Peeter Fredlund

Work load and work hours in relation to disturbed sleep and fatigue in a large representative sample.

OBJECTIVE To study the relation between work and background factors on the one hand and disturbed sleep and fatigue on the other. METHOD A representative national sample of 58,115 individuals was selected at regular intervals over a period of 20 years and interviewed on issues related to work and health. The data were subjected to a multiple logistic regression analysis. RESULTS The number of cases was 18,828 (32.8%) for fatigue and 7347 (12.8%) for disturbed sleep. For disturbed sleep, the significant predictors became: female gender, age above 49 years, present illness, hectic work, physically strenuous work, and shift work. For fatigue, the significant predictors became female gender, age below 49 years, high socioeconomic status, present illness, hectic work, overtime work, and physically strenuous work. CONCLUSION Work stress, shift work, and physical workload interfere with sleep and are related to fatigue.

A prospective study of fatal occupational accidents--relationship to sleeping difficulties and occupational factors.

Very little is known about the association between sleep and (fatal) occupational accidents. This study investigated this relationship using register data of self‐rated sleep difficulties, together with occupational and demographic characteristics. The variables were related to subsequent occupational fatal accidents. A national sample of 47 860 individuals was selected at regular intervals over a period of 20 years, and interviewed over the phone on issues related to work and health. The responses were linked to the cause of death register (suicides excluded) and the data set was subjected to a (multivariate) Cox regression survival analysis. One hundred and sixty six fatal occupational accidents occurred, and the significant predictors were: male vs. female: relative risk (RR)=2.30 with a 95% confidence interval (CI) of 1.56–3.38; difficulties in sleeping (past 2 weeks): RR=1.89 with CI=1.22–2.94; and non‐day work: RR=1.63 with CI=1.09–2.45. No significant effect was seen for age, socio‐economic group, hectic work, overtime (>50 h per week), or physically strenuous work. It was concluded that self‐reported disturbed sleep is a predictor of accidental death at work, in addition to non‐day work and male gender.

Cohort Profile: The Stockholm Public Health Cohort

The Stockholm Public Health Cohort was set up within the Stockholm County Council public health surveys to inform on determinants and consequences of significant contributors to the current burden of disease. Participants are 89 268 randomly selected individuals from the adult population of Stockholm County. Baseline surveys took place in 2002, 2006 and 2010 via self-administered questionnaires. So far, participants recruited in 2002 were re-surveyed twice, in 2007 and 2010, and those enrolled in 2006 were re-surveyed once, in 2010. Self-reported data are regularly supplemented by information from national and regional health data and administrative registers, for study participants and their relatives (including their offspring). Available data are extensive and include a wide array of health, lifestyle, perinatal, demographic, socio-economic and familial factors. The cohort is an international resource for epidemiological research, and the data available to the research community for specific studies obtained approval from the Stockholm Public Health Cohort Steering Committee and the Stockholm Regional Ethical Review Board.

Immigration, transition into adult life and social adversity in relation to psychological distress and suicide attempts among young adults.

Background The increasing incidence of mental health problems among young people is a major concern in many Western countries. The causal mechanisms underlying these trends are not well established, but factors influenced by current societal changes ought to be implicated. Such factors include immigration and social adversity as well as the timing of taking on adult social roles (e.g. gainful employment, parenthood and own housing tenure). We therefore examined relationships between these factors and the risks of psychological distress as well as suicide attempts in young adults, with a focus on gender differences. Methods We conducted a population-based study including 10,081 individuals aged 18–29, recruited in 2002 and 2006 in Stockholm, Sweden. Data were collected by record linkage and questionnaires. Results Non-European immigrants had an increased risk of distress, and female non-European immigrants had a markedly higher risk of suicide attempts. Both early parenthood (≤24 years) and not being a parent, being a student and the lack of own housing tenure were associated with distress, but only in women. In both sexes, financial strain was associated with the increased risk of distress and suicide attempts, while unemployment was only associated with distress. Conclusions Immigration from outside Europe and social adversity are associated with mental health problems in young adults, especially females. Postponed transition into adulthood is associated with poor mental health in young women. These factors are influenced by current societal changes, and may have contributed to the increasing incidence of mental health problems among young people in Western countries.

Snus (Swedish smokeless tobacco) use and risk of stroke: pooled analyses of incidence and survival

Snus is a moist smokeless tobacco product with high nicotine content. Its use has a short‐term effect on the cardiovascular system, but the relationship between snus use and stroke is unclear.

