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Biomedical subjects

C Nagata

Publications and source records attributed to C Nagata.

At least 55 records · Page 3Linked to original sources
PubMed1998

Associations of individuals' health-related behavior with their own or their spouses' smoking status.

BACKGROUND: Many studies indicated that smokers have poor health habits such as high alcohol consumption and imbalanced nutrient intakes. These habits could affect the health-related behavior of smokers' families. METHODS: To investigate the relationship between an individual's health-related behavior (nutrient intakes and participation in cancer screening) and their spouses' smoking status, we analyzed data collected using a self-administered questionnaire during a cohort study. We compared nutrient intakes and cancer screening participation rates between subjects grouped according to their spouses' smoking status, using a multivariate linear regression model to adjust for each subject's age and alcohol consumption. RESULTS: There was an association between husbands' and wives' smoking status (never and current only). Poor micronutrient intakes and cancer screening participation rates were associated with both the subjects' and their spouses' smoking habits. This tendency was most apparent among male smokers and nonsmoking women. However, among nonsmoking men and female smokers, there were no statistically significant differences between groups classified according to their spouses' smoking status. CONCLUSION: Spouses' smoking habits were associated with poor health-related behavior in their partners.

Adult↗
PubMed1997

Trends in the incidence rate and risk factors for breast cancer in Japan.

The incidence rate of breast cancer in Japan rose more than two-fold from 1959-60 to 1983-87. To assess to what extent this increase can be explained by changes in the prevalence of four major risk factors of breast cancer (i.e. age at menarche, age at first birth, age at menopause, and parity), we estimated the probability of developing breast cancer based on the joint distribution and relative risks of these four risk factors. The age-specific incidence rate during 1959-60 reported by the Miyagi Prefectural Cancer Registry was used to estimate the baseline hazard rate for women without the four risk factors in the same age group. Assuming that the baseline hazard rate is constant during all periods, we calculated the expected incidence rates during the periods of 1959-60, 1962-64, 1968-71, 1973-77, 1978-81, and 1983-87 for each age group. Large discrepancies were noted between the observed and expected incidence rates during 1983-87 in all age groups. The change in the joint distribution of the four risk factors accounted for less than 40% of the increase observed from 1959-60 to 1983-87, suggesting the effects of other powerful risk factors.

Adult↗
PubMed1997

Association of body mass index, physical activity, and reproductive histories with breast cancer: a case-control study in Gifu, Japan.

To further clarify risk factors for breast cancer in Japanese women, a self-administered questionnaire was completed by 157 cases with histologically confirmed breast cancer from 1989 to 1993 and by 369 age and residential area matched controls in Gifu, Japan. Conditional logistic regression model was used to assess the relations. Multivariate analyses showed that breast cancer risk decreased with body mass index for premenopausal women (RR = 0.45; 95 % CI = 0.22-0.92 for BMI > or = 23 vs. < 21 (kg/m2)), but the risk increased with body mass index for postmenopausal women (RR = 1.98; 95 % CI = 0.86-4.55 for BMI > or = 24 vs. < 21.5 (kg/m2)). The risk increased with a small number of births in pre- and post-menopausal women (1.83; 1.11-2.99 and 6.06; 2.40-15.3 for 1-2 births and nulliparity, respectively, vs. > or = 3 births). Ex- or current smoking increased the risk of breast cancer (2.31; 1.19-4.49). Reduced risk of premenopausal breast cancer was associated with high energy expenditure in physical activity during teenage, although the trend was not statistically significant.

Adult↗
PubMed1997

Associations of alcohol, height, and reproductive factors with serum hormone concentrations in postmenopausal Japanese women. Steroid hormones in Japanese postmenopausal women.

