Abstract 4667: Prediagnosis body mass index and smoking in relation to colon cancer survival: The NIH-AARP Diet and Health Study

Abstract

Abstract Modifiable lifestyle factors such as body mass index (BMI) and smoking have been related to risk of colon cancer incidence, but little is known the roles of these factors in colon cancer survival. Therefore, we examined associations between prediagnosis BMI and smoking and mortality among colon cancer survivors in the NIH-AARP Diet and Health Study, a prospective cohort study. Colon cancer cases were indentified through linkage of the cohort to state cancer registries which reported cancer diagnosis date, morphologic characteristic of cancer, and the initial course of cancer treatment. A questionnaire was administered to collect information about demographics, anthropometrics, diet, and lifestyle including smoking at study baseline (1995-96). Cox proportional hazard regression was used to estimate relative risks (RR) and 95% confidence intervals (CI). Multivariate models controlled for age at cancer diagnosis, calendar year of cancer diagnosis, sex, race, education, physical activity, self-rated health condition, personal history of diabetes and heart disease, diet quality, stage of cancer, and the initial cancer treatments. From 1995 to 2005, we identified a total of 4,675 incidence colon cancer cases (3,131 men and 1,544 women) among 497,557 men and women who were free of cancer and 50-71 years old at baseline. Mean age at colon cancer diagnosis was 68.7 years. Mean time from baseline to colon cancer diagnosis was 4.8 years. During follow-up of colon cancer cases up to 10 years (mean =3.7 years), 1,275 people died: 911 people died of colon cancer (mean age at death = 72.4 years). Most colon cancer cases were localized (n=1,118) or regional (n=1,189) and had surgery as the first treatment: 2,705 cases had surgery only and 1,127 cases had surgery with other treatments. We found that prediagnosis BMI was not associated with total and colorectal cancer mortality in colon cancer survivors. Compared to BMI 18.5-<25, relative risk (95% CI) of total mortality was 1.30 (0.73-2.33) for BMI <18.5, 1.03 (0.89-1.18) for BMI 25-<30, and 1.03 (0.88-1.21) for BMI≥30. On the other hand, prediagnosis smoking was related to a significantly higher risk of total and colon cancer death. Compared to never smokers, former smokers had a 17% increased risk of total mortality (RR=1.17, 95% CI:1.02-1.33) and current smokers had a 85% increased risk of total mortality (RR=1.85, 95% CI:1.54-2.23). Similar results were observed for colon cancer death. In addition, the results were similar across categories of cancer stage, initial treatments, age at cancer diagnosis (<60, 60-<70 and 70+ yrs), and time from the study entry to colon cancer diagnosis (2-<5, 5-<8 and 8+ yrs). In conclusion, pre-cancer BMI was not related to colon cancer survival, but pre-cancer smoking was associated with a significantly higher risk of total and colon cancer mortality among colon cancer survivors. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4667. doi:10.1158/1538-7445.AM2011-4667