Yutaka Hosoda

Prevalence and risks of dementia in the Japanese population : RERF's adult health study Hiroshima subjects

OBJECTIVES: To study the prevalence rate of dementia and its subtypes in Japan and to investigate the relationship of risk factors, such as demographic features and disease history, to the prevalence of Alzheimers disease or vascular dementia.

Noncancer disease incidence in the atomic bomb survivors : 1958-1986

Using the longitudinal data of the Adult Health Study (AHS) cohort collected during 1958-1986, we examined for the first time the relationship between exposure to ionizing radiation and the incidence of 19 nonmalignant disorders in the A-bomb survivors. Affected individuals were ascertained through the three-digit codes of the International Classification of Diseases which are encoded in the AHS database subsequent to diagnoses made on the basis of general laboratory tests, physical examinations, and history-taking conducted during biennial AHS examinations. The disease onset time was estimated using the mid-point between the AHS examination data when the disease was initially reported and the previously attended disease-free examination date. Dosimetry System 86 organ doses judged to be most appropriate were used. Tests of dose effects were performed assuming a linear relative risk model with stratified background incidence. For the entire study period, significant excess risk was detected for uterine myoma (P < 0.001), chronic liver disease and cirrhosis (P = 0.006), and thyroid disease (P < 0.0001), defined broadly as the presence of one or more of certain noncancerous thyroid conditions. The incidence of myocardial infarction was shown to be increased (P = 0.03) in later years (1968-1986) among the younger heavily exposed AHS subjects, confirming the results of the recent Life Span Study (LSS) noncancer mortality report on coronary heart disease. The findings for uterine myoma may serve as additional evidence indicating benign tumor growth as a possible consequence of radiation exposure. Our results indicating the involvement of radiation in the development of liver diseases are consistent with the report of increased mortality from liver cirrhosis with radiation dose in the LSS cohort. An effect of age at exposure was detected for nonmalignant thyroid disease (P = 0.02), with an increased risk for those exposed who were under 20 years of age, but not for older survivors. Thus the AHS data suggest that thyroid glands in the young are more radiosensitive not only to the development of malignancies, but also to the development of nonmalignant disorders as well. The findings hold independently of the dose effects observed for thyroid cancer. This study also shows that for the period 1958-1986 new occurrences of lens opacity are not increased with radiation dose (P = 0.39) in the AHS subjects.

Frequent isolation of propionibacterium acnes from sarcoidosis lymph nodes

Isolation of Propionibacterium acnes from biopsied lymph nodes of sarcoidosis patients and from the lymph nodes or other tissues of non-sarcoidosis patients was carried out, carefully avoiding contamination by skin-resident P. acnes. Out of 40 sarcoidosis lymph nodes examined, 31 nodes (77.5%) showed a positive culture of P. acnes, while 38 of 180 (21.1%) non-sarcoidosis tissues revealed positive results, the difference being significant (p less than 0.001). Among non-sarcoidosis tissues, the intra-thoracic lymph nodes demonstrated a positive culture in low percentages, while intra-abdominal lymph nodes indicated no positive culture. The possible role of this microorganism in the etiology of sarcoidosis is discussed.

Effects of Radiation on the Longitudinal Trends of Total Serum Cholesterol Levels in the Atomic Bomb Survivors

The effects of radiation on the long-term trends of the total serum cholesterol levels of the Hiroshima and Nagasaki atomic bomb survivors were examined using data collected in the Adult Health Study over a 28-year period (1958-1986). The growth-curve method was used to model the longitudinal age-dependent changes in cholesterol levels. For each sex, temporal trends of cholesterol levels were characterized with respect to age, body mass index, city and birth year. We then examined whether the temporal trends differed by radiation dose. We showed that the mean growth curve of cholesterol levels for the irradiated subjects were significantly higher than that for the unirradiated subjects, and that the increase was greater for women than for men. No difference in dose response was detected between Hiroshima and Nagasaki. An increased mean level of cholesterol was evident for irradiated women in general, but a notable increase was apparent in males only for the youngest birth cohort of 1935-1945. The difference in the mean cholesterol levels between the irradiated and unirradiated subjects diminished past 70 years of age. It is not known whether this is due to natural progression or is an artifact of nonrandom variation in the rate of participation in the examinations. The maximum predicted increase at 1 Gy for women occurred at age 52 years for the 1930 cohort: 2.5 mg/dl (95% CI 1.6-3.3 mg/dl) for Hiroshima and 2.3 mg/dl (95% CI 1.5-3.1 mg/dl) for Nagasaki. The corresponding increase for men occurred at age 29 years for the 1940 cohort: 1.6 mg/dl (95% CI 0.4-2.8) for Hiroshima and 1.4 mg/dl (95% CI 0.3-2.6) for Nagasaki. Controlling for cigarette smoking did not alter the dose-response relationship. Although the difference in the mean growth curves of the irradiated and unirradiated groups was statistically significant, there was a considerable overlap in the individual growth curves of the two groups. The significant sex difference and the greater magnitude of radiation effects in women suggest that hormonal changes resulting from radiation exposure, such as accelerated menopause, is an area worth investigating to delineate the mechanisms underlying the increased cholesterol levels of the irradiated female subjects. This increase may also partially explain the increased rate of coronary heart disease seen in the atomic bomb survivors.

