Background: The incidence of nasopharyngeal carcinoma (NPC) varies substantially worldwide, with an endemic pocket in Southeast Asia.
Method: We assessed lifestyle and genetic factors in relation to NPC risk among 681 NPC cases and 1,078 controls from Thailand. Evaluated lifestyle factors included traditionally preserved foods, tobacco smoking, betel quid chewing, and alcohol consumption. Genetic factors included six variants implicated in a previous a genome-wide association study (GWAS) of NPC and three variants residing near the CHRNA3 and TERT genes that were linked to lung cancer risk in Asian populations. Odds ratios (OR) and 95 % confidence intervals (95 % CI) were estimated using unconditional logistic regression.
Results: Frequent consumption of fermented vegetables was associated with increased NPC risk (OR of consumption ≥weekly vs. ≤rare 1.78, 95 % CI 1.24-2.55, p (trend) = 0.005), as was tobacco smoking (p (trend) < 0.001), former and current smokers displaying OR of 1.57 (95 % CI 1.10-2.30) and 2.00 (95 % CI 1.48-2.71) compared to never smokers, respectively. Four out of six genetic variants implicated in the recent NPC GWAS were associated with NPC risk (p (trend) ≤ 0.03), as well as two variants (rs402710 and rs2736098) on the TERT locus at 5p15.33 (p = 0.004 and p = 0.04, respectively).
Conclusions: These results strengthen our previous observation that tobacco smoking is an important risk factor of NPC in this population. Four out of six genetic variants identified in a recent NPC GWAS were confirmed, and the association noted with variants on 5p15.33 suggests that this locus is involved in NPC susceptibility, representing a novel finding in NPC epidemiology.