Naoyoshi Takatsuka

Sodium Intake and Risk of Death From Stroke in Japanese Men and Women

Background and Purpose— Despite the evidence for a positive association of dietary salt and blood pressure, the few prospective studies that have assessed the association between dietary salt and stroke have reported inconsistent results. The purpose of this study was to examine the relation between sodium intake and death from stroke in a population-based cohort of Japanese men and women. Methods— In 1992, usual diet including sodium intake was determined in 13 355 men and 15 724 women in Takayama City, Gifu, with the use of a validated food frequency questionnaire. Results— There were 269 stroke deaths (137 men and 132 women) between baseline and 1999. In men, the highest compared with the lowest tertile of sodium intake was significantly positively associated with death from total stroke after controlling for covariates (hazard ratio [HR]), 2.33; 95% CI, 1.23 to 4.45). Significantly positive associations were also observed between sodium intake and death from ischemic stroke (HR, 3.22; 95% CI, 1.22 to 8.53) as well as death from intracerebral hemorrhage (HR, 3.85; 95% CI, 1.16 to 12.7). A positive association between sodium intake and death from stroke in women was suggested, although the associations for total stroke and ischemic stroke were of borderline significance (HR, 1.70; 95% CI, 0.96 to 3.02 and HR, 2.10; 95% CI, 0.96 to 4.62, respectively). Conclusions— These prospective data support the hypothesis that dietary salt increases the risk of death from stroke.

Overtime, psychosocial working conditions, and occurrence of non-insulin dependent diabetes mellitus in Japanese men.

OBJECTIVES: To ascertain the effects of overtime and psychosocial job conditions on the occurrence of non-insulin dependent diabetes mellitus (NIDDM) in Japan. DESIGN: An eight year prospective cohort study. SETTING: An electrical company in Japan. PARTICIPANTS: In 1984, a mailed questionnaire was sent to industrial workers of an electrical company in Japan. After excluding those who had a history of diabetes mellitus or other chronic diseases, 2597 male respondents were prospectively followed up for the succeeding eight years. Data from 2194 (84%) who were completely followed up were analysed. The occurrence of NIDDM during the follow up period was assessed according to the WHO criteria on the basis of an annual screening programme. MAIN RESULTS: The age adjusted incidence of NIDDM was significantly higher in those who worked overtime more than 50 hours per month than in those who worked 25 hours or less per month (p < 0.05). It was significantly higher in those who worked with new technology at baseline than in those who did not (p < 0.05). Coxs proportional hazard model indicated that those who worked overtime more than 50 hours per month had 3.7 times higher risk of NIDDM after controlling for known risk factors (p < 0.01) and those who worked with new technology had 2.4 times higher risk of NIDDM (p < 0.05). CONCLUSIONS: It is suggested that longer overtime and use of new technology are risk factors of NIDDM in Japanese men.

Development of a screening questionnaire for tobacco/nicotine dependence according to ICD-10, DSM-III-R, and DSM-IV.

A 10-item questionnaire (the Tobacco Dependence Screener; TDS) for screening of tobacco/nicotine dependence according to ICD-10, DSM-III-R, and DSM-IV was newly developed. The reliability and validity were assessed in three samples of smokers in Japan. A total of 58 male smokers completed the TDS and the Fagerstrom Tolerance Questionnaire (FTQ), and they were interviewed using the World Health Organizations Composite International Diagnostic Interview (Sample 1). A total of 118 male and 36 female smoking outpatients completed the TDS and the FTQ and provided a breath sample for carbon monoxide measurement (Sample 2). A total of 194 male smokers joined a health education program using a health risk appraisal (HRA) and reported their smoking status and completed the TDS 6 months after receiving the HRA results (Sample 3). The Cronbachs alpha coefficients for the TDS ranged from .74 to .81 among the samples, whereas those for the FTQ ranged from .41 to .64. Receiver operator characteristic analyses indicated that the TDS had a better screening performance for ICD-10, DSM-III-R, and DSM-IV diagnoses than did the FFQ. The TDS score significantly and positively correlated with the severity of the diagnoses, the carbon monoxide levels, number of cigarettes smoked per day, and years of smoking. The TDS score was significantly lower in those who quit smoking than in those who did not quit smoking after the HRA. It is suggested that the TDS is a reliable and useful screening questionnaire for tobacco/nicotine dependence according to ICD-10, DSM-III-R, and DSM-IV.

