Did you know, February is American Heart Month? Since cardiovascular disease (CVD) is the leading cause of death in the United States, it seems necessary for the Vitamin D Council to address such a crucial cause.
While some aspects of CVD risk are unmodifiable, such as genetic predisposition, there are several ways you can take action towards maintaining good health. These steps may include:
- Spending 30 minutes a day exercising (preferably, outside practicing safe, sensible sun exposure)
- Regularly chatting with your doctor, especially if you are genetically predisposed to CVD
- Refraining from smoking
- Eating a heart-healthy diet, including consumption of mono and polyunsaturated fats, lots of fruits and veggies and fiber!
You can also get involved this month to help spread awareness and education on CVD to save lives! Simply visit Million Hearts or The American Heart Association’s websites to see how you can join the discussion.
Though not mentioned above as a modifiable risk factor for CVD, it is important to note that vitamin D has recently been a topic of interest related to heart health. Though the evidence is somewhat conflicting, many studies suggest vitamin D status may impact risk of heart disease, treatment outcomes, mortality and quality of life in CVD patients.
The research doesn’t stop here either. Every month, new evidence is emerging that further defines the relationship bet ween vitamin D and heart health. For example, a recent study evaluated the relationship between 25(OH)D status, all-cause mortality and cardiovascular mortality in patients with suspected angina pectoris, a type of localized chest pain often associated with inadequate blood supply to the heart called.
Researchers included a total of 4,114 Caucasian individuals with suspected stable angina pectoris (SAP). All the participants were selected from the Haukeland University Hospital and Stavanger University Hospital in Norway between April 14th, 1999 and April 26th, 2004.
Medical history, medication use, and CVD risk factors were recorded at baseline, as was vitamin D status, C-reactive protein, a common measure of inflammation, extent of coronary artery disease, if applicable, and kidney function. All participants were followed until death or conclusion of the study in 2013. Additionally, vitamin D levels were divided into four quartiles: the first and lowest quartiles included ranges from 3 -18 ng/ml, the second from 18 – 23 ng/ml, the third from 23 – 29 ng/ml, and the fourth between 28.- 79 ng/ml.
This is what the researchers found:
- The average vitamin D status was 24 ng/ml (59 nmol/l).
- Vitamin D status had a positive correlation with vitamin D supplementation, physical activity and some lab values, and an inverse correlation with smoking, BMI, inflammation, diabetes, kidney function and triglycerides (p < 0.05).
- During the follow-up period, a total of 895 individuals died from various unrelated causes, while 407 deaths occurred due to CVD.
- The three highest quartiles of vitamin D in comparison to the lowest were associated with a 0.56 odd ratio of all-cause mortality, indicating a dramatic protective effect of higher 25(OH)D levels.
- Similarly, the three higher quartiles of vitamin D in comparison to the first quartile were associated with a 0.57 odd ratio of CVD-related mortality.
- The relationship between vitamin D status, CVD mortality and all-cause mortality was described on a bell-shaped curve. On one end, vitamin D levels of < 16 ng/ml (40 nmol/l) were associated with risk of CVD and all-cause mortality, while on the upper end, levels of > 40 ng/ml (100 nmol/l) were also associated with an elevated risk of all-cause mortality but not CVD mortality.
The researchers concluded:
“In this observational study of Caucasian patients with suspected stable angina pectoris, we observe an inverse association between plasma 25(OH)D and the risk of CVD mortality, and a non-linear (U-shaped) association with the risk of all-cause mortality.”
Before we make any conclusions based on the results of this study, a few considerations should be addressed. While the researchers did find a threshold of 40 ng/ml (100 nmol/l) for increased all-cause mortality risk, it is important to note that the number of participants who were found to have levels in this range were relatively small. In fact, this group was only representative of 2% of the entire study population. A larger group would be required for analysis in order to make a better determination of the threshold level at which higher vitamin D status would no longer be protective.
The most likely reason for increased CVD > 40 ng/ml is that these subjects were in poor health and were already taking high doses of vitamin D. While the authors controlled for vitamin D intake, they did not control for dose of vitamin D taken. So, we don’t know whether they were taking 400 IU/day or 10,000 IU/day.
Additionally, it should also be noted that vitamin D supplementation was inversely associated with mortality risk. Until stronger research indicates otherwise, the Vitamin D Council recommends supplementation of between 5,000-10,000 IU per day in order to maintain healthy vitamin D levels.
Now is the perfect time to take a proactive step towards a better state of health. If you are planning on participating in American Heart Month education and promotion, please let us know! Email us at [email protected] to share how you will be joining the conversation.
Peterson, R. & Cannell, JJ. Celebrate American Heart Month by joining the conversation on vitamin D and cardiovascular disease. The Vitamin D Council Blog & Newsletter, 1/2018.
Degerud, E. et al. Plasma 25-hydroxyvitamin D and mortality in patients with suspected stable angina pectoris. Endocrine Society, 2018.