mortality among Swedish seafarers 1985-2013.

The aim was to investigate mortality among Swedish seafarers compared to the general population, and differences in mortality between occupational categories and differences over time. Longitudinal register-based cohort study of 85,169 Swedish seafarers registered in the Swedish Transport Agency's Seafarers' Registry (SR) 1985-2013. The cohort was matched with the Swedish Cause of Death Register. Standardized mortality ratios (SMRs) and 95% confidence intervals (CIs) were calculated stratified by gender, job category, start of sea service, and time registered in the SR. Seafarers were followed until 66 years of age. Mortality by diseases was analyzed for seafarers with at least 5 years of sea service and mortality due to external causes was analyzed for all seafarers. Total mortality was increased among men who started to work before 1985 (SMR: 1.27, 95% CI: 1.21-1.32) and borderline significantly increased among women (SMR: 1.14, 95% CI: 0.99-1.32). Mortality ratios due to lung cancer, accidents, suicides, and mental disorders including substance abuse, were increased among seafarers who started to work before 1985. Mortality risks were particularly increased among the crew. SMRs tended to decrease over time, but mortality due to accidents was still increased among the crew who started to work 1985 or later (SMR: 1.64, 95% CI: 1.02-2.63). Swedish seafarers had an increased mortality compared to the general population in 1985-2013, particularly the crew. There is still an increased mortality in accidents among crew who started to work 1985 or later.

Inability to Work Fulltime and the Association with Paid Employment One Year After the Work Disability Assessment: A Longitudinal Register-Based Cohort Study.

Disability benefit applicants with residual work capacity are often not able to work fulltime. In Dutch work disability benefit assessments, the inability to work fulltime is an important outcome, indicating the number of hours the applicant can sustain working activities per day. This study aims to gain insight into the association between inability to work fulltime and having paid employment 1 year after the assessment. The study is a longitudinal register-based cohort study of work disability applicants who were granted a partial disability benefit (n = 8300). Multivariable logistic regression analyses were conducted to study the association between inability to work fulltime and having paid employment 1 year after the assessment, separately for working and non-working applicants. For disability benefit applicants, whether working (31.9%) or not working (68.1%) at the time of the disability assessment, there was generally no association between inability to work fulltime and having paid employment 1 year later. However, for working applicants diagnosed with a musculoskeletal disease or cancer, inability to work fulltime was positively and negatively associated with having paid employment, respectively. For non-working applicants with a respiratory disease or with multimorbidity, inability to work fulltime was negatively associated with paid employment. Inability to work fulltime has limited association with paid employment 1 year after the disability benefit assessment, regardless of the working status at the time of assessment. However, within certain disease groups, inability to work fulltime can either increase or decrease the odds of having paid employment after the assessment.

Psychiatric disorders and mortality due to external causes following diagnosis of endometriosis at a young age: a longitudinal register-based cohort study in Finland

