Tobacco smoking and gastric cancer risk: an evaluation based on a systematic review of epidemiologic evidence among the Japanese population.
BACKGROUND
We evaluated the association between tobacco smoking and gastric cancer risk among the Japanese population based on a systematic review of epidemiologic evidence.


METHODS
Original data were collected by searches of MEDLINE using PubMed, complemented with manual searches. Evaluation of associations was based on the strength of evidence and the magnitude of association, together with biological plausibility, as evaluated previously by the International Agency for Research on Cancer.


RESULTS
Ten cohort studies and 16 case-control studies were identified. In men, most studies reported moderate or strong positive associations between smoking and gastric cancer. In women, the positive association was weaker than in men. Of eight studies (three cohort studies and five case-case control studies), two cohort and three case control studies reported a weakly to strongly increased risk of gastric cancer. The summary relative risk for current smokers was estimated to be 1.56 (95% confidence intervals 1.36-1.80), 1.79 (1.51-2.12), 1.22 (1.07-1.38) for the total population, men and women, respectively.


CONCLUSIONS
We conclude that there is convincing evidence that tobacco smoking moderately increases the risk of gastric cancer among the Japanese population.
Nishino
Yoshikazu
Y
Division of Epidemiology, Miyagi Cancer Center Research Institute, Natori, Miyagi, 981-1293, Japan. nishino-yo539@pref.miyagi.jp
Inoue
Manami
M
Tsuji
Ichiro
I
Wakai
Kenji
K
Nagata
Chisato
C
Mizoue
Tetsuya
T
Tanaka
Keitaro
K
Tsugane
Shoichiro
S
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D012907:Smoking / Q000453:epidemiology*; D013274:Stomach Neoplasms / Q000453:epidemiology*; D011795:Surveys and Questionnaires