Updated information on risk factors for lung cancer: findings from the JACC Study.
BACKGROUND
In Japan, lung cancer is the top cause of cancer death in men and the third leading cause in women. Updated information on risk factors for lung cancer, therefore, is of great importance. The Japan Collaborative Cohort Study, a large prospective study started in 1988, has provided such information.


METHODS
We reviewed published findings for lung cancer from the study. The endpoint was death from this cancer.


RESULTS
The major findings were as follows. (1) The relative risks in current smokers versus nonsmokers were 4.46 in men and 3.58 in women. (2) Cigarette smoking accounted for 67.0% of lung cancer deaths in men and only 14.6% in women. (3) More than 15 years of smoking cessation may be required to decrease the risk of lung cancer to the level of never smokers. (4) A reduced risk was associated with frequent intake of green-leafy vegetables and fruit in men but not in women. These foods seemed to decrease the risk in male current or former smokers more than in female nonsmokers. (5) Serum levels of alpha- and beta-carotenes,beta-cryptoxanthin, and lycopene were inversely correlated with the risk in men. (6) In a preliminary study, serum 8-hydroxy-deoxyguanosine was higher in current smokers than in nonsmokers.


CONCLUSIONS
The relative and attributable risks of smoking were smaller in Japan than in Western countries. In addition to smoking habits, therefore, we must pay attention to other risk factors for lung cancer or factors that modify the adverse effects of smoking including dietary factors.
Wakai
Kenji
K
Division of Epidemiology and Prevention, Aichi Cancer Center Research Institute, Japan. wakai@aichi-cc.jp
Ando
Masahiko
M
Ozasa
Kotaro
K
Ito
Yoshinori
Y
Suzuki
Koji
K
Nishino
Yoshikazu
Y
Kuriyama
Shin-ichi
S
Seki
Nao
N
Kondo
Takaaki
T
Watanabe
Yoshiyuki
Y
Ohno
Yoshiyuki
Y
Tamakoshi
Akiko
A
D000328:Adult; D000368:Aged; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008175:Lung Neoplasms / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D009752:Nutritional Status; D011446:Prospective Studies; D012306:Risk; D018570:Risk Assessment; D012307:Risk Factors; D012907:Smoking