Pesticides and Cancer Incidence: The Kangwha Cohort Study

Sull, Jae Woong; Yi, Sang Wook; Sohn, Tae Yong; Jee, Sun Ha; Nam, Chung Mo; Ohrr, Heechul

Abstract

OBJECTIVE
Few studies have examined the relationship between the risk of cancer and exposure to pesticides in Korea or in other East Asian that have until recently used chlorophenoxy herbicides. The aim of this study was to evaluate the relationship between the exposure to pesticides and cancer incidence.
METHODS
We conducted a prospective cohort study with a follow-up period of 13 years (1985-1998). The subjects included 2,687 male and 3,589 female Kangwha Island residents, Koreans aged fifty-five or more as of March 1985, who received a personal health interview and completed a health examination survey. A Cox proportional hazards models were used to estimate relative risks (RR).
RESULTS
At baseline, the mean age of the study participants in 1985 was 66.4 for males and 67.1 for females. During the 13 years follow-up, a total of 300 incidents of cancer in males and 146 in females developed. In males, the total cancer incidence in the highest group was RR, 1.4 (95% CI=1.0-1.9), p for trend=0.041, for digestive organ cancer incidence in the highest group, RR, 1.5 (95% CI=1.0-2.3), p for trend=0.057, for stomach cancer incidence in the highest group, RR, 1.6 (95% CI=0.9-2.8), p for trend=0.094, for gallbladder cancer incidence in the highest group, RR, 9.1 (95% CI=1.1-77.0), p for trend=0.014 were elevated according to the higher frequency of pesticide use per year. In particular, the risk of gallbladder cancer was very high. Although not significant, the risk of liver cancer was higher than in the non-exposed group (in the highest group, RR, 2.0 (95% CI=0.7-5.9)). In females, although not significant, breast cancer incidence in the highest exposure group was higher than in the non-exposed group (in the highest group, RR, 4.7 (95% CI=0.8-27.9)).
CONCLUSIONS
This study demonstrates that Korean farmers who use pesticides, particularly males, have a significantly higher total cancer incidence, particularly from digestive organ cancers such as, stomach, gallbladder, and liver cancer. In particular, the risk of gallbladder cancer was very high.