Children who live in countries at higher latitudes, such as Canada, where there is less sunlight for much of the year, are far more likely to develop juvenile diabetes than kids who live at or near the equator, new research says.

The findings suggest that a lack of vitamin D, which the body produces when ultraviolet light hits the skin, has a role in the development of the disease. Vitamin D can also be obtained from supplements and from some foods.

"We see this very characteristic signature that makes it unmistakeable that vitamin D deficiency is the cause of childhood type 1 diabetes," said study author Dr. Cedric F. Garland, professor of family and preventive medicine at University of California, San Diego.

Garland believes that vitamin D protects the cells that produce insulin. In type 1 diabetes, the body is unable to produce insulin, or cannot effectively use the insulin it creates.

Garland conducted the research along with scientists from UC San Diego and the Moores Cancer Center. The findings were published in the online edition of the journal Diabetologia.

Dr. Shayne P. Taback of the Manitoba Institute of Child Health in Winnipeg said the study adds strong evidence to the debate that vitamin D plays a role in the development of type 1 diabetes.

"The conclusion that vitamin D treatment may make a significant dent in how many children may actually get the disease I think needs to be tested, but is potentially very exciting," Taback said.

Taback believes that a clinical trial will be able to conclusively determine if a vitamin D deficiency directly causes the development of the disease.

According to supplementary information that accompanied the study, type 1 diabetes, also known as juvenile diabetes, is second only to asthma as the most common chronic disease in children.

According to the Juvenile Diabetes Research Foundation of Canada, more than 200,000 Canadians have type 1 diabetes. Canada has the sixth highest rate of the disease in children under 14 years of age in the world. Canadian juvenile diabetes rates are rising by three to five per cent per year.

The disease can lead to blindness in young and middle-aged adults, and other complications such as kidney failure.

The researchers suggested that children take a vitamin supplement of 1,000 international units (IU) per day, as well as get five to 10 minutes of sun exposure a day, to prevent the development of the disease.

But some doctors say that such a recommendation may be premature. Researchers are planning a major international study to test out the theory that vitamin D prevents juvenile diabetes.

Samantha Vineberg, whose five-year-old daughter Joelle has type one diabetes, says vitamin D supplements appear to be a low-risk option.

"If there is no harm in giving your child the vitamin D, then to me it's a preventative measure," she said.

Based on a report by CTV medical specialist Avis Favaro and producer Elizabeth St. Philip.


The association between ultraviolet B irradiance, vitamin D status and incidence rates of type 1 diabetes in 51 regions worldwide

S. B. Mohr & C. F. Garland & E. D. Gorham & F. C. Garland

Aims/hypothesis This study is an analysis of the relationship between ultraviolet B (UVB) irradiance, the primary source of circulating vitamin D in humans, and age-standardised incidence rates of type 1 diabetes mellitus in children, according to region of the world.

Materials and methods The association of UVB irradiance adjusted for cloud cover to incidence rates of type 1 diabetes in children aged <14 years during 1990-1994 in 51 regions worldwide was assessed using multiple regression. Incidence data were obtained from the DiabetesMondial Project Group.

Results Incidence rates were generally higher at higher latitudes (R2=0.25, p<0.001). According to multiple regression, UVB irradiance adjusted for cloud cover was inversely associated with incidence rates (p<0.05), while per capita health expenditure (p<0.004) was positively associated (overall R2=0.42, p<0.0001).

Conclusions/interpretation An association was found between low UVB irradiance and high incidence rates of type 1 childhood diabetes after controlling for per capita health expenditure. Incidence rates of type 1 diabetes approached zero in regions worldwide with high UVB irradiance, adding new support to the concept of a role of vitamin D in reducing the risk of the disease.