Association between infections and functional somatic disorders: a cross-sectional population-based cohort study.

OBJECTIVES: It has been suggested that infections can trigger functional somatic disorders (FSD). However, current evidence is limited by inconsistent findings in smaller studies conducted in clinical settings within selected populations and short follow-up times. We aimed to test the hypothesis that former infections are associated with FSD using data from nationwide registries and a large population-based cohort study, the Danish Study of Functional Disorders study. DESIGN: FSD cases were identified in a cross-sectional population-based cohort and linked retrospectively to former hospital contacts with infections identified in the Danish National Patient Registry. The associations between FSD and former infections within 17 years were analysed using logistic regressions to calculate ORs and 95% CIs adjusted for age, sex and subjective social status. SETTING: A population-based cohort in Denmark examined between 2011 and 2015. PARTICIPANTS: A total of 9656 men and women aged 18-76 years. MAIN OUTCOME MEASURES: FSD measured by various delimitations, including bodily distress syndrome (BDS), irritable bowel (IB), chronic fatigue (CF), chronic widespread pain (CWP), and multiple chemical sensitivity (MCS). RESULTS: Overall, infections were associated with increased risk of all delimitations of FSD. The associations were more pronounced for multisystemic FSD. The number of prior infections increased the risk in a dose-response manner (p<0.0001). Bacterial but not viral infections were significantly associated with BDS (OR 1.69 (95% CI 1.46 to 1.96)), IB (OR 1.41 (95% CI 1.06 to 1.88)), CWP (OR 1.47 (95% CI 1.13 to 1.90)) and CF (OR 1.62 (95% CI 1.34 to 1.96)), but not MCS. CONCLUSION: Former infections leading to hospital contacts were associated with a higher risk of having FSD. These associations were more pronounced for bacterial than viral infections, and more infections increased the risk in a dose-response manner. These results tend to support the idea that severe infections could play a role in FSD.

Examine the public health impacts of functional somatic disorders using the DanFunD study.

Background: Persistent physical symptoms (e.g. pain, fatigue) are prevalent in the population and some persons may develop a functional somatic disorder (FSD). We still need to explore the limits between general bodily sensations and FSD, and great controversies exist as regard delimitation, occurrence, risk factors, prognosis, and costs of FSD in the general population. This is mainly due to the lack of focused, sufficient powered, population-based epidemiological studies. Material and Methods: The DanFunD study is the largest focused population-based study on FSD and has the potential to answer these crucial questions regarding the FSD disorders. DanFunD has its origin in the Copenhagen area of Denmark and was initiated in 2009 by an interdisciplinary team of researchers including basic scientists, clinical researchers, epidemiologists, and public health researchers. A population-based cohort of nearly 10,000 people have filled in detailed questionnaires, gone through a thorough health examination, and a biobank is established. The cohort was re-examined after five years. Results:The prevalence of FSD in the Danish population is about 10-15% and is twice as common in women as in men. Persons with FSD report impaired daily activities and low self-perceived health, which qualifies FSD as a major public health problem. The research plan to unravel the risk factors for FSD employs a bio-psycho-social approach according to a detailed plan. Preliminary results are presented, and work is in progress. Likewise, plans for assessing prognosis and health care costs are provided. Conclusion: We invite researchers in the field to collaborate on this unique data material.

Register-based information on thyroid diseases in Europe: lessons and results from the EUthyroid collaboration.

Objective: Registers of diagnoses and treatments exist in different forms in the European countries and are potential sources to answer important research questions. Prevalence and incidence of thyroid diseases are highly dependent on iodine intake and, thus, iodine deficiency disease prevention programs. We aimed to collect European register data on thyroid outcomes to compare the rates between countries/regions with different iodine status and prevention programs. Design: Register-based cross-sectional study. Methods: National register data on thyroid diagnoses and treatments were requested from 23 European countries/regions. The provided data were critically assessed for suitability for comparison between countries/regions. Sex- and age-standardized rates were calculated. Results: Register data on ≥1 thyroid diagnoses or treatments were available from 22 countries/regions. After critical assessment, data on medication, surgery, and cancer were found suitable for comparison between 9, 10, and 13 countries/regions, respectively. Higher rates of antithyroid medication and thyroid surgery for benign disease and lower rates of thyroid hormone therapy were found for countries with iodine insufficiency before approx. 2001, and no relationship was observed with recent iodine intake or prevention programs. Conclusions: The collation of register data on thyroid outcomes from European countries is impeded by a high degree of heterogeneity in the availability and quality of data between countries. Nevertheless, a relationship between historic iodine intake and rates of treatments for hyper- and hypothyroid disorders is indicated. This study illustrates both the challenges and the potential for the application of register data of thyroid outcomes across Europe.