Hyperparathyroidism among Atomic Bomb Survivors in Hiroshima

To determine the effect of exposure to atomic bomb radiation on the occurrence of hyperparathyroidism, the prevalence was determined among a population of 3,948 atomic bomb survivors and their controls in Hiroshima. The diagnosis of hyperparathyroidism was based upon histopathological findings or the presence of consistent hypercalcemia and elevated levels of serum parathyroid hormone. Primary hyperparathyroidism was diagnosed in 19 persons (3 males, 16 females). Females had approximately a threefold higher overall prevalence of hyperparathyroidism than males (P less than 0.05). The prevalence rates of hyperparathyroidism increased with radiation dose (chi2(1) = 12, P less than 0.001) after adjusting for sex and age at the time of the bombing. The estimated relative risk was 4.1 at 1 Gy (95% confidence limits 1.7 to 14). There was some evidence that the effect of radiation was greater for individuals who were younger at the time of the bombing. In conclusion, exposure to atomic bomb radiation affected the occurrence of hyperparathyroidism, suggesting that doses of radiation lower than those used in radiotherapy may also induce this disorder.

Epidemiology of sarcoidosis: new frontiers to explore

Epidemiologic studies have been playing frontier roles to explore determinants of sarcoidosis by observing affected persons with the related population. Since 1990, more than 100 epidemiologic papers have been added to the Medline and PubMed databases. Of them, just a few were dated after March 2001. This article is focused on the papers after that time, referring to a number of previous important epidemiologic studies. The review is arranged according to two major epidemiologic categories: (1) host-related findings such as age, sex, race, familial clustering, and lifestyle; and also (2) time- and space-related findings such as exposures, geographical variation, local clustering, climate and seasonal variation, migration, and time-space clustering (transmission).

Reliability of the proposed international classification of high-resolution computed tomography for occupational and environmental respiratory diseases.

Reliability of the Proposed International Classification of High‐Resolution Computed Tomography for Occupational and Environmental Respiratory Diseases: Narufumi Suganuma, et al. Department of Environmental Medicine, Kochi Medical School

The incidence of thoracic vertebral fractures in a Japanese population, Hiroshima and Nagasaki, 1958–1986

The incidence of thoracic vertebral fractures (TVF) in a Japanese population of 14,607 individuals from Hiroshima and Nagasaki was determined by sex, age, birth cohort, and exposure to atomic bomb radiation. The diagnosis of TVF was based on lateral chest radiographs made from 1 July 1958 to 28 February 1986. The subjects, who were born between 1880 through 1939, were categorized by sex into 10-year birth cohorts. TVF incidence increased by a factor of 1.7 in all birth cohorts with each 10-year increase in age in females, but did not increase with age in males. The incidence was significantly lower in the younger birth cohorts in both sexes. The incidence declined by a factor of 0.5 in males and 0.6 in females for each 10-year decrease in the year of birth. TVF incidence did not differ between the cities, and no correlation with atomic bomb radiation exposure was demonstrated.

Changes in the peripheral vasculature of various organs in patients with sarcoidosis—Possible role of microangiopathy

SummaryVascular involvement in sarcoidosis is briefly reviewed with emphasis on the outcome of a 10-year project-study by the Sarcoidosis Research Committee of the Japanese Ministry of Health and Welfare. Examples of vascular disorder associated with sarcoidosis are presented, including basal lamina layering of the capillaries in the skeletal muscle, cardiac muscle, and lung, glomerulopathy in the kidney, vascular changes in the ocular fundus and bronchi, and impaired peripheral circulation that could be detected by thermography. According to our tentative definition, all of these disorders should be collectively called microangiopathy. The possible role of microangiopathy in the pathogenetic mechanism of sarcoidosis is also discussed. Although microangiopathy in sarcoidosis is a comprehensive term, it should be included, in addition to systemic granulomatous disease, as part of the clinicopathological entity of sarcoidosis.

Metal-Induced Lung Disease: Lessons from Japan's Experience

Metal‐Induced Lung Disease: Lessons from Japans Experience: Yukinori Kusaka, et al. Department of Environmental Health, School of Medicine, Fukui Medical University—Metals inducing occupational respiratory diseases, e.g. metal fever, acute and chronic pneumonia, asthma, bronchitis, chronic obstructive lung disease, pulmonary fibrosis and lung cancer are described. The metals mentioned are the following: aluminum, antimony, arsenic, barium, beryllium, cadmium, chromium, cobalt, copper, iron, lithium, manganese, mercury, nickel, platinum, rhodium, rare earth metals, titanium, uranium, vanadium, welding, zinc, zirconium. With respect to these metals, mechanism of the disease, disease statistics, case reports, diagnostic methods, patho‐physiology of the disease, and preventive measures including occupational exposure limits are also described. Experience in Japan on these issues is given in detail.