Having adequate levels of vitamin D during young adulthood may reduce the risk of adult-onset type 1 diabetes by as much as 50%, according to a study.
If confirmed in future studies, the findings could lead to a role for vitamin D supplementation in preventing the disease in adults, reported researchers with the Harvard School of Public Health.
“It is surprising that a serious disease such as type 1 diabetes could perhaps be prevented by a simple and safe intervention,” said lead author Kassandra Munger, ScD, research associate in the Department of Nutrition at HSPH.
This study provides the strongest findings to date to suggest that vitamin D may be protective against type 1 diabetes, according to a news release.
Previous studies have suggested that a shortage of vitamin D might boost type 1 diabetes risk, although those studies mostly examined the link between vitamin D levels in pregnancy or childhood and the risk of type 1 diabetes in children. Research in young adults uncovered an association between high vitamin D levels and a lowered risk of multiple sclerosis, suggesting that inadequate vitamin D in adulthood may be an important risk factor for autoimmune diseases in general.
The researchers conducted a prospective case-control study of U.S. military personnel on active duty, using blood samples from the Department of Defense Serum Repository, which contains more than 40 million samples collected from 8 million military personnel since the mid-1980s. Identifying 310 individuals diagnosed with type 1 diabetes between 1997 and 2009, the team examined blood samples taken before onset of the disease, and compared the samples with those of 613 people in a control group.
The researchers found that white, non-Hispanic, healthy young adults with higher serum levels of vitamin D had about half the risk of developing type 1 diabetes compared with those with the lowest levels of vitamin D. Although the researchers found no significant association among Hispanics and blacks, the authors said this lack of connection may be due to the small number of individuals in these groups.
“The risk of type 1 diabetes appears to be increased even at vitamin D levels that are commonly regarded as normal, suggesting that a substantial proportion of the population could benefit from increased vitamin D intake,” Alberto Ascherio, MD, MPH, DrPH, the studys senior author and a professor of epidemiology and nutrition at HSPH, said in the news release.
The study is scheduled for publication in the American Journal of Epidemiology. The study abstract is available at http://aje.oxfordjournals.org/content/early/2013/02/03/aje.kws243.abstract.