Traditional Cantonese diet and nasopharyngeal carcinoma risk: a large-scale case-control study in Guangdong, China

Table 3 Relationship between dietary habits with Chinese herbs and NPC

Intake frequency * and duration	Case/Ctrl	OR (95%CI)^#	P _trend
Herbal tea habit
Less than monthly (ref)	439/347	1.0
Monthly	425/717	0.46(0.38-0.56)	< 0.0001
Weekly or more	369/347	0.84(0.68-1.03)
Herbal tea (years)
Less than monthly (ref)	439/347	1.0
1-9	237/237	0.81(0.64-1.03)	< 0.0001
10-19	88/320	0.22(0.16-0.29)
≥20	146/457	0.25(0.19-0.31)
Slow-cooked soup habit
Less than monthly (ref)	313/214	1.0
Monthly	39/42	0.49(0.27-0.87)	< 0.001
Weekly or more	996/1184	0.58(0.47-0.72)
Slow-cooked soup (years)
Less than monthly (ref)	313/214	1.0
1-9	146/142	0.67(0.50-0.90)	< 0.0001
10-19	310/380	0.53(0.42-0.67)
≥20	250/659	0.22(0.18-0.28)

* Intake frequency was categorised as follows: less than monthly, < once per month; monthly, once per month to once per week; weekly or more, ≥ once per week; daily, ≥ once per day.
^# OR, odds ratio calculated among matched case and control groups, adjusting for sex, age, education, dialect and household type.

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