BackgroundEndometriosis diagnosed in adults is associated with increased risk of various psychiatric disorders. However, little is known concerning psychiatric comorbidity and mortality due to external causes associated with endometriosis diagnosed at a young age. Objective(s)In this longitudinal cohort study, we investigated the link between surgical diagnosis of endometriosis at a young age, and subsequent psychiatric disorders and mortality due to external causes. Additionally, we compared the occurrence of the most common psychiatric disorders between different sites of surgically confirmed endometriosis (ovarian versus other) due to possible different pain manifestations. Study DesignWe conducted a retrospective register-based cohort study. Altogether 4532 women with surgically confirmed diagnosis of endometriosis before the age of 25 in 1987–2012 were identified from the Finnish Hospital Discharge Register and matched with women without surgically diagnosed endometriosis for age and municipality on the index day (n=9014). Women were followed from the index day until the end of 2019 for the outcomes of interest, which included nine groups of psychiatric disorders (inpatient episodes since 1987, outpatient episodes since 1998) and death due to external causes, including deaths due to accidents, suicides, and violence (Finnish Register of Causes of Death). Cox proportional hazard models were applied to assess the crude and parity-adjusted hazard ratios and 95% confidence intervals. ResultsThe cohort’s median age was 22.9 years (interquartile range: 21.3–24.1) at the beginning and 42.5 years (36.7–48.3) after a median follow-up time of 20.0 years (14.5–25.7). We observed a higher hazard of depressive, anxiety, and bipolar disorders in women with endometriosis compared to the reference cohort. These differences appeared early and remained the same during the entire follow-up, irrespective of whether assessed from the data on inpatient episodes only, or using data on both in- and outpatient episodes. The corresponding adjusted hazard ratios were 2.57 (95% confidence interval 2.11–3.14) and 1.87 (1.65–2.12) for depressive disorders, 2.40 (1.81–3.17) and 2.09 (1.84–2.37) for anxiety disorders, 1.71 (1.30–2.26) and 1.66 (1.28–2.15) for bipolar disorders, respectively. A higher hazard was seen for nonorganic sleeping disorders for the first ten years only (3.83, 2.01–7.30) when assessed using the data on both in- and outpatient episodes. When based on inpatient records, a higher hazard for alcohol/drug dependence after 15 years of follow-up (2.07, 1.21–3.54) was observed. The difference in hazard for personality disorders tended to increase during follow-up (<10 years 2.12, 1.28–3.52; 10 years or more 3.08, 1.44–6.57). Depressive and anxiety disorders occurred more frequently in women with other than ovarian endometriosis. No difference in deaths due to external causes was observed between the endometriosis and reference cohorts. Conclusion(s)Surgical diagnosis of endometriosis at young age associated with increased incidence for several psychiatric disorders. Moreover, within the endometriosis population, psychiatric comorbidity was more common in women with other than ovarian endometriosis. We speculate that chronic pain is essential in the development of these psychiatric disorders, and that early and effective pain management is important in reducing the risk of psychiatric morbidity in young women. More research concerning the associations and management of endometriosis and associated psychiatric disorders is warranted.

Diabetic retinopathy is a predictor of chronic respiratory failure: A nationwide register-based cohort study

PurposeDiabetic retinopathy (DR) is a hypoxic retinal disease, but so far, the association with systemic hypoxia is poorly understood. Hence, the aim of this study was to evaluate cross-sectional and longitudinal associations between DR and chronic respiratory failure (CRF) in a national cohort. DesignCross-sectional and 5-year longitudinal register-based cohort study. MethodsBetween 2013 and 2018, we included patients with diabetes from the Danish Registry of Diabetic Retinopathy, who were each age and sex matched with five controls without diabetes. At index date, the prevalence of CRF was compared between cases and controls, and the longitudinal relationship between DR and CRF was assessed in a five-year follow-up. ResultsAt baseline, we identified 1,980 and 9,990 patients with CRF among 205,970 cases and 1,003,170 controls. The prevalence of CRF was higher among cases than controls (OR 1.75, 95% CI 1.65–1.86), but no difference between cases with and without DR was found.During follow-up, we identified 1,726 and 5,177 events of CRF among cases and controls, respectively. The incidence of CRF was higher among both cases with and without DR compared to controls (DR level 0: HR 1.24, 95% CI 1.16–1.33, DR level 1–4: HR 1.86, 95% CI 1.63–2.12), and higher among cases with DR compared to cases without DR (HR 1.54, 95% CI 1.38–1.72). ConclusionIn this study based on nationwide data, we found an increased risk of present and incident CRF in patients with diabetes with or without DR, and we identified DR as a predictor of future CRF.

