Teens who have very low levels of vitamin D are more than twice as likely to have high blood pressure and high blood sugar compared to those with normal levels of the vitamin, new research finds.
The study also found that those with the LOWEST levels of vitamin D were four times more likely to have metabolic syndrome, a combination of symptoms that includes big waists and high cholesterol and that raises the risk for heart disease and diabetes.
The teen study confirms results seen in adults, linking low levels with risk factors for heart disease, said the researchers led by Jared Reis of Johns Hopkins Bloomberg School of Public Health.
In the study, researchers analyzed data on 3,577 teens who participated in the National Health and Nutrition Examination Survey (NHANES) conducted from 2001-2004. The highest levels of vitamin D were found in whites, the lowest in blacks. Whites had almost twice as high levels as blacks.
After adjusting for factors such as race, body mass index, socioeconomic status and physical activity, researchers found the adolescents with the lowest levels of vitamin D were:
- 2.36 times more likely to have high blood pressure
- 2.54 times more likely to have high blood sugar
- 3.99 times more likely to have metabolic syndrome
It's well-known that the "sunshine" vitamin is needed to keep bones strong; recent research has also linked the vitamin to other possible health benefits.
Reis said more research will be needed to determine if vitamin D is really behind the health problems and whether getting more would make a difference.
"Although our study is important, we believe clinical trials designed to determine the effects of vitamin D supplementation on the risk of heart disease risk factors in adolescents should be conducted before recommendations can be made for vitamin D in the prevention of cardiovascular disease," Reis said.
The findings were being presented Wednesday at an American Heart Association conference in Palm Harbor, Fla.
Dr. Robert H. Eckel, the American Heart Association past president, says the study raises questions about whether the teens poor diet contributed to their low levels of vitamin D.
"These data on serum vitamin D levels in young people raise some concern about their food choices and even the amount of time they spend in the sunshine," he said.
The Canadian Cancer Society recommends that adults living in Canada consider taking vitamin D supplementation of 1,000 international units (IU) a day during the fall and winter. Those with dark skin, or who don't go outside often should consider taking 1,000 IU of vitamin D a day all year round.
The Cancer Society does not have a recommendation for vitamin D supplementation for teens or children.
