While we are being told of the dangers of going out into the sun, the sun does activate vitamin D. As time goes on, we are finding more information about the importance of vitamin D. Research appearing in the January 2008 issue of Circulation-the Journal of the American Heart Association shows that vitamin D may protect against heart disease and stroke. The researchers looked at information obtained in the Framingham Offspring Study. None of the 1739 subjects of the study had any heart problems at the beginning of the study.
Researchers measured vitamin D levels in the subjects and found that 28% of them had vitamin D levels that were lower than 15 ng/ml. The subjects were followed for slightly over 5 years and in that time 120 people had either a heart attack or stroke. It was found that the subjects with low vitamin D levels were 62% more likely to have a cardiovascular event. Low vitamin D levels are also associated with high blood pressure.
Other research, appearing in the Archives of Internal Medicine (June 2008; 9; 168(11):1174-80), looked at data from the Health Professionals Follow-up Study. Blood samples collected from men aged 40 to 75, taken between 1993 and 1995 were tested for 25-hydroxy vitamin D. During the following 10 years 454 men either had a non-fatal myocardial infarction or fatal heart disease. They were matched with the 900 subjects with similar age, smoking status, family history and other risk factors, who did not have heart disease. It was found that patients with plasma vitamin D levels lower than 15 ng/ml had a 2.4-fold increase in the risk for a heart attack when compared to subjects with serum vitamin D greater than 30 ng/ml.