Education level and risk of cancer incidence in the NIH-AARP Diet and Health Study Free

LB-371

The relationship between socioeconomic status (SES) and health has long been of interest to epidemiologists and social policy makers. We prospectively examined the association between SES and the risk of developing first primary cancers in the NIH-AARP Study, a cohort of 498,447 50-71 year olds without cancer at enrollment in 1995/96. We used highest attained education, reported at baseline, as a proxy for SES. During 5 years of follow-up, 34,955 cancers were identified in 8 state cancer registries. Cox proportional hazards models were utilized to estimate relative risks (RR) and 95% confidence intervals (95%CI) for subjects who did not complete high school compared to those with post-graduate education, stratified by sex. In age adjusted models, men with lower educational attainment had significantly increased risks of developing cancers of the lung (RR:4.27; 95% CI:3.64-5.00), head and neck (RR:1.88; 95%CI:1.38-2.58), esophagus (RR:3.34; 95% CI:2.13-5.23), stomach (RR:2.60; 95%CI:1.76-3.87), bladder (RR:1.63; 95%CI:1.32-2.02), colorectum (RR:1.34; 95%CI:1.14-1.58) and smoking-related cancers combined (RR:2.69, 95%CI:2.42-2.99). In contrast, lower education level was associated with a significantly decreased risks of localized (RR:0.78; 95%CI:0.71-0.86) and advanced (RR:0.78; 95%CI:0.62-0.98) prostate cancer. Women with lower education had increased risks of lung (RR:2.24; 95%CI:1.76-2.85), head and neck (RR:1.90; 95%CI:1.01-3.58), colorectum (RR:1.63; 95%CI:1.23-2.15) and smoking related cancers combined (RR:1.73; 95%CI:1.43-2.10), whereas those with less education were at lower risk of invasive breast (RR:0.72; 95%CI:0.61-0.84), and endometrial (RR:0.67; 95%CI:0.48-0.95) cancers. To identify factors that might account observed associations, we further adjusted for race, body mass index, physical activity, smoking, energy and alcohol intakes, and family cancer history, and, for pertinent cancers, screening practices and reproductive factors. After multivariate adjustment, positive associations persisted between education and cancers of the prostate, breast, and endometrium. For many other malignancies, especially smoking-related cancers in men (RR:1.80, 95% CI:1.61-2.00) and women (RR:1.29; 95%CI:1.06-1.57), the associations were attenuated but the increased risks among participants with lower education remained statistically significant. The existence of inverse SES-cancer associations, not completely attributable to smoking, warrants continued public health research.