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Biomedical subjects

Saeko Fujiwara

Publications and source records attributed to Saeko Fujiwara.

At least 19 recordsLinked to original sources
PubMed2006

Feasibility of freeze-dried sera for serological and molecular biological detection of hepatitis B and C viruses.

We compared hepatitis B virus (HBV) surface antigen, anti-hepatitis C virus (HCV) antibody, and HCV RNA quantification in frozen and freeze-dried serum samples to assess the usefulness of freeze-dried sera for detection of HBV and HCV. The results indicated that freeze-dried sera as well as frozen sera can be useful for serological and molecular biological analyses of HBV and HCV.

Freeze Drying↗
PubMed2006

Radiation dose-response relationships for thyroid nodules and autoimmune thyroid diseases in Hiroshima and Nagasaki atomic bomb survivors 55-58 years after radiation exposure.

CONTEXT: Effects of irradiation on thyroid diseases such as thyroid nodules and autoimmune thyroid diseases have not been evaluated among people exposed to radiation more than 50 years in the past. OBJECTIVE: To evaluate the prevalence of thyroid diseases and their radiation-dose responses in atomic bomb survivors. DESIGN, SETTING, AND PARTICIPANTS: Survey study comprising 4091 cohort members (mean age, 70 [SD, 9] years; 1352 men and 2739 women) who participated in the thyroid study at the Radiation Effects Research Foundation. Thyroid examinations were conducted between March 2000 and February 2003. MAIN OUTCOME MEASURES: Prevalence of thyroid diseases, including thyroid nodules (malignant and benign) and autoimmune thyroid diseases, and the dose-response relationship of atomic bomb radiation in each thyroid disease. RESULTS: Thyroid diseases were identified in 1833 (44.8%) of the total participants (436 men [32.2% of men] and 1397 women [51.0% of women]) (P<.001). In 3185 participants, excluding persons exposed in utero, not in the city at the time of the atomic bombings, or with unknown radiation dose, the prevalence of all solid nodules, malignant tumors, benign nodules, and cysts was 14.6%, 2.2%, 4.9%, and 7.7%, respectively. The prevalence of positive thyroid antibodies, antithyroid antibody-positive hypothyroidism, and Graves disease was 28.2%, 3.2%, and 1.2%, respectively. A significant linear dose-response relationship was observed for the prevalence of all solid nodules, malignant tumors, benign nodules, and cysts (P<.001). We estimate that about 28% of all solid nodules, 37% of malignant tumors, 31% of benign nodules, and 25% of cysts are associated with radiation exposure at a mean and median thyroid radiation dose of 0.449 Sv and 0.087 Sv, respectively. No significant dose-response relationship was observed for positive antithyroid antibodies (P = .20), antithyroid antibody-positive hypothyroidism (P = .92), or Graves disease (P = .10). CONCLUSIONS: A significant linear radiation dose response for thyroid nodules, including malignant tumors and benign nodules, exists in atomic bomb survivors. However, there is no significant dose response for autoimmune thyroid diseases.

Aged↗
PubMed2006

Human T-cell lymphotropic virus type-1 infection and risk of cancer: 15.4 year longitudinal study among atomic bomb survivors in Nagasaki, Japan.

The objective of the present study was to investigate the association between human T-lymphotropic virus type-1 (HTLV-1) infection and cancer risk in a longitudinal study. The study population consisted of 2729 atomic bomb survivors in Nagasaki Prefecture, Japan, who had no previous history of cancer at baseline. The baseline survey, including analysis of antibody to HTLV-1, took place during 1985-1987 and follow-up was performed until the end of 2001. There were 553 incident cases of malignant neoplasms during the observation period. After adjustment for sex, age and other variables, HTLV-1 infection was not associated with the risk of developing cancers of all sites, excluding adult T-cell leukemia (rate ratio 1.0, 95% confidence interval [CI] 0.76-1.4), stomach, colon and rectum, lung, female breast or other minor sites, but was associated with increased risk of liver cancer (rate ratio 2.1, 95%CI 1.0-4.6). The point estimate of the rate ratio for thyroid cancer was 3.0, but this was not significantly higher than 1 because of the small number of events (n = 11) and low prevalence of HTLV-1 seropositivity. These findings support the idea that HTLV-1 infection is not associated with an increased general cancer risk. Confounding by hepatitis C virus (HCV) and the interaction between HTLV-1 and HCV may explain the increased risk of liver cancer among HTLV-1 carriers. Further follow-up may be required to determine if HTLV-1 carriers are at increased risk of thyroid cancer.

