Ingelise Andersen

Social inequality in the prevalence of depressive disorders

Background: Uncertainties exist about the strength of the relation between socioeconomic position and depressive disorders. The aim of this study was to investigate the association between education, occupation, employment and income and depressive disorders measured as minor and major depression, as well as antidepressant prescriptions. Methods: Data were collected from a Danish cross-sectional study collected year 2000, comprising 9254 subjects, 55% women, and aged 36–56 years. Register-based information on education, income and prescription were used. Results: The prevalence of major depression DSM-IV algorithm was 3.3% among men and women, whereas minor depression and prescriptions revealed statistically significant higher prevalence among females. A social gradient was found for all depressive end-points with the strongest estimates related to major depressive disorder (MDD). The associations were as follows: MDD and low education odds ratio (OR) 2.38 (CI 95% 1.68 to 3.37), MDD and non-employment OR 11.67 (CI 95% 8.06 to 16.89), MDD and low income OR 9.78 (CI 95% 6.49 to 14.74). Education only explained a minor part of the association between non-employment and depressive disorders and no associations were found between education and prescription. This indicates a strong two-way association between depression and non-employment, low-income respectively. Conclusion: A social gradient in depressive disorders was found regardless of socioeconomic position being measured by education, occupation, employment or income. Severe socioeconomic consequences of depression are indicated by the fact that the associations with non-employment and low income were much stronger than the association with low education.

Smoking reduction, smoking cessation, and incidence of fatal and non-fatal myocardial infarction in Denmark 1976–1998: a pooled cohort study

Objective: To analyse the effects of smoking reduction and smoking cessation on incidence of myocardial infarction after adjustment for established cardiovascular risk factors. Design: Prospective cohort study with record linkage to mortality and hospital registers. The association of individual change in smoking with myocardial infarction was examined in Cox proportional hazard analyses with continuous heavy smokers (⩾5 cigarettes/day) as reference. Setting: Pooled data from three population studies conducted in Copenhagen, Denmark. Participants: 10 956 men and 8467 women with complete information on smoking habits at two examinations five to ten years apart were followed up from the second examination for a first hospital admission or death from myocardial infarction. Mean duration of follow up was 13.8 years. Main results: A total of 643 participants who were heavy smokers at baseline reduced their daily tobacco consumption by at least 50% without quitting between first and second examination, and 1379 participants stopped smoking. During follow up 1658 men and 521 women experienced a fatal or non-fatal myocardial infarction. After adjustment for cardiovascular risk factors, people who stopped smoking had a decreased risk of myocardial infarction, hazard ratio 0.71 (95% confidence intervals 0.59 to 0.85). Smoking reduction was not associated with reduced risk of myocardial infarction, hazard ratio 1.15 (95% confidence intervals 0.94 to 1.40). These associations remained unchanged after controlling for baseline illness in different ways. Conclusions: Smoking cessation in healthy people reduces the risk of a subsequent myocardial infarction, whereas this study provides no evidence of benefit from reduction in the amount smoked.

An epidemiological survey of hemiplegic migraine

The objective of the present study was to use systematic nation-wide case-finding methods to establish the prevalence and sex ratio of hemiplegic migraine (HM) in the entire Danish population of 5.2 million inhabitants. Affected patients were identified from three different recruitment sources: the National Patient Register, case records from private practising neurologists and advertisements. Based on the observed number of affected patients from each case-finding method, it was attempted to estimate the total number of affected patients by means of the statistical method known as capture- recapture. Two hundred and ninety-one affected patients were identified; 147 were familial HM from 44 different families, 105 were sporadic HM and 39 were unclassifiable HM. The HM sex ratio (M: F) was 1: 3. Based on the identified number of affected patients the prevalence of HM at the end of 1999 was estimated to be 0.01% in Denmark, where the familial and sporadic form were equally frequent.

Cohort Profile: The Copenhagen School Health Records Register

The Copenhagen School Health Records Register(CSHRR) is a database of health examination infor-mation on more than 350000 schoolchildren who everattended school in the central municipality of thecapital city of Denmark. For longer than 100 years,school-based health care has been provided to chil-dren in Copenhagen,

Clinical characteristics of 362 patients with familial migraine with aura

The objectives of the present study were to describe the clinical characteristics of patients with severe familial non-hemiplegic migraine with aura (NHMA) and to compare these data to those from cases in previous population-based Danish studies using the same methodology. NHMA families were recruited from the Danish patient registry and from Danish neurology practices. A total of 362 NHMA patients were diagnosed according to the 1988 International Headache Society criteria using a validated semistructured physician-conducted interview. Visual aura occurred in almost every NHMA attack. In aura without headache visual aura occurred primarily in isolation. Aura without headache was most common in older, male patients. Several clinical characteristics of familial NHMA differed from migraine with aura in the general population: firstly, the age at onset was lower, secondly, the age at cessation was higher, thirdly, aura symptoms were more severe and finally, the co-occurrence of migraine without aura was higher in familial NHMA. There seems to be a correlation between more severe symptoms and familial aggregation. These results have both clinical and scientific implications.