We measured serum levels of estradiol (E2), sex hormone-binding globulin SHBG), progesterone, and dehydroepiandrosterone sulfate (DHEAS) in 61 postmenopausal women drawn from female residents in a community in Japan to evaluate the relationships between these hormone levels and potential breast cancer risk factors. The information on reproductive history, body size, alcohol use, and physical activity was obtained by means of a self-administered questionnaire. There was a significant trend in increasing E2 level with increasing height after taking account of age and body mass index (BMI) (p for trend = 0.04). BMI was inversely associated with SHBG level after controlling age (p for trend = 0.01). Decreasing progesterone with increasing BMI was observed after controlling age and history of hysterectomy (P = 0.05). Alcohol consumption was positively associated with E2 level and there was a strong linear trend after controlling for age, height, and BMI (p for trend = 0.001). Trend for increasing DHEAS with alcohol consumption was also statistically significant after controlling for age and history of hysterectomy (p for trend = 0.01). Reproductive factors as well as physical activity were not related to any of the hormone levels.

Body Height↗
PubMed1997

Fat and fiber intakes in relation to serum estrogen concentration in premenopausal Japanese women.

It has been implied that fat and fiber intakes influence breast cancer risk. The effects of these dietary factors may be mediated by hormonal changes. We evaluated the relationships between fat or fiber intake and serum concentration of estradiol (E2) or sex hormone-binding globulin in premenopausal women. In 1994 blood samples were collected from each of 50 premenopausal healthy Japanese women on Days 11 and 22 of the menstrual cycle. Nutrient intakes were assessed by food frequency questionnaire in which the subjects were asked about their diets during one year before the study. Each nutrient intake was categorized into tertile after adjustment for total energy. Linear regression models, including age and cycle length as covariates, were utilized to evaluate the association between the nutrient intakes and the hormone concentrations. A statistically significant trend was observed between increasing fat intake and increasing E2 on Day 11 of the cycle (p = 0.05). The positive trend for increasing sex hormone-binding globulin on Day 22 with fat intake was of borderline significance (p = 0.06). There was a statistically significant inverse trend for E2 on Day 11 of the cycle with fiber intake (p = 0.05). It was suggested that fat as well as fiber intake should affect the hormone status.

Adult↗
PubMed1997

Decreased serum estradiol concentration associated with high dietary intake of soy products in premenopausal Japanese women.

We examined the cross-sectional relationship of soy product intake to serum concentrations of estradiol (E2) and sex hormone-binding globulin (SHBG) in 50 healthy premenopausal Japanese women. Intakes of soy products and various nutrients were estimated through a semiquantitative food-frequency questionnaire. Blood samples were drawn from each subject on Days 11 and 22 of her menstrual cycle. The intake of soy products was inversely correlated with E2 on Days 11 and 22 of the cycle after controlling for age, body mass index, cycle length, and intakes of total energy, fat, and crude fiber (r = -0.23, p = 0.08 and r = -0.32, p = 0.04, respectively). No significant correlation was observed between soy product intake and SHBG. There was a tendency for the intake of individual soy foods such as tofu and miso to be inversely correlated with E2 on Days 11 and 22 of the menstrual cycle. Miso intake was inversely significantly correlated with SHBG on Day 22 of the cycle (r = -0.36, p = 0.02). If the observed association is causal, our results suggest that the consumption of soy products lowers the risk of developing breast cancer risk modifying estrogen metabolism.

Adult↗
PubMed1997

Assessment of preference for breast cancer chemoprevention in Japanese young women.

Pills containing estrogen and progesterone or gonadotropin releasing hormone agonist have been considered valuable to prevent breast cancer. This study assessed preference for the combination-type pill for preventing breast cancer, to evaluate the hypothetical preventive effect of this agent among young Japanese women. The standard gamble method was applied. Fifty-five college students and 44 nursing school students aged between 18 and 41 years were asked to decide the probability of being affected by breast cancer at which they would start to take this agent. Preference score was calculated by subtracting the probability given by each respondent from 1, which corresponds to the value (utility) she allotted to the agent. The means of preference score were 0.58, 0.48, 0.37, and 0.27 for 100, 75, 50, and 25% of efficacy levels of the agent, respectively. Preference score was significantly lower in nursing school students and those whose knowledge about hormones were relatively high. Score of Health Locus of Control (HLC) was nonsignificantly negatively correlated with preference score at any efficacy level. HLC score was significantly higher among those who refused the agent with 50 and 25% efficacy levels at 100% level of breast cancer risk. The data suggest that perceived risk of this agent was not negligibly small in this population and school status, knowledge about hormones, and beliefs about health would affect preference for the agent. Understanding of preference for chemopreventive agents for breast cancer, especially those containing hormones, is important to assess their potential as future preventive agents and is helpful when planning a strategy of chemoprevention.

