Psychological attitudes and risk of breast cancer in Japan: a prospective study

OBJECTIVE

To examine the association between psychological factors and the risk of breast cancer prospectively in a non-Western population.

METHODS

Data from the Japan Collaborative Cohort (JACC) study were analyzed. From 1988 to 1990, 34,497 women aged 40-79 years completed a questionnaire on medical, lifestyle and psychosocial factors. The rate ratios (RRs) of their responses were computed by fitting to proportional hazards models.

RESULTS

During the mean follow-up period of 7.5 years, 149 breast cancer cases were documented. Those individuals who possessed "ikigai" (Japanese term meaning something that made one's life worth living) showed a significantly lower risk of breast cancer (multivariate-adjusted RR=0.66; 95% confidence interval [CI]=0.47-0.94). Those who perceived themselves as able to make decisions quickly also had a lower risk of breast cancer (multivariate-adjusted RR=0.56; 95% CI=0.36-0.87). The other factors investigated, including ease of anger arousal and self-perceived stress of daily life were not associated with breast cancer risk.

CONCLUSIONS

Although further studies will be necessary to verify these findings, our results suggest that having "ikigai" and being decisive decrease an individual's subsequent risk of breast cancer.

Lung cancer mortality and body mass index in a Japanese cohort: findings from the Japan Collaborative Cohort Study (JACC Study)

OBJECTIVE

To determine the relationship of body mass index (BMI) and BMI changes during adulthood to lung cancer mortality in a large-sized Japanese cohort.

METHODS

We followed 29,350 men for a maximum of 11 years in the Japan Collaborative Cohort Study for Evaluation of Cancer Risk (JACC Study), which was initiated from 1988 to 1990. Complementary log-log modeling was employed with age, smoking status, and family history of lung cancer as covariates. Anthropometric measurements used were BMI at baseline, BMI around age 20, and adulthood BMI loss defined between the two measurements. Independent effects of these three measurements on lung cancer mortality were evaluated by applying the method of generalized estimation equations to the model for adjustment of intra-individual correlation.

RESULTS

Never smokers showed that high BMI both at baseline and around age 20 significantly predict lung cancer mortality (P < 0.05). Adulthood BMI loss significantly (P < 0.05) elevated the risk for lung cancer mortality among current smokers, implying their enhanced vulnerability to lung cancer risk among smokers.

CONCLUSIONS

The risk for lung cancer mortality is elevated by a mechanism related to smoking-induced weight loss during adulthood.

High-Sensitivity C-Reactive Protein is Quite Low in Japanese Men at High Coronary Risk

BACKGROUND

Although numerous studies have demonstrated a positive association of high-sensitivity C-reactive protein (CRP) with the incidence of coronary heart disease (CHD), little information exists regarding this issue in Japanese.

METHODS AND RESULTS

The association between CRP and the Framingham Risk Score (FRS) was investigated in 2,523 middle-aged Japanese men without a medical history of CHD. CRP was significantly associated with this score obtained from all FRS factors. After dividing subjects into 4 categories of relative risk estimate for CHD, the geometric mean of CRP (mg/L) increased gradually with the CHD risk (below average: 0.39 [95% confidence interval, 0.37-0.41], average: 0.58 [0.50-0.67], moderately above average: 0.70 [0.57-0.86], high: 0.79 [0.58-1.09], trend p<0.001). However, it should be noted that the mean CRP concentration of the high-risk group was only 0.79 mg/L and a greater proportion (63.8%) of the high-risk subjects was in the low-risk range of CRP (<1 mg/L).

CONCLUSIONS

Circulating CRP well reflect the estimated CHD risk, indicating that CRP may be useful for coronary risk stratification in Japanese also. However, the details of the CRP level in Japanese must be investigated further by prospective studies to determine the Japanese-specific cutoff points for CHD risk evaluation.

White Blood Cell Count and Risk of All-Cause and Cardiovascular Mortality in Nationwide Sample of Japanese Results From the NIPPON DATA90

BACKGROUND

The association of white blood cell (WBC) count with all-cause and cardiovascular disease (CVD) mortality were examined in the National Integrated Project for Prospective Observation of Non-communicable Disease and Its Trends in the Aged (NIPPON DATA) 90.

