Screening student drinking behaviors: examining AUDIT criterion validity using CIDI-based alcohol use disorder as the 'gold standard'.

Introduction: High levels of alcohol consumption among college students have been observed across countries. Heavy drinking episodes are particularly prevalent in this population, making early identification of potentially harmful drinking critical from a public health perspective. Short screening instruments such as the Alcohol Use Disorders Identification Test (AUDIT) are serviceable in this regard. However, there is a need for studies investigating the criterion validity of AUDIT in the student population. The aim was to examine the criterion validity of the full AUDIT and AUDIT-C (the first three items directly gauging consumption patterns) in a sample of college and university students using 12-month prevalence of alcohol use disorder derived from an electronic, self-administered version of the World Health Organization (WHO) Composite International Diagnostic Interview, fifth version (CIDI 5.0), which serves as the 'gold standard'. Methods: The study population of the current study is derived from the SHoT study (Students' Health and Wellbeing Study), which is a large national survey of students enrolled in higher education in Norway. In a follow-up study of mental disorders among participants of the SHoT2022 study, students were invited to complete a self-administered electronic version of the CIDI. A random sample of 4,642 participants in the nested CIDI-sample was asked to fill out a set of screening instruments, including AUDIT, before starting CIDI. Based on Youden Index maximization, we estimated the sex-specific optimal cut-offs for AUDIT and AUDIT-C in relation to alcohol use disorder, as determined by CIDI. Results: For the full AUDIT, the optimal cut-offs were 9 for males and 10 for females. The corresponding cut-offs for AUDIT-C were 6 for males and 5 for females. The same optimal cut-offs for both the full AUDIT and AUDIT-C were replicated in bootstrapped analyses with 1,000 runs. Conclusion: The full AUDIT demonstrated acceptable criterion validity with a balance between sensitivity and specificity. However, for AUDIT-C, caution should be exercised when interpreting screening results among college and university students. In conclusion, the full AUDIT is a reliable screening instrument for college and university students, while further modification may be needed for AUDIT-C in this setting.

Establishing the Association Between Snus Use and Mental Health Problems: A Study of Norwegian College and University Students.

INTRODUCTION: Smoking and mental health problems are public health concerns worldwide. Studies on smoke-free tobacco products, especially snus are scarce. Snus is considered less harmful than smoking and in the United States allowed to be marketed accordingly, but may still add to the burden of disease. AIMS AND METHODS: Data stem from the Norwegian Students' Health and Wellbeing Study (SHoT study) in 2018 (162 512 invited, 50 054 (30.8%) completed). Smoking, snus use, health service and medication usage and mental health problems, including the Hopkins Symptom Checklist-25 (HSCL-25), were assessed using self-report. The aims were to explore the associations between smoking and snus use and mental health problems and treatments. Furthermore, the association between both daily smoking and daily snus use and mental health problems. Associations were tested with χ2-, t-tests, and logistic regression. RESULTS: Daily snus users had 38% increased odds (odds ratio [OR]: 1.38, CI: 1.30 to 1.46), and daily smokers had 96% increased odds (OR: 1.96, CI: 1.65 to 2.34) of having a high HSCL-25 score, adjusted for gender, low socioeconomic status (SES), using tobacco, participating in therapy and using antidepressants daily. CONCLUSIONS: Both daily smoking and daily snus use were associated with an increased level of mental health problems. The adjusted probability for mental health problems was lower for snus use; however, snus use prevalence was tenfold in our sample. IMPLICATIONS: Despite the lack of causal and directional conclusions, these associations may have implications for future legislation on snus. They also highlight the importance of more research, especially as snus is considered less harmful and seemingly replacing smoking in Norway.

Focus on Self-Presentation on Social Media across Sociodemographic Variables, Lifestyles, and Personalities: A Cross-Sectional Study.