Adolescent↗
PubMed1997

Factors associated with serum levels of estradiol and sex hormone-binding globulin among premenopausal Japanese women.

We measured serum levels of estradiol (E(2)) and sex hormone-binding globulin (SHBG) among 50 healthy premenopausal Japanese women in 1994 in Gifu, Japan, to investigate the relationships between potential risk factors for breast cancer and hormone levels. Using a self-administered questionnaire, we collected data on body size, physical activity, and previous disease history, as well as menstrual and reproductive histories of the woman and her mother. Blood samples were drawn from each subject on the 11th and 22nd days of her menstrual cycle. Higher serum E(2) levels were observed for women with shorter menstrual cycles. Age as well as cycle length were included in the regression models to determine the associations between hormone levels and study variables. Body mass index (BMI) was inversely related to SHBG level measured at the 11th day of the cycle, after adjusting for age and cycle length (r = -0.33; p = 0. 03). Women born in spring/summer had higher levels of E(2) on the 22nd day (p = 0.07) and higher levels of SHBG on both the 11th and 22nd days of the cycle (p = 0.01 and p = 0.06, respectively) than those born in other seasons. Physical activity at 13-15 years of age was inversely related to E(2) level on the 11th day of the cycle after controlling for age, cycle length, BMI, and birth month (r = -0.35; p = 0.04).

Adult↗
PubMed1997

Validation of simplified diet history questionnaire.

Simplified methods to estimate long term nutrient intakes would be needed for not only nutritional epidemiologic studies but also other ones. Based on data of diet history questionnaires (DHQ) which ask frequency and portion size for 169 items from 2,371 participants randomly selected from our cohort study in a rural city of Japan, we simplified the DHQ by eliminating some items using stepwise regression method. To examine the validity of the simplified DHQ (SDHQ), we obtained the SDHQs from 31 volunteers who had finished to complete one-day records once a month during the previous year, we calculated Pearson's correlation coefficient and calorie-adjusted correlation coefficient between the SDHQ and twelve one-day records for each nutrient intake value. Thirty one items were selected for our SDHQ. The mean values of most nutrient intakes from the SDHQ were more than those from twelve one-day records. The correlation coefficients between the SDHQ and twelve one-day records were more than 0.30 except for fat and monounsaturated fat. Calorie adjustment increased in the correlation coefficients for some nutrients. Our results suggest that the SDHQ is a validated and easy-to-use method for assessing long term 17 selected nutrient intakes.

Adult↗
PubMed1996

Cryocrystallography of 3-Isopropylmalate dehydrogenase from Thermus thermophilus and its chimeric enzyme.

The crystal structures of thermostable enzyme, 3-isopropylmalate dehydrogenase of Thermus thermophilus (10T) and a chimeric enzyme between T. thermophilus and Bacillus subtilus with one point mutation (cS82R), were determined at both 100 and 150 K. At the cryogenic condition, the volume of the unit cell decreased by 5% as a result of a contraction in the solvent region. Although the overall structures of both enzymes at low temperature were the same as that of 10T at room temperature, interactions between two domains and between two subunits in a functional dimer of cS82R were significantly altered. The decrease in the average temperature factor of 10T at low temperature and no significant decrease for cS82R suggested that the structure of the engineered enzyme (cS82R) may have many conformational substates even at low temperature, while the native enzyme (10T) at low temperature has a more definite conformation than that at room temperature. The location of water molecules around the enzyme molecule and the calculation of the radii of gyration suggested that cS82R had a weaker hydration than 10T.

Journal Article↗
PubMed1996

Birth season and breast cancer risk in Japan.

