Radiation exposure and circulatory disease risk: Hiroshima and Nagasaki atomic bomb survivor data, 1950-2003

Objective To investigate the degree to which ionising radiation confers risk of mortality from heart disease and stroke

Lymphocyte subset characterization associated with persistent hepatitis C virus infection and subsequent progression of liver fibrosis

This study aims to deepen understanding of lymphocyte phenotypes related to the course of hepatitis C virus (HCV) infection and progression of liver fibrosis, in a cohort of atomic-bomb survivors. The study subjects comprise three groups: 162 HCV persistently infected, 145 spontaneously cleared, and 3511 uninfected individuals. We found increased percentages of peripheral blood TH1 and total CD8 T cells and decreased percentages of NK cells in the HCV persistence group, compared with the other two groups, after adjustment for age, gender, and radiation exposure dose. Subsequently, we found that increased TH1 cell percentages in the HCV persistence group were significantly associated with an accelerated time-course reduction in platelet counts―accelerated progression of liver fibrosis―while TC1 and NK cell percentages were inversely associated with the progression. This study suggests that TH1 immunity is enhanced by persistent HCV infection, and that percentages of peripheral TH1, TC1, and NK cells may help predict progression of liver fibrosis.This research was based on RERF Research Protocols 3-09, 4-02, 2-00, 9-92, and was supported in part by the U.S. National Institute of Allergy and Infectious Diseases (NIAID Contract HHSN272200900059C)

Skin Cancer Incidence among Atomic Bomb Survivors from 1958 to 1996

The radiation risk of skin cancer by histological types has been evaluated in the atomic bomb survivors. We examined 80,158 of the 120,321 cohort members who had their radiation dose estimated by the latest dosimetry system (DS02). Potential skin tumors diagnosed from 1958 to 1996 were reviewed by a panel of pathologists, and radiation risk of the first primary skin cancer was analyzed by histological types using a Poisson regression model. A significant excess relative risk (ERR) of basal cell carcinoma (BCC) (n = 123) was estimated at 1 Gy (0.74, 95% confidence interval (CI): 0.26, 1.6) for those age 30 at exposure and age 70 at observation based on a linear-threshold model with a threshold dose of 0.63 Gy (95% CI: 0.32, 0.89) and a slope of 2.0 (95% CI: 0.69, 4.3). The estimated risks were 15, 5.7, 1.3 and 0.9 for age at exposure of 0-9, 10-19, 20-39, over 40 years, respectively, and the risk increased 11% with each one-year decrease in age at exposure. The ERR for squamous cell carcinoma (SCC) in situ (n = 64) using a linear model was estimated as 0.71 (95% CI: 0.063, 1.9). However, there were no significant dose responses for malignant melanoma (n = 10), SCC (n = 114), Paget disease (n = 10) or other skin cancers (n = 15). The significant linear radiation risk for BCC with a threshold at 0.63 Gy suggested that the basal cells of the epidermis had a threshold sensitivity to ionizing radiation, especially for young persons at the time of exposure

Prognostic Value of the Cold Pressor Test for Hypertension based on 28-year Follow-up

Several stress tests have been used to predict the development of hypertension. No conclusion, however, has been reached on the effectiveness of these tests as a predictor of hypertension in later years.　　 The present study examines the prognostic values of blood pressure response to cold and resting blood pressure for future hypertension, based on a follow-up study over 28 years of 824 individuals (mean age: 35.8 ± 10.8 yr) whose resting blood pressure had been normal at baseline.　　 A significant determinant of blood pressure response to cold stimulus was age in these normotensive subjects. A higher response was observed as age increased. There was also a significant seasonal variation in blood pressure response to cold, suggesting the need to standardize a time to perform the cold pressor test.　　 Hypertension has developed in 343 individuals during the 28 years of follow-up, with a mean incidence rate of 24.6 per 10^3 person-years. Both systolic and diastolic responses were significant as a predictor of future hypertension after adjusting for attained age, resting blood pressure, and body mass index at baseline. However, a comparison between resting blood pressure and response to cold indicated that the cold pressor test is not as effective a predictor of hypertension as resting blood pressure. Radiation exposure was not significant either as a background risk or as a possible modifier of the relationship between the blood pressure response and the development of hypertension.　　 The current results suggest that blood pressure response to cold supplements resting blood pressure for predicting hypertension.This publication is based on a manuscript (MS 09-94) resulting from research performed at the Radiation Effects Research Foundation (RERF), Hiroshima and Nagasaki, Japan. RERF is a private foundation funded equally by the Japanese Minister of Health and Welfare and the US Department of Energy through the National Academy of Sciences

Effect of Angiotensin Converting Enzyme Inhibitor and Benzodiazepine Intake on Bone Loss in Older Japanese

We investigated the effects of several frequently described medication regimens on annual percentage change in bone mineral density (BMD). A longitudinal cohort study (a retrospective analysis) was conducted. Subjects in the Adult Health Study (a prospective cohort study begun in 1958) have been followed through biennial medical examinations in Hiroshima, Japan. Participants were 2,111 subjects (67% women; aged 47-95 years) who were undergoing biennial health examinations from 1994 to 2000. The subjects were examined for the effect of certain drugs on bone mineral change during baseline and one follow-up (4 year later) measurements. Mean annual percentage change in BMD at the femoral neck was -0.38% for men, and -1.14% for women. After adjustment for sex, age, change of weight, alcohol consumption, and smoking status, annual percentage change in BMD decreased by 0.61 % among individuals taking angiotensin converting enzyme (ACE) inhibitors continuously in comparison with individuals who had not taken them (p=0.002): also decreased 0.40% among individuals taking benzodiazepines (BZDs) continuously (p=0.034). Our results suggest that careful consideration should be given to the use of ACE inhibitors and BZDs in a cohort of Japanese elderly