Upward social comparison and aspects of self-presentation on social media such as feedback-seeking and strategic self-presentation may represent risk factors for experiencing negative mental health effects of social media use. The aim of this exploratory study was to assess how adolescents differ in upward social comparison and aspects of self-presentation on social media and whether these differences are linked to sociodemographic variables, lifestyle, or personality. The study was based on cross-sectional data from the "LifeOnSoMe" study performed in Bergen, Norway, including 2023 senior high school pupils (response rate 54%, mean age 17.4, 44% boys). Nine potentially relevant items were assessed using factor analysis, and latent class analysis was used to identify latent classes with distinct patterns of responses across seven retained items. The retained items converged into one factor, called "focus on self-presentation". We identified three groups of adolescents with a low, intermediate, and high focus on self-presentation. Associations between identified latent classes and covariates were assessed using regression analyses. Being a girl, higher extraversion, lower emotional stability, more frequent alcohol consumption, and having tried tobacco were associated with membership in the high-focus group. These results suggest some characteristics that are associated with a higher focus on self-presentation and that could inform targeted interventions.

The Epidemiology of Insomnia and Sleep Duration Across Mental and Physical Health: The SHoT Study.

OBJECTIVE: Numerous epidemiological studies have been conducted to examine the prevalence and comorbidities of insomnia and document sleep duration, but a common limitation in many studies is the lack of use of agreed-upon definitions of insomnia, as well as insufficient statistical power to examine comorbid mental and physical disorders/conditions. AIM: To examine the prevalence of insomnia operationalized according to formal DSM-5 criteria and differences in mean sleep duration across a wide range of mental and physical disorders, examining men and women separately. MATERIALS AND METHODS: Data stem from the SHoT study (Students' Health and Wellbeing Study), a national survey of all college and university students in Norway. In all, 162,512 students aged 18-35 received an invitation to participate, of whom 50,054 students completed the internet-based survey (attendance rate: 30.8%). Insomnia was defined according to the Diagnostic and Statistical Manual of Mental Disorders (5th ed.) criteria and sleep duration was calculated separately for weekdays and weekends. Self-reported mental and physical disorders/conditions were assessed using a pre-defined list modified to fit this age group. Pearson chi-squared tests were used to examine the prevalence of insomnia across the various mental and physical disorders/conditions in men and women separately, and log-link binomial regression analysis were used to calculate effect-sizes, adjusting for age. RESULTS: The prevalence of insomnia in both sexes was significantly higher across all mental disorders compared with a healthy reference group. Among females, the prevalence of insomnia ranged from 61.3% for comorbid depression (adj. RR = 2.49, 95% CI: 2.40) to 83.3% for comorbid schizophrenia (adj. RR = 3.37, 95% CI: 2.61-4.35). For males, the insomnia prevalence ranged from 32.3% for comorbid autism/Asperger (adj. RR = 2.02, 95% CI: 1.39-2.92) to 74.2% for comorbid eating disorder (adj. RR = 4.51, 95% CI: 3.87-5.27). The overall prevalence of insomnia was also significantly higher across most physical conditions compared with the healthy reference group, although generally lower compared to the mental disorders. For females, the insomnia prevalence ranged from 25% for comorbid multiple sclerosis (not significant) to 65.4% for comorbid chronic fatigue syndrome/ME (adj. RR = 2.66, 95% CI: 2.44-2.89). For males, the insomnia prevalence ranged from 20% for both comorbid cancer and diabetes (not significant) to 74.2% for comorbid fibromyalgia (adj. RR = 4.35, 95% CI: 2.96-6.39). Similar patterns were observed for sleep duration, with a significantly shorter sleep duration for across many physical disorders, but especially mental disorders. CONCLUSION: Insomnia and short sleep duration are strongly associated with a range of different disorders and conditions. Insomnia is most strongly associated with mental disorders, and physical conditions characterized by some level of psychological or psychosomatic properties.

Increasing similarities between young adults' smoking and snus use in Norway: a study of the trends and stages of smoking and snus epidemic from 2010 to 2018.