Consumption of coffee, green tea, oolong tea, black tea, chocolate snacks and the caffeine content in relation to risk of diabetes in Japanese men and women

Although the inverse association between coffee consumption and risk of diabetes has been reported numerous times, the role of caffeine intake in this association has remained unclear. We evaluated the consumption of coffee and other beverages and food containing caffeine in relation to the incidence of diabetes. The study participants were 5897 men and 7643 women in a community-based cohort in Takayama, Japan. Consumption of coffee, green tea, oolong tea, black tea and chocolate snacks were measured with a semi-quantitative FFQ in 1992. At the follow-up survey in 2002, the development of diabetes and the time of diagnosis were reported. To assess the association, age, smoking status, BMI, physical activity, education in years, alcohol consumption, total energy intake, fat intake and womens menopausal status were adjusted. Among men who consumed one cup per month to six cups per week and among those who consumed one cup per d or more, the associated hazard ratios were 0.69 (95 % CI 0.50, 0.97) and 0.69 (95 % CI 0.49, 0.98) compared with those who drank little to no coffee, with a P value for trend of 0.32. The hazard ratios for women with the same coffee consumption patterns were 1.08 (95 % CI 0.74, 1.60) and 0.70 (95 % CI 0.44, 1.12), with a P value for trend of 0.03. The association between estimated total caffeine intake and risk of diabetes was insignificant both among men and among women. The results imply that coffee consumption decreased the risk of developing diabetes. The protective effect may exist aside from the influence of caffeine intake.

A prospective cohort study of soy product intake and stomach cancer death

The relationship between intake of soy products and death from stomach cancer was examined in a community-based prospective study of Japanese men and women in Takayama, Japan. Over 7 years of follow-up, 121 deaths from stomach cancer (81 men and 40 women) occurred among 30 304 (13 880 men and 16 424 women) participants who were at least 35 years of age. Diet including the intake of soy products and isoflavones was assessed by a validated semiquantitative food–frequency questionnaire at the beginning of the study. In men, the highest compared to the lowest tertile of total soy product intake was significantly inversely associated with death from stomach cancer after controlling for covariates (hazard ratios=0.50; 95% confidence intervals (CIs) 0.26-0.93, P for trend=0.03). Decreased hazard ratios for the highest compared to the lowest tertiles of total soy product intake (hazard ratios=0.49; 95% CI 0.22–1.13) was observed in women, although this association was of marginal significance. These data suggest that soy intake may reduce the risk of death from stomach cancer.

Association of diet and other lifestyle with onset of menopause in Japanese women

OBJECTIVES To evaluate the cross-sectional relationships of dietary and other lifestyle variables to menopause. METHODS A total of 4186 female residents aged 45-55 in Takayama City, Japan, responded to a self-administered questionnaire (the response rate was 89.3%). Diet in the past year was assessed by semiquantitative food frequency questionnaire. Using the logistic regression model, associations between study variables and menopausal status were estimated in terms of odds ratio (OR). RESULTS Nulliparity and lower relative weight were significantly associated with menopause after controlling for age (P < 0.05). The association of smoking with menopause was marginally significant after controlling for age (P = 0.06). Higher intakes of fat, cholesterol, and coffee were inversely and significantly associated with later menopause after controlling for age, total energy, parity, menarche age, and relative weight (ORs for the highest tertiles of fat, cholesterol and coffee intakes were 0.78, 0.79, and 0.70, respectively, P < 0.05). The highest tertiles of calcium and soy product intakes were significantly associated with menopause after controlling for the covariates (ORs = 1.25 and 1.42, respectively, P < 0.05), but postmenopausal women who had menopause at later age showed higher calcium intake than those who had menopause at early age. CONCLUSION Dietary factors appear to be associated with onset of menopause.

