American Journal of Epidemiology Advance Access originally published online on July 17, 2006
American Journal of Epidemiology 2006 164(6):556-566; doi:10.1093/aje/kwj233
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Original Contribution |
Prospective Study of Fruits and Vegetables and Risk of Oral Premalignant Lesions in Men
1 Department of Epidemiology, Harvard School of Public Health, Boston, MA
2 Department of Oral Health Policy and Epidemiology, Harvard School of Dental Medicine, Boston, MA
3 New England Research Institutes, Watertown, MA
4 Channing Laboratory, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA
5 Department of Nutrition, Harvard School of Public Health, Boston, MA
6 Division of Dental Public Health, School of Dentistry, University of Puerto Rico Medical Sciences, San Juan, PR
Correspondence to Dr. Kaumudi Joshipura, Division of Dental Public Health, School of Dentistry, Office A141E, Medical Sciences Campus, GPO Box 3650367, San Juan, PR 00936-5067 (e-mail: kjoshipura{at}rcm.upr.edu; kaumudi_joshipura{at}hms.harvard.edu).
The authors prospectively evaluated fruit and vegetable consumption and the incidence of oral premalignant lesions among 42,311 US men in the Health Professionals Follow-up Study. Diet was assessed every 4 years by food frequency questionnaires. The authors confirmed 207 cases of clinically or histopathologically diagnosed oral premalignant lesions occurring between 1986 and 2002. Multivariate-adjusted relative risks were calculated from proportional hazards models. Significant inverse associations were observed with citrus fruits, citrus fruit juice, and vitamin-C-rich fruits and vegetables, indicating 30–40% lower risks with greater intakes (e.g., citrus fruit juice quintile 5 vs. quintile 1 relative risk = 0.65, 95% confidence interval: 0.42, 0.99). 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 (quintile 5 vs. quintile 1 relative risk = 0.41, 95% confidence interval: 0.20, 0.82; p = 0.01). No associations were observed with total vegetables or with ß-carotene-rich or lycopene-rich fruits and vegetables. For current smokers, green leafy vegetables (ptrend = 0.05) and ß-carotene-rich fruits and vegetables (ptrend = 0.02) showed significant linear trends of increased risk (one additional serving/day relative risk = 1.7). The risk of oral premalignant lesions was significantly reduced with higher consumption of fruits, particularly citrus fruits and juices, while no consistent associations were apparent for vegetables.
cohort studies; diet; fruit; leukoplakia; mouth neoplasms; precancerous conditions; tobacco
Abbreviations: CI, confidence interval; OPL, oral premalignant lesion; RR, relative risk