Number of traumatic brain injuries and temporal associations with depression: A register-based cohort study.

OBJECTIVE: To explore the association of the number of traumatic brain injuries (TBIs) and temporal associations with the subsequent risk of depression in the population. METHODS: National register-based cohort study on all individuals registered with TBI (ICD-10: S06, ICD-8: 85.0-85.5) from 1977 to 2015 in Denmark (n = 494,216) and a sex- and age-matched reference population (n = 499,505). The associations with the number of TBIs and time to depression (0-6, 7-12 and more than 12 months following TBI) were analyzed using Cox proportional hazard regression. RESULTS: During a follow-up of mean 14.5 (SD 11.3) years, a total of 27,873 (5.6%) individuals who had at least one TBI and 15,195 (3.0%) in the reference population were diagnosed with a depression. First-time TBI was associated with a higher risk of depression in both men (HR = 1.73 [95% CI:1.67-1.79]) and women (HR = 1.66 [95% CI:1.61-1.70]) after multiple adjustments for educational status and comorbidities including previous depression, and the association became stronger in a dose-response association with the number of TBIs (test for trend p < 0.01). The HRs for depression were highest the first 6 months after the TBI in both men (HR = 5.69 [95% CI:4.66-6.94]) and women (HR = 4.55 [95% CI:3.93-5.26]) and decreased gradually the following year but remained elevated from one year after TBI until end of follow-up independent of the number of TBIs (p < 0.01). The associations did not vary with age or calendar time. CONCLUSION: Traumatic brain injury is associated with a higher risk of depression, especially in the first months after TBI and the risk increases with the number of TBIs.

Distinct health-related risk profiles among middle-aged and older adults with risky alcohol use from the Danish general population.

BACKGROUND: Knowledge is lacking on distinct health-related risk profiles among the substantial group of middle-aged and older adults with risky alcohol use (AU). Such profiles could inform the planning of interventions and prevention. AIMS: To 1) identify distinct health-related profiles based on different types of health-related functioning limitations and distress and 2) assess associations between these profiles and age, sex, and health-relevant behaviors (e.g., smoking). METHODS: Cross-sectional nation-wide Danish health survey with n = 6630 adults aged 55-64 and n = 7605 aged 65-74 with at least risky AU (>84 g ethanol/week in women, >168 in men). Health-related risk profiles were identified with Latent Class Analysis (LCA). Multinomial regression was applied for the association between risk profiles and auxiliary variables. RESULTS: A six-class LCA solution was found among 55-64 year-olds (classes: 'Normative' [61%], 'Distress' [6%], 'Mental health limitations [5%]', 'Pain-related distress [10%]', 'Broad limitations and pain distress [7%]', 'High overall burden' [11%]) and a five-class solution among 65-74 year-olds. Most classes were comparable across age groups. The 'Distress'-class characterized by pain-distress, tiredness-distress, and sleep-related distress (6%) only showed in the younger group. In both age groups, auxiliary covariates (high-risk AU, possible alcohol use disorder, weekly smoking) were positively associated with problematic profile membership (vs. normative class membership). CONCLUSION: Middle-aged and older adults with risky AU have distinct health-related profiles relevant for the form and content of prevention and interventions. Despite their distinct features, almost all problematic health profiles warrant careful attention regarding high-risk AU and probable alcohol use disorder.

Three different approaches to delimitation of functional somatic disorders: DanFunD.

