Noritaka Tokui

Dietary factors and stomach cancer mortality

The present study examined the relationship between stomach cancer and the low intake of fresh fruit and vegetables and/or a high intake of pickled, preserved or salted foods and frequent use of cooking oil. During 139 390 person–year of follow-up of over 13 000 subjects, 116 died from stomach cancer. Using a Cox proportional hazards–regression analysis of relative risk (RR, 95% CI) controlling for age, sex, smoking and other dietary factors, a significant decline was found with a high consumption of green and yellow vegetables (RR=0.4, 95% CI=0.2–0.9). Reductions of between 40 and 50% were also observed with a high consumption of fresh foods (fruit, cuttle fish, tofu, and potatoes), but these associations were not statistically significant. The risk was significantly increased by the high consumption of processed meat (RR=2.7, 95% CI=1.0-7.4) and by the frequent use of cooking oil (RR=4.0, 95% CI=1.3-11.8). The high consumption of pickled food and traditional soups also increased risk, but not significantly. The findings suggest that a diet high in salt and low in vitamins may be associated with an increase in stomach cancer.

Prospective study of screening for stomach cancer in Japan

Although screening for stomach cancer is a widespread community service in Japan, the benefits of the screening program remain unclear. Our study investigated prospectively the relation between participation in stomach‐cancer screening during the past 12 months and subsequent deaths. Data was derived from the Japan Collaborative Cohort Study, in which 480 stomach‐cancer deaths were identified during an 8‐year follow‐up period. Cox proportional hazard regression was used to estimate the relative risk of death from stomach cancer and that from other causes while adjusting for potential confounding factors. In men, screening participation was associated significantly with a reduced risk of death from stomach cancer (relative risk [RR] = 0.54; 95% confidence interval [CI] = 0.41–0.70). The extent of the risk reduction was greater than potential health selection (for deaths other than stomach, RR = 0.71). The adjustment for potential confounding variables, however, attenuated the difference in risk of death (stomach cancer, RR = 0.65; other causes, RR = 0.71). In women, the magnitude of the association between screening participation and death from stomach cancer (RR = 0.74; 95% CI = 0.52–1.07) was equal to that for deaths from non‐stomach cancers (RR = 0.74). Subgroup analysis showed that women with a parental history of stomach cancer had a reduced risk of death from stomach cancer associated with screening (RR = 0.32; 95% CI = 0.12–0.87). The present results underline the potential for selection bias in observational studies, and thus it remains an open question whether screening for stomach cancer is effective.

A prospective study of stomach cancer death in relation to green tea consumption in Japan

To evaluate whether green tea consumption provides protection against stomach cancer death, relative risks were calculated using Cox proportional hazards regression analysis in the Japan Collaborative Study for Evaluation of Cancer Risk, sponsored by the Ministry of Health and Welfare (JACC Study). The study was based on 30 370 men and 42 481 women aged 40–79. After adjustment for age, smoking status, history of peptic ulcer, family history of stomach cancer along with certain dietary items, the risks associated with drinking one or two, three or four, five to nine, and 10 or more cups of green tea per day, relative to those of drinking less than one cup per day, were 1.6 (95% CI: 0.9–2.9), 1.1 (95% CI: 0.6–1.9), 1.0 (95% CI: 0.5–2.0), and 1.0 (95% CI: 0.5–2.0), respectively, in men (P for trend=0.669), and 1.1 (95% CI: 0.5–2.5), 1.0 (95% CI: 0.5–2.5), 0.8 (95% CI: 0.4–1.6), and 0.8 (95% CI: 0.3–2.1), respectively, in women (P for trend=0.488). We found no inverse association between green tea consumption and the risk of stomach cancer death.

Prospective study of diabetes mellitus and liver cancer in Japan

Previous studies have identified the association between diabetes mellitus and liver cancer. However, the detail of this association is still unclear, in terms of confounding factors, the trend according to the duration of diabetes, and the interaction between diseases associated with the liver cancer and this association. The purpose of the present study was to examine the association between diabetes and liver cancer in view of the trend and the interaction.

