Takao Kitano

An epidemiological study with risk analysis of liver diseases in the general population living in a methyl mercury polluted area.

STUDY OBJECTIVE--The aim was to determine the actual prevalence of liver disease and to investigate the contribution of various risk factors to liver disease among the population in a methyl mercury polluted area. DESIGN--The study was a population based cross sectional mass screening survey. A case-control study was designed to estimate the role of various risk factors for liver diseases. SETTING--The study was confined to a small rural town 10 km north of Minamata City. SUBJECTS--1406 persons aged 50 to 69 years were examined (78.3% of the total population of this age in the locality). MEASUREMENTS AND MAIN RESULTS--Measurements of liver disease were made on the basis of haematological, physical, and ultrasonographic examinations. Data on liver risk factors were collected by questionnaire, and by measurement of body height, weight (obesity), and hepatitis B surface antigen (HBsAg). The prevalence rate of liver tumour was 0.5% in males, liver cirrhosis was found in 0.5% of males and 0.1% of females, and hepatitis was seen in 5.4% of males and 1.0% of females. Frequency rates of risk factors for liver disease among subjects with obesity were significantly higher in the female patient group, and the frequency rate among subjects with alcoholic drinking habits was significantly higher in the male patient group. The odds ratio of past history of blood transfusion showed the highest value among other related factors (7.73) and the attributable risk for this was very high (87.1%); HBsAg was next in rank (odds ratio 3.04; attributable risk 67.1%). CONCLUSIONS--The prevalence of liver disease in this methyl mercury polluted area was not increased, contrary to what was expected based on the standard mortality ratios. The main risk factors for liver disease in this area appear to be alcoholic drinking habits and a history of blood transfusion.

Allergic contact dermatitis in shiitake (Lentinus edodes (Berk) Sing) growers

A 42‐year‐old female shiitake grower was investigated to clarify the etiology of skin lesions which developed during the planting Of shiitake hyphae into bed logs. She complained of repeated eczematous skin lesions during the planting season, from March to July, for 10 years. She handled 7,000 pieces of small conic Mucks made of beech, with shiitake hyphae attached in their surface, per day, and 300,000 pieces altogether per season. She was positive on patch testing with extracts of shiitake hyphae. In contrast, female shiitake growers with skin lesions associated with work other than planting, and without skin lesions, were negative on patch testing to she hyphae. Moderate allergenicity was observed to extracts of shiitake hyphae in a guinea pig maximization test. These findings indicated the etiology of skin lesions in shiitake growers to be allergic contact dermatitis induced by shiitake hyphae.

Differential expression of basement membrane type-IV collagen α1, α2, α5 and α6 chains among the histological subtypes of adenoid cystic carcinoma

Six distinct α(IV) chains in the basement membrane (BM) of adenoid cystic carcinoma (ACC) of the salivary gland were immunohistochemically examined by anti-α(IV) chain-specific antibodies, and their expressions were compared with the histological subtypes and the expressions of cytokeratin 19 (CK19), cytokeratin 14 (CK14) and α-smooth muscle actin (α-SMA) and Ki-67. In the BM of normal salivary ducts, α1(IV), α2(IV), α5(IV) and α6(IV) chains were continuously stained, but α3(IV) and α4(IV) chains were negative. In the tubular and cribriform subtypes of ACC, tubules with continuous staining of α5(IV) and α6(IV) chains showed the biphasic-staining pattern among the expressions of CK19, CK14 and α-SMA. However, in cancer-cell nests with discontinuous or negative staining of α5(IV) and α6(IV) chains, the biphasic pattern was ambiguous. In the solid subtype, the staining of α1(IV) and α2(IV) chains was discontinuous, the staining of α5(IV) and α6(IV) chains was negative and the biphasic-staining pattern was unclear. The mitotic activity of cancer cells analyzed by the Ki-67 labeling index was significantly related to the expression of α5(IV) and α6(IV) chains in the cribriform subtype. These results suggest that BM irregularity with the differential expression of α(IV) chains in ACC closely relates to cell proliferation, cell differentiation and histological structure.

Correlation between forearm bone mineral density and body composition in Japanese females aged 18–40 years

ObjectiveThe purpose of this study was to clarify the relationship between forearm bone mineral density (BMD), body mass index (BMI), and body composition focusing on body fat percentage (BF%) in Japanese females 18 to 40 years old.MethodsSubjects were 2,280 females 18–40 years old. Anthropometric measurements were taken, and a medical history was obtained by questionnaire, including age at the time of the study and age at menarche. BF% was measured by bioelectrical impedance analysis. Forearm BMD was measured using dual-energy X-ray absorptiometry (DXA). The correlations of BMD with BMI and BF% were analyzed using a structural equation model.ResultsThe standardized regression coefficients for the path from BMI to BMD and the path from BF% to BMD were 0.538 and −0.184 respectively. The squared multiple correlation of BMD was 0.146. In addition, the standardized regression coefficient for the path from BMI to BF% was 0.896.ConclusionThe results showed a positive correlation between BMD and BMI and an inverse correlation between BMD and BF%. At the same time, it was noted that BF% increased with BMI. This indicated that BMD is dependant on BF% in subjects who have a similar BMI. Therefore, this study concluded that it is necessary to take body composition measurements into account when examining the relationship between BMI and BMD, especially in young females.