OBJECTIVE: The Danish Study of Functional Disorders (DanFunD) approaches functional somatic disorders (FSD) with three delimitations: Five functional somatic syndromes (FSS), Bodily Distress Syndrome (BDS), and eight data-driven symptom profiles (SP). This paper presents each delimitation and discusses optimal approaches for further original research into FSD epidemiology. METHODS: A total of 9656 adults from the general Danish population participated in this cross-sectional study. Case assignment of the three FSD delimitations was based on self-reported symptom questionnaires. Overlap of FSS, BDS, and SP and their association with poor self-perceived health were calculated as descriptive statistics and shown with Venn diagrams. Difference in self-perceived health between participants with severe FSD were compared with participants with no FSD and calculated as risk ratios with generalized linear models with binomial family and log link. RESULTS: We found pronounced overlaps between any FSS, BDS, and the SP with multiple symptoms as well as for multi-organ BDS and the SP with all symptoms. Symptoms and syndromes related to clusters of musculoskeletal and general symptoms contributed particularly to poor health as did multi-organ BDS and categories of SP with multiple symptoms. CONCLUSION: Each of the three delimitations has its strengths and weaknesses, and with this study, we offer a contribution to a more valid delimitation of FSD. Future research within DanFunD and other epidemiological studies may benefit from using more than just one delimitation for capturing the diverse nature of the FSD.

Irritable bowel, chronic widespread pain, chronic fatigue and related syndromes are prevalent and highly overlapping in the general population: DanFunD.

Prevalence of functional somatic syndromes (FSS) in the general population varies with observed overlap between syndromes. However, studies including a range of FSS are sparse. We investigated prevalence and characteristics of various FSS and the unifying diagnostic construct bodily distress syndrome (BDS), and identified mutual overlap of the FSS and their overlap with BDS. We included a stratified subsample of 1590 adults from a randomly selected Danish general population sample (n = 7493). Telephonic diagnostic interviews performed by three trained physicians were used to identify individuals with FSS and BDS. Prevalence of overall FSS was 9.3%; 3.8% for irritable bowel, 2.2% for chronic widespread pain, 6.1% for chronic fatigue, 1.5% for whiplash associated disorders, and 0.9% for multiple chemical sensitivity. Prevalence of BDS was 10.7% where 2.0% had the multi-organ type. FSS were highly overlapping with low likelihood of having a "pure" type. Diagnostic agreement of FSS and BDS was 92.0%. Multi-syndromatic FSS and multi-organ BDS were associated with female sex, poor health, physical limitations, and comorbidity. FSS are highly prevalent and overlapping, and multi-syndromatic cases are most affected. BDS captured the majority of FSS and may improve clinical management, making the distinction between multi- and mono-syndromatic patients easier.

Prevalence of functional somatic syndromes and bodily distress syndrome in the Danish population: the DanFunD study.

Aims: Little is known about the prevalence and characteristics of functional somatic syndromes (FSS) such as irritable bowel syndrome (IBS), fibromyalgia (FM), chronic fatigue syndrome (CFS), whiplash associated disorders (WAD), multiple chemical sensitivity (MCS), and bodily distress syndrome (BDS) in the general population when they are investigated simultaneously. Method: This cross-sectional study is based on the Danish Study of Functional Disorders (DanFunD) cohort consisting of 9656 adults from the general population. FSS and BDS were identified by questionnaires and characterized by age, sex, vocational training, physical health and comorbidity with physical and psychiatric disease. Results: In total, 16.3% (95% CI: 15.6-17.1) of the participants fulfilled the criteria for at least one FSS, ranging from 1.7% for WAD to 8.6% for CFS, and 16.1% (95% CI: 15.4-16.9) fulfilled the criteria for BDS. Cases had a high risk of poor self-perceived health, limitations in daily activities, and a high psychiatric comorbidity, all increasing with the number of syndromes in each individual. However, the associations differed across the various FSS. Mutual overlaps of IBS, FM and CFS were greater than could be expected by chance. Conclusions: FSS and BDS are prevalent in the adult Danish population, and cases have high risk of poor self-perceived health, limitation in daily activities, and psychiatric comorbidity. These associations were particularly strong for cases with multiple FSS and multi-organ BDS.

The unifying diagnostic construct of bodily distress syndrome (BDS) was confirmed in the general population.