Recent studies suggest that prenatal or early post-natal factors may influence future breast cancer risk. To investigate whether month of birth is a risk factor for breast cancer, we analyzed the distribution of month of birth for 81,162 women died of breast cancer and 1,334,650 women died of cancers at all sites, who were reported to the Ministry of Health and Welfare from 1972-90 in Japan. After considering each birth year seasonal variations in month of birth were not shown statistically significant in any age-group through using chi 2 test (df = 11). The negative results were also confirmed in residential area and period category.

Breast Neoplasms↗
PubMed1996

A case-control study of myelodysplastic syndromes among Japanese men and women.

To determine the risk factors of the myelodysplastic syndromes (MDS) we conducted a case-control study in Japan. One hundred and sixteen MDS patients were diagnosed from 1 September to 31 October 1992 and from 1 August to 31 October 1993 in the 32 hospitals enrolled in the idiopathic Disorders of Hematopoietic Organs Research Committee. Age, sex, and hospital-matched controls were selected for each case. Information on cigarette smoking and drinking habits, hair dye use, history of keeping pet animals, and occupational exposures to organic solvents, lead and radiation was obtained from self-administered questionnaires. Conditional logistic regression was applied to this individually matched case-control study and odds ratios (ORs) were computed to estimate association between each exposure variable and risk of MDS. Alcohol drinking was associated with increased risk of MDS (OR = 2.15; 95% confidence interval = 1.12-4.16) and there was a significant trend in risk with increasing amounts of ethanol consumed per week (P < 0.05). We also found elevated ORs for cigarette smokers (OR = 1.80), users of hair dye products (OR = 1.77), and workers exposed to organic solvents (OR = 1.50), although these ratios were not statistically significant. Exposure to pet animals was not associated with risk of MDS. The association observed between alcohol drinking and MDS was still eminent even after adjusted with other variables of cigarette smoking, hair dye use and occupational exposure to organic solvents, and the dose-response relationship was also confirmed.

Adult↗
PubMed1996

Prevalence of hormone replacement therapy and user's characteristics: a community survey in Japan.

OBJECTIVES: It is quite recently that much interest has been paid to the benefits of hormone replacement therapy (HRT) in Japan. We conducted a community survey in Japan in 1992 to examine the prevalence of HRT use and factors related to HRT use. METHODS: A total of 8791 female residents aged 45-64 years old in a city of the Gifu Prefecture, Japan, responded to the questionnaire including medical and reproductive histories, lifetime occupational history, diet, exercise, smoking and drinking habits, and use of vitamin supplements or medications. The response rate was 94.2%. RESULTS: Overall, 2.5% of women reported current use of HRT and 6.3% had used HRT previously. The highest prevalence of current use was found among postmenopausal women with surgical menopause (4.8%). Current users were more likely to have participated in cancer screenings, and to have used vitamin supplements or calcium during the past year. CONCLUSIONS: HRT use rate was 2.5% among female residents aged 45-64 years old in a Japanese community in 1992. Current users may have more regard for their health status.

Climacteric↗
PubMed1996

Decreased serum retinol levels in women with cervical dysplasia.

To examine the relationship of dietary and serum vitamin A to the risk of cervical dysplasia, a case-control study was conducted in Miyagi, Japan. Cases were 137 women who were found by Papanicolaou test screening and histological examination provided by Miyagi Cancer Society between October 1987 and September 1988 to have cervical dysplasia. Controls were selected from participants of the general health examination provided by the Society and individually matched to cases on age and screening date. The consumption of retinol or carotene-rich foods during the past 7 days was assessed at interview. Information was also collected about other risk factors of cervical dysplasia, such as reproductive histories and sexual behaviour. The mean serum retinol levels were significantly lower among cases compared with controls, although dietary intake levels of retinol and carotene were not different between the two groups. When examined by tertile, the risk of cervical dysplasia was significantly higher among women in the highest tertile of dietary vitamin A level. An inverse association was observed between serum retinol level and risk of cervical dysplasia, although it did not achieve statistical significance.