Family history and the risk of stomach cancer death in Japan: Differences by age and gender

Familial aggregation of stomach cancer has long been observed. The effect on disease risk of family history and its magnitude according to the type of affected relatives, however, is not well known. We conducted a prospective analysis using the JACC study (Japan Collaborative Cohort Study For Evaluation of Cancer Risk, sponsored by Monbusho) data. During the follow‐up period, 662 stomach cancer deaths were documented. A positive history of stomach cancer in one or more first‐degree relatives was associated with a significantly increased risk of death from the disease in both men (RR 1.60; 95% CI 1.11–2.31) and women (RR 2.47; 95% CI 1.50–4.06). In the subanalysis stratified by age, the association between positive family history and stomach cancer was stronger in the age group from 40–59 (RR 2.62; 95% CI 1.34–5.11 for men and RR 5.88; 95% CI 2.70–12.82 for women) than in the age group from 60–79 (RR 1.31; 95% CI 0.84–2.05 for men and RR 1.44; 95% CI 0.72–2.88 for women). In the age group from 40–59, men with fathers history and women with mothers and sisters history of the disease had a significantly increased risk (RR 3.14; 95% CI 1.51–6.55, RR 10.46; 95% CI 4.54–24.12, RR 13.39; 95% CI 3.89–46.12, respectively). When 2 or more family members were affected, the increment in the risk was prominent especially in women (RR 9.45; 95% CI 4.46–20.05). These results suggest the existence of a certain subtype of stomach cancer that is inherited more often by women from one generation to the next in gender‐influenced fashion. Any preventive strategy should take into account the degree of individual susceptibility.

A nested case–control study of stomach cancer in relation to green tea consumption in Japan

To evaluate whether green tea consumption provides protection against stomach cancer, the relative risks (RRs) were calculated in the Japan Collaborative Study for Evaluation of Cancer Risk, sponsored by the Ministry of Health and Welfare (JACC Study). The study was based on 157 incident cases and 285 controls aged 40–79 years. Cox proportional hazards regression analysis was used to estimate the RRs for stomach cancer. It was found that green tea consumption had no protective effect against stomach cancer. After adjustment for age, smoking status, H. pylori infection, history of peptic ulcer, and family history of stomach cancer along with certain dietary elements, the risks associated with drinking one or two, three or four, five to nine, and 10 or more cups of green tea per day, relative to those of drinking less than one cup per day, were 1.3 (95% confidence interval (CI): 0.6–2.8), 1.0 (95% CI: 0.5–1.9), 0.8 (95% CI: 0.4–1.6), and 1.2 (95% CI: 0.6–2.5), respectively (P for trend=0.899). We found no inverse association between green tea consumption and the risk of stomach cancer.

Individual and joint impact of family history and Helicobacter pylori infection on the risk of stomach cancer: a nested case–control study

We used 202 cases of stomach cancer and 394 controls nested within the Japan Collaborative Cohort Study For Evaluation of Cancer Risk (JACC study) to investigate whether family history has an independent effect on the risk of stomach cancer after controlling for the Helicobacter pylori infection. A positive history of stomach cancer in one or more first-degree relatives was associated with an increased risk of the disease in women, but not in men after controlling for H. pylori infection and other confounding variables. Women with both a family history and H. pylori infection were associated with more than five-fold increased risk of the disease (OR 5.10, 95% CI 1.58–16.5) compared to those without these factors. These results suggest the existence of inherited susceptibility to the disease in women, and that measurements of H. pylori infection together with the family history allow meaningful evaluation of risk beyond that provided by either factor alone.