Female↗
PubMed2006

Levels of antibodies to microorganisms implicated in atherosclerosis and of C-reactive protein among atomic bomb survivors.

Although it has been suggested that cardiovascular disease incidence is increased among atomic bomb survivors, the existence of a causal relationship between radiation exposure and atherosclerosis is unclear. Microbial infections, including those caused by Chlamydia pneumoniae, Helicobacter pylori and cytomegalovirus, have recently been implicated in atherosclerosis. Since immune function is somewhat impaired among atomic bomb survivors, their immune defense against such infections might be diminished. To investigate this possibility, we measured antibody levels to the above microorganisms in the sera of survivors. We found that the levels of IgG and IgA antibodies to Chlamydia pneumoniae decreased significantly with radiation dose, whereas the levels of IgG antibodies to Helicobacter pylori or cytomegalovirus remained unchanged. The inflammation marker C-reactive protein was significantly and positively associated with level of antibodies to Chlamydia pneumoniae only in heavily exposed (>or=1000 mGy) survivors. These results may suggest that among atomic bomb survivors, immune response to Chlamydia pneumoniae is diminished and chronic inflammatory reactions related to Chlamydia pneumoniae infection are present.

Aged↗
PubMed2006

[Etiology and epidemiology of osteoporosis in men].

One-half to two-thirds of men with osteoporosis have secondary osteoporosis. The most important causes are heavy drinking, medication, and hypogonadism. Bone mineral density (BMD) slowly decreases with age in men, but prevalence of osteoporosis reached more than 20 percents among men aged 80 years and older. BMD is a major predictor for fracture risk in men as well as women, and predictive ability of BMD in men is similar with that in women. Smoking is a stronger predictor for future fracture in men compared with women. Previous fracture, alcohol drinking, steroid usage, and family history have similar predictive ability for fracture risk in both men and women.

Adult↗
PubMed2006

[Fracture risk assessment tool].

World Health Organization (WHO) has proposed the use of 10-year absolute risk for fracture (calculated based on incidence and life span) using clinical risk factors as new intervention thresholds. Eight risk factors to be included in the fracture assessment risk tool are age, bone mineral density or body mass index (BMI) when bone density is not available, steroid use, parental history of femoral neck fracture, history of osteoporotic fracture, smoking, excessive alcohol consumption, and rheumatoid arthritis. WHO has proposed that a treatment-intervention threshold be established in accordance with the medical situation in each country.

Aging↗
PubMed2006

[Clinical sign--height loss and vertebral deformity].

Loss of height may be an important clinical sign of vertebral deformation and/or fracture in postmenopausal women and elderly men. The presence of at least one spine fracture will lead to about a 2 cm decrease in height. Guidelines in the U.S. say that height loss greater than 1.5 inches or more from the maximum height among asymptomatic women may be associated with osteoporotic vertebral compression fractures. In Japan, the prevalence of spine deformation starts to increase among individuals in their early 70's, as does the prevalence of those with spine deformation at two or more vertebrae. It has been reported that not only individuals with clinical spine fracture but those with spine deformation show diminished activity of daily living (ADL) and quality of life (QOL) and also high mortality. Spine fracture should be suspected among individuals whose stature has decreased even if they manifest no symptoms.

Aged↗
PubMed2005

Smoking and alcohol habits as risk factors for benign digestive diseases in a Japanese population: the radiation effects research foundation adult health study.

