Mortality and cancer morbidity of finnish chlorophenoxy herbicide applicators: An 18‐year prospective follow‐up

Abstract

An 18-year follow-up for mortality and cancer morbidity was conducted in a cohort of 1,909 men who had started spraying chlorophenoxy herbicides (mixture of 2,4-dichlorophenoxyacetic acid [2,4-D] and 2,4,5-trichlorophenoxyacetic acid [2,4,5-T]) in 1955 through 1971. In all, 384 persons had died during the follow-up, and there was a slight deficit in natural deaths (standardized mortality ratio [SMR] 0.84; 95% confidence interval [CI] 0.75-0.94). By contrast, there was a small, nonsignificant increase in accidental and violent deaths. The overall cancer mortality was slightly less than in the general population (SMR 0.83; 95% CI 0.65-1.02), and not a single case of death of non-Hodgkin's lymphomas (NHL) or soft tissue sarcomas (STS) was detected. With regard to cancer morbidity, the incident cases showed a slight deficit compared to the population figure (standardized incidence ratio [SIR] 0.81; 95% CI 0.67-0.97). One case of NHL was found (2.4 expected with 10 years of latency), but not a single case of STS (0.8 expected with 10 years of latency). While our study does not support the contention that spraying of 2,4-D and 2,4,5-T containing herbicides carries any significant risk of cancer, the medium to low statistical power of the study does not allow any far reaching negative conclusions regarding the carcinogenicity of the agents.

Residential Herbicide Use and Risk of Non-Hodgkin Lymphoma

“…NHL or malignant lymphoma risk was linked to phenoxyacetic acid herbicides, in several studies (9, 10, 15) but not in others (11,(16)(17)(18). Cohorts of workers who manufacture 2,4-D and other phenoxy herbicides have not shown statistically significant excesses of NHL (19)(20)(21), but most were small cohorts that lacked sufficient power to detect moderate increases in risk (22).…”

The non-Hodgkin lymphomas: A review of the epidemiologic literature

“…Relative risk estimates for other categories of exposure duration (one year or more) ranged between 0.66 and 1.21. In a Finnish cohort of employers involved in chemical brushwood control, Asp et al 76 reported an inverse association with chlorophenoxy herbicides (SMR 5 0.35, 95% CI: 0.01-1.97).…”

Issues of Agricultural Safety and Health

“…The strongest association links non-Hodgkin's lymphoma and 2, 4-D, phenoxyacetic acid herbicide (10). Other studies have not shown the association to be consistent (7,81). Several meta-analyses of cancers in agricultural associations have shown increased risk for lip cancer and multiple myeloma (1, 15, 48, 120).…”