A recent study suggested that vitamin D status is a modifiable risk factor for anemia.
Approximately one out of every three individuals is affected by anemia worldwide. Anemia is a condition characterized by an inadequate amount of healthy red blood cells. Red blood cells are the body’s primary means of delivering oxygen to the body’s tissues. When the body does not have enough red blood cells, one often feels tired and weak.
While vitamin B12 and iron are most widely recognized for their role in anemia, researchers have begun investigating the role vitamin D may play. They have found that vitamin D deficiency is directly related to reticulocytosis, the increase of immature red blood cells, which can cause anemia to develop.
In addition, research has shown a high prevalence of vitamin D deficiency in patients with anemia. However, much of this research has been conducted in specific study populations, including the elderly and African Americans. In an effort to understand the role of vitamin D in anemia among the general population within the U.S., researchers recently analyzed data from the National Health and Nutrition Examination Survey (NHANES) 2001-2006.
The researchers analyzed the vitamin D levels and the incidence of anemia among 5,456 adults. Here is what they found:
- The average vitamin D levels were 23.5 ng/ml.
- Prevalence of anemia was 3.9%.
- After controlling for age, sex, race, BMI, presence of Chronic Kidney Disease, inflammatory levels, vitamin B12 levels, iron levels and other confounding factors, each 1 ng/ml increase in vitamin D status corresponded to a 3% reduced risk of anemia (p = 0.049).
- Adults considered deficient in vitamin D (< 20 ng/ml) were about 1.5 times more likely to be anemic compared to vitamin D sufficient adults (> 20 ng/ml).
The researchers summarized their findings,
“Our analyses suggest that low 25OHD levels are strongly associated with anemia in a large, nationally representative sample of community-dwelling individuals from the United States.”
They continued by stating,
“The association between vitamin D status and anemia is of potentially great public health importance because over half of the US population suffers from low 25OHD.”
This study possessed multiple strengths. First, the researchers controlled for multiple confounding factors, enabling them to better isolate the relationship between vitamin D and anemia. In addition, the study included a very large sample population that is representative of the average adult population in the U.S., allowing the researchers to produce generalizable results. However, the study was only cross-sectional. Thus, this is only the beginning of a long research process to understand the role of vitamin D in anemia. The researchers call for longitudinal studies and eventually randomized controlled trials.
Tovey, A. & Cannell, JJ. Vitamin D status inversely related to anemia, according to new study. The Vitamin D Council Blog & Newsletter, January 2016.