Cancer mortality and farming in South Korea: an ecologic study

Objective The aim of this study was to examine the geographical difference of cancer mortality to determine any potential associations between cancer mortality and farming in South Korea. Methods We calculated standardized mortality ratios (SMRs) based on age- and gender-specific cancer mortality rates for 245 geographic areas, using the registered death data from 2000 to 2004 that were obtained from the Korea National Statistical Office. Using the data from the Agriculture Census in 1995, we obtained the farming index. Poisson regression analysis was used to evaluate the associations between cancer mortality and farming after adjustment for socioeconomic factors. Results The SMR analyses based on 62,403 annual average cancer deaths yielded regional variations for all cancers combined in men (SMR = 70-192) and women (SMR = 80-132). With increasing farming index we found significantly elevated cancer mortality of esophagus, stomach, brain, and leukemia for men, and of esophagus and stomach for women, whereas the SMR for colorectal and gall bladder cancers were inversely associated with farming. The results were similar when the analyses were repeated after the exclusion of metropolitan areas. Conclusions Our findings suggest a possible association between farming and mortality from a few cancer sites in South Korea.