Positive Health Online

Abstract

MASEREJIAN and co-authors, Department of Epidemiology, Harvard School of Public Health, Boston, MA, USA, nmaserej@post.harard.edu, have studied antioxidant vitamins and the risk of pre-cancerous lesions of the mouth.

Background

Case-control studies indicate that vitamins C, E, A and carotenoids decrease risk of oral premalignant lesions (OPLs) and oral cancer, but clinical trials have failed to find protective effects of beta-carotene and suggest that vitamin E may increase the risk. The aim of this study was to prospectively evaluate the association between intake of vitamins C, E, A and carotenoids and incidence of OPL.

Methodology

Participants were 42,340 men in the Health Professionals Follow-up Study who provided information on supplement use and diet every 2-4 years by food frequency questionnaire. 207 clinically or histopathologically diagnosed OPL events were found to have occurred between 1986 and 2002. Multivariate-adjusted relative risks of OPL were calculated with proportional hazards models.

Results

Total intake of vitamin C, vitamin A or carotenoids was not significantly associated with OPL risk. Dietary vitamin C was significantly associated with reduced risk (quintile 5 vs. 1, relative risk = 0.52, p(trend) = 0.04), but no association with supplemental vitamin C was observed. Inverse associations were apparent for beta-cryptoxanthin and alpha-carotene intake. No clear relationship emerged with beta-carotene, lycopene or lutein/zeaxanthin. Vitamin E was associated with increased risk (quintile 5 vs. 1, relative risk = 1.86), particularly among current smokers and with supplemental intake (current-smokers, supplement dose tertile 3 vs. 1, relative risk = 3.07, p(trend) = 0.01). For current smokers, beta-carotene also increased risk.

Conclusion

Vitamin C from dietary sources, but not supplements, was associated with a reduced risk of oral premalignant lesions. The observed increased risk for current smokers with high vitamin E or beta-carotene intake should be explored further.

References

Maserejian NN, Giovannucci E, Rosner B, Joshipura K. Prospective study of vitamins C, E, and A and carotenoids and risk of oral premalignant lesions in men. International Journal of Cancer 120 (5): 970-977, Mar 1, 2007.

Comment

The above abstract did not divulge the supplement levels for Vitamin C used, not the forms. This would be most helpful in order to help understand the reduced risk of oral cancer found with dietary Vitamin C, but not with supplemental sources.