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Logo of nihpaAbout Author manuscriptsSubmit a manuscriptHHS Public Access; Author Manuscript; Accepted for publication in peer reviewed journal;
Cancer. Author manuscript; available in PMC 2009 October 1.
Published in final edited form as:
Cancer. 2008 October 1; 113(7): 1676–1684.
doi: 10.1002/cncr.23788

Table 4

Hazards ratio (HR) of respiratory tract carcinomas in relation to combined levels of cigarette smoking status, and frequency of incense use, Singapore Chinese Health Study 1993-2005
Level of incense use

Non-current usersLow
(day/all times)
P for trend
Upper respiratory tract Nasopharyngeal carcinoma
 Never smokers
  No. cases305714
  HR (95% CI)*1.0 (referent)0.7 (0.5-1.2)1.0 (0.5-2.0)0.49
 Ever smokers
  No. cases10559
  HR (95% CI)*1.0 (referent)1.4 (0.7-2.7)1.4 (0.6-3.5)0.38
Upper respiratory tract Non-nasopharyngeal carcinoma
 Never smokers
  No. cases5257
  HR (95% CI)*1.0 (referent)2.2 (0.8-5.9)3.3 (1.0-10.7)0.04
 Ever smokers
  No. cases148217
  HR (95% CI)*1.0 (referent)1.3 (0.7-2.4)1.7 (0.8-3.5)0.16
Lung cancer
 Never smokers
  No. cases6914023
  HR (95% CI)*1.0 (referent)0.8 (0.6-1.1)0.7 (0.4-1.1)0.09
 Ever smokers
  No. cases9042970
  HR (95% CI)*1.0 (referent)1.1 (0.8-1.3)1.0 (0.7-1.4)0.88
*Adjusted for age at recruitment, year of interview, gender, dialect group, level of education, body mass index, number of cigarettes/day, number of years of smoking, time since smoking cessation, alcohol consumption, dietary intakes of isothiocyanate, beta-cryptoxanthin, lutein, lycopene and summed Chinese preserved foods, and for women, number of children (see details in the Materials and Methods).
Including both never and former users of incense.