Incense Use and Smoking
A dose-dependent, increased risk of non-NPC upper
respiratory tract carcinomas was present in both
never-smokers and ever-smokers, but the association
was only found to be statistically significant among
never-smokers (Pfor trend 5.04) (Table 4). Among
never-smokers, a 3-fold increased risk was observed
for individuals who used incense during the day or
at all times. Incense use was found to be unrelated
to the risk of NPC or lung carcinoma, regardless of
cigarette smoking status.