High Fruit Intake Lowers Risk of Oral Precancer in Men

NEW YORK OCT 04, 2006 (Reuters Health) - Men who consume higher quantities of fruits, especially citrus fruits and juices, have a significantly lower risk of developing oral premalignant lesions, according to findings published in the September issue of the American Journal of Epidemiology.

"Virtually all oral squamous cell carcinomas arise from a premalignant precursor," Dr. Kaumudi Joshipura, of Harvard School of Public Health, Boston, Massachusetts, and colleagues write.  "Epidemiologic studies have found that 16 to 40 percent of oral premalignant lesions (OPLs) transform to cancer," they note.

The researchers prospectively examined fruit and vegetable consumption and the incidence of OPLs among 42,311 U.S. men enrolled in the Health Professionals Follow-up Study.  Food frequency questionnaires were used to assess diet every 4 years. 

A total of 207 cases of OPL occurred between 1986 and 2002.

Citrus fruits, citrus fruit juice, and vitamin C-rich fruits and vegetables were associated with a significantly lower risk of OPLs.  Greater intakes were linked to 30% to 40% lower risks.  For example, the relative risk of OPL with highest intake of citrus fruit juice compared with the lowest intake was 0.65. 

"Inverse associations with fruits did not vary by smoking status and were stronger in analyses of baseline consumption, with a 10-year lag time to disease follow-up," Dr. Joshipura"s team reports.

Total vegetable and beta-carotene-rich or lycopene-rich fruits and vegetables were not associated with OPLs. 

Among current smokers, green leafy vegetables and beta-carotene-rich fruits and vegetables showed significant linear trends of increased risk with each additional serving per day (RR = 1.67 and RR = 1.65, respectively). However, because of the small number of smokers, this finding should be viewed with caution, the investigators say.

Overall, they conclude, "Dietary recommendations to increase consumption of fruits are appropriate for preventing oral precancer and cancer."

SOURCE:

• Am J Epidemiol 2006;164:556-5