Mortality in chemical workers potentially exposed to 2,4-dichlorophenoxyacetic acid

(2,4-D) 1945-94: an update.

Burns CJ, Beard KK, Cartmill JB

Occup Environ Med. 2001 Jan;58(1):24-30.

Department of Epidemiology, The Dow Chemical Company, 1803 Building,

Midland, MI 48674, USA.

[Record supplied by publisher]

OBJECTIVE: To update and add to a previously identified cohort of employees
potentially exposed to the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D). The
putative association between 2,4-D and non-Hodgkin’s lymphoma has been debated
for more than a decade.


METHODS: Cohort members were male employees of The
Dow Chemical Company who manufactured or formulated 2,4-D any time from
1945 to the end of 1994. Their mortality experience was compared with national
rates and with more than 40 000 other company employees who worked at the same
location.


RESULTS: 330 Deaths were observed among 1517 people compared with
365 expected (standardised mortality ratio (SMR)=0.90, 95% confidence interval
(95% CI) 0.81 to 1.01). There were no significantly increased SMRs for any of the
causes of death analyzed. When compared with the United States rates, the SMR for
non-Hodgkin’s lymphoma (NHL) was 1.00 (95% CI 0.21 to 2.92). The internal
comparison with other Dow employees showed a non-significant relative risk of 2.63,
(95% CI 0.85 to 8.33). Death was attributed to amyotrophic lateral sclerosis (ALS)
for three cohort members. Compared with the other company employees, the relative
risk was 3.45 (95% CI 1.10 to 11.11). The cases were employed in the manufacture
or formulation of 2,4-D at different periods (1947-9, 1950-1, and 1968-86), and for
varying durations of time (1.3, 1.8, and 12.5 years).


CONCLUSION: There was no
evidence of a causal association between exposure to 2,4-D and mortality due to all
causes and total malignant neoplasms. No significant risk due to NHL was found.
Although not an initial hypothesis, an increased relative risk of ALS was noted. This
finding is unsupported by other animal and human studies.


Original Source: http://www.lougehrigsdisease.net/als_research_abstracts/mortality_in_chemical_workers_po.htm

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