Financial difficulties among youth prenatally exposed to substances: a longitudinal register-based cohort study

Aim The receipt of long-term financial social assistance (FSA) as an indicator of financial difficulties among Finnish youth with prenatal substance exposure (PSE) was investigated in comparison with unexposed youth. Methods Data from national health and social welfare registers were collected for 18–24-year-old exposed (n = 355) and unexposed (n = 1011) youth. The influence of youth and maternal characteristics and out-of-home care (OHC) on the association between PSE and youth’s long-term FSA receipt was studied by generalized linear models and mediation analyses. Results Exposed youth had an increased likelihood of long-term FSA receipt (OR 4.89, 95% CI 3.76, 6.37) but the difference with unexposed was attenuated following adjustments for youth and maternal characteristics and OHC (AOR 1.33, 95% CI 0.89, 1.98). Maternal long-term FSA receipt (0.48, 95% CI 0.35, 0.64) and OHC (0.63, 95% CI 0.47, 0.83) mediated a large proportion of the association between PSE and youth’s long-term FSA receipt. Youth’s mental or behavioral disorders partly mediated the association (0.21, 95% CI 0.14, 0.30), but the mediating effect of lack of secondary education was minor (0.03, 95% CI 0.01, 0.07). Conclusion Receipt of long-term FSA among youth with PSE likely reflects maternal substance abuse linked with maternal financial situation and care instability in childhood.

Adverse childhood experiences and neurodevelopmental disorders among youth with and without prenatal substance exposure: A longitudinal matched register-based cohort study.

Background: Previous research has shown an association between adverse childhood experiences (ACEs) and secondary mental health problems in youth with prenatal substance exposure (PSE), but the association between ACEs and neurodevelopmental disorders is less clear. Methods: This longitudinal register-based cohort study investigated relationships between health at birth, ACEs (out-of-home care (OHC) and maternal adversities), and neurodevelopmental disorders among youth with PSE (alcohol/drugs, n = 615) and matched unexposed controls (n = 1787). Hospital medical records and register data were merged and analysed using Cox regression models. Results: Conduct and emotional disorders (International Statistical Classification of Diseases and Related Health Problems ICD-10, F90-F94) were more common among the exposed than the controls but only when the exposed and controls with no OHC were compared. The difference appeared in hyperkinetic disorders (ADHD, F90), mixed disorders of conduct and emotions (F92) and emotional disorders with onset specific to childhood (F93). Among the exposed and controls with OHC, over 40% had received an F90-F94 diagnosis. Regarding specific developmental disorders (F80-F83, e.g., impairments in speech and language and scholastic skills) the moderate difference between the exposed and controls attenuated after adjustment for OHC. Again, the rates were highest among the exposed with OHC and the controls with OHC. OHC and maternal risks were interrelated and, together with male sex and low birth weight, were associated with neurodevelopmental disorders both among the exposed and controls and decreased the difference between them. Conclusions: A strong association between ACEs and neurodevelopmental disorders was found. Brain research is needed to examine whether ACEs worsen neurodevelopmental outcomes caused by PSE.

Out-of-home care and diagnosed mental and behavioral disorders among youth with and without prenatal substance exposure – A longitudinal register-based cohort study

A majority of youths with prenatal substance exposure (PSE) have experienced out-of-home care (OHC), but there is a lack of studies on its association with mental health in adolescence and adulthood. The main aim of this retrospective longitudinal cohort study was to explore whether type of OHC (family/institutional) and number of OHC placements are associated with mental and behavioral disorders among youth with PSE (n = 393) and unexposed controls (n = 147) after controlling for the effect of important confounding factors. Before these analyses, characteristics of OHC and factors associated with the age at entry to care were analyzed separately in both groups. Data from hospital medical records and nine registers were merged and analyzed using descriptive statistics, Pearson correlations and multivariate Cox regression models. Exposed youths entered OHC earlier in life, and the lifetime duration of OHC was longer with more placements and a higher proportion of family-type OHC. Despite these differences in OHC history, a high number of placements was associated with behavioral and emotional disorders with onset in childhood and adolescence (International Statistical Classification of Diseases ICD-10, F90-F98) among both the exposed and controls. Among the exposed, the number of placements and institutional care were also associated with later appearing mental and behavioral disorders (F10-F69). The results suggest that interventions to support placement stability and favor family-type care could be beneficial in the promotion of mental health among children and youth entering OHC.