OBJECTIVES: Bodily distress syndrome (BDS) has been shown to encompass a range of functional somatic syndromes (FSS) such as irritable bowel syndrome (IBS), fibromyalgia (FM), and chronic fatigue syndrome (CFS) in clinical samples. This study aimed to explore symptom clusters and test classification of individuals with illness similar to the BDS criteria in a general population sample. METHODS: A stratified subsample of 1590 individuals from the DanFunD part two cohort was included. Symptoms were assessed with the Research Interview for Functional somatic Disorders, performed by trained physicians. In 44 symptoms pooled from criteria of IBS, FM, CFS, and BDS, symptom clusters were explored with explorative factor analysis. Confirmation of symptom clusters of BDS in the previously described 25- and 30-item BDS checklists was performed with confirmatory factor analysis. Classification of individuals into illness groups was investigated with latent class analysis. RESULTS: Four symptom clusters (cardiopulmonary, gastrointestinal, musculoskeletal, general symptoms/fatigue) corresponding to the BDS subtypes and their corresponding FSS were identified and confirmed. A three-class model including 25 BDS items had the best fit for dividing participants into classes of illness: One class with low probability, one class with medium probability, and one class with high probability of having ≥4 symptoms in all symptom clusters. CONCLUSION: The BDS concept was confirmed in the general population and constitutes a promising approach for improved FSS classification. It is highly clinical relevant being the only diagnostic construct defining the complex multi-organ type.

RIFD - A brief clinical research interview for functional somatic disorders and health anxiety.

OBJECTIVE: Epidemiological research in functional somatic disorders such as irritable bowel syndrome, fibromyalgia, chronic fatigue syndrome, and bodily distress syndrome and related conditions such as health (illness) anxiety is often based on self-reported questionnaires or layman interviews. This study presents and describes the Research Interview for Functional somatic Disorders (RIFD) and provides first data regarding RIFD's ability to identify cases with functional somatic disorders and health anxiety in a two-phase design following self-reported symptom questionnaires. METHODS: RIFD was performed by phone by trained family physicians on a stratified subsample of 1590 adults from a Danish general population cohort (n = 7493). Criterion validity was tested in a small preliminary test including 25 RIFD participants using Schedules of Clinical Assessment in Neuropsychiatry (SCAN), performed by a specialist in functional somatic disorders, as gold standard. Interrater reliability between interviewers was tested in 15 participants. RESULTS: Compared with the comprehensive SCAN, preparation and conduction of RIFD were feasible and prompt. RIFD was well accepted by both interviewers and interviewees. RIFD identified cases with significantly more impairment than identified non-cases. Based on small preliminary tests, RIFD showed promising psychometric properties. CONCLUSION: RIFD was a feasible, well-accepted and promising instrument for use in large epidemiological studies. However, larger studies investigating its psychometric properties are needed.

Irritable bowel symptoms, use of healthcare, costs, sickness and disability pension benefits: A long-term population-based study.

Objectives: Irritable bowel syndrome (IBS) is associated with increased healthcare use and work absenteeism. We aimed to investigate long-term use of healthcare services and social benefits across IBS symptom groups. Additionally, we estimated excess healthcare costs. Methods: A longitudinal population-based study comprising two 5-year follow-up studies: The Danish part of the Multinational Monitoring of Trends and Determinants in Cardiovascular Disease (Dan-MONICA) 1 (1982-1987) and Inter99 (1999-2004) recruited from the western part of Copenhagen County. The total study population (n = 7278) was divided into symptom groups according to degree of IBS definition fulfillment at baseline and/or 5-year follow-up and was followed until 31 December 2013 in Danish central registries. Poisson regression was used for the analyses adjusting for age, sex, length of education, comorbidity, cohort membership and mental vulnerability. Results: IBS symptom groups compared to no IBS symptoms were associated with an increased number of contacts with primary and secondary healthcare, as well as weeks on sickness and disability benefits. Accounting for mental vulnerability decreased the estimates and all but two associations between IBS symptom groups and outcomes remained statistically significant. The two associations that became insignificant were contacts with psychiatric hospitals and weeks on disability pension. The excess unadjusted healthcare costs for IBS were 680 Euros per year and the overall association between symptom groups and total healthcare costs were statistically significant. Conclusions: IBS symptoms influence the long-term use and costs of healthcare, as well as the use of social benefits in the general population. Mental vulnerability explained some, but not all, of the use of healthcare and social benefits.

A step towards a new delimitation of functional somatic syndromes: A latent class analysis of symptoms in a population-based cohort study.

