Risk factors for cancer among elderly: The Jerusalem longitudinal cohort study

Objective: Cancer risk in the elderly is about ten-fold higher than in younger age groups. Although several risk factors have been associated with cancer incidence among the general population, little is known about cancer risk factors among individuals entering old age without evidence of disease. Material and methods: A historic cohort study of an age homogenous representative cohort of community-dwelling subjects born 1920-1921, enrolled in the Jerusalem Longitudinal Study. Subjects were aged 70 at baseline (1990) and underwent comprehensive assessment of numerous domains. Cancer incidence from age 70 to 88 (1990-2008) was ascertained from the Israel Cancer Registry. Results: The cohort included 435 persons free from cancer at 1990 and the median follow-up was 16.1. years. Malignancies occurred among 59 persons (13.6%). Using Cox regression multiple analyses, diabetes mellitus (HR=2.28, 95% CI: 1.27-4.09) and smoking pack years (HR=1.01 per year, 95% CI: 1.001-1.022) were associated with increased risk of developing cancer after controlling for sex. On the other hand, gender, poor self-rated health, lower educational level and physical inactivity were not associated with cancer. Conclusions: Diabetes mellitus and smoking pack years at age 70 are associated with an elevated risk of developing cancer. The possibility of detection bias in the association of diabetes mellitus with the risk cancers cannot be ruled out.