Whereas low serum folate levels have
been observed in head and neck cancer patients before (54,
55), the analytic studies report mixed results (17, 19, 56).
Folate was associated with slightly increased risk of oral
cavity cancers (OR, 1.3; 95% CI, 0.8-2.2) in a hospital-based
case-control study conducted in Uruguay, but the results
were not statistically significant (17).