BACKGROUND: The prevalence of smoking has been decreasing in Norway for decades. In contrast, the prevalence of snus use has recently increased substantially, especially among females. While there is a clear social gradient in smoking, with a higher smoking prevalence among individuals with low socioeconomic status (SES), a possible social gradient in snus use has been less studied. The aim of the current study was to investigate the trends of smoking and snus use and to examine whether ongoing changes in snus use are similar to prior smoking epidemic development. METHODS: The study was based on the 2010 (n = 5836), 2014 (n = 13,319) and 2018 (n = 24,515) waves from a nation-wide, cross-sectional, health survey of higher education in Norway (the SHoT study). Variables on smoking, snus use, gender, age and SES were used. Chi-square tests and logistic regression analyses were used to test significance, and Mantel-Haenszel weights were used to test the trends in stratified cross-tabulations. RESULTS: Daily smoking decreased from 5.9 to 1.5% between 2010 and 2018, while daily snus use increased from 13.4 to 19.9%. Female snus use almost doubled, from 10.9 to 19.2%. Low SES was associated with both daily smoking and snus use across all three waves. Occasional smoking was also associated with low SES at all waves, but occasional snus use was only associated with low SES in 2010. There were no significant changes over time in either the association between occasional or daily smoking and SES or the association between occasional or daily snus use and SES. CONCLUSIONS: The overall smoking decrease indicated that the Norwegian smoking epidemic is in its latest stage. Steady male snus use, doubled female snus use and a clear social gradient in snus use all indicate that the snus epidemic in Norway has progressed. If this trend continues, a main implication is that snus prevalence will soon peak, first in males and then in females.

DiaSHoT18: A cross-sectional national health and well-being survey of university students with type 1 diabetes.

OBJECTIVE: To achieve a better understanding in how university students live with and are able to manage their type 1 diabetes (T1D). METHODS: In 2018, all fulltime Norwegian students aged 18 to 35 years pursuing higher education were invited into a national survey, which included data on demographics and health. In all, 162 512 students fulfilled these inclusion criteria. Students that stated having diabetes were asked to answer further questions about their diabetes care. RESULTS: We included data from 50 054 students responding to the survey, and identified 324 students with T1D (64% females, mean age 23 years, mean HbA1c 7.65% [60 mmol/mol]). Male students had a lower HbA1c (7.28% vs 7.86%, 56 vs 62 mmol/mol), reached an HbA1c of <7.5% (58 mol/mol) more often (62.2% vs 44.2%) and were using continuous glucose measurement (CGM) less often (19.5% vs 36.7%). Exercise and smoking habits in students with T1D were equal to the non-diabetic group. More students with T1D were overweight or obese (44.1% vs 32.2%). Students who achieved an HbA1c <7.5% (58 mmol/mol) measured their blood sugar more often, had a lower body-mass index, exercised more and were smoking less. An HbA1c >7.5% (58 mmol/mol) was associated with less activity, more overweight or obesity, and smoking. The use of continuous subcutaneous insulin infusion and CGM was not associated with a better metabolic control. CONCLUSIONS: These data have implications for the follow-up of adolescents and young adults, showing the need to focus on general lifestyle habits, especially in female subjects, whereas the use of technical devices might be of secondary importance.

Economic Circumstances in Childhood and Subsequent Substance Use in Adolescence - A Latent Class Analysis: The youth@hordaland Study.

The aim of the present study was to investigate the association between longitudinal registry-based data on family income during childhood and self-reported substance use in adolescence, including potential alcohol- or drug problems. Data from the Norwegian population-based youth@hordaland-survey was employed, and the analyzed included n = 8,983 adolescents aged 16-19 years. This information was linked to registry-based information about childhood family income for seven consecutive years prior to adolescents' participation in the youth@hordaland-survey. Latent class analyses (LCA) were used to examine associations between patterns of family economic circumstances in childhood and subsequent substance use in adolescence. Based on the LCA, we identified four distinct patterns of family economic circumstances: a 'never poor' (89.3%) group, followed by two groups characterized by moving in (3.0%) or out (4.6%) of poverty, and a final 'chronically poor' (3.1%) group. Several findings were of interest: the chronically poor reported less daily snus use, fewer had tried alcohol, were less likely to report frequent intoxication, and less prone to have potential alcohol- or drug-related problems compared to all other groups. They were also less likely to have tried any illicit drug compared to those moving in or out of poverty. Finally, the chronically poor reported more daily smoking than the never poor group, but less daily smoking than the moving out of poverty group. The never poor group was less likely to have tried any illicit drugs compared to the groups moving into or out of poverty, and less likely to smoke daily compared to the moving out of poverty group. In other words, the present study somewhat surprisingly suggested lower substance use among the chronically poor adolescents compared to other adolescents on several of the measures of substance use.