METHODS AND RESULTS

A total of 6,756 Japanese residents (2,773 men and 3,983 women) throughout Japan without a history of CVD were followed for 9.6 years. A Cox proportional hazards regression model was used to estimate the relative risk (RR) and 95% confidence interval (CI). We documented 576 deaths with 161 deaths from CVD. Overall, after adjusting for several confounders including age, sex, body mass index at baseline, smoking status, alcohol consumption, regular exercise, diastlic blood pressure, total cholesterol, high-density lipoprotein-cholesterol and hemoglobin A1c, a graded association between WBC count and higher risk of all-cause mortality was observed (WBC of 9,000-10,000 cells/mm(3) vs WBC of 4,000-4,900: RR =1.61, 95% CI: 1.07-2.40, p for trend =0.02). Elevated WBC count was almost significantly associated with high risk of CVD mortality (WBC of 9,000-10,000 vs WBC of 4,000-4,900: RR =1.79, 95% CI: 0.97-3.71). These associations strengthened among women. Stratified by smoking status, never-smokers with WBC counts of 9,000-10,000 had a 3.2 fold elevated risk for CVD death compared with those with WBC counts of 4,000-4,900.

CONCLUSIONS

The WBC count may have potential as a predictor for all-cause mortality, particularly CVD mortality.

The transition to menopause reinforces adiponectin production and its contribution to improvement of insulin-resistant state

OBJECTIVE

To evaluate the influence of menopausal status on the serum adiponectin concentration and investigate whether the contribution of adiponectin to insulin resistance is modified by menopausal status.

SUBJECTS

We conducted a population-based, cross-sectional study of 207 premenopausal and 206 postmenopausal Japanese women.

MEASUREMENTS

Data on anthropometric characteristics, fasting serum adiponectin, glucose and insulin concentrations were used. Insulin resistance (homeostasis model assessment of insulin resistance: HOMA-IR) was calculated.

RESULTS

Postmenopausal women had significantly higher HOMA-IRs than premenopausal women [1.50 (1.42, 1.59) vs 1.18 (1.12, 1.24), geometric mean (1 standard error range), P = 0.005]. Paradoxically, adiponectin levels in postmenopausal women were also significantly higher than those in premenopausal women [10.3 (9.95, 10.7) vs 9.04 (8.71, 9.39), P = 0.028]. Multiple regression analysis showed that body mass index (BMI) was the only significantly independent predictor [standardized partial regression coefficients (sbeta) = 0.319, P < 0.001] for HOMA-IR among premenopausal women, whereas both BMI and adiponectin were the significant predictors among postmenopausal (sbeta = 0.334 and -0.141, P < 0.001 and < 0.05, respectively). When the subjects were restricted to those without metabolic disorders including high blood pressure, hypertriglyceridaemia, hypo-HDL cholesterolaemia and high fasting glucose, adiponectin (sbeta = -0.249, P < 0.05) was the only significant predictor for HOMA-IR among postmenopausal women but BMI was not significant (sbeta = 0.223, P = 0.075).

CONCLUSIONS

The transition to menopause increases serum adiponectin concentrations. And the significant and negative association between adiponectin and HOMA-IR was observed only after menopause. Therefore, adiponectin may play a role in the improvement of an incipient insulin-resistant state after, rather than before, menopause.

Determinants of self-rated health: Could health status explain the association between self-rated health and mortality?

The purpose of this study was to investigate factors related to self-rated health and to mortality among 2490 community-living elderly. Respondents were followed for 7.3 years for all-cause mortality. To compare the relative impact of each variable, we employed logistic regression analysis for self-rated health and Cox hazard analysis for mortality. Cox analysis stratified by gender, follow-up periods, age group, and functional status was also employed. Series of analysis found that factors associated with self-rated health and with mortality were not identical. Psychological factors such as perceived isolation at home or 'ikigai (one aspect of psychological well-being)' were associated with self-rated health only. Age, functional status, and social relations were associated both with self-rated health and mortality after controlling for possible confounders. Illnesses and functional status accounted for 35-40% of variances in the fair/poor self-rated health. Differences by gender and functional status were observed in the factors related to self-rated health. Overall, self-rated health effect on mortality was stronger for people with no functional impairment, for shorter follow-up period, and for young-old age group. Although, illnesses and functional status were major determinants of self-rated health, economical, psychological, and social factors were also related to self-rated health.

Perceived psychological stress and serum leptin concentrations in Japanese men

OBJECTIVE

To examine epidemiologically whether subjects with higher stress perception levels have higher leptin concentrations.

