Defining the data gap: What do we know about environmental exposure, hazards and risks of pharmaceuticals in the European aquatic environment?

Active pharmaceutical ingredients (APIs) and their transformation products inevitably enter waterways where they might cause adverse effects to aquatic organisms. Identifying the potential risks of APIs in the environment is therefore a goal and current strategic direction of environmental management described in the EU Strategic Approach to Pharmaceuticals in the Environment and the Green Deal. This is challenged by a paucity of monitoring and ecotoxicity data to adequately describe risks. In this study we analyze measured environmental concentrations (MECs) of APIs from 5933 sites in 25 European countries as documented in the EMPODAT database or collected by the German Environment Agency for the time period between 1997 and 2020. These data were compared with empirical data on the ecotoxicity of APIs from the U.S. EPA ECOTOX database. Although 1763 uniquely identifiable APIs are registered with the European Medicines Agency (EMA) for sale in the European Economic Area (EEA), only 312 (17.7%) of these are included in publicly available monitoring data, 36 (1.8%) compounds have sufficient ecotoxicological data to derive a PNEC, and only 27 (1.5%) compounds meet both the hazard and exposure data requirements required to to perform an environmental risk assessment according to EMA guidelines. Four of these compounds (14.8%) had a median risk quotient (RQ) > 1. Endocrine disruptors had the highest median RQ, with 7.0 and 5.6 for 17α-ethinyl-estradiol and 17ß-estradiol respectively. A comparison of in-silico and empirical exposure data for 72 APIs demonstrated the high protectiveness of the current EMA guidelines, with predicted environmental concentrations (PECs) exceeding median MECs in 98.6% of cases, with a 100-fold median increase. This study describes the data shortfalls hindering an accurate assessment of the risk posed to European waterways by APIs, and identifies 68 APIs for prioritized inclusion in monitoring programs, and 66 APIs requiring ecotoxicity testing to fill current data gaps.

Sleep interventions for children with attention deficit hyperactivity disorder (ADHD): A systematic literature review.

OBJECTIVE/BACKGROUND: Healthy sleep is particularly important for children with attention deficit hyperactivity disorder (ADHD), as sleep disturbances might aggravate disease symptoms. This review aims to synthesize and report evidence on the effectiveness of sleep interventions in increasing sleep, quality of life (QoL), and ADHD symptoms among children with ADHD. PATIENTS/METHODS: The systematic literature review follows the Cochrane Collaboration methodology recommendations for literature reviews. Four databases were used based on the population, intervention, control and outcome (PICO) framework. Controlled trials with minimum 20 children in each group, aged 6-18, and published from 2005 and onwards were included. Results from the studies were reported in forest plots and three of the seven review outcomes were synthesized in meta-analyses. RESULTS: The search identified 7710 records; of which 4808 abstracts were screened. After fulltext-screening of 99 papers, eight papers from five studies were included. The studies included behavioral sleep interventions and pharmacological interventions using melatonin and eszopiclone. For six of the seven outcomes, the effect sizes were small to moderate and the certainty of the evidence was low. For one outcome, sleep disturbances, the effect size was a moderate -0.49 standardized mean differences (95% confidence interval -0.65;-0.33), with a moderate certainty of evidence for the behavioral interventions for children aged 5-13 years with ADHD. CONCLUSIONS: This review identified few and heterogeneous studies. A moderate certainty of evidence for a moderate effect size was only obtained for sleep disturbances from the behavioral interventions. A low certainty of the evidence for a moderate effect size was found for the total sleep time from the pharmacological intervention using melatonin and one behavioral intervention, which indicates that these sleep interventions impact sleep quantity and quality among children with ADHD.

Prevention of sick leave at the workplace: design of a cluster-randomized controlled trial of a problem-solving intervention among employees with common mental disorders.