Relationship between Health Status and Psychological Distress among the Inhabitants in a Methylmercury-Polluted Area in Japan

Abstract This study examined the relationship between health parameters and psychological distress among inhabitants of methylmercury-polluted areas in Japan. The subjects were 133 inhabitants over the age of 40 yr living in two methylmercury-polluted villages. Information on demographic factors, health status, and mental health was obtained using questionnaires, including the General Health Questionnaire (GHQ). The proportional odds model was used to estimate the adjusted odds ratios of factors associated with a higher GHQ score after adjustment for age, gender, and district. Very poor self-rated health status, a high number (5+) of subjective symptoms, having monthly outpatient visits and medical house calls, and receiving compensation for methylmercury poisoning were significantly associated with psychological distress. Poor physical condition may lead to the development of psychological distress.

Relationship between RBC Mercury Levels and Serum n3 Polyunsaturated Fatty Acid Concentrations among Japanese Men and Women

Aims. To evaluate potential health risk and benefits of fish consumption, the association of fish consumption with total mercury levels in red blood cells (RBCs) and serum eicosapentaenoic acid (EPA) concentrations was examined. Subjects and Methods. Study subjects were 269 Japanese (98 men and 171 women) living in a remote island of Kagoshima, and their blood was drawn in 1994. Results. Total mercury levels were related to weekly fish consumption among women (P = 0.035) but not among men (P = 0.643). However, serum EPA levels were not related to fish consumption in both women and men. In contrast, EPA levels in the high-density ipoprotein (HDL) fraction of the sera were significantly related to fish consumption (P values for men and women were 0.014 and 0.073, resp.). Interestingly, mercury levels were related to serum EPA levels and EPA in the HDL fraction of the sera (P = 0.001) among women (P = 0.005) but not among men. Sex differences in fish species consumed may be an explanation for the observed sex difference. Conclusion. Those findings suggest that the health benefit of fish consumption can be maximized by the careful selection of fish species consumed.

ESTIMATION OF THE BODY COMPOSITION OF YOUNG JAPANESE WOMEN MEASURED BY SIMPLE ANTHROPOMETRIC MEASUREMENTS

Abstract Body fat, fat mass, and fat free mass as a percentage of body composition were estimated by two methods: underwater weighing and skinfold thicknesses (skinfolds) at the triceps and subscapular regions. This study compares the results of the two different methods among 126 healthy women aged 19 – 20 years. The values of percent body fat as estimated by underwater weighing and by skinfolds of the Nagamine and Suzuki model were correlated; however, the estimates by skinfolds were significantly (p 2 = 0.501 and RMSE=0.007018) While there was no difference between the average of body fat percent as estimated by underwater weighing and the Nagamine and Suzuki model, there was a difference between underwater weighing and this new model in a cross-validation study. However this new model was more closely correlated with underwater weighing than the Nagamine and Suzuki model and this new model was a more accurate estimate of obesity than the Nagamine and Suzuki model. We therefore speculate that this new model is more suitable for current Japanese young women in general surveys.

Risk estimation for hypertension based on follow-up health examination data in a small village in Kumamoto prefecture, Japan

The estimation of risk for incidence of hypertension was carried out by follow-up study in a small village in Kumamoto Prefecture, Japan (N=750, 48.2±15.2months). The most significant risk in both sexes was blood pressure at entry. As for other risks, age, total cholesterol, and BMI in females were significant risks for systolic and diastolic blood pressure changes to greater than the borderline level. These factors in males were not significant. From the results of analysis using Cox’s proportional hazards model, drinking in males was shown to be a significant risk for diastolic change, and in females for systolic change. It was concluded that excessive drinking in both sexes and obesity in females led to important health problems associated with hypertension among the subjects of the study.

Serial study on the association between body mass index and hypertension in rural Japanese.

The objective of this study was to examine the association between body mass index (BMI) and blood pressure. Two sets of cross-sectional data were obtained from annual health examinations for adults aged 40 years and over (n=1,327 in 1993; n=1,302 in 2000) in Tsunagi area of Kumamoto Prefecture, Japan. BMI was associated with mean blood pressure and with prevalence of hypertension both in 1993 and 2000. The association was independent of age, smoking status and alcohol consumption. A significant increase in risk of hypertension was found in most categories of BMI 25.0 and above, and a greater than three fold increase in those with BMI of 27 and above compared with those with BMI of 18.5–22.9. Although mean blood pressure and prevalence of hypertension sharply decreased in 2000 compared with that in 1993, BMI was positively and independently associated with increased blood pressure.

Effect of Long-term Intake of VB1-Enriched Rice on a Local Population.

糖質摂取量が比較的多い農業従事者のビタミンB1摂取量を把握するとともに, B1強化米を長期間 (6カ月間) 投与し, 血中B1値, トランスケトラーゼ活性などの測定によりその改善効果を検討した。1) 調理損耗を見込んだB1摂取量は, 男0.67±0.20mg, 女0.60±0.21mgで, 摂取率 (摂取量/所要量×100) は, 72.2±25.7%, 89.5±30.8%であった。2) 血中B1値は, 投与前23.3±5.8ng/mlが, 投与後は42.5±7.9ng/mlと改善された。3) 血中B1値の投与前後の変化率は, 192±70%で, 変化率を高, 中, 低の3区分ごとに食事摂取内容をみると高率群において体重当り米摂取量, 穀類エネルギー比, 糖質エネルギー比が有意に高く, タンパク質エネルギー比は有意に低値であった。4) 血中B1値とタンパク質摂取量, Ca摂取量に正相関, また男においてアルコール摂取量と負相関, 女では糖質エネルギー比に負相関が認められた。5) 血中B1変化率別にみた食事内容から, とくに米摂取量が多く, タンパク質エネルギー比の低いグループにB1強化米投与の有効性を確認した。