Washington, June 5 : Researchers at the Moores Cancer Center at University of California, San Diego (UCSD) and the Department of Family and Preventive Medicine, have found that exposure to sun and higher vitamin D levels may help reduce the risk of type 1 diabetes in children.
The study showed that sun exposure and vitamin D levels might play a crucial role in risk of the disease in kids.
The researchers found that populations living at or near the equator, where there is abundant sunshine (and ultraviolet B irradiance) have low incidence rates of type 1 diabetes.
On the other hand, populations at higher latitudes, where available sunlight is scarcer, have higher incidence rates.
These findings add new support to the concept of a role of vitamin D in reducing risk of this disease.
Ultraviolet B (UVB) exposure triggers photosynthesis of vitamin D3 in the skin. This form of vitamin D also is available through diet and supplements.
"This is the first study, to our knowledge, to show that higher serum levels of vitamin D are associated with reduced incidence rates of type 1 diabetes worldwide," said Cedric F. Garland, Dr. P.H., professor of Family and Preventive Medicine in the UCSD School of Medicine, and member of the Moores UCSD Cancer Center.
"This research suggests that childhood type 1 diabetes may be preventable with a modest intake of vitamin D3 (1000 IU/day) for children, ideally with 5 to 10 minutes of sunlight around noontime, when good weather allows. Infants less than a year old should not be given more than 400 IU per day without consulting a doctor," he added.
The association of UVB irradiance to incidence of type 1 diabetes remained strong even after the researchers accounted for per capita healthcare expenditure. This was an important consideration because regions located near the equator tend to have lower per capita healthcare expenditures, which could result in under-reporting of type 1 diabetes.
The researchers created a graph with a vertical axis for diabetes incidence rates, and a horizontal axis for latitude. The latitudes range from -60 for the southern hemisphere, to zero for the equator, to +70 for the northern hemisphere. They then plotted incidence rates for 51 regions according to latitude. The resulting chart was a parabolic curve that looks like a smile.
In the paper the researchers call for public health action to address widespread vitamin D inadequacy in U.S. children.
"This study presents strong epidemiological evidence to suggest that we may be able to prevent new cases of type 1 diabetes," said Garland.
"By preventing this disease, we would prevent its many devastating consequences."
The study is published June 5 in the online version of the scientific journal Diabetologia.