BACKGROUND: Common mental disorders are highly prevalent in the working population, affecting about 1 in 5 persons in the Organisation for Economic Co-operation and Development countries. About 30% of those affected have a first period of sick leave. Despite several attempts to reduce the risk of sick leave among employees with common mental disorders, there is a lack of knowledge about effective, preventive interventions which aim to reduce such risks. This protocol describes the design of a study to evaluate the effectiveness of a problem-solving intervention delivered by first-line managers to employees with common mental disorders on the prevention of sick leave during the 12-month follow-up. METHODS/DESIGN: The study applies a two-armed cluster-randomized trial design of a problem-solving intervention conducted in private-sector companies. First-line managers are randomized into intervention- or control groups by computer-generated random numbers, allocation ratio 1:1. Employees are eligible if at risk for future sick leave due to common mental disorders. These are identified by self-reported psychological health measured by the General Health Questionnaire 12-item, cut-off ≥3, or a positive answer to risk of sick leave. The intervention is based on problem-solving principles. It involves the training of the first-line managers who then deliver the intervention to employees identified at risk of sick leave. First-line managers in the control group receives a lecture. Primary outcome is number of registered days of sick leave due to common mental disorders during the 12-month follow-up. Secondary outcomes are general health, psychological symptoms, work performance, work ability and psychosocial work environment. A process evaluation will examine the intervention's reach, fidelity, dose delivered, dose received, satisfaction and context. Research assistants managing the screening procedure, outcome assessors and employees are blinded to randomization and allocation. DISCUSSION: The study includes analyses of the intervention's effectiveness and an alongside process evaluation. Methodological strengths and limitations, for example the risk of selection bias, attrition and risk of contamination are discussed. TRIAL REGISTRATION: Clinicaltrials.gov NCT04975750 Date of registration: 08/16/2021.

Sick leave due to mental disorders, morbidity and mortality: a prospective study of discordant twin pairs.

PURPOSE: To investigate if sick leave due to mental disorders increases the risk of morbidity measured by inpatient and specialized outpatient care, and mortality among women and men, independent of familial factors. METHODS: An open cohort study of 4979 twin pairs discordant for sick leave due to mental disorders was conducted in 2005-2013. Twins were followed up in the cause of death and national patient registries until the end of study, emigration, death, and inpatient and specialized outpatient care. Conditional Cox proportional hazard regression, adjusting for the familial factors shared by the twins, was used to calculate hazard ratios (HR) with 95% confidence intervals (CI). In case of non-proportional hazards, time-varying covariates were used. RESULTS: Sick leave due to mental disorders increased the risk for inpatient care among men (HR: 1.90, CI 1.66-2.17) and women (HR: 1.39, CI 1.27-1.51). For men, the risk of outpatient care was higher the first 2 years (HR: 2.08, CI 1.87-2.31), after which it was attenuated (HR: 1.32, CI 1.02-1.70). For women, the HR was 1.57 (CI 1.47-1.68) for the whole study time. There was an increased risk of death among men (HR: 2.91, CI 1.70-4.99), but not among women (HR: 0.84, CI 0.53-1.35). CONCLUSIONS: Sick leave due to mental disorders was a risk factor for mortality for men only, and increased the risk of inpatient and specialized outpatient care among both women and men, but the risks were higher for men when stratifying for sex.

Suicide attempt following sickness absence and disability pension due to common mental disorders: a prospective Swedish twin study.

PURPOSE: The aim of this study was to investigate if sickness absence and disability pension (SA/DP) in general and due to specific common mental disorders (CMDs) are associated with subsequent suicide attempt among women and men by taking familial factors (genetics and shared environment) into consideration. METHODS: This register-based cohort study includes 4871 twin pairs 18-65 years of age discordant for SA/DP due to CMDs 2005-2010. Twins were followed up for suicide attempt from inpatient and specialised outpatient care until December 2012. Conditional Cox proportional hazards regression models, adjusting for familial factors, were used to calculate hazard ratios (HR) with 95% confidence intervals (CI). RESULTS: SA/DP due to CMDs was associated with a higher risk of suicide attempt (HR 3.14, CI 2.51-3.93). The risk of suicide attempt was five times higher among men and three times higher among women, compared to the SA/DP unaffected co-twins. In the diagnosis-specific analysis, SA/DP due to anxiety disorders resulted in the highest HR (4.09, CI 2.37-7.06) for suicide attempt, followed by depressive disorders (HR 3.70, CI 2.66-5.14) and stress-related disorders (HR 1.96, CI 1.35-2.84). The stratified analysis on zygosity indicates that there seems to be a genetic influence on the associations between SA/DP due to CMDs and suicide attempt, particularly among women and among those with SA/DP due to depressive disorders. CONCLUSIONS: SA/DP due to CMDs was a risk factor for suicide attempt among women and men. Genetic factors might explain part of the associations for women and for those with SA/DP due to depressive disorders.

The validity of socioeconomic status measures among adolescents based on self-reported information about parents occupations, FAS and perceived SES; implication for health related quality of life studies.

