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. 2013 Feb 1;8(2):e54561. doi: 10.1371/journal.pone.0054561

Table 3. Association between quartiles of betaine intake and lung cancer risk.

Models Quartiles of betaine intake P** trend
1 2 3 4
Case n (%) 911 (55.51) 713 (49.38) 650 (47.07) 547 (42.80)
Control n(%) 730 (44.49) 731 (50.62) 731 (52.93) 731 (57.20)
Overall
Reduceda OR (95% CI) 1.00 0.83 (0.71–0.96) 0.78 (0.67–0.90) 0.67 (0.58–0.79) <0.0001
Poverall <0.0001
Completeb OR (95% CI) 1.00 0.85 (0.73–1.00) 0.81 (0.69–0.95) 0.71 (0.61–0.84) <0.0001
P* overall 0.0006
Stratified by smoking status
Never Smokers
Reducedc OR (95% CI) 1.00 1.07 (0.73–1.57) 0.87 (0.59–1.27) 1.00 (0.69–1.45) 0.702
P* overall 0.635
Completed OR (95% CI) 1.00 1.06 (0.72–1.57) 0.86 (0.58–1.28) 1.03 (0.70–1.52) 0.869
P* overall 0.614
Former Smokers
Reducedc OR (95% CI) 1.00 0.92 (0.73–1.16) 0.83 (0.66–1.05) 0.71 (0.56–0.89) 0.002
P* overall 0.023
Completed OR (95% CI) 1.00 0.95 (0.74–1.21) 0.86 (0.67–1.11) 0.75 (0.59–0.96) 0.017
P* overall 0.112
Current Smokers
Reducedc OR (95% CI) 1.00 0.70 (0.55–0.88) 0.75 (0.59–0.95) 0.51 (0.39–0.66) <0.0001
P* overall <0.0001
Completed OR (95% CI) 1.00 0.73 (0.57–0.93) 0.80 (0.62–1.02) 0.55 (0.42–0.73) 0.0001
P* overall 0.0003
a

Adjusted for sex, race/ethnicity, age, pack-years, total caloric intake, smoking status.

b

Adjusted for sex, race/ethnicity, age, pack-years, total caloric intake, family cancer history, dust exposure, second-hand smoke, emphysema, hay fever, asthma, addiction index, alcohol, time since smoking cessation, smking status.

c

Adjusted for sex, race/ethnicity, age, pack-years, total caloric intake.

d

Adjusted for sex, race/ethnicity, age, pack-years, total caloric intake, family cancer history, dust exposure, second-hand smoke, emphysema, hay fever, asthma, addiction index, alcohol, time since smoking cessation.

*

p-value, chi-square test using quartiles of betaine intake as categorical variable.

**

p-value, test for linear trend using quartiles of betaine intake as continuous variable.