Shift Workers,
Painters, and Firefighters Face Higher Risk for
Cancer
[Posted 12/27/07]
A study
conducted by an international team of scientists
commissioned by the World Health Organization (WHO)
has uncovered a connection between cancer risk and
working the night shift. The study also concluded
that occupational exposures to workplace hazards and
chemicals increase the risk of cancer to painters
and firefighters. Preliminary findings were
published in the December 2007 issue of The
Lancet Oncology.
After
analyzing a number of epidemiologic studies, the
expert working group assembled by the International
Agency for Research on Cancer (IARC) came to the
following conclusions:
1. Shift work
that involves circadian disruption is “probably
carcinogenic to humans.” Studies of nurses and
flight attendants indicate that women with
long-term histories of working at night have higher
incidences of breast cancer than women who do not
work at night. The disruption of the circadian
system that is caused by exposure to light at night
is thought to be responsible.
“Shift
work that interferes with regular nighttime sleep
disrupts circadian rhythms, our body’s natural
clock,” said Dr. Erhard Haus who chaired a subgroup
of the study. “This impedes biologic function by
suppressing the immune system, reducing melatonin
production and may damage genes leading to the
production of abnormal cells.”
Up to
20% of the working population in the US and Europe
is engaged in night-shift work.
2. Occupational
exposure as a painter is “carcinogenic to humans.” Studies of
painters confirmed an increase in the risks of lung
cancer and bladder cancer and pointed to increased
levels of genetic damage. Increases in childhood
leukemia appear to be linked to maternal exposure
before or during pregnancy.
Exposure to chemical solvents, pigments, and
additives, as well as workplace hazards such as
asbestos and crystalline silica, is common for
painters.
3.
Occupational exposure as a firefighter is “possibly
carcinogenic to humans.”
While data varied across populations of
firefighters, studies nonetheless indicated that
the relative risks for testicular cancer, prostate
cancer, and non-Hodgkin lymphoma for firefighters
are high compared to those for the general public.
Intermittent exposures to toxic chemicals provide a
plausible mechanism for respiratory carcinogenesis.
Related Links:
The Lancet Oncology
(free login required)
IARC Press Release
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