School performance and the risk of suicide attempts in young adults: a longitudinal population-based study

BACKGROUND Poor school performance is strongly associated with attempted suicide, but the mechanisms underlying this association are uncertain. We examined this relationship and the extent to which it is explained by (i) adult health behaviours and (ii) social conditions. Furthermore, we examined the potential modifying role of previous suicidal thoughts in the relationship. METHOD We conducted a longitudinal cohort study of 6146 individuals aged 18-33 years, recruited in 2002 and 2006 in Stockholm and resurveyed in 2007 and 2010 respectively. We estimated the risk of reported lifetime suicide attempts at follow-up among individuals without a history of suicide attempts at baseline and in relation to compulsory school-leaving grades, controlling for possible confounders and mediators. RESULTS There were 91 cases of self-reported suicide attempts during the follow-up (5-year incidence of 1.5%). ORs ranged from 3.35 [95% confidence interval (CI) 1.88-5.96] for those in the lowest grade quartile to 2.60 (95% CI 1.48-4.57) and 1.76 (95% CI 0.99-3.13) for those in the second and third quartiles respectively. The relationship between school performance and risk of suicide attempts did not differ by sex. Adult health behaviours and social conditions marginally attenuated, but did not explain, the relationship. The gradient varied with baseline history of suicidal thoughts, and was found only among individuals without such a history. CONCLUSIONS Poor school performance was found to predict suicide attempts among young adults without a history of suicidal thoughts. Adult health behaviours and social conditions did not explain this relationship. Instead, other factors linked with poor school performance, such as poor coping ability, may increase the risk of suicide attempts.

Use of Scandinavian Moist Smokeless Tobacco (Snus) and the Risk of Atrial Fibrillation.

Background: Snus is a smokeless tobacco product, widely used among Swedish men and increasingly so elsewhere. There is debate as to whether snus is an acceptable “harm-reduction” tobacco product. Since snus use delivers a dose of nicotine equivalent to cigarettes, and has been implicated in cardiac arrhythmia because of associations with sudden cardiovascular death, a relation with atrial fibrillation is plausible and important to investigate. Methods: To assess the relation between use of snus and risk of atrial fibrillation, we carried out a pooled analysis of 7 prospective Swedish cohort studies. In total, 274,882 men, recruited between 1978 and 2004, were followed via the National Patient Register for atrial fibrillation. Primary analyses were restricted to 127,907 never-smokers. Relative risks were estimated using Cox proportional hazard regression. Results: The prevalence of snus use was 25% among never-smokers. During follow-up, 3,069 cases of atrial fibrillation were identified. The pooled relative risk of atrial fibrillation was 1.07 (95% confidence interval = 0.97–1.19) in current snus users, compared with nonusers. Conclusion: Findings from this large national pooling project indicate that snus use is unlikely to confer any important increase in risk of atrial fibrillation.

Who takes paternity leave? : A cohort study on prior social and health characteristics among fathers in Stockholm

Progress towards gender equality involves changes in the traditional parental division – female caring and male breadwinning. One aspect is increased parental leave for fathers, which may benefit the health of mothers, children, and fathers themselves. We examined how social and health characteristics (2002) were associated with paternity leave in excess of the ‘father quota’ of 60 days (2003–2006) in the Stockholm Public Health Cohort. Generally, fathers with stable social position, fit lifestyles, and good health had increased chances of paternity leave uptake. Our findings may contribute to identifying target groups for parental leave strategies among fathers; they indicate also that research on gender equality and public health must carefully address the problems of confounding and health-related selection.

School performance and the risk of suicidal thoughts in young adults: population-based study.

Although low school performance is related to attempted and completed suicide, its relationship with suicidal thoughts has been less clear. We conducted a population-based study including 10081 individuals aged 18–29 years in Stockholm, Sweden, and found a clear positive gradient in the risk of lifetime suicidal thoughts with decreasing levels of compulsory school leaving grades. This relationship was somewhat attenuated but remained significant in multivariate models accounting for family background, severe adult psychopathology and adult socioeconomic conditions. School failure is associated with an increased risk of experiencing suicidal thoughts and may also increase the tendency of acting upon them.

Prevalence of Voice Disorders in the General Population, Based on the Stockholm Public Health Cohort

OBJECTIVE To investigate the prevalence of voice disorders in the general population. STUDY DESIGN Analysis of data from the Stockholm Public Health Cohort. METHODS A public health survey was distributed to an open cohort of 114,538 adults >18 years of age in the area of Stockholm County, Sweden. The survey included one question about voice problems, estimating the extent of occurrence of voice problems, excluding voice problems during colds/upper airway infections. The question was tested for validity and reliability in n = 166 voice healthy individuals and n = 183 patients with benign voice lesions. The construct validity was tested against two established self-assessment questionnaires. The question was established to correspond to tiring, strain, and hoarseness. Prevalence of voice problems and correlations with age, gender, occupation, hearing, smoking, and socio-economic status were calculated. RESULTS The overall prevalence of voice disorders in the entire group was estimated to 16.9%, where 15.5% voice problems were rated to occur to a small extent and 1.4% to a great extent. Women were significantly more prone to report voice problems than men. The highest ratings of a great extent of voice problems were found in both women and men >85 years of age. As for occupation, the highest prevalence of voice problems was found in teaching and service occupations. CONCLUSIONS The prevalence of voice problems was estimated to 16.9% in the entire group. Women reported significantly more voice problems than men and voice problems were significantly more common in ages >65. This study of self-reported voice problems in a general population is one of the largest of its kind.