BackgroundEvidence for a link between long-term exposure to air pollution and lung cancer is limited to Western populations. In this prospective cohort study, we examined this association in a Japanese population.MethodsThe study comprised 63 520 participants living in 6 areas in 3 Japanese prefectures who were enrolled between 1983 and 1985. Exposure to particulate matter less than 2.5 µm in aerodynamic diameter (PM2.5), sulfur dioxide (SO2), and nitrogen dioxide (NO2) was assessed using data from monitoring stations located in or nearby each area. The Cox proportional hazards model was used to calculate the hazard ratios associated with the average concentrations of these air pollutants.ResultsThe 10-year average concentrations of PM2.5, SO2, and NO2 before recruitment (1974–1983) were 16.8 to 41.9 µg/m3, 2.4 to 19.0 ppb, and 1.2 to 33.7 ppb, respectively (inter-area range). During an average follow-up of 8.7 years, there were 6687 deaths, including 518 deaths from lung cancer. The hazard ratios for lung cancer mortality associated with a 10-unit increase in PM2.5 (µg/m3), SO2 (ppb), and NO2 (ppb) were 1.24 (95% confidence interval: 1.12–1.37), 1.26 (1.07–1.48), and 1.17 (1.10–1.26), respectively, after adjustment for tobacco smoking and other confounding factors. In addition, a significant increase in risk was observed for male smokers and female never smokers. Respiratory diseases, particularly pneumonia, were also significantly associated with all the air pollutants.ConclusionsLong-term exposure to air pollution is associated with lung cancer and respiratory diseases in Japan.

We conducted a large‐scale, hospital‐based case‐control study to evaluate differences and similarities in the risk factors of female breast cancer according to menopausal status. This study is based on a questionnaire survey on life style routinely obtained from outpatients who first visited the Aichi Cancer Center Hospital between January 1, 1988 and December 31, 1992. Among 36,944 outpatients, 1,186 women with breast cancer detected by histological examination were taken as the case group (607 premenopausal women and 445 postmenopausal women) and 23,163 women confirmed to be free of cancer were selected as the control group. New findings and reconfirmed factors of breast cancer were as follows. 1) The risk of at least one breast cancer history among subjects’ first‐degree relatives was relatively high among pre‐ as well as post‐menopausal women. 2) A protective effect of physical activity against breast cancer was observed among both pre‐ and post‐menopausal women. 3) Dietary control decreased the risk of premenopausal breast cancer. 4) Current smoking and drinking elevated the risk of breast cancer in premenopausal women. 5) Decreasing trends of breast cancer risk were associated with intake of bean curd, green‐yellow vegetables, potato or sweet potato, chicken and ham or sausage in premenopausal women, while in postmenopausal women a risk reduction was associated with a more frequent intake of boiled, broiled and/or raw fish (sashimi). Further study will be needed to clarify the age group‐ and/or birth cohort‐specific risk factors for breast cancer among the young generation in Japan.

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Aldehyde dehydrogenase-2 (ALDH2) degrades acetaldehyde metabolized from ethanol. Its encoding gene ALDH2 has a functional polymorphism: ALDH2 Glu487LYS: An association between this polymorphism and esophageal cancer among alcoholics has been reported. To further evaluate the gene-environment interaction, a hospital-based case-control study was conducted. Cases were 102 patients with histologically confirmed esophageal cancer and controls were 241 non-cancer outpatients of Aichi Cancer Center. ALDH2 genotypes were examined by a PCR-CTPP method developed in our laboratory, which does not require a digestion stage. Logistic regression analysis was employed for estimation of relative risk and gene-environment interaction. The allele frequency for ALDH2 Lys487 was 0.28, consistent with previous reports. The age, sex, smoking and drinking status adjusted odds ratio for the ALDH2 Glu/Lys and Lys/Lys genotypes as compared with the Glu/Glu genotype was 3.43 (95% CI 1.74-6.75). The odds ratio for heavy drinking was 49.6 (14.5-169.4) among Lys487 carriers and 7.84 (2.77-22.2) for the Glu/Glu genotype. The gene-environment interaction between alcohol drinking and the ALDH2 Lys487 allele was 6.84 (2.39-19.6), whereas no significant interaction was obtained with smoking status. Although limited because of its prevalent case-control design, our study revealed a strong gene-environment interaction between ALDH2 polymorphism and heavy alcohol consumption. Taking the observed high risk of esophageal cancer in association with the ALDH2 Lys487 allele into consideration, reducing alcohol intake may be most protective among Lys487 allele carriers of this polymorphism.

To study the relation between allium vegetable intake and cancer of the esophagus (EC) and stomach (SC) in Yangzhong city, which is one of the highest-risk areas for these cancers in Jiangsu province, China, a simultaneous case-referent study was conducted using histopathologically confirmed cases (EC: n = = = =81, SC: n = = = =153) and population-based referents (n = = = =234).

From these results it appears that smoking habit, which has long been considered a sole important determinant, has only a modest role, if any, in pancreatic cancer in Japanese.

Methylenetetrahydrofolate reductase (MTHFR) is a key enzyme in the metabolism of folate, whose role in gastric carcinogenesis is controversial. The authors performed a meta-analysis and individual data pooled analysis of case-control studies that examined the association between C677T and A1298C polymorphisms (the former being associated with low folate serum levels) and gastric cancer (meta-analyses: 16 studies, 2,727 cases and 4,640 controls for C677T and seven studies, 1,223 cases and 2,015 controls for A1298C; pooled analyses: nine studies, 1,540 cases and 2,577 controls for C677T and five studies, 1,146 cases and 1,549 controls for A1298C). An increased risk was found for MTHFR 677 TT in the meta-analysis (odds ratio (OR) = 1.52, 95% confidence interval (CI): 1.31, 1.77) and pooled analysis (OR = 1.49, 95% CI: 1.14, 1.95). No association resulted for MTHFR 1298 CC (meta-OR = 0.94, 95% CI: 0.65, 1.35; pooled OR = 0.90, 95% CI: 0.69, 1.34). Results from the pooled analysis of four studies on C677T stratified according to folate levels showed an increased risk for individuals with low (OR = 2.05, 95% CI: 1.13, 3.72) versus high (OR = 0.95, 95% CI: 0.54, 1.67) folate levels. Overall, these findings support the hypothesis that folate plays a role in gastric carcinogenesis.