BACKGROUND: Research has shown inconsistencies in results and difficulties in conceptualization of assessment of socioeconomic status (SES) among adolescents. The aim of this study was thus to test the validity of self-reported information on SES in two age-groups (11-13 and 14-16 years old) in an adolescent population and to evaluate its relationship to self-reported health related quality of life (HRQOL). Different measures of SES commonly used in research in relation to HRQOL were tested in this study; parent's occupations status, family material affluence status (FAS) and perceived SES. METHOD: A cross-sectional study, with a sample of 948 respondents (n = 467, 11-13 years old and n = 481, 14-16 years old) completed questionnaires about SES and HRQOL. The adolescents' completion rates were used, with chi2-test, to investigate differences between gender and age-group. Correlation was used for convergent validity and ANOVA for concurrent validity. RESULTS: We found a low completion rate for both fathers' (41.7 %) and mothers' (37.5 %) occupation status, and a difference in completion rate between gender and age-groups. FAS had the highest completion rate (100 %) compared to parent's occupations status and perceived SES. The convergent validity between the SES-indicators was weak (Spearman correlation coefficient below 0.3), suggesting that the indicators measured different dimensions of SES. Both FAS and perceived SES showed a gradient in mean HRQOL between low and high SES in relation to HRQOL, this was significant only for perceived SES (p < 0.01, both age-groups). CONCLUSION: This study indicates the need for considering different approaches to measures of SES among adolescences and when evaluating SES in relation to HRQOL. Further research is needed to investigate sustainable ways to measure SES, delineating the relevance of tangible measures of education, occupation and income in relation to the perceived socioeconomic status in comparison with others in immediate social networks and in society at large.

'Through my eyes': health-promoting factors described by photographs taken by children with experience of cancer treatment.

BACKGROUND: Health promotion for children with cancer should be based on the children's own needs and desires. Because there is a lack of knowledge in this area, the aim of this study was to explore what promotes health from the perspective of children with experience of cancer treatment. METHODS: Fifteen children between 8 and 12 years of age participated in focus groups with three children in each group. The children were given a camera and instructions to photograph subjects that promote their health. Focus group discussions were based on the photographs and the children's own description of those photographs. The analysis of focus group discussions and photographs was conducted using inductive content analysis. RESULTS: According to the children, health-promoting factors are defined as meaningful relationships, recreational activities and a trustful environment. Meaningful relationships include togetherness within the family, affection for pets and friendship with peers. Recreational activities include engagement in play and leisure, withdrawal for relaxation and feeling enjoyment. Trustful environment includes confidence in significant others and feeling safe. CONCLUSIONS: Knowledge from this study can contribute to health promotion interventions and quality improvements in the health care of children with experience of cancer treatment. Children's experiences with what promotes health in their everyday lives provide a better understanding of the type of support children prefer when promoting their own health.

Synergistic effect between back pain and common mental disorders and the risk of future disability pension: a nationwide study from Sweden.

BACKGROUND: The aim of this study was to analyse a possible synergistic effect between back pain and common mental disorders (CMDs) in relation to future disability pension (DP). METHOD: All 4,823,069 individuals aged 16-64 years, living in Sweden in December 2004, not pensioned in 2005 and without ongoing sickness absence at the turn of 2004/2005 formed the cohort of this register-based study. Hazard ratios (HRs) and 95% confidence intervals (CIs) for DP (2006-2010) were estimated. Exposure variables were back pain (M54) (sickness absence or inpatient or specialized outpatient care in 2005) and CMD (F40-F48) [sickness absence or inpatient or specialized outpatient care or antidepressants (N06a) in 2005]. RESULTS: HRs for DP were 4.03 (95% CI 3.87-4.21) and 3.86 (95% CI 3.68-4.04) in women and men with back pain. HRs for DP in women and men with CMD were 4.98 (95% CI 4.88-5.08) and 6.05 (95% CI 5.90-6.21). In women and men with both conditions, HRs for DP were 15.62 (95% CI 14.40-16.94) and 19.84 (95% CI 17.94-21.94). In women, synergy index, relative excess risk due to interaction, and attributable proportion were 1.24 (95% CI 1.13-1.36), 0.18 (95% CI 0.11-0.25), and 2.08 (95% CI 1.09-3.06). The corresponding figures for men were 1.45 (95% CI 1.29-1.62), 0.29 (95% CI 0.22-0.36), and 4.21 (95% CI 2.71-5.70). CONCLUSIONS: Co-morbidity of back pain and CMD is associated with a higher risk of DP than either individual condition, when added up, which has possible clinical implications to prevent further disability and exclusion from the labour market.