BACKGROUND: Although an association between benign digestive diseases and smoking or drinking habits was reported, consistent results have not been obtained either in European, American or Japanese populations. METHODS: Smoking and alcohol habits as risk factors for the incidence of gastric ulcer, duodenal ulcer, chronic liver disease and cirrhosis as well as cholelithiasis were examined using the longitudinal data of the Adult Health Study collected biennially between 1958 and 1998. During 1958-1998, 1,093 gastric ulcers, 437 duodenal ulcers, 2,054 chronic liver diseases and cirrhoses, and 1,136 cholelithiasis cases were newly detected based on medical history, fluoroscopy or endoscopy and ultrasonography. Smoking and drinking histories were obtained from five and three questionnaires, respectively, administered during different periods. The relative risks (RRs) for ever smoked to never smoked and that for ever drank to never drank were estimated after adjustment for city, sex, age, birth cohort, calendar time and radiation dose. RESULTS: The analysis showed a positive association of smoking with gastric ulcer (RR: 2.03, 95% CI: 1.71-2.41), duodenal ulcer (RR: 1.31, 95% CI: 0.99-1.72), chronic liver disease and cirrhosis (RR: 1.23, 95% CI: 1.08-1.39) and cholelithiasis (RR: 1.19, 95% CI: 1.02-1.40), and a positive association of drinking with chronic liver disease and cirrhosis (RR: 1.10, 95% CI: 0.99-1.23). CONCLUSIONS: The peptic ulcer, chronic liver disease and cholelithiasis incidence increased significantly with smoking, and the chronic liver disease incidence increased significantly with drinking simultaneously in a prospective study of a Japanese population.

Adolescent↗
PubMed2005

Effects of radiation on the longitudinal trends of hemoglobin levels in the Japanese atomic bomb survivors.

The late effects of radiation on the hematopoietic system have not been fully evaluated. We examined the long-term effects of radiation exposure on hemoglobin levels in the Japanese atomic bomb survivors over a 40-year period from 1958 to 1998. Compared to the unexposed survivors, the mean hemoglobin levels for those exposed to a bone marrow dose of 1 Gy were significantly reduced by 0.10 g/dl (95% CI: 0.04 to 0.16) or 0.67% at 40 years of age (P < 0.0001) and by 0.24 g/dl (95% CI: 0.08 to 0.40) or 1.8% at 80 years of age. Radiation effects are greater for smokers than for nonsmokers at age less than 35 years (P < 0.01), although cigarette smoking was associated with increased hemoglobin levels. Sex and birth cohort differences in radiation effects were not found after adjusting for smoking. The radiation-induced reduction in hemoglobin levels could not be explained by the presence of certain anemia-associated diseases.

Adult↗
PubMed2005

[Epidemiology of osteoporosis].

The risk of osteoporotic fracture is lower in Asia and Africa than Caucasian women in the USA and Europe, but worldwide projections showed that it will probably increase markedly in the future. By 2050,the number of hip fracture increased three to four times higher than that in the present, and over half of all hip fracture will occur in Asia. Up to 50% of the variation in peak bone mass may be determined genetically. Sex hormone deficiency plays a major role in development of osteoporosis. In addition, nutrition, physical activity, cigarette smoking, and alcohol consumption also affects bone mass. Modification of these risk factors is important to prevent osteoporosis and consequent fracture in future generations.

Activities of Daily Living↗
PubMed2005

Serum uric acid concentration as a risk factor for cardiovascular mortality: a longterm cohort study of atomic bomb survivors.

OBJECTIVE: To elucidate the association of serum uric acid concentration with cardiovascular mortality risk. METHODS: Serum uric acid level measured from 1966 through 1970 in 10,615 Japanese individuals from a cohort of atomic bomb survivors was analyzed for association with subsequent cardiovascular and all-cause mortality until 1999 using the Cox proportional hazard model. RESULTS: During an average followup of 24.9 years, 5225 deaths occurred, of which 1984 were ascribed to cardiovascular disease. In men, after adjustment for age, elevated serum uric acid level was associated with both cardiovascular and all-cause mortality. After additional adjustment for potential cardiovascular disease risk factors including body mass index, smoking status, alcohol consumption, systolic blood pressure, cholesterol level, and histories of hypertension, diabetes and cardiovascular disease, elevated serum uric acid level in men was associated with all-cause mortality but not with cardiovascular mortality. In women, even after these adjustments, elevated serum uric acid level was significantly associated with cardiovascular and all-cause mortality. CONCLUSION: Increased serum uric acid level is a significant and independent risk factor for cardiovascular mortality in women and for all-cause mortality in both men and women.

Adult↗
PubMed2005

[Recommendations based on the evidence for secondary prevention of fractures/osteoporosis].

