Susanne Oksbjerg Dalton

Cancer risk among statin users: a population-based cohort study.

Hydroxymethylglutaryl‐CoA reductase inhibitors (statins) have been linked with potential chemopreventive effects; however, the data are conflicting. We conducted a population‐based cohort study using data from the Prescription Database of North Jutland County and the Danish Cancer Registry for the period 1989–2002. In a study population of 334,754 county residents, we compared overall and site‐specific cancer incidence among 12,251 statin users (≥2 prescriptions) with cancer incidence among nonusers and users of other lipid‐lowering drugs (n = 1,257). Statistical analyses were based on age‐standardization and Poisson regression analysis, adjusting for age, gender, calendar period and use of NSAIDs, hormone replacement therapy and cardiovascular drugs. We identified 398 cancer cases among statin users during a mean follow‐up period of 3.3 years (range 0–14 years). The age‐ and gender‐standardized incidence rates of cancer overall were 596 per 100,000 person‐years among statin users, 645 per 100,000 person‐years among nonusers and 795 per 100,000 person‐years among users of other lipid‐lowering drugs. Adjusted rate ratios for cancer overall among statin users were 0.86 (95% CI, 0.78–0.95) compared to nonusers and 0.73 (95% CI, 0.55–0.98) compared to users of other lipid‐lowering drugs. No significantly increased or decreased rate ratios were observed for any of the studied site‐specific cancers (liver, colorectum, lung, breast, prostate, female genital organs and lymphatic and haematopoietic tissue), but most estimates tended to be less than 1.0. Stratification by duration of follow‐up or number of prescriptions revealed no clear trends. In summary, individuals prescribed statins experienced a slightly reduced cancer incidence compared to population controls of nonusers and users of other lipid‐lowering drugs. Larger and longer‐term studies are needed to determine the potentially protective effect of statin use on cancer development.

Autoimmune diseases and severe infections as risk factors for schizophrenia: A 30-year population-based register study

OBJECTIVE Autoimmune diseases have been associated with an increased risk of schizophrenia. It has been suggested that brain-reactive autoantibodies are part of the mechanisms behind this association. Furthermore, an increased permeability of the blood-brain barrier has been observed during periods of infection and inflammation. The authors therefore investigated whether autoimmune diseases combined with exposures to severe infections may increase the risk of schizophrenia METHOD Nationwide population-based registers in Denmark were linked, and the data were analyzed in a cohort study using survival analysis. All analyses were adjusted for calendar year, age, and sex. Incidence rate ratios and accompanying 95% confidence intervals (CIs) as measures of relative risk were used. RESULTS A prior autoimmune disease increased the risk of schizophrenia by 29% (incidence rate ratio=1.29; 95% CI=1.18-1.41). Any history of hospitalization with infection increased the risk of schizophrenia by 60% (incidence rate ratio=1.60; 95% CI=1.56-1.64). When the two risk factors were combined, the risk of schizophrenia was increased even further (incidence rate ratio=2.25; 95% CI=2.04-2.46). The risk of schizophrenia was increased in a dose-response relationship, where three or more infections and an autoimmune disease were associated with an incidence rate ratio of 3.40 (95% CI=2.91-3.94). The results remained significant after adjusting for substance use disorders and family history of psychiatric disorders. Hospital contact with infection occurred in nearly 24% of individuals prior to a schizophrenia diagnosis. CONCLUSIONS Autoimmune disease and the number of infections requiring hospitalization are risk factors for schizophrenia. The increased risk is compatible with an immunological hypothesis in subgroups of schizophrenia patients.

Mind and cancer: does psychosocial intervention improve survival and psychological well-being?

The aim of this review was to evaluate the scientific evidence for an effect of psychosocial intervention on survival from cancer and well-being and in particular on anxiety and depression. A literature search yielded 43 randomised studies of psychosocial intervention. Four of the eight studies in which survival was assessed showed a significant effect, and the effect on anxiety and depression was also inconsistent, indicating three possible explanations: (i) only some of the intervention strategies affect prognosis and/or well-being and in only certain patient groups; (ii) the effect was weak, so that inconsistent results were found in the generally small study populations; or (iii) the effect was diluted by the inclusion of unselected patient groups rather than being restricted to patients in need of psychosocial support. Thus, large-scale studies with sound methods are needed in which eligible patients are screened for distress. Meanwhile, the question of whether psychosocial intervention among cancer patients has a beneficial effect remains unresolved.

