Household inhalants exposure and nasopharyngeal carcinoma risk: a large-scale case-control study in Guangdong, China

Table 2 Association between household inhalants and nasopharyngeal carcinoma risk

Exposure factors	Case	Control	OR (95 % CI)^a	P
Incense use frequency
Never	287	572	1.00 (reference)	-
Occasionally	405	647	1.03 (0.83, 1.27)	0.812
Frequently	1130	1035	1.73 (1.43, 2.09)	< 0.001
P_trend ^b				< 0.001
Mosquito coil use frequency
Never	633	841	1.00 (reference)	-
Occasionally	671	816	1.03 (0.88, 1.22)	0.682
Frequently	497	574	0.97 (0.81, 1.17)	0.764
Cooking frequency
Never	862	1041	1.00 (reference)	-
Less than daily	266	365	0.95 (0.77, 1.17)	0.643
Daily	712	858	1.04 (0.87, 1.23)	0.681
Wood stove use
No	585	1135	1.00 (reference)	-
Yes	1260	1140	1.95 (1.65, 2.31)	< 0.001

^aORs (odds ratios) were adjusted for age (years, continuous variable), sex (male, female), education (high school or less, college or more), housing type (block, bungalow), cigarette smoking pack-years (never smoker, less than 20 pack-years, more than 20 pack-years), salted fish (less than monthly, monthly, weekly or more), preserved vegetables (less than monthly, monthly, weekly or more), tea (less than monthly, monthly, weekly or more), herbal tea (less than monthly, monthly, weekly or more), slow-cooked soup (less than monthly, monthly, weekly or more), family history of NPC (no, yes)
^bLinear trends tests were performed by treating ordered categorical variables as continuous variables

ISSN: 1471-2407