Service users' experiences of participation in decision making in mental health services.

ACCESSIBLE SUMMARY: Despite the potential positive impact of shared decision making on service users knowledge and experience of decisional conflict, there is a lack of qualitative research on how participation in decision making is promoted from the perspective of psychiatric service users. This study highlights the desire of users to participate more actively in decision making and demonstrates that persons with SMI struggle to be seen as competent and equal partners in decision-making situations. Those interviewed did not feel that their strengths, abilities and needs were being recognized, which resulted in a feeling of being omitted from involvement in decision-making situations. The service users describe some essential conditions that could work to promote participation in decision making. These included having personal support, having access to knowledge, being involved in a dialogue and clarity about responsibilities. Mental health nurses can play an essential role for developing and implementing shared decision making as a tool to promote recovery-oriented mental health services. ABSTRACT: Service user participation in decision making is considered an essential component of recovery-oriented mental health services. Despite the potential of shared decision making to impact service users knowledge and positively influence their experience of decisional conflict, there is a lack of qualitative research on how participation in decision making is promoted from the perspective of psychiatric service users. In order to develop concrete methods that facilitate shared decision making, there is a need for increased knowledge regarding the users' own perspective. The aim of this study was to explore users' experiences of participation in decisions in mental health services in Sweden, and the kinds of support that may promote participation. Constructivist Grounded Theory (CGT) was utilized to analyse group and individual interviews with 20 users with experience of serious mental illness. The core category that emerged in the analysis described a 'struggle to be perceived as a competent and equal person' while three related categories including being the underdog, being controlled and being omitted described the difficulties of participating in decisions. The data analysis resulted in a model that describes internal and external conditions that influence the promotion of participation in decision making. The findings offer new insights from a user perspective and these can be utilized to develop and investigate concrete methods in order to promote user's participation in decisions.

Sickness absence due to back pain or depressive episode and the risk of all-cause and diagnosis-specific disability pension: A Swedish cohort study of 4,823,069 individuals.

BACKGROUND: The aim of this study was to investigate the associations between sickness absence due to back pain or depressive episode with future all-cause and diagnosis-specific disability pension, while adjusting for comorbidity and socio-demographics, for all and stratifying for sex. METHOD: In total, 4,823,069 individuals aged 16-64 years, living in Sweden at the end of 2004, not on old-age or disability pension in 2005 and without ongoing sickness absence at the turn of 2004/2005 formed the study population. Crude and adjusted hazard ratios (HRs) for all-cause and diagnosis-specific disability pension (2006-2010) in relation to diagnosis-specific sickness absence with sickness benefits paid by the Social Insurance Agency were estimated using Cox regression. RESULTS: The HR for all-cause disability pension was 7.52 (7.25-7.52) in individuals with an incident sick-leave spell due to back pain, compared to individuals without sickness absence in 2005 in the fully adjusted (socio-demographics and comorbidity) model. The fully adjusted (multivariate) HRs for diagnosis-specific disability pension were musculoskeletal diagnoses 23.87 (22.75-25.04), mental 2.49 (2.27-2.73) or all other diagnoses, 3.44 (3.17-3.75). In individuals with an incident sick-leave spell due to a depressive episode in 2005, the multivariate adjusted HR for all-cause disability pension was 12.87 (12.42-13.35), while the multivariate HRs for disability pension due to musculoskeletal diagnoses were 4.39 (3.89-4.96), for mental diagnoses 25.32 (24.29-26.38) and for all other somatic diagnoses 3.44 (3.09-3.82). Men who were sickness absent due to a depressive episode had a higher HR for disability pension compared to women. CONCLUSION: Results indicate that sickness absence due to a depressive episode or back pain is a strong risk factor for a future disability pension due to mental, musculoskeletal or other somatic diagnoses.

Incidence of disability pension and associations with socio-demographic factors in a Swedish twin cohort.

