Fiber intake and risk of nasopharyngeal carcinoma: a case-control study.

Some studies examined the inverse relation between nasopharyngeal carcinoma (NPC) risk and dietary fibers in endemic populations. By means of a hospital-based case-control study, we verified whether this association was also present in Italy in connection with various types of dietary fibers. Cases were 198 patients with incident, histologically confirmed, NPC admitted to major teaching and general hospitals during 1992-2008. Controls were 594 patients admitted for acute, nonneoplastic conditions to the same hospital network of cases. Information was elicited using a validated food frequency questionnaire including 78 foods, food groups, or dishes. Odds ratios (OR) and corresponding 95% confidence intervals (CI) were estimated for quartiles of intake of different types of fiber after allowance for energy intake and other potential confounding factors. Total fiber intake was inversely related to risk of NPC (OR = 0.58 for the highest vs. the lowest quartile of intake; 95% CI: 0.34-0.96). We found an inverse association for total soluble (OR = 0.58; 95% CI: 0.35-0.96) and total insoluble fiber (OR = 0.56; 95% CI: 0.33-0.95), in particular cellulose (OR = 0.57; 95% CI: 0.33-0.96), and lignin (OR = 0.51; 95% CI: 0.31-0.85). In conclusion, this study suggests that dietary intake of soluble and insoluble fibers is inversely related to NPC risk in a nonendemic southern population.