OBJECTIVES: The current delimitation of functional somatic syndromes (FSS) is inconsistent. We aimed to investigate somatic symptom profiles in the general adult population to contribute to a new, data-driven delimitation of FSS. METHODS: Information on 31 self-reported somatic symptoms used in the delimitation of various FSS and bodily distress syndrome (BDS) was obtained from the DanFunD study-a population-based cohort study on 9656 adults (participation 33.6%) from Greater Copenhagen, Denmark. Latent class analysis was used to identify symptom profiles. The profiles were described by their relation with sex, age, chronic disease, self-perceived health, symptom impact, self-reported FSS, and BDS case-status. RESULTS: Eight symptom profiles were identified. The largest profile had no symptoms (49% of the population). Three profiles were characterized by a few, specific symptoms: muscle and joint pain (17%), gastrointestinal symptoms (6%), and general symptoms (13%). Three profiles had multiple symptoms in specific combinations: musculoskeletal and general symptoms (7%); fatigue, musculoskeletal and gastrointestinal symptoms (3%); and cardiopulmonary, gastrointestinal and general symptoms (3%). Lastly, one profile (2%) had high probability of all symptoms. The last four profiles (15%) were strongly associated with BDS case-status, poor self-perceived health and high impact of symptoms. Analyses excluding persons with multi-symptomatic chronic disease showed similar results. CONCLUSIONS: We identified eight symptom profiles characterized by specific combinations of symptoms. Four of these had multiple symptoms from several bodily systems showing large overlap with BDS, possibly indicating subtypes of FSS. The profiles contribute to a new delimitation of FSS by illustrating the importance of specific symptom combinations.

Somatic symptom profiles in the general population: a latent class analysis in a Danish population-based health survey.

PURPOSE: The aim of this study was to identify and describe somatic symptom profiles in the general adult population in order to enable further epidemiological research within multiple somatic symptoms. METHODS: Information on 19 self-reported common somatic symptoms was achieved from a population-based questionnaire survey of 36,163 randomly selected adults in the Capital Region of Denmark (55.4% women). The participants stated whether they had been considerably bothered by each symptom within 14 days prior to answering the questionnaire. We used latent class analysis to identify the somatic symptom profiles. The profiles were further described by their association with age, sex, chronic disease, and self-perceived health. RESULTS: We identified 10 different somatic symptom profiles defined by number, type, and site of the symptoms. The majority of the population (74.0%) had a profile characterized by no considerable bothering symptoms, while a minor group of 3.9% had profiles defined by a high risk of multiple somatic symptoms. The remaining profiles were more likely to be characterized by a few specific symptoms. The profiles could further be described by their associations with age, sex, chronic disease, and self-perceived health. CONCLUSION: The identified somatic symptom profiles could be distinguished by number, type, and site of the symptoms. The profiles have the potential to be used in further epidemiological studies on risk factors and prognosis of somatic symptoms but should be confirmed in other population-based studies with specific focus on symptom burden.

Irritable bowel symptoms and the development of common mental disorders and functional somatic syndromes identified in secondary care - a long-term, population-based study.

OBJECTIVE: Irritable bowel syndrome (IBS) is associated with mental vulnerability, and half of patients report comorbid somatic and mental symptoms. We aimed to investigate the relationship between an IBS symptom continuum and the subsequent development of common mental disorders (CMDs) and functional somatic syndromes (FSSs). METHODS AND STUDY DESIGN: A longitudinal population-based study comprising two 5-year follow-up studies, Dan-MONICA 1 (1982-1987) and Inter99 (1999-2004), recruited from the western part of Copenhagen County. The total study population (n = 7,278) was divided into symptom groups according to the degree of IBS definition fulfillment at baseline and/or follow-up and was followed until December 2013 in Danish central registries. Cox regression was used for the analyses, adjusting for age, sex, length of education and cohort membership. In a subsequent analysis, we adjusted for mental vulnerability as a risk factor for both CMDs and FSSs, including IBS. RESULTS: Over a 5-year period, 51% patients had no IBS symptoms, 17% patients had IBS symptoms without abdominal pain, 22% patients had IBS symptoms including abdominal pain and 10% patients fulfilled the IBS definition. IBS and IBS symptoms including abdominal pain were significantly associated with the development of CMDs and other FSSs identified in secondary care. When adjusting for mental vulnerability, IBS and IBS symptoms including abdominal pain were no longer associated with CMDs, but the significant relationship to other FSSs remained. CONCLUSION: In a clinical setting, the perspective should be broadened to individuals not fulfilling the symptom cluster of IBS but who report frequent abdominal pain. Additionally, it is important to combine symptom-based criteria of IBS with psychosocial markers such as mental vulnerability, because it could guide clinicians in decisions regarding prognosis and treatment.