Dietary glycemic index, glycemic load, and intake of carbohydrate and rice in relation to risk of mortality from stroke and its subtypes in Japanese men and women

We assessed the relationship of the dietary glycemic index (GI), glycemic load (GL), and intake of carbohydrate and rice, and risk of mortality from stroke and its subtypes. The cohort consisted of 12,561 men and 15,301 women residing in Takayama, Japan, in 1992. At the baseline, a food frequency questionnaire was administered; and the dietary GI, GL, and intake of carbohydrates and rice were estimated. Deaths from stroke occurring in the cohort were prospectively noted until 1999 with data from the office of the National Vital Statistics. The risk of mortality from stroke was assessed with a Cox proportional hazard model after adjusting for age; body mass index; smoking status; physical activity; history of hypertension; education; and intake of total energy, alcohol, dietary fiber, salt, and total fat. The risk of stroke subtypes was assessed in the age-adjusted model. The hazard ratios of total stroke comparing the highest vs the lowest quartiles of the dietary GI were 0.78 (95% confidence interval [CI], 0.41-1.47) with P(trend) = .50 in men and 2.09 (95% CI, 1.01-4.31) with P(trend) = .10 in women. Among women, the association was also significant with the risk of ischemic stroke (hazard ratio = 2.45; 95% CI, 1.01-5.92; P(trend) = .03); and a significant positive trend was also observed between dietary GL and mortality from hemorrhagic stroke (P(trend) = .05). The current study implies that diets with a high dietary GI increase the risk of mortality from stroke among Japanese women.

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 for 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.

Predicting the progression of cervical precursor lesions by human papillomavirus genotyping: A prospective cohort study

Only a subset of cervical precursor lesions progress to cervical cancer and because of the lack of the predictive markers, it cannot be ascertained which lesions will progress or not. To estimate the risk of disease progression associated with human papillomavirus (HPV) genotypes, we followed 570 Japanese women with cytological LSIL (low‐grade squamous intraepithelial lesion) and histological CIN (cervical intraepithelial neoplasia) grade 1–2 lesions (479 CIN 1; 91 CIN 2) at 3 to 4 month intervals for a mean follow‐up period of 39.1 months. At entry, we detected HPV DNA in cervical samples by polymerase chain reaction‐based methodology. Over the period of follow‐up period, 46 lesions progressed to CIN 3 while 362 regressed to normal cytology. Women with multiple HPV infections were more likely to have persistent lesions (hazard ratio [HR] for regression, 0.65; 95% confidence interval [CI], 0.42–1.02; p = 0.07); however, multiple infections did not increase the risk of progression (HR for progression, 1.04; 95% CI, 0.37–2.94; p = 0.94). After adjusting for CIN grade and womens age, HRs for progression to CIN 3 (vs. women with low‐risk types or negative for HPV DNA) varied markedly by HPV genotype: type 16 (11.1, 95% CI: 1.39–88.3); 18 (14.1, 0.65–306); 31 (24.7, 2.51–243); 33 (20.3, 1.78–231); 35 (13.7, 0.75–251); 52 (11.6, 1.45–93.3); 58 (8.85, 1.01–77.6); other high‐risk types (4.04, 0.47–34.7). HPV 45 was not detected in our study subjects. The cumulative probability of CIN 3 within 5 years was 20.5% for HPV 16, 18, 31, 33, 35, 52 and 58; 6.0% for other high‐risk types; 1.7% for low‐risk types (p = 0.0001). In conclusion, type‐specific HPV testing for women with LSIL/CIN 1–2 lesions is useful for identifying populations at increased or decreased risk of disease progression.

Cigarette smoking and other lifestyle factors in relation to the risk of pancreatic cancer death: a prospective cohort study in Japan.

OBJECTIVE To examine the association of smoking and lifestyle factors with pancreatic cancer death in the prospective design. METHODS Mortality from pancreatic cancer in regard to smoking, body mass index, physical activity, and alcohol, coffee and green tea intake, was studied in a prospective cohort of 30,826 inhabitants in Takayama, Japan. In 1992, each subject completed a self-administered questionnaire on demographic information, smoking, drinking habits, diet, exercise and medical histories. The response rate was 85.3%. RESULTS From 1992 to 1999, 33 men and 19 women died due to pancreatic cancer. Hazard ratios and 95% confidence intervals were determined using Cox proportional hazards models. Women who were defined as current smokers at baseline had significant and increased risk of pancreatic cancer death after adjustment for age, body mass index and history of diabetes mellitus (Hazard ratio: 4.77, 95% confidence intervals: 1.58-14.4). There were significant positive associations of pancreatic cancer death with the years of smoking and the number of cigarettes consumed daily in women in a dose-dependent manner. Current smokers indicated a non-significant risk increase in men (Hazard ratio: 3.81, 95% confidence intervals: 0.88-16.6). Body mass index, physical activity, and alcohol, coffee and green tea intake were not significantly associated with pancreatic cancer death. CONCLUSIONS These data suggested that smoking increases the risk of death from pancreatic cancer in Japanese women.