RESEARCH METHODS AND PROCEDURES

In this cross-sectional study, the study population comprised 1062 male workers at local government offices in central Japan. Self-administered questionnaires were distributed in 1997. Awareness of stress was assessed by the question: "Do you have much stress in your life?" and participants were asked to select from four possible responses: "very much," "much," "ordinary," or "little." Blood samples were also collected after fasting 12 hours overnight to determine serum leptin concentrations.

RESULTS

The mean (standard deviation) age and BMI were 50.2 (6.4) years and 23.3 (2.6) kg/m(2), respectively. Crude leptin concentrations according to stress categories were 2.86, 3.26, 3.32, and 3.54 ng/mL, respectively, and leptin concentrations adjusted for age, BMI, physical activity, drinking and smoking habits, overtime work, shift work, sleep duration, and availability of confidants were 2.96, 3.24, 3.34, and 3.43 ng/mL for "little," "ordinary," "much," and "very much," respectively (p = 0.03 by one-way analysis of covariance; p < 0.01 by test of linear trend). Significant associations were also observed among the level of perceived psychological stress and work-related stressors, variables related to sleep, and other psychological variables.

DISCUSSION

This study showed that subjects who perceived psychological stress had high leptin levels, which provides epidemiological evidence that psychological stress may have the potential effect of increasing blood levels of the pleiotropic peptide, leptin.

Factors associated with life space among community-living rural elders in Japan

OBJECTIVE

The study objective was to identify factors associated with life space to examine the service needs of the elderly. Cross-sectional study.

SAMPLE

2,409 community-living elderly in a rural town in Japan.

MEASUREMENTS

Daily activity level was used as a proxy for life space. Respondents were asked about their daily activity, health status, and psychosocial factors in a self-administered questionnaire. Factors associated with life space were identified using general linear models. Relative associations of each factor with life space were tested using stepwise multiple regression procedure.

RESULTS

Elderly in a smaller life space were significantly older, had more illnesses, worse activities of daily living (ADL), and poor self-rated health. Poor psychological well-being and fewer social relations were also associated with a smaller life space. Age and ADL difficulty accounted for 51.7% of life space variations. In addition, more elderly with ADL difficulty expressed unmet needs for transportation and socializing opportunities.

CONCLUSIONS

Life space was related not only to age or health status but also to environmental or psychosocial factors. Appropriate services for a vulnerable population may have a positive effect on elderly health. Moreover, elderly life space may be used as an indicator to identify people at risk in order to provide more effective community-based programs for the elderly.

Eating fast leads to obesity: findings based on self-administered questionnaires among middle-aged Japanese men and women

BACKGROUND

Few epidemiologic studies have examined the association between the rate of eating and obesity. In this study, we cross-sectionally examined the association of the self-reported rate of eating with current Body Mass Index (BMI), and BMI-change from 20 years of age to the current age.

METHODS

Subjects were 3737 male (mean age +/- standard deviation and mean BMI +/- standard deviation: 48.2 +/- 7.1 years and 23.3 +/- 2.7 kg/m(2)) and 1005 female (46.3 +/- 7.0 years and 21.8 +/- 2.8 kg/m(2)) Japanese civil servants. We measured self-reported categorical rate of eating, current BMI, BMI at age 20, and BMI-change from age 20. Energy intake was assessed over a 1-month period with a brief-type diet history questionnaire.

RESULTS

The multiple regression analysis in which the current BMI was regressed by categorical rate of eating, energy intake, age, and lifestyle factors showed that current BMI steadily increased by -0.99, -0.67, 0.81, and 1.47 kg/m(2) along with the progress of categorical rate of eating from the 'medium' group to 'very slow', 'relatively slow', 'relatively fast', and 'very fast' groups, respectively, in men. In women, the corresponding values were -1.06, -0.35, 0.50, and 1.34 kg/m(2). When the BMI increment from age 20 to current age was regressed in the same manner, the increment was -0.63, -0.34, 0.57, and 1.05 kg/m(2) in men and -0.71, -0.32, 0.34, and 1.14 kg/m(2) in women, respectively. Additionally, both BMI at age 20 and current height were positively associated with rate of eating.

CONCLUSIONS

Our results among middle-aged men and women suggest that eating fast would lead to obesity.