Somatic Symptoms: Prevalence, Co-Occurrence and Associations with Self-Perceived Health and Limitations Due To Physical Health - A Danish Population-Based Study.

A high number of somatic symptoms have been associated with poor health status and increased health care use. Previous studies focused on number of symptoms without considering the specific symptoms. The aim of the study was to investigate 1) the prevalence of 19 somatic symptoms, 2) the associations between the symptoms, and 3) the associations between the somatic symptoms, self-perceived health and limitations due to physical health accounting for the co-occurrence of symptoms. Information on 19 somatic symptoms, self-perceived health and limitations due to physical health was achieved from a population-based questionnaire survey of 36,163 randomly selected adults in the Capital Region of Denmark in 2006/07. Chain graph models were used to transparently identify and describe the associations between symptoms, self-perceived health and limitations due to physical health. In total, 94.9% of the respondents were bothered by one or more of the 19 somatic symptoms. The symptoms were associated in a complex structure. Still, recognisable patterns were identified within organ systems/body parts. When accounting for symptom co-occurrence; dizziness, pain in legs, respiratory distress and tiredness were all strongly directly associated with both of the outcomes (γ>0.30). Chest pain was strongly associated with self-perceived health, and other musculoskeletal symptoms and urinary retention were strongly associated with limitations due to physical health. Other symptoms were either moderate or not statistically associated with the health status outcomes. Opposite, almost all the symptoms were strongly associated with the two outcomes when not accounting for symptom co-occurrence. In conclusion, we found that somatic symptoms were frequent and associated in a complex structure. The associations between symptoms and health status measures differed between the symptoms and depended on the co-occurrence of symptoms. This indicates an importance of considering both the specific symptoms and symptom co-occurrence in further symptom research instead of merely counting symptoms.

Gastrointestinal symptoms related to the irritable bowel syndrome - a longitudinal population-based register study.

OBJECTIVE: Functional gastrointestinal (GI) symptoms can develop into persistent states often categorised as the irritable bowel syndrome (IBS). In the severe end of the GI symptom continuum, other coexisting symptoms are common. We aimed to investigate the GI symptom continuum in relation to mortality and development of GI diseases, and to examine if coexisting symptoms had an influence on the outcomes. MATERIAL AND METHODS: A longitudinal population-based study comprising two 5-year follow-up studies: Dan-Monica1 (1982-1987) and Inter99 (1999-2004). IBS was defined according to a population-based IBS definition. The pooled cohort (n = 7278) was followed until December 2013 in Central Registries. RESULTS: Fifty-one percent had no GI symptoms, 39% had GI symptoms but never fulfilled the IBS definition, 8% had fluctuating IBS and 2% had persisting IBS. There was no significant association between symptom groups and mortality (p = 0.47). IBS and GI symptoms with abdominal pain were significantly associated with development of GI diseases. Only GI symptoms with abdominal pain were associated with development of severe GI diseases (HR: 1.38; 95% CI: [1.06-1.79]). There were no statistically significant interactions between symptom groups and coexisting symptoms in relation to the two outcomes. CONCLUSIONS: GI diseases were seen more frequently, but IBS was not associated with severe GI diseases or increased mortality. Clinicians should be more aware when patients do not fulfil the IBS definition, but continue to report frequent abdominal pain. Coexisting symptoms did not influence mortality and development of GI diseases.

A longitudinal cohort study of intelligence and later hospitalisation with mental disorder.

