Tatsuhiko Kubo

Industry-based retrospective cohort study of the risk of prostate cancer among rotating-shift workers

Objectives:  The risk of prostate cancer among shift workers was examined in the present industry‐based retrospective cohort study.

Body mass index and oxidative DNA damage: A longitudinal study

Leanness has been shown to be related to an increased risk of some cancer forms, including lung cancer. However, biological evidence supporting a causal link between leanness and carcinogenesis is limited. The authors investigated longitudinally the association between body mass index (BMI) and levels of urinary 8‐hydroxydeoxyguanosine (8‐OHdG), a marker of oxidative DNA damage, using data from 174 healthy employees who participated in a lifestyle intervention study. 8‐OHdG levels were measured using automated high‐performance liquid chromatography and adjusted for urinary creatinine levels. Analysis of repeated measurements using a random effects model detected a statistically significant inverse association between BMI and 8‐OHdG levels (P = 0.003); one unit decrease in BMI was associated with a 2.7% (95% confidence interval 0.9–4.4) increase in 8‐OHdG levels. The association was pronounced among men consuming less than 20 cigarettes per day (8.8% increase per unit decrease in BMI) and among non‐smoking men (3.7% increase). The results based on a longitudinal observation suggest that weight loss is associated with increased oxidative DNA damage, a state presumably related to an increased risk of cancer. (Cancer Sci 2007; 98: 1254–1258)

Diabetes mellitus and kidney cancer risk: The results of Japan Collaborative Cohort Study for Evaluation of Cancer Risk (JACC Study)

Background:  Diabetes mellitus (DM) is reported as being a risk factor associated with kidney cancer in Western countries. The incidence of both kidney cancer and DM is lower in Japan than the other developed countries, albeit on the rise.

Dietary Habits and Risk of Urothelial Cancer Death in a Large-Scale Cohort Study (JACC Study) in Japan

Abstract: The Japan Collaborative Cohort (JACC) Study was established in 1988–1990 and consisted of 46,465 men and 64,327 women observed until the end of 2003. A self-administered food frequency questionnaire was used as a baseline survey, and associations of dietary habits with the risk of ovarian cancer death were evaluated, taking into consideration age, menstrual and reproductive, anthropometric, and lifestyle factors. During the observation period, 77 women died of ovarian cancer. Hazard ratios for dietary factors were calculated by Coxs proportional hazards model. Being adjusted only for age, high intakes of dried or salted fish and Chinese cabbage were positively associated with the risk of ovarian cancer death, and the risk increased dose-dependently. In contrast, intake of soybean curd (tofu) was inversely associated with the risk. After being adjusted for age and potential confounding factors, the results regarding the intakes of dried or salted fish and Chinese cabbage did not change. However, the significance relating to the intake of soybean curd (tofu) was attenuated. From the results of this cohort study, it was suggested that high intakes of dried or salted fish and Chinese cabbage were potential risk factors of ovarian cancer death. In contrast, however, a high intake of soy bean curd (tofu) might have preventive effects against the risk.

Effect of hospital volume on clinical outcome in patients with acute pancreatitis, based on a national administrative database.

Objective: This study aimed to investigate the relationship between hospital volume and clinical outcome in patients with acute pancreatitis, using a Japanese national administrative database. Methods: A total of 7007 patients with acute pancreatitis were referred to776 hospitals in Japan. Patient data were corrected according to the severity of acute pancreatitis to allow the comparison of risk-adjusted in-hospital mortality and length of stay in relation to hospital volume. Hospital volume was categorized based on the number of cases during the study period into low-volume (<10 cases), medium-volume (10-16 cases), and high-volume hospitals (HVHs, >16 cases). Results: Increased hospital volume was significantly associated with decreased relative risk of in-hospital mortality in both patients with mild and those with severe acute pancreatitis. The odds ratios for HVHs were 0.424 (95% confidence interval [CI], 0.228-0.787; P = 0.007) and 0.338 (95% CI, 0.138-0.826; P = 0.017), respectively. Hospital volume was also significantly associated with shorter length of stay in patients with mild acute pancreatitis. The unstandardized coefficient for HVHs was −0.978 days (95% CI, −1.909 to −0.048; P = 0.039). Conclusions: This study demonstrated that hospital volume influences the clinical outcome in both patients with mild and those with severe acute pancreatitis.