Mood and neurotic disorders among youth with prenatal substance exposure: A longitudinal register-based cohort study

BackgroundPrenatal substance exposure is associated with mood and neurotic disorders but this association is complex and understudied. This study investigated the recorded use of specialised healthcare services for mood and neurotic disorders among youth with prenatal substance exposure in comparison with an unexposed matched cohort. Furthermore, the influence of adverse maternal characteristics and out-of-home care (OHC) is investigated. MethodsThis longitudinal register-based matched cohort study included 594 exposed and 1735 unexposed youth. Cox proportional hazard regression models were applied to study the first episode of mood and neurotic disorders in specialised healthcare from 13 years of age, and the influence of adverse maternal characteristics and OHC. Mediation analysis was applied to study the mediating effect of OHC on the association between prenatal substance exposure and the disorders. ResultsThe exposed cohort had a two-fold higher likelihood of being treated at specialised healthcare for mood and neurotic disorders compared with the unexposed cohort (HR 2.34, 95% CI 1.86–2.95), but this difference was attenuated to non-significant levels (AHR 1.29, 95% CI 0.92–1.81) following adjustments with adverse maternal characteristics and OHC. OHC mediated 61% (95% CI 0.41–0.94) of the association between prenatal substance exposure and youth's mood and neurotic disorders. LimitationsRegister data likely include more severe cases of disorders, and as an observational study, causality cannot be assessed. ConclusionMood and neurotic disorders are more common following prenatal exposure to substances and interlinked with significant adversities in the postnatal caregiving environment and OHC.

Healthcare use, sickness absence, and disability pension among colorectal cancer survivors and population references in Sweden

Background Colorectal cancer (CRC) has negative long-term impacts on survivors’ health and work capacity. We aimed to investigate specialized healthcare use and sickness absence and disability pension among CRC survivors and matched references. Material and methods In this longitudinal register-based cohort study, 6679 patients with a first primary CRC in 2008–2011 (when aged 18–62) and 26,716 CRC-free matched references were followed from 2 years before up to 5 years after diagnosis date. Mean numbers of hospital days and outpatient visits were illustrated for survivors and references for the 7-year period. Crude and adjusted mean numbers of sickness absence/disability pension net days were calculated for post-diagnosis Years 3 and 5. Results Survivors’ healthcare use was higher compared to their references throughout the 7 years around CRC diagnosis and was mostly due to CRC, secondary neoplasms, and digestive disorders. In Year 5, survivors had 1.94 mean outpatient visits and 2.13 mean inpatient days (compared to 1.00 and 0.82 for references, respectively). Survivors’ adjusted mean sickness absence/disability pension days amounted to 85 d in Year 3 and 77 in Year 5 (compared to 57 and 54 d in the references). Higher mean number of future days was found among women, lower-educated, foreign-born, with previous comorbidities or previous mental disorders. Those with many sickness absence days in 2 years pre-diagnosis had the highest number of future sickness absence/disability pension days. Conclusions Post-diagnostic healthcare use remained high among CRC survivors, mostly due to cancer (CRC and other neoplasms) and digestive diagnoses. Their sickness absence and disability pension decreased gradually over the period but remained higher than among references. Pre-morbid characteristics may be used in early work-related clinical planning for the survivors.

Overall and diagnosis-specific sickness absence and disability pension in colorectal cancer survivors and references in Sweden