Social inequality in incidence of and survival from cancer in a population-based study in Denmark, 1994–2003: Summary of findings

The purpose of this nationwide, population register-based study was to describe variations in cancer incidence and survival by social position in a social welfare state, Denmark, on the basis of a range of socioeconomic, demographic and health-related indicators. Our study population comprised all 3.22 million Danish residents born in 1925-1973 and aged >or=30 years, who were followed up for cancer incidence in 1994-2003 and for survival in 1994-2006, yielding 147,973 cancers. The incidence increased with lower education and income, especially for tobacco- and other lifestyle-related cancers, although for cancers of the breast and prostate and malignant melanoma the association was inverse. Conversely there was a general increase in incidence among early retirement pensioners, persons living in rented housing and those living in the smallest dwellings. Also incidence rates were generally higher in persons living alone compared to those living with a partner and in the capital area compared to the rural areas. Social inequality in the prognosis of most cancers was observed, despite the equal access to health care in Denmark, with poorer relative survival related to fewer advantages, regardless of how they were measured, often most pronounced in the first year after diagnosis. Also living alone and having somatic or psychiatric comorbidity negatively impacted the relative survival after most cancers. Our study shows that inequalities in cancer incidence and survival must be addressed in all aspects of public health, with interventions both to reduce incidence and to prolong survival.

Mind and cancer: do psychological factors cause cancer?

Abstract We have reviewed the evidence for an association between major life events, depression and personality factors and the risk for cancer. We identified and included only those prospective or retrospective studies in which the psychological variable was collected independently of the outcome. The evidence failed to support the hypothesis that major life events are a risk factor for cancer. The evidence was inconsistent for both depression and personality factors. Chance, bias or confounding may explain this result, as many of the studies had methodological weaknesses. The generally weak associations found, the inconsistency of the results, the unresolved underlying biological mechanism and equivocal findings of dose–response relationships prevent a conclusion that psychological factors are established risk factors. However, certain intriguing findings warrant further studies, which must, however, be well conducted and large and include detailed information on confounders.

Social inequality and incidence of and survival from breast cancer in a population-based study in Denmark, 1994-2003

We investigated the effects of socioeconomic, demographic and health-related indicators on the incidence of and survival from lung cancer diagnosed in Denmark in 1994-2003 with follow-up through 2006 using information from nationwide registers. The analyses were based on data on 21,492 patients with lung cancer in a cohort of 3.22 million persons born between 1925 and 1973 and aged >or=30 years. There was a general pattern of decreasing lung cancer incidence with increasing social advantage, being married and decreasing urbanicity. The presence of somatic or psychiatric disorders increased the incidence. The most advantaged groups of men had better short-term survival, and a similar tendency was seen for women. The relative 5-year survival after lung cancer was similarly low in most groups, 8% for men and 9% for women, except for groups of patients living in small apartments, with unknown tenure or schizophrenia and for divorced or single men.

Risk for cancer in a cohort of patients hospitalized for schizophrenia in Denmark, 1969–1993

We investigated the cancer risk of patients hospitalized for schizophrenia in a nationwide cohort study. All 22766 adults admitted for schizophrenia, ICD-8 295, in Denmark between 1969 and 1993 were followed up for cancer through 1995. The incidence of site-specific cancers was compared with national incidence rates, adjusted for sex, age and calendar time. The risk for cancer was increased for both men and women during the first year of follow-up. When the first year of follow-up was excluded, the risk for all tobacco-associated cancers and for prostate and rectal cancers was reduced for male patients with schizophrenia. The standardized incidence ratio (SIR) of lung cancer was marginally reduced (SIR, 0.86; 95% CI: 0.65, 1.02) for male patients with schizophrenia; this was due, however, to a reduction in risk for older patients. An increased risk for breast cancer found for female patients with schizophrenia (SIR, 1.20; 95% CI: 1.05, 1.38) should be interpreted with caution, given the high proportion of nulliparous women with schizophrenia in Denmark. The data might support reduced risks for prostate and rectal cancer among male patients with schizophrenia, whereas a changing smoking pattern might explain the reduced risk for tobacco-related cancers.