An observational study using a national administrative database to determine the impact of hospital volume on compliance with clinical practice guidelines.

Background:Little information is available on the relationship between hospital volume and compliance with clinical practice guidelines (CPGs). Objectives:To investigate the relationship between hospital volume and compliance with CPGs using a Japanese administrative database. Design and Subjects:This was an observational study that included 60,842 patients with acute cholangitis from 829 hospitals in Japan. Measures:Hospital volume was categorized into the following 3 groups based on the number of cases of acute cholangitis during the study period: low-volume hospitals (LVHs; n = 20,869), medium-volume hospitals (MVHs; n = 18,387), and high-volume hospitals (HVHs; n = 21,586). We further collected patient data with regard to CPGs for acute cholangitis, and counted the number of recommendations that had been complied with for each patient. CPGs compliance score was defined as the rate of compliance with these recommendations for each patient (range, 0–10). Aggregated CPGs compliance score was measured according to hospital volume. Results:Mean CPGs compliance score in HVHs was significantly higher than that in MVHs and LVHs (6.8 ± 1.6 vs. 5.6 ± 1.5 vs. 3.9 ± 1.4, respectively; P < 0.001). Multiple linear regression analysis revealed that hospital volume was most significantly associated with CPGs compliance score. The standardized coefficient for CPGs compliance score in HVHs was 0.689, whereas that of MVHs was 0.366 (P < 0.001). Conclusions:This study demonstrated that hospital volume was significantly associated with compliance with CPGs and that the Japanese administrative database was a viable tool for the monitoring of compliance with CPGs.

Body mass index influences the outcome of acute pancreatitis: an analysis based on the Japanese administrative database.

Objective This study aimed to investigate the relationship between body mass index (BMI) and risk of death in patients with acute pancreatitis (AP) using a Japanese national administrative database. Methods We analyzed a total of 6002 patients with AP. We collected patient information, including sex, age, BMI, severity of AP based on the Japan Pancreas Society scoring system, and prognosis. We classified BMI into 5 categories (underweight [BMI, <18.5], normal range [18.5–24.9], preobese [25–29.9], obese class I [30–34.9], and obese class II/III [>35]) and investigated the relationship between each category and risk of death in AP. Results There was a good correlation between the Japanese AP severity score and in-hospital mortality. Overall mortality of severe pancreatitis was 7.0% (n = 2245). Mortality in each BMI category was as follows: underweight, 6.4%; normal range, 3.6%; preobese, 2.4%; obese class I, 3.2%; and obese class II/III, 5.7%. Underweight and obese class II/III patients had significantly higher relative risk (RR) of death in AP compared with preobese patients after adjusting for sex, age, and severity of AP (RR, 2.7; 95% confidence interval, 1.6–4.5; and RR, 6.4; 95% confidence interval, 1.9–20.9, respectively). Conclusions Underweight or overweight was the independent risk factor for mortality in AP.

Endoscopic submucosal dissection for gastric cancer in elderly Japanese patients: An observational study of financial costs of treatment based on a national administrative database

There is currently little information on the medical economic outcomes of endoscopic submucosal dissection (ESD) for gastric cancer (GC) in elderly patients. This study therefore aimed to investigate the medical economic outcomes of ESD in elderly patients with GC using a national administrative database.

An industry-based cohort study of the association between weight gain and hypertension risk among rotating shift workers.

Objectives:We investigated whether the association between shift work and hypertension is independent of weight gain. Methods:Subjects were 10,173 male employees (9209 daytime workers, 964 three-shift workers; mean follow-up period: 12.7 years). Hypertension was defined as systolic blood pressure 140 mm Hg or more or diastolic blood pressure 90 mm Hg or more. The risk of developing hypertension among shift workers was estimated using a Cox proportional hazards model with adjustment for several factors. Results:Analysis revealed that “shift work” (hazard ratio [HR]: 1.85; 95% confidence interval [CI]: 1.68, 2.03), “baseline body mass index” (HR: 1.13; 95% CI: 1.12, 1.15), and “increase in body mass index during follow-up” (HR: 1.15; 95% CI: 1.13, 1.17) were significant independent risk factors for hypertension. Conclusions:Shift work is a significant risk factor for hypertension that is independent of both starting weight and weight gained over years of work.

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.