Associations between symptoms of eating disturbance and frequency of physical activity in a non-clinical, population-based sample of adolescents.

BACKGROUND: Physical activity is an important factor related to eating disorders, but the relationship between symptoms of eating disorders and physical activity is multifaceted. The aims of this study were to investigate how symptoms of eating disturbance (ED) were associated with physical activity, and to explore potential sex differences and the potential moderating effects from body mass index (BMI) scores. METHODS: Data stem from a large population-based survey of 10,172 Norwegian adolescents aged 16 to 19 years, the youth@hordaland-survey. The main dependent variable was self-reported number of days with physical activity per week, while the main independent variable was self-reported symptoms of ED using the five-item Eating Disturbance Screening (EDS-5) questionnaire. Control variables included sex, age, socioeconomic status, and BMI. RESULTS: Girls reported substantially more symptoms of ED compared with boys (M = 3.02 versus 1.32, d = 0.80, p < 0.001), as well as fewer days with physical activity per week (M = 2.88 versus 3.46, d = - 0.28, p < 0.001). For both sexes, symptoms of ED were negatively associated with physical activity (adjusted mean differences (adj. mean diff) ranging from - 0.03 to - 0.08, all p < 0.05). Interaction analyses showed, however, that associations between symptoms of ED and physical activity were significantly moderated by BMI scores for both girls (p < 0.01) and boys (p < 0.05). Specifically, ED symptoms were associated with lower physical activity levels among adolescents with higher BMI scores. CONCLUSIONS: The present study indicates that symptoms of ED were overall negatively associated with physical activity for both sexes during adolescence. However, associations between ED symptoms and physical activity levels differed considerably across the weight spectrum.

Short rest between shifts (quick returns) and night work is associated with work-related accidents.

PURPOSE: The aim of this study was to examine whether less than 11 h between shifts (i.e., quick returns, QRs) and night shifts is associated with self-reported work-related accidents, near accidents or dozing off at work in a sample of nurses. METHODS: The study was based on cross-sectional data from 1784 nurses (response rate = 60%; mean age = 40.1 years, SD = 8.4; 91% female). Negative binomial regression analyses were conducted to investigate the association between the shift exposures, and eight different self-reported work-related items on accidents, near accidents and dozing off at work, controlling for demographics and work factors. RESULTS: The number of QRs during a year was positively associated with seven of the eight items on work-related accidents, near-accidents and dozing off at work, and number of night shifts was positively associated with five items. Some of the key findings were that QRs were associated with nurses causing harm to themselves (incidence rate ratio [IRR] = 1.009; 95% CI = 1.005-1.013), causing harm to patients/others (IRR = 1.006; 95% CI = 1.002-1.010) and causing harm to equipment (IRR = 1.004; 95% CI = 1.001-1.007); while night shifts were associated with nurses involuntarily dozing off at work (IRR = 1.015; 95% CI = 1.013-1.018), dozing off while driving to/from work (IRR = 1.009; 95% CI = 1.006-1.011), and harming patients/others (IRR = 1.005; 95% CI = 1.001-1.009). CONCLUSION: QRs and night shifts were both associated with the self-reported work-related accidents, near-accidents and dozing off at work. Studies that can establish the causal relationship between QRs and accidents are called for.

Use of alcohol, tobacco and illicit drugs among ethnic Norwegian and ethnic minority adolescents in Hordaland county, Norway: the youth@hordaland-survey.