For Japanese women aged 65 years and older and men aged 75 years and older, osteoporosis screening through the use of DXA is recommended. For those with risk factors of osteoporosis and bone fracture among postmenopausal women younger than 65 years of age and men younger than 75, osteoporosis screening is considered to be beneficial. Regarding effectiveness of the screening among perimenopausal women, there is simply no evidence to recommend the screening. Further investigation is necessary into the effectiveness of using QUS for osteoporosis screening, as accuracy tends to suffer depending on the type of QUS device used and the level of values measured.

Absorptiometry, Photon↗
PubMed2005

[Osteoporosis and sunlight].

Vitamin D deficiency causes osteomalacia, osteoporosis and may contribute to bone fractures. Vitamin D is synthesized in the skin by the sunlight exposure and is also obtained from dietary sources. In the U.S., it was recommended that the adequate intake of vitamin D for adults aged from 51-70 years and 70 and more required 400 and 600 IU/day, respectively. Since dietary intake of vitamin D for middle-aged and elderly Japanese is estimated to be 300-400 IU/day, approximately 100-200 IU/day should be provided through the skin. Considering the risks of skin cancer caused by sunlight exposure, short trips outside amid life's daily routine on sunny days, and 30-60 minutes on rainy days and during times when sun exposure is inadequate to produce enough vitamin D in the skin would be appropriate.

Adult↗
PubMed2004

Self-reported number of remaining teeth is associated with bone mineral density of the femoral neck, but not of the spine, in Japanese men and women.

Recent studies suggest that a small number of remaining teeth may be associated with low skeletal bone mineral density (BMD) in postmenopausal women. Estrogen deficiency after menopause is considered potential cause relating to tooth loss accompanied by low skeletal BMD in women. Since estrogen plays a dominant role in regulating the male skeleton, it is likely that a small number of remaining teeth also may be associated with low skeletal BMD in men. However, it remains uncertain whether tooth loss is associated with low skeletal BMD in both men and women. We investigated the association between self-reported number of remaining teeth and BMD of the spine and the femoral neck in a cohort of 1914 Japanese subjects aged 48-95 years who were recruited from the Adult Health Study conducted by the Radiation Effects Research Foundation (RERF). BMD of the spine and the femoral neck was measured by dual energy X-ray absorptiometry (DXA). Tooth count was self-reported in response to a simple question to subjects about the number of remaining teeth they had at the time of the survey. Multiple regression analysis adjusted for age, weight, height, smoking, estrogen use, and years since menopause revealed a significant association between number of remaining teeth and BMD of the femoral neck in both men and women; however, no association was found between number of remaining teeth and BMD of the spine in both sexes. Retention of four teeth was significantly associated with a 0.004 g/cm2 increase in femoral neck BMD in men (P<0.05), which was similar to that observed in women (P<0.01). Our results suggest the presence of common causes, except age and body weight, relating to tooth loss accompanied by low BMD of the femoral neck in both men and women.

Age Factors↗
PubMed2004

Uncertainty in estimating probability of causation in a cross-sectional study: joint effects of radiation and hepatitis-C virus on chronic liver disease.

Exposure to other risk factors is an important consideration in assessing the role played by radiation in producing disease. A cross-sectional study of atomic-bomb survivors suggested an interaction between whole-body radiation exposure and chronic hepatitis-C viral (HCV) infection in the etiology of chronic liver disease (chronic hepatitis and cirrhosis), but did not allow determination of the joint-effect mechanism. Different estimates of probability of causation (POC) conditional on HCV status resulted from additive and multiplicative models. We therefore estimated the risk for radiation conditional on HCV status using a more general, mixture model that does not require choosing between additivity or multiplicativity, or deciding whether there is interaction, in the face of the large uncertainty. The results support the conclusion that POC increases with radiation dose in persons without HCV infection, but are inconclusive regarding individuals with HCV infection, the lower confidence bound on estimated POC for radiation with HCV infection being zero over the entire dose range. Although the mixture model may not reflect the true joint-effect mechanism, it avoids restrictive model assumptions that cannot be validated using the available data yet have a profound influence on estimated POC. These considerations apply more generally, given that the additive and multiplicative models are often used in POC related work. We therefore consider that an empirical approach may be preferable to assuming a specific mechanistic model for estimating POC in epidemiological studies where the joint-effect mechanism is in doubt.

Cross-Sectional Studies↗