RESUMO
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.
Assuntos
Doenças Cardiovasculares/mortalidade , Causas de Morte , Escolaridade , Disparidades nos Níveis de Saúde , Doenças Respiratórias/mortalidade , Adulto , Distribuição por Idade , Idoso , Consumo de Bebidas Alcoólicas/epidemiologia , Doenças Cardiovasculares/diagnóstico , Estudos de Coortes , Intervalos de Confiança , Dinamarca , Feminino , Comportamentos Relacionados com a Saúde , Humanos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Neoplasias/epidemiologia , Estudos Prospectivos , Doenças Respiratórias/diagnóstico , Medição de Risco , Distribuição por Sexo , Fumar/epidemiologia , Taxa de Sobrevida , Populações VulneráveisRESUMO
The Social Inequality in Cancer (SIC) cohort study was established to determine pathways through which socioeconomic position affects morbidity and mortality, in particular common subtypes of cancer. Data from seven well-established cohort studies from Denmark were pooled. Combining these cohorts provided a unique opportunity to generate a large study population with long follow-up and sufficient statistical power to develop and apply new methods for quantification of the two basic mechanisms underlying social inequalities in cancer-mediation and interaction. The SIC cohort included 83 006 participants aged 20-98 years at baseline. A wide range of behavioural and biological risk factors such as smoking, physical inactivity, alcohol intake, hormone replacement therapy, body mass index, blood pressure and serum cholesterol were assessed by self-administered questionnaires, physical examinations and blood samples. All participants were followed up in nationwide demographic and healthcare registries. For those interested in collaboration, further details can be obtained by contacting the Steering Committee at the Department of Public Health, University of Copenhagen, at inan@sund.ku.dk.
Assuntos
Disparidades nos Níveis de Saúde , Neoplasias/epidemiologia , Classe Social , Adulto , Idoso , Idoso de 80 Anos ou mais , Consumo de Bebidas Alcoólicas/epidemiologia , Estudos de Coortes , Dinamarca/epidemiologia , Escolaridade , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de Risco , Comportamento Sedentário , Fumar/epidemiologia , Determinantes Sociais da Saúde , Fatores Socioeconômicos , Adulto JovemRESUMO
Educational-related gradients in coronary heart disease (CHD) and mediation by behavioral risk factors are plausible given previous research; however this has not been comprehensively addressed in absolute measures. Questionnaire data on health behavior of 69,513 participants, 52 % women, from seven Danish cohort studies were linked to registry data on education and incidence of CHD. Mediation by smoking, low physical activity, and body mass index (BMI) on the association between education and CHD were estimated by applying newly proposed methods for mediation based on the additive hazards model, and compared with results from the Cox proportional hazards model. Short (vs. long) education was associated with 277 (95 % CI: 219, 336) additional cases of CHD per 100,000 person-years at risk among women, and 461 (95 % CI: 368, 555) additional cases among men. Of these additional cases 17 (95 % CI: 12, 22) for women and 37 (95 % CI: 28, 46) for men could be ascribed to the pathway through smoking. Further, 39 (95 % CI: 30, 49) cases for women and 94 (95 % CI: 79, 110) cases for men could be ascribed to the pathway through BMI. The effects of low physical activity were negligible. Using contemporary methods, the additive hazards model, for mediation we indicated the absolute numbers of CHD cases prevented when modifying smoking and BMI. This study confirms previous claims based on the Cox proportional hazards model that behavioral risk factors partially mediates the effect of education on CHD, and the results seems not to be particularly model dependent.
Assuntos
Escolaridade , Comportamentos Relacionados com a Saúde , Índice de Massa Corporal , Estudos de Coortes , Doença das Coronárias/epidemiologia , Doença das Coronárias/prevenção & controle , Dinamarca/epidemiologia , Exercício Físico , Humanos , Estilo de Vida , Masculino , Modelos de Riscos Proporcionais , Sistema de Registros , Fatores de Risco , Fatores Sexuais , Fumar/efeitos adversos , Fumar/epidemiologia , Inquéritos e QuestionáriosRESUMO
The survival of non-Hodgkin lymphoma patients strongly depends on a range of prognostic factors. This registry-based clinical cohort study investigates the relation between socioeconomic position and prognostic markers in 6234 persons included in a national clinical database in 2000-2008, Denmark. Several measures of individual socioeconomic position were achieved from Statistics Denmark. The risk of being diagnosed with advanced disease, as expressed by the six prognostic markers (Ann Arbor stage III or IV, more than one extranodal lesion, elevated serum lactate dehydrogenase (LDH), performance status of two or more, presence of B symptoms and International Prognostic Index (IPI) of two or more), increased with decreasing level of education, in patients living alone, and in men. For instance, a significant decrease in the odds of being diagnosed with elevated LDH (p=0.02), high performance status (p=0.004), high IPI score (p=0.004) and B symptoms (p=0.02) was seen with higher level of education, whereas high stage of disease was significantly less likely in the higher educated (odds ratio [OR]=0.85 (0.74-0.99)). The difference in risk seemed not to be mediated by differences in histological subgroups reflecting aggressiveness of disease among the social groups. One of the most likely mechanisms of the social difference is longer delay in those with low socioeconomic position. The findings of social inequality in prognostic markers in non-Hodgkin lymphoma (NHL) patients could already be implemented in the clinical practice if general practitioners (GP's) and physicians on hospitals paid special attention to patients with low educational level and unspecific symptoms.
Assuntos
Linfoma não Hodgkin/mortalidade , Adulto , Idoso , Idoso de 80 Anos ou mais , Dinamarca/epidemiologia , Escolaridade , Feminino , Humanos , Renda , Masculino , Estado Civil/estatística & dados numéricos , Pessoa de Meia-Idade , Prognóstico , Sistema de Registros , Fatores SocioeconômicosRESUMO
This paper investigates the association between individually measured socioeconomic status (SES) and all-cause survival in colorectal cancer patients, and explores whether factors related to the patient, the disease, or the surgical treatment mediate the observed social gradient. The data were derived from a nationwide clinical database of all adenocarcinomas of the colon or rectum diagnosed in Denmark between 2001 and 2004 (inclusive). These data were linked to those from several central registries providing information on income, education, and housing status, as well as to data on comorbidity from previous hospitalizations and use of medication. Only patients with colorectal cancer as their first primary tumour and those born after 1920 were included. A total of 8763 patients were included in the study. Cox proportional hazard regression models revealed a positive social gradient in survival for increasing levels of education and income, and in owners versus renters of housing. A series of regression analyses were used to test potential mediators of the association between the socioeconomic indicators and survival by stepwise inclusion of lifestyle factors (smoking, alcohol intake, body mass index), comorbidity, stage of disease, mode of admission, type of operation, specialization of the surgeon, and curative versus palliative resection. A causal diagram guided the analyses. Inclusion of comorbidity, and to a lesser extent lifestyle, reduced the variation associated with SES, while no evidence of a mediating effect was found for disease or surgical treatment factors. This indicates that the difference in survival among colorectal cancer patients from different social groups was probably not caused by unintentional differences in treatment factors related to surgery, and suggests that primary prevention of chronic diseases among the socially deprived might be one way to reduce social differences in prognosis.