Rice Pudding
1st Dec 2007, 00:26
Shift work can cause cancer, agency says
Reuters | Saturday, 01 December 2007
LATE SHIFT: Shift workers and firefighters have a higher risk of cancer than the general population and such work should probably be classified as carcinogenic, the International Agency for Research on Cancer says.
Shift workers and firefighters have a higher risk of cancer than the general population and such work should probably be classified as carcinogenic, the International Agency for Research on Cancer has said.
A team of 24 scientists who sifted through the evidence said more studies must confirm the link, but found that shift work that disturbs the body's internal clock appears to have cancer-causing effects, too.
This internal clock regulates circadian rhythms, a complex system that signals cells to produce various hormones at various times.
"Shiftwork that involves circadian disruption is probably carcinogenic to humans," the IARC, the cancer agency of the World Health Organisation, said in a statement.
The finding could affect a significant number of people.
"Nearly 20 percent of the working population in Europe and North America is engaged in shiftwork. Shiftwork is most prevalent in the health-care, industrial, transportation, communications, and hospitality sectors," the IARC said.
"Among the many different patterns of shiftwork, those that include nightwork are most disruptive to the circadian system ... Occupational exposure as a firefighter is possibly carcinogenic to humans," it added.
A full report will be published in the December issue of The Lancet Oncology medical journal, but the conclusions are based on years of published research.
In 2001, a team at the Fred Hutchison Cancer Research Centre in Seattle found that women who work night shifts may have a 60 percent greater risk of breast cancer.
Another study in 2004 suggested that night lights may raise the risk of childhood leukemia. And several tests in mice show that circadian clock genes are disrupted in tumour cells.
In 2006, Japanese researchers reported that people who work a mix of day and night shifts may face a greater risk of dying from heart disease.
Other studies provide evidence that firefigghters, who breathe in smoke, chemicals and dust and who also work shifts, have a higher risk of cancer and heart disease.
The shift work findings may all have to do with the body's response to light, and that could explain why shift work might affect cancer risk.
The brain's pineal gland produces the hormone melatonin after the body is exposed to a certain amount either sunlight or artificial light. It is stimulated by darkness, and so production is disrupted when people are up at night with the lights on.
A reduction in melatonin is linked to an increased risk of certain cancers. Melatonin acts as an antioxidant protecting DNA from the type of damage that leads to cancer and heart disease.
Reuters | Saturday, 01 December 2007
LATE SHIFT: Shift workers and firefighters have a higher risk of cancer than the general population and such work should probably be classified as carcinogenic, the International Agency for Research on Cancer says.
Shift workers and firefighters have a higher risk of cancer than the general population and such work should probably be classified as carcinogenic, the International Agency for Research on Cancer has said.
A team of 24 scientists who sifted through the evidence said more studies must confirm the link, but found that shift work that disturbs the body's internal clock appears to have cancer-causing effects, too.
This internal clock regulates circadian rhythms, a complex system that signals cells to produce various hormones at various times.
"Shiftwork that involves circadian disruption is probably carcinogenic to humans," the IARC, the cancer agency of the World Health Organisation, said in a statement.
The finding could affect a significant number of people.
"Nearly 20 percent of the working population in Europe and North America is engaged in shiftwork. Shiftwork is most prevalent in the health-care, industrial, transportation, communications, and hospitality sectors," the IARC said.
"Among the many different patterns of shiftwork, those that include nightwork are most disruptive to the circadian system ... Occupational exposure as a firefighter is possibly carcinogenic to humans," it added.
A full report will be published in the December issue of The Lancet Oncology medical journal, but the conclusions are based on years of published research.
In 2001, a team at the Fred Hutchison Cancer Research Centre in Seattle found that women who work night shifts may have a 60 percent greater risk of breast cancer.
Another study in 2004 suggested that night lights may raise the risk of childhood leukemia. And several tests in mice show that circadian clock genes are disrupted in tumour cells.
In 2006, Japanese researchers reported that people who work a mix of day and night shifts may face a greater risk of dying from heart disease.
Other studies provide evidence that firefigghters, who breathe in smoke, chemicals and dust and who also work shifts, have a higher risk of cancer and heart disease.
The shift work findings may all have to do with the body's response to light, and that could explain why shift work might affect cancer risk.
The brain's pineal gland produces the hormone melatonin after the body is exposed to a certain amount either sunlight or artificial light. It is stimulated by darkness, and so production is disrupted when people are up at night with the lights on.
A reduction in melatonin is linked to an increased risk of certain cancers. Melatonin acts as an antioxidant protecting DNA from the type of damage that leads to cancer and heart disease.