Effect of dietary antioxidants and risk of oral, pharyngeal and laryngeal squamous cell carcinoma according to smoking and drinking habits.

Several intervention trials and prospective studies have reported that beta-carotene supplementation is not associated with a decreased risk of several cancers among smokers and drinkers, and that it may even have adverse effects in these groups. The relationship between dietary antioxidant intake and the risk of head and neck squamous cell carcinoma (HNSCC) has been examined intensively, but little is known about the effects of antioxidants on HNSCC with respect to smoking and drinking habits. Here, we conducted a case-control study of 385 histologically confirmed cases of HNSCC (193 oral, 132 pharyngeal and 60 laryngeal), excluding nasal and paranasal cancer, and 1925 age-matched and sex-matched cancer-free outpatient controls using data from the Hospital-based Epidemiologic Research Program at Aichi Cancer Center, Japan. The intake of nutrients and food groups was assessed with a food frequency questionnaire, and multivariate-adjusted odds ratios for cancer were estimated for smoking and drinking habits using logistic models. The results showed an overall inverse association between the intake of dietary antioxidants, including carotene, and vitamins C and E, and risk of HNSCC. The protective effect of these antioxidants was seen in both men and women. High consumption of antioxidants was associated with a decreased risk of HNSCC among smokers, drinkers and those with both smoking and drinking habits. These findings suggest that dietary antioxidant intake prevents HNSCC in smokers and drinkers.