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People residing at higher latitudes, with lower exposure to sunlight/ultraviolet B (UVB) rays, have at least a 2-fold greater risk of developing leukemia than equatorial populations, according to research published in PLOS ONE.
“These results suggest that much of the burden of leukemia worldwide is due to the epidemic of vitamin D deficiency we are experiencing in winter in populations distant from the equator,” said Cedric Garland, DrPH, of the University of California San Diego in La Jolla, California.
“People who live in areas with low solar ultraviolet B exposure tend to have low levels of vitamin D metabolites in their blood. These low levels place them at high risk of certain cancers, including leukemia.”
Dr Garland and his colleagues analyzed age-adjusted incidence rates of leukemia in 172 countries and compared that information with cloud cover data from the International Satellite Cloud Climatology Project.
The team found that leukemia rates were highest in countries relatively closer to the poles, such as Australia, New Zealand, Chile, Ireland, Canada, and the United States.
And leukemia rates were lowest in countries closer to the equator, such as Bolivia, Samoa, Madagascar, and Nigeria.
The researchers also discovered that leukemia incidence was inversely associated with cloud-adjusted UVB irradiance in males (P≤0.01) and females (P≤0.01) in both hemispheres.
The association persisted in males (P≤0.05) and females (P≤0.01) after the team controlled for elevation and life expectancy.
The researchers said it’s plausible that the association is due to vitamin D deficiency.
This study follows similar investigations by Dr Garland and his colleagues in which they looked at other cancers, including breast, colon, pancreas, bladder, and multiple myeloma. In each study, the team found that reduced UVB radiation exposure and lower vitamin D levels were associated with higher risks of cancer.
“These studies do not necessarily provide final evidence,” Dr Garland said, “but they have been helpful in the past in identifying associations that have helped minimize cancer risk.” 
People residing at higher latitudes, with lower exposure to sunlight/ultraviolet B (UVB) rays, have at least a 2-fold greater risk of developing leukemia than equatorial populations, according to research published in PLOS ONE.
“These results suggest that much of the burden of leukemia worldwide is due to the epidemic of vitamin D deficiency we are experiencing in winter in populations distant from the equator,” said Cedric Garland, DrPH, of the University of California San Diego in La Jolla, California.
“People who live in areas with low solar ultraviolet B exposure tend to have low levels of vitamin D metabolites in their blood. These low levels place them at high risk of certain cancers, including leukemia.”
Dr Garland and his colleagues analyzed age-adjusted incidence rates of leukemia in 172 countries and compared that information with cloud cover data from the International Satellite Cloud Climatology Project.
The team found that leukemia rates were highest in countries relatively closer to the poles, such as Australia, New Zealand, Chile, Ireland, Canada, and the United States.
And leukemia rates were lowest in countries closer to the equator, such as Bolivia, Samoa, Madagascar, and Nigeria.
The researchers also discovered that leukemia incidence was inversely associated with cloud-adjusted UVB irradiance in males (P≤0.01) and females (P≤0.01) in both hemispheres.
The association persisted in males (P≤0.05) and females (P≤0.01) after the team controlled for elevation and life expectancy.
The researchers said it’s plausible that the association is due to vitamin D deficiency.
This study follows similar investigations by Dr Garland and his colleagues in which they looked at other cancers, including breast, colon, pancreas, bladder, and multiple myeloma. In each study, the team found that reduced UVB radiation exposure and lower vitamin D levels were associated with higher risks of cancer.
“These studies do not necessarily provide final evidence,” Dr Garland said, “but they have been helpful in the past in identifying associations that have helped minimize cancer risk.”
People residing at higher latitudes, with lower exposure to sunlight/ultraviolet B (UVB) rays, have at least a 2-fold greater risk of developing leukemia than equatorial populations, according to research published in PLOS ONE.
“These results suggest that much of the burden of leukemia worldwide is due to the epidemic of vitamin D deficiency we are experiencing in winter in populations distant from the equator,” said Cedric Garland, DrPH, of the University of California San Diego in La Jolla, California.
“People who live in areas with low solar ultraviolet B exposure tend to have low levels of vitamin D metabolites in their blood. These low levels place them at high risk of certain cancers, including leukemia.”
Dr Garland and his colleagues analyzed age-adjusted incidence rates of leukemia in 172 countries and compared that information with cloud cover data from the International Satellite Cloud Climatology Project.
The team found that leukemia rates were highest in countries relatively closer to the poles, such as Australia, New Zealand, Chile, Ireland, Canada, and the United States.
And leukemia rates were lowest in countries closer to the equator, such as Bolivia, Samoa, Madagascar, and Nigeria.
The researchers also discovered that leukemia incidence was inversely associated with cloud-adjusted UVB irradiance in males (P≤0.01) and females (P≤0.01) in both hemispheres.
The association persisted in males (P≤0.05) and females (P≤0.01) after the team controlled for elevation and life expectancy.
The researchers said it’s plausible that the association is due to vitamin D deficiency.
This study follows similar investigations by Dr Garland and his colleagues in which they looked at other cancers, including breast, colon, pancreas, bladder, and multiple myeloma. In each study, the team found that reduced UVB radiation exposure and lower vitamin D levels were associated with higher risks of cancer.
“These studies do not necessarily provide final evidence,” Dr Garland said, “but they have been helpful in the past in identifying associations that have helped minimize cancer risk.”