Abstract
BACKGROUND: Published studies suggesting a relationship between vitamin D and some common cancers sparked interest in the association of vitamin D with head and neck cancers. Prolonged darker months in Finland are associated with lower levels of ultraviolet B radiation, raising concerns about low vitamin D levels. METHODS: We used a nested case--control study in the prospective Alpha-Tocopherol Beta Carotene (ATBC) Study of male smokers in Finland, to examine the relationship between serum 25(OH)D and risk of developing squamous cancers of the head and neck. Using conditional logistic regression, we calculated the multivariate adjusted ORs and CIs comparing those with serum 25(OH)D adequate levels of 50 to <75 nmol/L to those <25.0. RESULTS: We identified incident cancers of the oral cavity (n = 134), pharynx (n = 48), and larynx (n = 158). Median serum vitamin D was 31 nmol/L (interquartile range: 21-48), which is below the 50 nmol/L cutoff point was considered adequate for bone and overall health. Comparing those with serum 25(OH)D below 25 nmol/L to those 50 to <75 nmol/L as the referent, the OR was 1.35 (95% CI: 0.53-3.43, P(trend) = 0.65) for overall head and neck cancers. Stratification by cancer subsites of the oral cavity, pharynx, and larynx (P(trend) = 0.93, 0.78, 0.26, respectively) or by season of blood draw also showed no association. CONCLUSIONS: Our study showed no association between serum 25(OH)D and risk of head and neck cancers. IMPACT: This study does not support the hypothesis that greater vitamin D exposure would reduce the risk of developing head and neck squamous cancers.