PurposeTo longitudinally investigate overall and diagnosis-specific sickness absence (SA) and disability pension (DP) in colorectal cancer (CRC) survivors and references and to identify potential risk factors.MethodsThis longitudinal register-based cohort study included all patients living in Sweden, diagnosed with a first primary CRC in 2008–2011 when aged 18–62 (n=6679), and their matched references (n=26 716). Net days of SA (in SA spells >14 days) and DP were analyzed from 2 years before through 5 years after diagnosis, overall and by specific diagnoses. Among survivors, risk factors for future SADP were explored using logistic regression.ResultsIn survivors, SA peaked in year 1 postdiagnosis, with 62.5% having at least some SA, and then gradually decreased to 20.1% in year 5. In the 2 years after diagnosis, CRC was the most common SA diagnosis in survivors, while SA due to mental diagnoses remained similar to the references. Notable risk factors for postdiagnostic SA or DP were rectal cancer diagnosis, advanced cancer stage at diagnosis, lower educational level, born outside of Sweden, and pre-diagnostic SA, mental morbidity, and comorbidities.ConclusionDuring 5 years after a CRC diagnosis, CRC survivors had higher levels of postdiagnostic SA and DP than the references, which was mostly due to CRC diagnoses. Although their SA lowered gradually, it did not return to pre-diagnostic levels.Implications for Cancer SurvivorsOur results provide valuable information for patients with CRC diagnosis, especially that most have none or low levels of SA/DP after a few years.

Prenatal substance exposure, adverse childhood experiences and diagnosed mental and behavioral disorders - A longitudinal register-based matched cohort study in Finland.

Both prenatal substance exposure (PSE, alcohol/drugs) and experiences during the first years of life have powerful effects on brain development. However, only a few studies have investigated the combined effect of PSE and adverse childhood experiences (ACEs) on mental and behavioral disorders among exposed adolescents and adults. This longitudinal register-based cohort study 1) compared the nature and extent of diagnosed mental and behavioral disorders among youth with PSE and matched unexposed controls, and 2) investigated the influence of PSE, health in infancy and ACEs (maternal risk factors and out-of-home care, OHC) on diagnoses of mental and behavioral disorders. The data consisted of 615 exposed youth aged 15–24 years and 1787 matched unexposed controls. Data from hospital medical records and nine registers were merged for the analysis. Descriptive analysis methods and Cox regression were used. The results showed that the prevalence of mental and behavioral disorders was twice as high among exposed compared with controls. The highest levels of mental and behavioral disorders and ACEs were found among exposed with at least one OHC episode. The difference in the risk of mental and behavioral disorders between exposed and controls diminished after controlling for the effect of ACEs. Low birth weight, maternal risk factors, and OHC were the strongest predictors of mental and behavioral disorders. The results suggest that PSE alone does not explain poorer mental health among exposed youth. Risk factors accumulate, and low birth weight and ACEs are strongly associated with increased risk of mental and behavioral disorders.

Change in popliteal angle and hamstrings spasticity during childhood in ambulant children with spastic bilateral cerebral palsy. A register-based cohort study

BackgroundMuscle contractures are developing during childhood and may cause extensive problems in gait and every day functioning in children with cerebral palsy (CP). The aim of the present study was to evaluate how the popliteal angle (PA) and hamstrings spasticity change during childhood in walking children with spastic bilateral CP.MethodsThe present study was a longitudinal register-based cohort study including 419 children (1–15 years of age) with spastic bilateral CP, gross motor function classification system (GMFCS) level I, II and III included in the Norwegian CP Follow-up Program (CPOP). From 2006 to 2018 a total of 2193 tests were performed. The children were tested by trained physiotherapists yearly or every second year, depending on GMFCS level and age. The PA and the hamstrings spasticity (Modified Ashworth scale (MAS)) were measured at every time point. Both legs were included in the analysis.ResultsThere was an increase in PA with age for all three GMFCS levels with significant differences between the levels from 1 up to 8 years of age. At the age of 10 years there was no significant difference between GMFCS level II and III. At the age of 14 years all three GMFCS levels had a mean PA above 40° and there were no significant differences between the groups. The hamstrings spasticity scores for all the three GMFCS levels were at the lower end of the MAS (mean < 1+), however they were significantly different from each other until 8 years of age. The spasticity increased the first four years in all three GMFCS levels, thereafter the level I and II slightly increased, and level III slightly decreased, until the age of 15 years.ConclusionThe present study showed an increasing PA during childhood. There were significantly different PAs between GMFCS level I, II and III up to 8 years of age. At the age of 14 years all levels showed a PA above 40°. The spasticity increased up to 4 years of age, but all the spasticity scores were at the lower end of the MAS during childhood.

