Dietary patterns and risk of nasopharyngeal carcinoma: a population-based case-control study in southern China

BACKGROUND Dietary factors, such as consumption of preserved foods, fresh vegetables, and fruits, have been linked to the risk of nasopharyngeal carcinoma (NPC). However, little is known about associations between dietary patterns and the risk of NPC in NPC-endemic areas. OBJECTIVES We aimed to evaluate whether dietary patterns are associated with NPC risk. METHODS We studied 2554 newly diagnosed NPC patients aged 20-74 y living in 3 endemic regions of southern China, and 2648 population-based controls frequency-matched to case patients by age, sex, and region, between 2010 and 2014. Dietary components were derived from food frequency data in adulthood and adolescence using principal component analysis. Four dietary components were identified and highly similar in adulthood and adolescence. We used multivariable unconditional logistic regression to calculate ORs with 95% CIs for the association between dietary patterns and NPC risk. RESULTS Compared with the lowest quartile, individuals in the highest quartile of the "plant-based factor" in adulthood had a 52% (OR: 0.48; 95% CI: 0.38, 0.59) decreased risk of NPC, and those in the highest quartile of the "animal-based factor" had a >2-fold (OR: 2.26; 95% CI: 1.85, 2.77) increased risk, with a monotonic dose-response trend (P-trend < 0.0001). Similar but weaker associations were found in adolescence. High intakes of the "preserved-food factor" were associated with increased NPC risk in both periods, although stronger associations were found in adolescence. Results from joint analysis and sensitivity analyses indicated that dietary factors in adulthood might be more stable and robust predictors of NPC risk than those in adolescence. CONCLUSIONS Our results deliver compelling evidence that plant- and animal-based dietary factors are associated with NPC risk, and provide more insights on the associations of diets and cancer risk that may assist healthy diet recommendations.