High blood pressure in any adult can lead to a greater incidence of strokes, heart attacks and kidney disease. African Americans have higher rates of hypertension than Caucasians of similar age and sex. A recent study at University of Rochester Medical Center found that the discrepancy between vitamin D levels measured in African American and Caucasian participants might be a contributing factor in the differences of their blood pressure measurements.
Dr. Kevin Fiscella and his colleagues performed the study that evaluated the vitamin D levels in almost 2,000 African Americans and over 5,000 non-Hispanic Caucasians from a National Health and Nutrition survey collected between 2001-2006. The researchers compared the vitamin D blood levels in the black and white participants against their systolic blood pressure readings. Factors such as cardiovascular fitness, percent body fat, physical activity levels and social support were statistically controlled for in calculations.
The researchers found that 61 percent of blacks and 11 percent of whites had vitamin D levels that were significantly low. Only 2 percent of blacks and 25 percent of whites had vitamin D levels in a more acceptable range. Blood pressure differences were measured adjusted for socio-demographics and other health characteristics and then compared with vitamin D levels.
According to e! science news, “when the researchers excluded participants on blood pressure medication, the effect of vitamin D explained 40% of the difference in blood pressure,” with African American subjects being higher.
Vitamin D production is directly affected by UV light exposure to the skin. Those with darker skin absorb less UV light. Combined with the fact that many people live in colder, less sunny climates, their body’s natural ability to make vitamin D is reduced. Additionally, many African Americans have lactose intolerance so are less able to get vitamin D in their diet.