Regional trends in avoidable hospitalisations due to complications among population with diabetes in Finland in 1996−2011: a register-based cohort study

ObjectivesDiabetes requires continuous medical care including prevention of acute complications and risk reduction for long-term complications. Diabetic complications impose a substantial burden on public health and care delivery. We examined...

Long-term risk factors for substance-induced and primary psychosis after release from prison. A longitudinal study of substance users

PurposeThe purpose of this study was to determine long-term risk factors for substance-induced and primary psychosis after release from prison. MaterialWe used a longitudinal register-based cohort study combining European version of Addiction Severity Index (Europ-ASI) interviews and the Swedish inpatient register. The study included 6217 individuals who were in the Swedish criminal justice system from 2001 to 2006. MeasurementsThe outcomes were substance-induced and primary psychosis as defined by the International Classification of Disease — 10th version. All variables for estimating baseline risk were drawn from the Europ-ASI interview, and included information on substance use, demographics and health. The interview database and the inpatient register were coupled, and groups were compared by using tests of significance and logistic regression. ResultsPolydrug use was the strongest predictor for substance induced psychosis (OR=9.55, 95% CI 3.42–26.67), but all substances imposed an increased risk. Previous psychiatric hospitalization and non-drug related hallucinations were significant, but weaker, risk factors. The only substance variable that predicted primary psychosis was cannabis (OR=2.62, 95% CI 1.39–4.96), but previous psychiatric hospitalization (OR=3.22, 95% CI 2.27–4.54) and non-drug related hallucinations (OR=4.00, 95% CI 2.82–5.67) were even stronger predictors. ConclusionsCannabis use was a risk factor for primary psychosis, but other health related individual risk factors were even more important. Polydrug use was the strongest risk factor for substance-induced psychosis.

Is congenital malformation a risk factor for caries development in Swedish adolescents?

Objective. The aim of this study was to investigate whether various forms of congenital malformations are risk factors for approximal caries development in Swedish adolescents. Materials and methods. This longitudinal register-based cohort study included all adolescents (n = 18 142) of 13 years of age who resided in the county of Stockholm, Sweden, in 2000. The cohort was followed until individuals were 19 years of age. Dental caries (decayed, missing and filled teeth/surfaces (DMFT/S)) were collected from the Public Health Care Administration in Stockholm. Data concerning pre- and perinatal factors and parental socio-demographic determinants were collected from Swedish National Registers. Results. In a logistic regression analysis, neither congenital malformation nor any sub-group of congenital malformation registered at birth were significantly associated with an enhanced risk of approximal caries increment in adolescents between 13–19 years of age. The final multivariate logistic regression model, adjusted for possible maternal and family socio-demographic confounders, showed that congenital malformation of the ‘circulatory system' was significantly associated with a decreased risk of approximal caries increment, between 13–19 years of age (OR = 0.33; 95% CI = 0.12–0.88). Conclusions. Congenital malformation should not be considered as a risk factor for approximal caries development in Swedish adolescents today. Noticeably, adolescents with congenital heart diseases exhibited less risk of developing approximal caries, which was probably related to prevention programs allocated to these children in Sweden.

Unemployment at a young age and later sickness absence, disability pension and death in native Swedes and immigrants

Background: Youth unemployment is an increasing problem for societies around the world. Research has revealed negative health effects of unemployment, and this longitudinal register-based cohort study examined the relationship between unemployment and later sickness absence, disability pension and death among youth in Sweden. Method: The study group of 199 623 individuals comprised all immigrants born between 1968 and 1972 who immigrated before 1990 (25 607) and a random sample of native Swedes in the same age-range (174 016). The baseline year was 1992, and the follow-up period was from 1993 to 2007. Subjects with unemployment benefit in 1990–91, disability pension in 1990–92, severe disorders leading to hospitalization in 1990–92 and subjects who emigrated during follow-up were excluded. Results: Those who were unemployed in 1992 had elevated risk of ≥60 days of sickness absence (OR 1.02–1.49), disability pension (HR 1.08–1.62) and all except native Swedish women had elevated risk of death (HR 1.01–1.65) during follow-up compared with non-unemployed individuals. The risk of future sickness absence increased with the length of unemployment in 1992 (OR 1.06–1.54), and the risk of sickness absence increased over time. A larger part of the immigrant cohort was unemployed at baseline than native Swedes. Selection to unemployment by less healthy subjects may explain part of the association between unemployment and the studied outcomes. Conclusion: Unemployment at an early age may influence the future health of the individual. To a society it may lead to increased burdens on the welfare system and productivity loss for many years.

