Circulating 25-hydroxyvitamin D (25OHD) may not have a protective effect against oral and oropharyngeal cancers, according to a study published in the International Journal of Cancer.1
Mechanistic and observational evidence suggested that vitamin D may inhibit cancer incidence and progression, but findings from previous studies regarding the protective effects of circulating 25OHD for head and neck cancer (HNC) risk are conflicting.
For this study, investigators analyzed data from 5133 HNC cases and 5984 controls from trials included in the Genetic Associations and Mechanisms in Oncology (GAME-ON) Network from Europe, North America, and South America. Using Mendelian randomization, the researchers evaluated whether there is a causal association between oral/oropharyngeal cancers and 25OHD levels among patients with 5 single nucleotide polymorphisms associated with circulating 25OHD.
Results suggested there is no causal link between 25OHD levels and oral cancer (odds ratio [OR], 0.86; P = .22), oropharyngeal cancer (OR, 1.28; P = 0.4), and both sites combined (OR, 1.01; P = .93).
Replicated studies in the United Kingdom Biobank and pooled estimates further suggested no protective effect of circulating 25OHD against the incidence of oral (OR, 0.86) and oropharyngeal (OR, 0.85) cancers.
The authors concluded that “a clinically relevant protective effect of 25OHD on oral and oropharyngeal cancer risk is unlikely and supplementation of the general population with 25OHD is unlikely to be beneficial in preventing these cancers.”
- Dudding T, Johansson M, Thomas SJ, Brennan P, Martin RM, Timpson NJ. Assessing the causal association between 25-hydroxyvitamin D and the risk of oral and oropharyngeal cancer using Mendelian randomization. Int J Cancer. 2018 Mar 14. doi: 10.1002/ijc.31377 [Epub ahead of print]