Yoshiharu Hoshiyama

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.

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.

Reproductive and menstrual factors and thyroid cancer among Japanese women: the Japan Collaborative Cohort Study.

AIM Thyroid cancer is more frequent in women than in men, suggesting the potential role of reproductive and menstrual factors in this cancer. To investigate the association with these factors, we examined 37,986 women involved in the Japan Collaborative Cohort (JACC) Study from 1988 to 1997. METHODS Reproductive and menstrual factors were assessed with a self-administered questionnaire at baseline. Hazard ratios (HR) and 95% confidence intervals (95% CI) of thyroid cancer incidence were estimated using Cox proportional hazards regression. RESULTS Eighty-six new cases of thyroid cancer were recorded during 379,281 person-years of follow-up. Overall incidence rate was 22.7 per 100,000 person-years, with a diagnosed peak of 38.2 per 100,000 at 55-59 years old. Multivariate HRs of 0.56 (95% CI 0.25-1.24) and 0.52 (95% CI 0.24-1.16) were observed for women who had experienced pregnancy or a live birth, respectively, but without statistical significance. Further, we saw no associations with other factors, such as age at menarche, age at menopause, age at first birth, or hormone use. CONCLUSIONS There was no significant association between thyroid cancer and reproductive and menstrual factors in the present study. Additional cohort studies should further examine this possible relationship among Japanese women.

Association of Lifestyle Parameters with the Prevention of Hypertension in Elderly Japanese Men and Women: A Four-Year Follow-up of Normotensive Subjects

To study the association of lifestyle parameters with the future risk of hypertension in normotensive subjects, a baseline questionnaire and a four-year follow-up were performed in 445 normotensive Japanese at 35 to 89 years of age. In 60 to 69 year old subjects, the changes of blood pressure during four years were negatively correlated with the amount of boiled rice intake in men and with Japanese tea intake in women. Multiple logistic regression analysis revealed that miso-soup intake at two bowls per day or over was protective against hypertension during follow-up (p<0.05). These results indicate that food intake is important in the prevention of hypertension in the elderly.

Prospective study of transfusion history and thyroid cancer incidence among females in Japan

A link between hepatitis C virus (HCV) infection and thyroid cancer was recently reported in a series of case‐control studies in southern Italy. A prospective study could reinforce these findings. However, cohort studies that began before 1990 rarely assessed serological HCV infection. In addition, thyroid cancer is rare and generally has a good prognosis. Therefore, incidence outcome data are required, rather than mortality data, to evaluate the risk of thyroid cancer. Blood transfusion history might be a possible substitute measure to evaluate the cancer risks associated with HCV infection because blood transfusions were the major HCV transmission route in Japan until 1992. The purpose of our study was therefore to examine the association between transfusion history and thyroid cancer. A baseline survey of members of the JACC Study was conducted from 1988 until 1990, which involved 110,792 participants from 45 areas throughout Japan. Data were collected from a total of 37,983 women with no history of cancer at the baseline (337,906 person‐years) and 79 cases of thyroid cancer were identified among this group. A history of blood transfusion marginally increased the risk of thyroid cancer [risk ratio (RR) = 1.77, 95% confidence interval (CI) = 0.95–3.30], and a history of transfusion and/or liver disease significantly increased the thyroid cancer risk (RR = 1.84, 95% CI = 1.07–3.16). These results indirectly support an association between HCV and thyroid cancer. In addition, our data reveal an association between blood transfusion and thyroid cancer, which might be facilitated by transfusion‐associated immunomodulation.