OBJECTIVE: To describe potential differences in unhealthy behaviours among ethnic Norwegian adolescents and minority adolescents from countries within the European Union, European Economic Area or US (EU/EEA countries) and adolescents from non-EU/EEA countries. Specifically, we aimed to investigate ethnic differences in use of alcohol, tobacco and illicit drugs, and potential confounding due to socio-demographic characteristics. DESIGN: Cross-sectional population-based study of adolescents aged 16-19 (N = 10,122), with self-reported ethnicity as grouping variable, and self-reported use of alcohol, tobacco and illicit drugs as dependent variables. RESULTS: We found that minority adolescents from EU/EEA and non-EU/EEA countries differed from ethnic Norwegian adolescents on important indicators of unhealthy behaviours. Compared to Norwegian adolescents, adolescents from EU/EEA were more likely to report having tried to smoke, to be a daily smoker and to ever having tried an illicit drug (adjusted odds ratio (OR) ranging from 2.01 to 3.74). They were, however, less likely to have tried snus (a form of smokeless tobacco; adjusted OR 0.64; confidence interval (CI) 95% 0.43-0.97) and to report daily snus use (adjusted OR 0.31; CI95% 0.15-0.67). There were no differences in having tried alcohol. Non-EU/EEA adolescents were less likely to have ever tried alcohol (OR 0.24; CI95% 0.18-0.31), snus (OR 0.47; CI95% 0.34-0.65) and to smoke (0.68; CI95% 0.52-0.91), and less likely to report daily snus use (OR 0.36; CI95% 0.21-0.62) compared to Norwegian adolescents. There were no differences with regard to having tried illicit drugs and reporting being a daily smoker. All differences observed were robust to adjustment for age, gender and family socio-economic status. CONCLUSION: The presents study identified important differences in unhealthy behaviours across different ethnic groups in Norway. The differences in the prevalence of unhealthy behaviours among ethnic minorities are still relevant in a public health perspective, and potential mechanisms should be investigated further.

Physical activity is independently associated with reduced mortality: 15-years follow-up of the Hordaland Health Study (HUSK).

BACKGROUND: Physical activity (PA) is associated with lower risk for non-communicable diseases and mortality. We aimed to investigate the prospective association between PA and all-cause and cause-specific mortality, and the impact of other potentially contributing factors. METHOD: Data from the community-based Hordaland Health Study (HUSK, 1997-99) were linked to the Norwegian Cause of Death Registry. The study included 20,506 individuals born 1950-1957 and 2,225 born in 1925-1927 (baseline age 40-49 and 70-74). Based on self-report, individuals were grouped as habitually performing low intensity, short duration, low intensity, longer duration or high intensity PA. The hazard ratios (HR) for all-cause and cause-specific mortality during follow-up were calculated. Measures of socioeconomic status, physical health, mental health, smoking and alcohol consumption were added separately and cumulatively to the model. RESULTS: PA was associated with lower all-cause mortality in both older (HR 0.75 (95% CI 0.67-0.84)) and younger individuals (HR 0.82 (95% CI 0.72-0.92)) (crude models, HR: risk associated with moving from low intensity, short duration to low intensity, longer duration PA, and from low intensity, longer duration to high intensity). Smoking, education, somatic diagnoses and mental health accounted for some of the association between physical activity and mortality, but a separate protective effect of PA remained in fully adjusted models for cardiovascular (HR 0.78 (95% CI 0.66-0.92)) and respiratory (HR 0.45 (95% CI 0.32-0.63) mortality (both age-groups together), as well as all-cause mortality in the older age group (HR 0.74, 95%CI 0.66-0.83). CONCLUSION: Low intensity, longer duration and high intensity physical activity was associated with reduced all-cause, respiratory and cardiovascular mortality, indicating that physical activity is beneficial also among older individuals, and that a moderate increase in PA can be beneficial.

Insomnia symptoms and mortality: a register-linked study among women and men from Finland, Norway and Lithuania.