Prospective study of vegetable consumption and liver cancer in Japan

We examined the relationship between vegetable consumption and the risk of death from liver cancer in a cohort study in Japan. This analysis is based on data from 6,049 subjects aged 40 to 79 years enrolled in a cohort study conducted in Fukuoka Prefecture, Japan. The follow‐up period was from 1986 to 1999. All liver cancer deaths were recorded. The vegetable consumption was classified into 3 groups: “once per week or less,” “2–4 times per week” and “daily intake.” The Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence interval (95% CI). A total of 51 male and 22 female liver cancer deaths were recorded during 62,343 person‐years of follow‐up. The “once per week or less” group was considered the referent group. In males, the multivariate HRs of liver cancer deaths were 0.61 (95% CI: 0.33–1.14) and 0.25 (95% CI: 0.11–0.59) in the “2–4 times per week” and “daily intake” groups, respectively. In females, the multivariate HRs were 0.44 (95% CI: 0.13–1.51) and 0.51 (95% CI: 0.16–1.69), respectively. The multivariate HRs were also reported by history of hepatitis and cirrhosis. In those without a history of these conditions, the multivariate HRs were 0.54 (95% CI: 0.27–1.09) and 0.36 (95% CI: 0.16–0.83). In those with a history of these conditions, the multivariate HRs were 0.58 (95% CI: 0.22–1.56) and 0.37 (95% CI: 0.13–1.06), respectively. Our study reveals an inverse association between vegetable consumption and the risk of death from liver cancer. These results provide further evidence of the protective effect of vegetables against liver cancer.

Visual display terminal work and sick building syndrome--the role of psychosocial distress in the relationship.

Visual Display Terminal Work and Sick Building Syndrome—The Role of Psychosocial Distress in the Relationship: Tatsuhiko Kubo, et al. Department of Clinical Epidemiology, Institute of Industrial Ecological Sciences, University of Occupational and Environmental Health—The present study investigated the association between visual display terminal (VDT) work and sick building syndrome (SBS) and the role of psychosocial factors in the relationship. Subjects were 2,161 Japanese office workers who responded to a cross‐sectional anonymous self‐administered questionnaire survey. Questions included were derived from the Miljömedicin 040, a validated questionnaire on SBS symptoms. After exclusion of data with missing information, data for 1,881 subjects were used for analysis. Multivariate logistic regression was used to estimate the odds ratio for SBS with adjustment for potential confounding factors, including psychosocial work stress. In multivariate analysis, the odds ratio for SBS was significantly elevated for men engaged in VDT work for 4 or more hours a day (OR=2.5, 95%CI: 1.0, 5.9) compared with less than 1 hour a day, showing a significant trend association (P for trend=0.04). In women, although the odds ratio for SBS with VDT use of 4 or more hours a day was somewhat elevated with adjustment for non‐psychosocial factors (OR=1.5, 95%CI: 0.5, 4.3), the increase was greatly attenuated after adjustment for psychosocial work distress (OR=1.1). In conclusion, our study suggests that extended hours of VDT use might be related to increased SBS symptoms. Moreover, psychosocial distress related to VDT work might mediate the relationship between VDT use and SBS symptoms in women.

Years of life lost due to cancer in a cohort study in Japan.

BACKGROUND We estimated the burden of cancer using mortality and years of life lost according to life tables in a cohort study in Japan. METHODS A cohort of 13,270 subjects established in the late 1980s in Japan was followed annually for the vital status of all subjects until 2003. For subjects who died, the underlying cause of death was ascertained from the death certificate. Crude mortality rate from cancer per 100,000 person-years was calculated, and years of life lost (YLL) as well as the average years of life lost (AYLL) were computed using the 1995 life tables in Japan. RESULTS During the follow-up period, we recorded a total 839 cancer deaths (517 men and 322 women), representing 35.5% of deaths from all causes. Overall crude cancer mortality was 654.9 per 100 000 person-years in men and 312.6 in women. Total YLL due to cancer was 7035.3 years in men and 5627.0 years in women. Overall AYLL due to all cancers was 13.6 years less than life expectancy in men and 17.5 years in women. CONCLUSION These results showed that cancer was the leading cause of death in this cohort; with stomach, liver and lung cancer the three most frequent cancers in both sexes. YLL and AYLL reflect the cost of dying from cancer in terms of years of life expectancy lost. The different mortality statistics used here may be useful in public health considerations of cancer burden.