Migration background: a risk factor for caries development during adolescence

The influence of child and parental migration background on the risk of approximal caries increment in Swedish adolescents was investigated. This retrospective longitudinal register-based cohort study included all 13-yr-old adolescents (n = 18,142) who were resident in the County of Stockholm, Sweden, in 2000, and followed them up to 19 yr of age. At follow-up, 15,538 subjects were examined. Caries data [decayed, missing, and filled teeth/surfaces (DMFT/S)], were collected from a dental database. Socio-demographic determinants were collected from Swedish National Registers. After adjustments for socio-demographic confounders, logistic regression analysis revealed that adolescents with foreign-born parents, irrespective of whether the child was born in Sweden or abroad, exhibited a significantly elevated risk for approximal caries increment (DMFSa > 0), and developed, on average, 0.53 and 1.14 more approximal caries lesions, respectively, compared with their counterparts with Swedish-born parents. Furthermore, adolescents born in eastern Europe exhibited an increased risk for approximal caries increment (DMFSa > 0) and developed, on average, 1.06 more approximal caries lesions compared with Swedish-born adolescents. In conclusion, parental migration background must be considered as a risk factor for caries development during adolescence, irrespective of whether or not the adolescent was born in Sweden.

Maternal overweight and smoking: prenatal risk factors for caries development in offspring during the teenage period

This study aimed to investigate pre- and perinatal determinants as risk factors for caries development in offspring. In this longitudinal register-based cohort study, we included all children (n = 18,142), of 13 years of age who resided in the county of Stockholm, Sweden, in 2000. The cohort was followed until individuals were 19 years of age. In total, 15,538 subjects were examined. Dental caries (decayed, missing and filled teeth/surfaces), were collected from the Public Health Care Administration in Stockholm. Data concerning pre- and perinatal factors, as well as parental socio-demographic determinants, were collected from the Swedish Medical Birth Register and Swedish National Registers at Statistics Sweden. Mean approximal caries increment (DMFSa) was 1.34 +/- 2.74. The results showed that the prenatal factors, "maternal smoking" and "maternal overweight" exhibited an increased risk of approximal caries increment, (OR 1.33; 95% CI = 1.22-1.44) and (OR 1.21; 95% CI = 1.07-1.37), respectively. Concerning maternal overweight, the excess risk enhanced in relation to the magnitude of the caries increment and maternal smoking was significant across the various DMFSa outcome cut-off levels. In conclusion, this study demonstrates that the prenatal factors, maternal overweight, as well as smoking, are risk factors for approximal caries development in offspring during the teenage period.

Risk for unemployment of cancer survivors: A Danish cohort study

Aim To investigate whether cancer survivors are at an increased risk for unemployment after cancer. Materials and methods A cohort of 65,510 patients who were part of the workforce in the year before diagnosis and a random sample of 316,925 age and gender-matched controls were followed for up to 20 years in a longitudinal register-based cohort study. Demographic, socioeconomic and health-related information were obtained through Danish administrative registers. Results Cancer survivors had a small but significantly increased risk for unemployment following cancer. Stratified analyses showed that the risk for unemployment was highest amongst persons aged 50–60 years at time of diagnosis. Risk factors for unemployment were found to be manual work, medium income and vocational education. Conclusion Generally, cancer patients were at a small increased risk for unemployment and low socioeconomic position was a significant risk factor.