Researchers from a recent study published by the American Journal of Preventative Medicine discovered that the association between vitamin D status and hypertension may be impacted by race and gender.
Hypertension is defined as having blood pressure (BP) above 140/90, and is considered severe at levels above 180/120. This is a highly prevalent health condition globally, affecting up to 40% of adults over the age of 25. Additionally, high BP is known to be the leading preventable risk factor contributing to conditions such as stroke, heart attack, renal failure and heart failure.
While the causes of hypertension are generally unknown, researchers have identified several factors that may contribute to high BP. This includes, but is not limited to, genetics, an unhealthy diet, high sodium intake, a sedentary lifestyle, being overweight or obese and smoking. Additionally, there has been an abundance of research that has linked vitamin D status to hypertension.
Like hypertension, vitamin D deficiency is highly prevalent worldwide, with approximately 1/3 of the global population affected.Due to the high prevalence of both of these conditions, and the adverse health implications if left untreated, research is continuously exploring the relationship between these two variables. In a new study, researchers analyzed the relationship between vitamin D and hypertension in relation to race and gender.
A total of 18,607 participants were selected from continuous NHANES surveys from 2001-2010. Patients were excluded if they were under the age of 20, had missing BP, vitamin D data or were pregnant. All individuals participated in a home interview which included information about demographics, lifestyle behaviors and health status and had lab tests completed to measure vitamin D status and blood pressure.
This is what the researchers found:
- Approximately 35% of the included participants had hypertension, with the highest prevalence in non-Hispanic black females (44.7%) and males (40.3%) and the lowest prevalence in non-Hispanic white females (35.8%) and males (36.9%).
- After adjusting for confounding variables, every 4 ng/ml increase in vitamin D status was significantly associated with a 0.47 mmHg decrease in systolic blood pressure (SBP) (95% CI: –0.06 – – 0.33; p = 0.006).
- There was a significant relationship between vitamin D status and SBP in non-Hispanic white individuals but not non-Hispanic black or Hispanic Americans (p=0.005).
- The relationship between vitamin D and SBP was stronger in females than it was in males (p < 0.05).
The researchers concluded:
“Higher levels of VitD are significantly associated with lower BP among U.S. adults.”
“This relationship differs according to ethnicity and gender with a significant inverse association among non-Hispanic whites, females, non-Hispanic white females, and non-Hispanic black females.”
There were some limitations of this study that must be addressed. First, this study did not measure vitamin D status over time, leaving the researchers unable to determine if the participant’s available vitamin D levels accurately reflected their true status. Additionally, as the design of this study was cross-sectional, the researchers were unable to prove a causal relationship exists. Further studies exploring this subject are crucial in order to better understand the relationship between vitamin D status and blood pressure across all populations.
Peterson, R. The relationship between vitamin D and blood pressure may be impacted by race and gender. The Vitamin D Council Blog & Newsletter, 9/2017.