Dietary B vitamin and methionine intakes and lung cancer risk among female never smokers in China.
OBJECTIVE
B vitamins and methionine have been postulated to have potential effects on carcinogenesis; however, findings from previous epidemiologic studies on B vitamins, methionine, and lung cancer risk are inconsistent. We investigated associations of dietary intakes of B vitamins (i.e., riboflavin, niacin, vitamin B6, folate, and vitamin B12) and methionine with lung cancer risk among female never smokers.


METHODS
The Shanghai Women's Health Study, a population-based, prospective cohort study, included 74,941 women. During a median follow-up of 11.2 years, 428 incident lung cancer cases accrued among 71,267 women with no history of smoking or cancer at baseline. Baseline dietary intakes were derived from a validated, interviewer-administered food frequency questionnaire. Cancer incidence and vital status were ascertained through annual linkage to the Shanghai Cancer Registry and Shanghai Vital Statistics Registry databases and through biennial in-person follow-ups with participants. Adjusted hazard ratios (HR) and 95 % confidence intervals (CI) were calculated using Cox regression.


RESULTS
Dietary riboflavin intake was inversely associated with lung cancer risk (HR = 0.62; 95 % CI = 0.43-0.89; p trend = 0.03 for the highest quartile compared with the lowest). A higher than median intake of methionine was associated with lower risk of lung cancer (HR = 0.78; 95 % CI = 0.60-0.99); however, there was no dose-response relation. Intakes of other B vitamins were not associated with lung cancer risk.


CONCLUSIONS
Our study suggests that dietary riboflavin intake may be inversely associated with lung cancer risk among female never smokers, which warrants further investigation.
Division of Epidemiology and Vanderbilt Epidemiology Center, Vanderbilt University School of Medicine, 1161 21st Avenue South, MCN B-2104, Nashville, TN 37232-2400, USA.
Yumie
Y
Takata
Qiuyin
Q
Cai
Alicia
A
Beeghly-Fadiel
Honglan
H
Li
Martha J
MJ
Shrubsole
Bu-Tian
BT
Ji
Gong
G
Yang
Wong-Ho
WH
Chow
Yu-Tang
YT
Gao
Wei
W
Zheng
Xiao-Ou
XO
Shu
D002681:China / Q000453:epidemiology; D015331:Cohort Studies; D005260:Female; D006801:Humans; D015994:Incidence; D008175:Lung Neoplasms / Q000453:epidemiology* / Q000517:prevention & control; D008715:Methionine / Q000008:administration & dosage*; D008875:Middle Aged; D011446:Prospective Studies; D012042:Registries; D012307:Risk Factors; D012907:Smoking / Q000453:epidemiology; D011795:Surveys and Questionnaires; D014803:Vitamin B Complex / Q000008:administration & dosage*
D014803:Vitamin B Complex; D008715:Methionine