New research published in the journal Hepatology has found that low vitamin D levels may increase the risk of hepatocellular cancer.
Hepatocellular cancer (HCC) is the most common form of liver cancer and accounts for 80% of all cancers that start in the liver. This type of liver cancer begins in the main type of liver cell, called the hepatocyte, whereas other liver cancers begin in different cells such as in the bile ducts or blood vessels lining the liver.
While research on the link between vitamin D and cancer is continuously expanding, there has been only one previous trial looking at vitamin D levels and HCC incidence. This single past study followed patients within a cohort in China and found only a small non-significant increased risk of developing HCC if you had low vitamin D levels.
In an effort to expand knowledge on the relationship between vitamin D status and HCC, researchers in the present study looked at a potential relationship between the two in a large cohort of Western Europeans from 10 different countries.
They analyzed data from the European Prospective Investigation into Cancer and Nutrition (EPIC) study. EPIC was a longitudinal cohort study that looked at the relationship between diet, lifestyle and environment and incidence of different cancers among 520,000 men and women enrolled between 1992 and 2000. Blood samples were drawn at enrollment into the study, so researchers can look at the baseline vitamin D levels of participants among other things.
The researchers followed these participants from baseline (sometime between 1992 and 2000, depending on the individual) up until 2010. They looked at who developed HCC in that time. They found that in this EPIC cohort, 138 people developed HCC. The researchers then matched these 138 people with 138 people who didn’t develop any sort of cancer (controls) from the same cohort.
They wanted to know, at baseline, did vitamin D levels correlate at all with risk of developing HCC up until 2010?
Here is what the researchers found:
- The average vitamin D level at baseline of those who developed HCC was 18.56 ng/ml, compared to 21.48 ng/ml in the control group who didn’t.
- Sixty-two percent of those with HCC had a vitamin D level at baseline less than 20 ng/ml.
- A vitamin D level less than 20 ng/ml at baseline was significantly related to an increased risk of developing HCC.
The researchers concluded,
“In this incidence density-matched case-control study nested within a large cohort of Western European populations, we observe a statistically significant inverse association for pre-diagnostic serum 25(OH)D concentration and risk of first incident HCC.”
The vitamin D levels were only measured once before HCC diagnosis. If vitamin D was measured multiple times, the researchers note they could have a better estimate of the role vitamin D may play in risk for HCC. Furthermore, the design of the study makes it unclear if vitamin D deficiency causes an increased risk of HCC or if there is a confounding factor that causes both.
This study is the second of its kind to look at the relationship between vitamin D and HCC. There is still much research to be done to determine the role that vitamin D plays in HCC incidence and the underlying mechanisms, if any exist.