TABLE 12-1 Summary from Eighth Biennial Update of Findings in Occupational, Environmental, and Veterans Studies Regarding the Association Between Specific Health Outcomes and Exposure to Herbicidesa


Sufficient Evidence of Association
Epidemiologic evidence is sufficient to conclude that there is a positive association. That is, a positive association has been observed between exposure to herbicides and the outcome in studies in which chance, bias, and confounding could be ruled out with reasonable confidence.b For example, if several small studies that are free of bias and confounding show an association that is consistent in magnitude and direction, there could be sufficient evidence of an association. There is sufficient evidence of an association between exposure to the chemicals of interest and the following health outcomes:
Soft-tissue sarcoma (including heart)
* Non-Hodgkin’s lymphoma
* Chronic lymphocytic leukemia (CLL) (including hairy cell leukemia and other chronic B-cell leukemias)
* Hodgkin’s disease Chloracne
Limited or Suggestive Evidence of Association
Epidemiologic evidence suggests an association between exposure to herbicides and the outcome, but a firm conclusion is limited because chance, bias, and confounding could not be ruled out with confidence.b For example, a well-conducted study with strong findings in accord with less compelling results from studies of populations with similar exposures could constitute such evidence. There is limited or suggestive evidence of an association between exposure to the chemicals of interest and the following health outcomes:
Laryngeal cancer
Cancer of the lung, bronchus, or trachea
Prostate cancer
* Multiple myeloma
* AL amyloidosis
Early-onset peripheral neuropathy (category clarification from Update 2008)
Porphyria cutanea tarda
Parkinson’s disease
Hypertension
Ischemic heart disease
Type 2 diabetes (mellitus)
Spina bifida in offspring of exposed people
Inadequate or Insufficient Evidence to Determine Association
The available epidemiologic studies are of insufficient quality, consistency, or statistical power to permit a conclusion regarding the presence or absence of an association. For example, studies fail to control for confounding, have inadequate exposure assessment, or fail to address latency. There is inadequate or insufficient evidence to determine association between exposure to the chemicals of interest and the following health outcomes that were explicitly reviewed:
Cancers of the oral cavity (including lips and tongue), pharynx (including tonsils), or nasal cavity (including ears and sinuses)
Cancers of the pleura, mediastinum, and other unspecified sites within the respiratory system and intrathoracic organs
Esophageal cancer
Stomach cancer


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