Do factors in the psychosocial work environment mediate the effect of socioeconomic position on the risk of myocardial infarction? Study from the Copenhagen Centre for Prospective Population Studies

Aim: To investigate whether the effect of socioeconomic position on risk of myocardial infarction (MI) is mediated by differential exposure or differential susceptibility to psychosocial work environment. Methods: Data were used from three prospective population studies conducted in Copenhagen. A total of 16 214 employees, 44% women, aged 20–75 years, with initial examination between 1974 and 1992 were followed until 1996 for incident (hospital admission or death) MI. Register based information on job categories was used. Psychosocial job exposures were measured indirectly by means of a job exposure matrix based on the Danish Work Environment Cohort Study 1990. Results: During follow up, 731 subjects were diagnosed with an MI: 610 men and 121 women (35% fatal). The hazards by socioeconomic position showed a graded effect with a hazard ratio (HR) of 1.57 (95% CI 1.23 to 2.03) for unskilled workers compared to executive managers. Despite a strong and graded association in risk of MI related to decision authority and skill discretion, only skill discretion mediated the effect of socioeconomic position. The HR for unskilled workers was reduced to 1.47 (0.93 to 2.31) after adjustment for decision authority and other cardiovascular risk factors, and to 1.07 (0.72 to 1.60) after adjustment for skill discretion and cardiovascular risk factors. No sign of synergy was found. Conclusions: Decision authority and skill discretion were strongly related to socioeconomic position; and the effect on risk of MI was partially mediated by skill discretion. Improvements in psychosocial work environment, especially possibilities for skill discretion, might contribute to reducing the incidence of MI and social inequality in MI.

Increasing prevalence of depression from 2000 to 2006.

Aim: Depression is the leading cause of disability and is projected to become the second highest burden of disease (measured in disability-adjusted life years) by 2020, but only a few studies have examined changes over time in the occurrence of depression. The aim of this study is to provide evidence to the hypothesis that the prevalence of depression is rising in the Danish population. We will do that in a longitudinal design among adult Danes by studying the trends from 2000 to 2006 of major depressive disorder (MDD) as well as the distribution across the whole Major Depression Inventory (MDI) scale. In addition, we will investigate whether the trend in MDD is similar across socioeconomic groups. Methods: A random sample of 4759 Danes in their forties and fifties were followed in a longitudinal study based on postal questionnaires answered in 2000 and 2006. Results: The prevalence of MDD increased from 2.0% to 4.9% during 2000–06. Also the distribution of the MDI score in its entirety moves higher up the scale, with the 90th percentile changing from 12 in year 2000 to 20 in 2006. The increasing prevalence is in absolute terms more pronounced among women in their forties and in lower socioeconomic positions. Conclusions: The rising MDI score indicates that MDD as well as mental health generally is of public health concern.

Impact of Burnout and Psychosocial Work Characteristics on Future Long-Term Sickness Absence. Prospective Results of the Danish PUMA Study Among Human Service Workers

Objectives: The objective of this study was to examine if burnout and psychosocial factors predicted long-term sickness absence (>2 weeks) at work unit level. Methods: Data were collected prospectively at 82-work units in human services (PUMA cohort, PUMA: Danish acronym for Burnout, Motivation and Job satisfaction) followed up during the proceeding 18 months regarding onset of long-term sickness absence. Questionnaire data regarding burnout and psychosocial factors were aggregated at work unit level. We used Poisson regression models with psychosocial factors and burnout as predictors of long-term sickness absence for more than 18 months based on data from a national absence register. Results: Long-term sickness absence was predicted by psychosocial factors and by burnout at work unit level. Conclusion: To reduce sickness absence, organizations within human services should improve the psychosocial work environment, and equally important, the organizations should be attentive to employees with symptoms of burnout.

Education and cause-specific mortality: the mediating role of differential exposure and vulnerability to behavioral risk factors.

Background: Differential exposures to behavioral risk factors have been shown to play an important mediating role on the education–mortality relation. However, little is known about the extent to which educational attainment interacts with health behavior, possibly through differential vulnerability. Methods: In a cohort study of 76,294 participants 30 to 70 years of age, we estimated educational differences in cause-specific mortality from 1980 through 2009 and the mediating role of behavioral risk factors (smoking, alcohol intake, physical activity, and body mass index). With the use of marginal structural models and three-way effect decomposition, we simultaneously regarded the behavioral risk factors as intermediates and clarified the role of their interaction with educational exposure. Results: Rate differences in mortality comparing participants with low to high education were 1,277 (95% confidence interval = 1,062 to 1,492) per 100,000 person-years for men and 746 (598 to 894) per 100,000 person-years for women. Smoking was the strongest mediator for cardiovascular disease, cancer, and respiratory disease mortality when conditioning on sex, age, and cohort. The proportion mediated through smoking was most pronounced in cancer mortality as a combination of the pure indirect effect, owing to differential exposure (men, 42% [25% to 75%]; women, 36% [17% to 74%]) and the mediated interactive effect, owing to differential vulnerability (men, 18% [2% to 35%], women, 26% [8% to 50%]). The mediating effects through body mass index, alcohol intake, or physical activity were partial and varied for the causes of deaths. Conclusion: Differential exposure and vulnerability should be addressed simultaneously, as these mechanisms are not mutually exclusive and may operate at the same time.

Additive interaction in survival analysis: use of the additive hazards model.

It is a widely held belief in public health and clinical decision-making that interventions or preventive strategies should be aimed at patients or population subgroups where most cases could potentially be prevented. To identify such subgroups, deviation from additivity of absolute effects is the relevant measure of interest. Multiplicative survival models, such as the Cox proportional hazards model, are often used to estimate the association between exposure and risk of disease in prospective studies. In Cox models, deviations from additivity have usually been assessed by surrogate measures of additive interaction derived from multiplicative models—an approach that is both counter-intuitive and sometimes invalid. This paper presents a straightforward and intuitive way of assessing deviation from additivity of effects in survival analysis by use of the additive hazards model. The model directly estimates the absolute size of the deviation from additivity and provides confidence intervals. In addition, the model can accommodate both continuous and categorical exposures and models both exposures and potential confounders on the same underlying scale. To illustrate the approach, we present an empirical example of interaction between education and smoking on risk of lung cancer. We argue that deviations from additivity of effects are important for public health interventions and clinical decision-making, and such estimations should be encouraged in prospective studies on health. A detailed implementation guide of the additive hazards model is provided in the appendix.