Adolescent↗
PubMed1996

Choice of response scale for health measurement: comparison of 4, 5, and 7-point scales and visual analog scale.

To compare the feasibility of response scales with different numbers of steps for measuring health status, we assessed the ease of completing 4, 5, and 7-point scales and a visual analog scale. Four forms of the questionnaire, each of which consisted of the same ten questions about health status, but with a different type of scale among the four above mentioned, were given to 48 patients with a variety of conditions and diagnoses. The forms were attached together and the order in which they were presented was systematically varied considering permutations of forms. Respondents were asked to complete the forms following the order of the sheets. The 5-point scale form was most commonly chosen as the easiest to complete, and item omission was least frequent with this form. Similar high- reliability results in terms of Cronbach's alpha were achieved for each of the four forms. An additional survey among 153 patients confirmed the results of the first survey. The selection of the easiest scale to complete varied by sex (men preferred the 7-point scale), but was not affected by the conditions or diagnoses of the patients. The study suggests that the 5-point scale is most useful for measuring health status.

Chi-Square Distribution↗
PubMed1995

Effects of menstrual and reproductive factors on the risk of breast cancer: meta-analysis of the case-control studies in Japan.

To elucidate the magnitude of the effect of menstrual and reproductive factors on breast cancer occurrence among Japanese women, we reviewed eight case-control studies previously conducted in Japan and used a quantitative method (meta-analysis) to summarize the data. While individual studies have different methods and populations, the estimated odds ratios (ORs) in the studies were statistically homogeneous for all study variables. It was confirmed that early age at menarche, late age at first birth, and premenopausal status are significantly associated with risk of breast cancer; an estimated combined OR of 0.68 (95% confidence interval (CI): 0.59-0.77) was obtained for women with onset of menstruation after age 16 compared to those before age 14. Nulliparous women had higher risk than women with first birth before age 25 (OR = 1.56 95%, CI: 1.27-1.91). The OR for women with first birth after age 35 was 2.26 (95% CI: 1.85-2.77) compared to women at first birth before age 25. Premenopausal women had a higher risk than women with menopause before age 50 (OR = 2.21, 95% CI: 1.53-3.20). We also found a significant protective effect of high parity after controlling for age at first birth and the other menstrual factors. The OR estimate for 3 or more births compared to nulliparity was 0.68 (95% CI: 0.54-0.86). The meta-analysis provided quantitative estimates of breast cancer risk among Japanese women with improved precision.

Age Factors↗
PubMed1995

Systemic lupus erythematosus: a case-control epidemiologic study in Japan.

BACKGROUND: Systemic lupus erythematosus (SLE) is designated by the Japanese government as one of the intractable diseases and all patients, who suffer from these diseases, are registered to get financial aid for treatment. Using newly registered SLE patients, a case-control study was conducted to evaluate potential risk factors. METHODS: Two-hundred and eighty-two women SLE patients, newly registered to receive financial aid for treatment, and 292 randomly selected health examination participants at public health centers (controls) were surveyed from April 1988 through March 1990. By means of a self-administered questionnaire, data concerning demographic variables, smoking and drinking habits, past medical and reproductive history, and family history were collected. RESULTS: Based on unconditional logistic regression analysis, the risk of SLE was significantly increased for current smokers (age-adjusted odds ratio (OR) = 2.31, 95% confidence interval (CI) 1.34-3.97). Alcohol and milk intake were inversely associated with risk. Family histories of asthma and collagen diseases, including SLE, were associated with significantly elevated risk of SLE (OR = 2.07, 95% CI 1.14-3.77; OR = 5.20, 95% CI 1.08-24.95, respectively). Regarding reproductive function, women with menarche at age 15 or later had significantly higher risk than those, who started menstruating before age 12 (OR = 3.82, 95% CI 1.66-8.81 for menarche at > 15 years and OR = 2.90, 95% CI 1.14-7.39 for menarche at > or = 16y). CONCLUSIONS: Our study suggests several risk factors, including smoking, family history, and reproductive history that may increase the risk of SLE.

Adolescent↗