PURPOSE: The incidence of disability pension (DP), especially due to mental diagnoses, has increased in many countries, but knowledge of socio-demographic risk factors for DP is limited. Further, the influences of genetics and early-life factors (jointly called familial factors) on these associations remain to be studied. The aims were to study incidence of DP (due to all and mental diagnoses) and associations with socio-demographic factors, and also to establish whether associations differ with DP diagnosis and sex, and are influenced by familial factors. METHODS: A prospective cohort study of all twins born in 1928-1958 (n = 52,609) in Sweden was conducted. The twins were followed from 1993 to 2008 regarding DP. Cox proportional hazard models were applied. RESULTS: The cumulative incidence of DP was 17 %. Of all the DP diagnoses 20 % were mental. Higher age (≥45 years), being a woman or unmarried, and/or living in a semi-urban area were risk factors for DP. Low education, being a blue-collar worker or being self-employed predicted either higher (all diagnoses) or lower (mental diagnoses) risk of DP. Rural areas were associated with DP due to mental diagnoses. The estimates varied for men and women. After adjustment for familial factors the associations of DP with education and marital status were attenuated and no longer significant. Similar results were apparent for DP due to mental diagnoses and socioeconomic status. CONCLUSIONS: Familial factors may select individuals into some of the established risk environments for DP. Studies investigating the causes of DP need to take such confounding into account.

The construct validity of a self-report questionnaire focusing on health promotion interventions in mental health services.

Health promotion has become a widespread concept, although little empirical research as to its importance and outcome has been performed in the mental health field. The aim of the present study was to investigate the construct validity of a newly developed Health Promotion Intervention Questionnaire, intended to measure patients' subjectively experienced health-promoting interventions within mental health services. A total of 135 participants responded to the questionnaire and to validation measures assessing psychiatric symptoms, empowerment, helping alliance and satisfaction with care. Bivariate correlations showed that overall perceived health-promoting interventions were positively correlated to, helping alliance, client satisfaction with care and empowerment. Stepwise multiple regression analysis showed that the strongest relationship was found between perceived health promotion intervention and helping alliance. In conclusion, the construct validity of the scale was satisfactory, except for one of its subscales where further investigations are needed.

Nurses' conceptions of how health processes are promoted in mental health nursing.

The health and well-being of the individual is a central goal in nursing, and health promotion seeks to enable people to increase control over and improve their health. In mental health care, health is often described in negative terms such as the absence of mental illness, which may create hopelessness and constitute a barrier to a policy of health promotion. The aim of this study was to describe nurses' conceptions of how health processes are promoted in mental health nursing. Twelve nurses working in mental health care were interviewed and the data were analysed using a phenomeographic approach. The nurses expressed 11 different conceptions of the phenomenon, which were summarized into three descriptive categories: presence, balance of power, and focus on health. The findings show that the nurses expressed ambiguous attitudes towards meeting the patient in mental health care. It is suggested that the goal of nursing care should be clarified for nurses in practice, otherwise they may adopt the perspectives of other mental health professionals.

Patients' conceptions of how health processes are promoted in mental health nursing. A qualitative study.

The most important goal of nursing care is to promote the subjective experience of health. The health promoting efforts of mental health care nurses must be aimed at creating encounters where the patient will be confirmed both existentially and as an individual worthy of dignity. The patient in mental health care is often viewed by the nurse as nothing more than a passive recipient of care and the belief in the patient's potential is minimal. This can lead to a situation where the patient loses control in the caring situation and feels unable to improve his/her health, which conflicts with the goal of the nursing care. The aim of the study was to describe patients' conceptions of how health processes are promoted in mental health nursing. Twelve patients with experience of mental health nursing were interviewed, and the data material was analysed using a phenomenographic approach. The results show 13 different conceptions of the phenomenon, and these were summarized into four descriptive categories: interaction, attention, development and dignity. The conceptions described show that the patients need to be treated as equals and that the nurse must trust the patient's ability to make decisions and to promote his/her health process. It is suggested that mental health nursing should be built on humanistic science and its view that every individual has the ability to grow and develop. This view is one of the most important preconditions for the promotion of health processes in mental health nursing.

The Swedish Twin Registry: a unique resource for clinical, epidemiological and genetic studies.

The Swedish Twin Registry (STR), which today has developed into a unique resource, was first established in the late 1950s to study the importance of smoking and alcohol consumption on cancer and cardiovascular diseases whilst controlling for genetic propensity to disease. Since that time, the Registry has been expanded and updated on several occasions, and the focus has similarly broadened to most common complex diseases. In the following, we will summarize the content of the database, describe for the first time recent data collection efforts and review some of the principal findings that have come from the Registry.

Extra-intestinal manifestations associated with irritable bowel syndrome: a twin study.