Risk for Hospitalization With Depression After a Cancer Diagnosis: A Nationwide, Population-Based Study of Cancer Patients in Denmark From 1973 to 2003

PURPOSE As more people survive cancer, it is necessary to understand the long-term impact of cancer. We investigated whether cancer survivors are at increased risk for hospitalization for depression. METHODS We linked data on all 5,703,754 persons living in Denmark on January 1, 1973, or born thereafter to the Danish Cancer Registry and identified 608,591 adults with a diagnosis of cancer. Follow-up for hospitalization for depression in the Danish Psychiatric Central Register from 1973 through 2003 yielded 121,227,396 person-years and 121,304 hospitalizations for depression. The relative risk (RR) for depression among cancer survivors relative to the cancer-free population was estimated by Poisson regression analysis with adjustment for age and period and stratified by sex, site of cancer, and extent of disease. RESULTS The risk for depression in the first year after a cancer diagnosis was increased, with RRs ranging from 1.16 (95% CI, 0.90 to 1.51) in women with colorectal cancer to 3.08 (95% CI, 1.88 to 5.02) in men with brain cancer. Decreasing but still significant excess risks during subsequent years were observed for most specific cancers. The risk remained increased throughout the study period for both men and women surviving hormone-related cancers, for women surviving smoking-related cancers, and for men surviving virus- and immune-related cancers. CONCLUSION This study confirms an increased risk for depression in patients facing a disruptive event like cancer. Early recognition and effective treatment are needed to prevent admission of cancer survivors for depression.

Social inequality and incidence of and survival from cancer in a population-based study in Denmark, 1994-2003: Background, aims, material and methods

The purpose of this register-based study was to identify variations in cancer incidence and survival after cancer in Denmark on the basis of a range of socioeconomic, demographic and health-related indicators. The indicators were level of education, disposable income, affiliation to the work market, social class, housing tenure, size of dwelling, cohabitation status, type of district, ethnicity, Charlson comorbidity index, depression and schizophrenia measured at the individual level on an annual basis. The study population comprised all Danish residents born between 1925 and 1973 and aged >or=30 years, who were followed up for cancer incidence in 1994-2003 and for survival in 1994-2006. The study was based on 3.22 million persons, yielding almost 26 million person-years and 147,973 cancers. In this paper, we provide a detailed description of the indicators and the statistical methods, and we discuss the strengths and limitations of our approach.

Social Inequalities and Mortality in Europe - Results from a Large Multi-National Cohort

Background Socio-economic inequalities in mortality are observed at the country level in both North America and Europe. The purpose of this work is to investigate the contribution of specific risk factors to social inequalities in cause-specific mortality using a large multi-country cohort of Europeans. Methods A total of 3,456,689 person/years follow-up of the European Prospective Investigation into Cancer and Nutrition (EPIC) was analysed. Educational level of subjects coming from 9 European countries was recorded as proxy for socio-economic status (SES). Cox proportional hazard models with a step-wise inclusion of explanatory variables were used to explore the association between SES and mortality; a Relative Index of Inequality (RII) was calculated as measure of relative inequality. Results Total mortality among men with the highest education level is reduced by 43% compared to men with the lowest (HR 0.57, 95% C.I. 0.52–0.61); among women by 29% (HR 0.71, 95% C.I. 0.64–0.78). The risk reduction was attenuated by 7% in men and 3% in women by the introduction of smoking and to a lesser extent (2% in men and 3% in women) by introducing body mass index and additional explanatory variables (alcohol consumption, leisure physical activity, fruit and vegetable intake) (3% in men and 5% in women). Social inequalities were highly statistically significant for all causes of death examined in men. In women, social inequalities were less strong, but statistically significant for all causes of death except for cancer-related mortality and injuries. Discussion In this European study, substantial social inequalities in mortality among European men and women which cannot be fully explained away by accounting for known common risk factors for chronic diseases are reported.