Evidence on the association between insomnia symptoms and mortality is limited and inconsistent. This study examined the association between insomnia symptoms and mortality in cohorts from three countries to show common and unique patterns. The Finnish cohort comprised 6605 employees of the City of Helsinki, aged 40-60 years at baseline in 2000-2002. The Norwegian cohort included 6236 participants from Western Norway, aged 40-45 years at baseline in 1997-1999. The Lithuanian cohort comprised 1602 participants from the City of Palanga, aged 35-74 years at baseline in 2003. Mortality data were derived from the Statistics Finland and Norwegian Cause of Death Registry until the end of 2012, and from the Lithuanian Regional Mortality Register until the end of 2013. Insomnia symptoms comprised difficulties initiating sleep, nocturnal awakenings, and waking up too early. Covariates were age, marital status, education, smoking, alcohol, physical inactivity, obesity, diabetes, cardiovascular diseases, depression, shift work, sleep duration, and self-rated health. Cox regression analysis was used. Frequent difficulties initiating sleep were associated with all-cause mortality among men after full adjustments in the Finnish (hazard ratio 2.51; 95% confidence interval 1.07-5.88) and Norwegian (hazard ratio 3.42; 95% confidence interval 1.03-11.35) cohorts. Among women and in Lithuania, insomnia symptoms were not statistically significantly associated with all-cause mortality after adjustments. In conclusion, difficulties initiating sleep were associated with mortality among Norwegian and Finnish men. Variation and heterogeneity in the association between insomnia symptoms and mortality highlights that further research needs to distinguish between men and women, specific symptoms and national contexts, and focus on more chronic insomnia.

Use of sleep medications and risk of cancer: a matched case-control study.

BACKGROUND: Previous research suggests a possible link between sleep-medication use and mortality, especially cancer deaths, but findings are mixed, and large population-based studies are lacking. METHODS: Data from the Finnish Public Sector study were linked to the Finnish Cancer Register and the Drug Prescription Register of Finland. A total of 5053 cancer cases (mean age of 57.4 years) diagnosed in 2002-2011, and their 24,388 controls free of cancer and matched for sex, age, socioeconomic status, employer, and geographical area, were identified. The use of sleep medications was defined as purchases of prescribed sleep medications. RESULTS: Both quantity and duration of prior sleep-medication use during the seven years studied were associated with increased odds of having cancer. Compared with participants not using sleep medications, the odds ratio was 1.18-fold (95% confidence interval (CI): 1.01-1.39) for those who used >100 defined daily doses per year and 1.16-fold (95% CI: 1.01-1.34) for those who had such a medication for >3 years. Site-specific analyses showed a more pronounced association of quantity and duration of sleep-medication use with subsequent cancer of the respiratory system (odds ratio for >100 defined daily doses per year vs. no use: 3.47; 95% CI: 1.97-6.11). No associations were found with other cancer sites. CONCLUSION: In this register-based study, sleep-medication use was associated with an increased cancer incidence of the respiratory system. Further studies are needed to examine potential carcinogenic mechanisms associated with hypnotic medications.

Insomnia as a risk factor for ill health: results from the large population-based prospective HUNT Study in Norway.

Insomnia co-occurs with many health problems, but less is known about the prospective associations. The aim of the current study was to investigate if insomnia predicts cumulative incidence of mental and physical conditions. Prospective population-based data from the two last Nord-Trøndelag Health Studies (HUNT2 in 1995­97 and HUNT3 in 2006­08), comprising 24 715 people in the working population, were used to study insomnia as a risk factor for incidence of physical and mental conditions. Insomnia was defined according to the 4th edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV). Insomnia at HUNT2 was a significant risk factor for incidence of a range of both mental and physical conditions at HUNT3 11 years later. Most effects were only slightly attenuated when adjusting for confounding factors, and insomnia remained a significant risk factor for the following conditions in the adjusted analyses: depression [odds ratio (OR): 2.38, 95% confidence interval (CI): 1.91­2.98], anxiety (OR: 2.08, 95% CI: 1.63­2.64), fibromyalgia (OR: 2.05, 95% CI: 1.51­2.79), rheumatoidarthritis (OR: 1.87, 95% CI: 1.29­2.52), whiplash (OR: 1.71, 95% CI: 1.21­2.41), arthrosis (OR: 1.68, 95% CI: 1.43­1.98), osteoporosis (OR:1.52, 95% CI: 1.14­2.01, headache (OR: 1.50, 95% CI: 1.16­1.95,asthma (OR: 1.47, 95% CI: 1.16­1.86 and myocardial infarction (OR:1.46, 95% CI: 1.06­2.00). Insomnia was also associated significantly with incidence of angina, hypertension, obesity and stroke in the crude analyses, but not after adjusting for confounders. We conclude that insomnia predicts cumulative incidence of several physical and mental conditions. These results may have important clinical implications, and whether or not treatment of insomnia would have a preventive value for both physical and mental conditions should be studied further.