BACKGROUND: Little is known about the role of genetic and environmental factors in irritable bowel syndrome. Various extra-intestinal manifestations are more prevalent in cases than in controls. Genetic effects may be important in the liability to develop functional bowel disorders. AIMS: To evaluate the associations of irritable bowel syndrome with several disorders co-morbid with the condition, using both a case-control design and a co-twin control design. METHODS: A sample of 850 Swedish twin pairs, aged 18-85 years, was contacted for a telephone interview. Through a diagnostic algorithm, 72 unrelated cases of irritable bowel syndrome and 216 age- and gender-matched controls were identified. Fifty-eight twin pairs discordant for irritable bowel syndrome were evaluated in co-twin analyses. RESULTS: Renal problems (odds ratio (OR)=3.3; confidence interval (CI), 1.3-8.2), obesity (OR=2.6; CI, 1.0-6.4), underweight in the past (OR=2.4; CI, 1.1-6.4), gluten intolerance (OR=9.0; CI, 1.4-60.1), rheumatoid arthritis (OR=3.2; CI, 1.1-9.4) and poor self-rated health (OR=1.8; CI, 1.0-3.2) were significantly associated with irritable bowel syndrome. In the co-twin analyses, the only factors maintaining significance were renal and recurrent urinary tract problems. CONCLUSIONS: The association between irritable bowel syndrome and renal and urinary tract problems does not reflect a genetic or familial mediation. Eating disorders in childhood represent a familial-environmental influence on irritable bowel syndrome, whereas the association with rheumatoid arthritis and perhaps gluten intolerance probably reflects genetic mediation.

Education and the risk of Alzheimer's disease: findings from the study of dementia in Swedish twins.

The association between dementia and education was studied in 143 twin pairs discordant for dementia, using a matched-pair design, and in 221 dementia cases and 442 unrelated controls from the same twin registry, using a case-control design. Low education was defined as 6 years or less of schooling. Case-control analyses with prevalent cases showed low education to be a risk for Alzheimer's disease but not dementia in general. Low education did not significantly predict incident cases. In the matched-pairs analysis, which controls for genetic and other familial influences, differences in education between demented twins and twin partners were not statistically significant. However, for Alzheimer's disease, odds ratios resulting from matched pairs and case-control analyses were similar. Twins' comparative reports about intellectual involvement earlier in their lives suggest a long-standing difference on this dimension, with less involvement by the twin who became demented.

Age and sex differences in genetic and environmental factors for self-rated health: a twin study.

OBJECTIVES: Self-rated health has been shown to be a predictor for future health status and mortality. The purpose of this study was to investigate age-group and sex differences in genetic and environmental sources of variation for self-rated health. METHODS: A sample of twins from the Swedish Twin Registry participated in a computer-assisted telephone interview with assessment of self-rated health. Structural equation model analyses on 1,243 complete twin pairs provided estimates of genetic and environmental components of variance. RESULTS: Individual differences primarily reflected individual specific environmental influences at all ages. The increase in total variance across age groups was primarily due to genetic influences in the age groups 45--74 years and greater environmental influences in the oldest age group (>74). No significant sex differences were found in variance components. DISCUSSION: Genetic variance in the two middle age groups (45--74) could reflect genetic susceptibility to age-dependent illnesses not yet expressed in the youngest group. The findings suggest that it might be more fruitful to explore the origins of individual differences for self-rated health in the context of an individual's age and birth cohort rather than in the context of sex.

Dementia and occupational exposure to magnetic fields.

OBJECTIVES: The purpose of the present report was to assess whether occupational magnetic field exposure is a risk factor for dementia, in particular for Alzheimer's disease. METHODS: Case-control analyses were applied to 77 dementia cases, 55 of whom had Alzheimer's disease, ascertained from the population-based Swedish twin register. Two reference groups were derived, with 228 and 238 persons, respectively. Occupations were linked to a job-exposure matrix based on magnetic field measurements. Primary occupation, last occupation before reference date, and the occupation with the highest magnetic field exposure during the subject's lifetime were evaluated. RESULTS: For primary occupation, all relative risk estimates were close to unity. For last occupation, at the exposure level > or = 0.2 microT, a relative risk was found for dementia estimated at 3.3 [95% confidence interval (95% CI) 1.3-8.6] and 3.8 (95% CI 1.4-10.2) for reference groups 1 and 2, respectively. The relative risk for Alzheimer's disease was estimated at 2.4 (95% CI 0.8-6.9) and 2.7 (95% CI 0.9-7.8), respectively. For the occupation with the highest magnetic field exposure, the relative risk estimates were close to unity for reference group 1 and slightly elevated for reference group 2. The relative risk estimates were greater for the subjects who were younger at onset (< or =75 years). CONCLUSIONS: These results only partially support previous findings, but they indicate that occupational magnetic field exposure may possibly influence the development of dementia.