Low levels of vitamin D may lead to cancer in smokers

Decreased levels of vitamin D may raise the risk of developing tobacco-related cancer in those who smoke, a new study has warned.
In the study published in journal Clinical Chemistry, researchers measured plasma vitamin D levels in blood samples collected in 1981-1983 from 10,000 Danes from the general population.
Researchers then followed the study participants for up to 28 years through the Danish Cancer Registry. Of the participants, 1,081 eventually developed a tobacco-related cancer.
The authors determined that the median vitamin D concentration among these participants was only 14.8 ng/mL, versus the higher 16.4 ng/mL median concentration found for all participants together.

These results show for the first time that the risk of tobacco-related cancers as a group is associated with lower concentrations of vitamin D, researchers said.
The data also indicate that tobacco smoke chemicals may influence vitamin D metabolism and function, while vitamin D may conversely modify the carcinogenicity of tobacco smoke chemicals.

If further research confirms this, it would be consistent with previous studies demonstrating the anti-tumorigenic effects of vitamin D derivatives, as well as the correlation of vitamin D deficiency with favourable cancer-forming conditions and increased susceptibility to tobacco smoke carcinogens.
The low vitamin D levels were not connected with risk of other cancer types.

"Our analyses show that the association between lower concentrations of plasma vitamin D and higher risk of cancer may be driven by tobacco-related cancer as a group, which has not been shown before," said author Borge G Nordestgaard.
"This is important for future studies investigating the association between plasma vitamin D and risk of cancer," Nordestgaard said.