Sleep disturbances as a predictor of cause-specific work disability and delayed return to work.

STUDY OBJECTIVE: To examine sleep disturbances as a predictor of cause-specific work disability and delayed return to work. DESIGN: Prospective observational cohort study linking survey data on sleep disturbances with records of work disability (> or = 90 days sickness absence, disability pension, or death) obtained from national registers. SETTING: Public sector employees in finland. PARTICIPANTS: 56,732 participants (mean age 44.4 years, 80% female), who were at work and free of work disability at the study inception. MEASUREMENTS AND RESULTS: During a mean follow-up of 3.3 years, incident diagnosis-specific work disability was observed in 4,028 (7%) employees. Of those, 2,347 (60%) returned to work. Sleep disturbances 5-7 nights per week predicted work disability due to mental disorders (hazard ratio [HR] 1.6, 95% confidence interval [CI] 1.3-1.9) and diseases of the circulatory system (HR = 1.6, 95% CI 1.2-2.1), musculoskeletal system (HR = 1.6, 95% CI 1.4-1.8) and nervous system (HR = 1.5, 95% CI 1.0-2.2), and injuries and poisonings (HR = 1.6, 95% CI 1.2-2.1) after controlling for baseline age, sex, socioeconomic status, night/shift work, health behaviors (e.g., smoking, exercise), diagnosed somatic diseases, use of pain killers, depression, and anxiety. In addition, sleep disturbances prior to disability were associated with higher likelihood of not returning to work after work disability from musculoskeletal diseases (HR = 1.2, 95% CI 1.1-1.7) and, in men, after work disability due to mental disorders (HR = 4.4, 95% CI 1.7-11.1). CONCLUSIONS: Sleep disturbances are associated with increased risk for subsequent disabling mental disorders and various physical illnesses. They also predict the outcome of work disability due to musculoskeletal disorders.

The epidemiology of insomnia: associations with physical and mental health. The HUNT-2 study.

OBJECTIVE: The aim of the present study was to examine the association of insomnia symptoms with demographic and physical and mental conditions in a large population-based study. METHODS: Cross-sectional data on insomnia and comorbid conditions were gathered from 47,700 individuals aged 20-89 in Norway. Comorbid conditions included anxiety and depression and the following physical conditions: asthma, allergy, cancer, hypertension, diabetes, migraine, headache, osteoporosis, fibromyalgia rheumatoid arthritis, arthrosis, Bechterew's disease, musculoskeletal disorders, and obesity (body mass index >30). RESULTS: Insomnia symptoms were found in 13.5% of the population and were more prevalent among women, older adults, and in individuals with less education. Reporting insomnia symptoms significantly increased the associations with a range of conditions, especially mental conditions, pain conditions with uncertain etiology and, to a lesser extent, chronic pain conditions. These findings remained significant also when adjusting for a range of potential confounders, whereas the association between insomnia and somatic conditions was largely reduced to a nonsignificant level in the fully adjusted analyses. CONCLUSION: This study demonstrates that insomnia symptoms are associated with a range of different conditions. The findings suggest that the independent contribution of insomnia is strongest on conditions characterized by some level of psychological or psychosomatic properties.