Explaining the Socioeconomic Variation in Cancer Risk in the Norwegian Women and Cancer Study

Abstract

Associations between level of education and cancer risk is well supported by scientific evidence, but previous studies could only partly adjust for relevant confounding factors. In this article, we examined how risk of cancer varies with level of education and identified factors that explain this variation using data from a prospective cohort study, including 93,638 Norwegian women who responded to an extensive questionnaire in 1991/1992 or 1996/1997. A total of 3,259 incident primary invasive cancer cases were diagnosed during followup, which ended in December 2001. We used Cox proportional hazards model to calculate relative risks (RR) with 95% confidence intervals (95% CI). Besides a similar overall risk of female cancers by level of education, we observed differing risks between educational groups for cancers of the lung, breast, cervix, kidney, and skin melanoma. Women with >16 years of education had an increased risk of breast cancer (RR, 1.46; 95% CI, 1.19-1.79) and a decreased risk of lung cancer (RR, 0.30; 95% CI, 0.13-0.70) and cervical cancer (RR, 0.38; 95% CI, 0.17-0.85) compared with the lowest educated women (7-9 years). The middle educated (13-16 years) had the lowest risk of kidney cancer (RR, 0.24; 95% CI, 0.08-0.71), whereas the risk of skin melanoma was highest among women with 10 to 12 years of education (RR, 1.53; 95% CI, 1.05-2.24) compared with the lowest educated women. After multivariate adjustment for potential confounders related to level of education, the variation in cancer risk according to educational levels declined into nonsignificance for all these sites. (Cancer Epidemiol Biomarkers Prev 2005;14(11):2591 -7)

Educational level and risk of colorectal cancer in EPIC with specific reference to tumor location

“…24 The association between CRC risk and lower education in Southern Europe may possibly be linked to an increased prevalence of lower educated participants living in rural areas adhering to the Mediterranean diet. 25 They might for example have a higher consumption of home grown grains, fruits and vegetables that was not sufficiently captured by the dietary factors we entered into our models. However our findings might also be due to chance.…”

Circulating Adiponectin Levels and Expression of Adiponectin Receptors in Relation to Lung Cancer: Two Case-Control Studies

“…The reported inverse association with BMI is thought to be due to uncontrolled confounding for the effects of smoking; indeed, a large prospective cohort study failed to demonstrate any association between body weight and lung cancer risk [16]. Lung cancer prevalence is higher among individuals of lower socioeconomic and educational level, an effect thought to be in part mediated through the effects of smoking [38, 39]. Similarly, the association between heavy alcohol intake and lung cancer appears also to be due to a confounding effect of smoking [40].…”

Socioeconomic inequalities in cancer incidence and mortality—a spatial analysis in Bremen, Germany

“…The effects of social inequality on human health in industrialized countries have been observed particularly for chronic degenerative diseases, e.g., cardiovascular and respiratory diseases, diabetes and cancer. Several studies have been carried out in Scandinavia and Great Britain in the last 2 decades (Braaten et al 2005;Coleman et al 2004;Dalton et al 2008;Shack et al 2008), especially regarding the influence on cancer incidence and mortality. For various types of cancer, socioeconomic differences were discovered, mostly showing an inverse association between social class and mortality and morbidity: the higher the social class, the lower the incidence and mortality of cancer (Faggiano et al 1997).…”