OBJECTIVE: Few studies on the associations between pre-morbid IQ and mental disorders are based on comprehensive assessment of intelligence in both women and men and include a wide range of confounding variables. Thus, the objective of the present study was to examine the association between pre-morbid IQ and hospitalisation with any mental disorder, including possible gender differences in the association. METHODS: The study population was born in 1959-61 and premorbid IQ was assessed with the WAIS between 1982 and 1994. Information on mental disorders was obtained from Danish hospital registers with a mean follow-up interval of 21.1years. A total of 1106 participants were analysed. RESULTS: Those with a mental disorder had a significantly lower mean pre-morbid IQ score than those without. For women, the adjusted IQ difference was 8.5 points, and for men it was 5.1 points. A decrease of one standard deviation in pre-morbid IQ was associated with 83% greater risk of developing a mental disorder among women (HR=1.83, 95% CI: 1.41-2.36), and 36% among men (HR=1.36, 95% CI: 1.07-1.73). The interaction between gender and IQ was not statistically significant. Associations did not differ noteworthy between verbal and non-verbal IQ. CONCLUSIONS: Pre-morbid IQ was found to be significantly associated with the development of mental disorder.

Preoperative smoking status and postoperative complications: a systematic review and meta-analysis.

OBJECTIVE: To systematically review and summarize the evidence of an association between preoperative smoking status and postoperative complications elaborated on complication type. BACKGROUND: The conclusions of studies examining the association between preoperative smoking and postoperative complications are inconsistent, thus there is a need for a review and meta-analysis to summarize the existing evidence. METHODS: A systematic review and meta-analysis based on a search in MEDLINE, EMBASE, CINAHL, and PsycINFO. Included were original studies of the association between smoking status and postoperative complications occurring within 30 days of operation. In total, 9354 studies were identified and reviewed for eligibility and data were extracted. Forest plots and summarized relative risks (RR) including 95% confidence intervals (CIs) were estimated for various complication types. RESULTS: Of the 9354 identified studies, 107 studies were included in the meta-analyses and based on these, 157 data sets were extracted. Preoperative smoking was associated with an increased risk of various postoperative complications including general morbidity (RR=1.52, 95% CI: 1.33-1.74), wound complications (RR=2.15, 95% CI: 1.87-2.49), general infections (RR=1.54, 95% CI: 1.32-1.79), pulmonary complications (RR=1.73, 95% CI: 1.35-2.23), neurological complications (RR=1.38, 95% CI: 1.01-1.88), and admission to intensive care unit (RR=1.60, 95% CI: 1.14-2.25). Preoperative smoking status was not observed to be associated with postoperative mortality, cardiovascular complications, bleedings, anastomotic leakage, or allograft rejection. CONCLUSIONS: Preoperative smoking was found to be associated with an increased risk of the following postoperative complications: general morbidity, wound complications, general infections, pulmonary complications, neurological complications, and admission to the intensive care unit.

Alcohol-attributable and alcohol-preventable mortality in Denmark: an analysis of which intake levels contribute most to alcohol's harmful and beneficial effects.

The aim of the study was to quantify alcohol-attributable and -preventable mortality, totally and stratified on alcohol consumption in Denmark 2010, and to estimate alcohol-related mortality assuming different scenarios of changes in alcohol distribution in the population. We estimated alcohol-attributable and -preventable fractions based on relative risks of conditions causally associated with alcohol from meta-analyses and information on alcohol consumption in Denmark obtained from 14,458 participants in the Danish National Health Survey 2010 and corrected for adult per capita consumption. Cause-specific mortality data were obtained from the Danish Register of Causes of Death. In total, 1,373 deaths among women (5.0% of all deaths) and 2,522 deaths among men (9.5% of all deaths) were attributable to alcohol, while an estimated number of 765 (2.8%) and 583 (2.2%) deaths were prevented by alcohol. Of the alcohol-attributable deaths, 73 and 81% occurred within the high alcohol consumption group (>14/21 drinks/week for women/men). A reduction of 50% in the alcohol consumption was associated with a decrease of 1,406 partly alcohol-attributable deaths (46%) and 37 alcohol-preventable deaths (3%). Total compliance with sensible drinking guidelines with a low risk limit (<7/14 drinks/week) and a high risk limit (<14/21 drinks/week) was associated with a reduction of 2,380 and 1,977 alcohol-attributable deaths, respectively. In summary, 5.0% of deaths among women and 9.5 % of deaths among men were attributable to alcohol in Denmark 2010. The minority of Danish women and men had high alcohol consumption (16 and 26%). However, the majority of all alcohol-attributable deaths among women and men were caused by high consumption (73 and 81%).