Past and Recent Salted Fish and Preserved Food Intakes Are Weakly Associated with Nasopharyngeal Carcinoma Risk in Adults in Southern China.

<bold>Background: </bold>Chinese-style salted fish intake in early life is considered an established risk factor for nasopharyngeal carcinoma (NPC). However, results for adult intakes of salted fish and preserved foods are inconsistent.<bold>Objective: </bold>The aim of this study was to ascertain the relations of Chinese-style hard and soft salted fish and preserved food intakes with NPC risk.<bold>Methods: </bold>We conducted a population-based case-control study in southern China with 2554 NPC cases identified through a rapid case ascertainment system and 2648 healthy controls, frequency-matched on age, sex, and area. Subjects (aged 20-74 y) were interviewed via a food-frequency questionnaire, including information on portion size. Data were also collected on alcohol consumption and potential confounders. Food intake was grouped into 3-5 energy-adjusted intake levels during adulthood (10 y prior) and adolescence (16-18 y). For childhood (at age 10 y), intake frequency of selected food items was collected. Multivariate-adjusted ORs with 95% CIs were estimated via logistic regression.<bold>Results: </bold>We found no association between NPC and intake of hard Chinese-style salted fish during adulthood, and an increased risk at the highest level of intake during adolescence (OR: 1.19; 95% CI: 1.03, 1.39). In contrast, we found a decreased risk for the middle intake level of soft salted fish during adulthood (OR: 0.68; 95% CI: 0.57, 0.81) and adolescence (OR: 0.71; 95% CI: 0.59, 0.85). Preserved foods showed contrasting risk profiles, e.g., the highest adult intake level of salted egg (OR: 1.51; 95% CI: 1.22, 1.87) and fermented black beans (OR: 0.67; 95% CI: 0.56, 0.80). Associations with NPC were weaker than previously reported, e.g., for weekly childhood intake of salted fish (OR: 1.56; 95% CI: 1.24, 1.97).<bold>Conclusions: </bold>Hard and soft salted fish have different risk profiles. Salted fish and other preserved foods were at most weak risk factors for NPC in all periods and may play a smaller role in NPC occurrence than previously thought. [ABSTRACT FROM AUTHOR]