Factors related to frequency of engaging in outside activities among elderly persons living an independent life at home

We examined by cross-sectional design the association between the frequency of outside activity and the demographic, health problem, lifestyle, psychosocial and environmental factors among 239 community-dwelling elderly Japanese people (105 men and 134 women) aged 65 years and older, who lived independently at home. The associations of the outside activities more than 6-7 days per week based on a categorical questionnaire choice with potential factors were expressed by odds ratio (OR) and 95% confidence interval (CI) calculated through logistic regression analysis by sex. The proportions of those engaging in outside activity more than 6-7 days per week were 38.1% and 21.6% among men and women, respectively. The associations of the factors belonging to various fields with the frequency of engaging in outside activities were clearly pronounced among men. Elderly men engaging in outside activities more often were scored less for depression and more socially active than men engaging in outside activities less often. Multiple regression analysis revealed meeting and talking often with friend (OR=4.18, 95% CI: 1.06-16.5), current alcohol consumption (3.01, 1.06-8.54), having any hobby (3.59, 0.94-13.7), and easy access to public transportation (3.43, 1.28-9.16) as significant or borderline significant factors related to engaging in outside activities more than 6-7 days per week. Women who were currently employed engaged in outside activities more frequently. The frequency of engaging in outside activities was associated with factors belonging to various fields among elderly people living independently, particularly among men, suggesting its usefulness as an indicator of comprehensive well-being.

Association between parental histories of hypertension, diabetes and dyslipidemia and the clustering of these disorders in offspring

BACKGROUND

Familial aggregation of hypertension, diabetes and dyslipidemia has been well reported. However, only a few studies have assessed to what extent parental histories were involved in the clustering of these diseases.

METHOD

In 2002, associations between parental histories of hypertension, diabetes and dyslipidemia and the clustering of high blood pressure, hyperglycemia and dyslipidemia in individuals were assessed on the basis of 5010 Japanese men and women aged 33-66 years. Risk factor clusters were defined as those having at least two of the three clinical disorders.

RESULTS

Compared with persons with no parental history of the three diseases, those who had 1, 2 and 3 or more parental histories had risk factor clusters, 1.25 (95% CI: 1.07, 1.47), 1.46 (95% CI: 1.16, 1.84) and 1.41 (95% CI: 0.95, 2.11) times higher, respectively, after adjusting for confounding factors. ORs by 1, 2 and 3 of maternal history were 1.33 (95% CI: 1.12, 1.58), 1.65 (95% CI: 1.16, 2.35) and 1.69 (95% CI: 0.64, 4.42), respectively (trend P < 0.001). However, the number of paternal history was not associated with risk factor clusters.

CONCLUSION

We conclude that familial history, particularly maternal history, is an important aid to prevention strategy and public health practice for metabolic disorders.

Plasma fibrinogen levels and cardiovascular risk factors in Japanese schoolchildren

BACKGROUND

Plasma fibrinogen level has been recognized as an independent risk factor for atherosclerosis and its thrombotic complications in adults. The present study aimed to clarify the association between plasma fibrinogen levels and cardiovascular risk factors in Japanese children.

METHODS

A total of 294 schoolchildren (145 boys and 149 girls) aged 10-13 years in a town in Nagano Prefecture, Japan, were surveyed in 2000 for body mass index (BMI), plasma fibrinogen, serum C-reactive protein (CRP), serum total cholesterol, serum high-density lipoprotein (HDL) cholesterol, hemoglobin (Hb) A1c, and ratio of serum total cholesterol to serum HDL cholesterol (TCHR).

RESULTS

The mean value and standard deviation of plasma fibrinogen level among the schoolchildren was 226.0+/-39.7 mg/dL for boys and 245.3+/-40.9 mg/dL for girls; significantly higher for girls. Among plasma fibrinogen tertiles, serum CRP tended to increase with plasma fibrinogen in both boys and girls. An increasing trend was also found in serum total cholesterol in boys, and in TCHR, HbA1c and BMI in girls. Multiple linear regression analysis revealed significant associations of plasma fibrinogen with serum CRP and HbA1c in both sexes, with TCHR in boys, and with BMI in girls.

CONCLUSIONS

Plasma fibrinogen levels were associated with cardiovascular risk factors such as serum CRP, TCHR, HbA1c, and BMI in Japanese schoolchildren.

Comparison of Circulating Adiponectin and Proinflammatory Markers Regarding Their Association With Metabolic Syndrome in Japanese Men

BACKGROUND

Anti-inflammatory and proinflammatory molecules purportedly play an important role in developing metabolic syndrome (MetS). However, little is known as to the relative importance of these molecules in the association with MetS.

METHODS AND RESULTS

We studied 624 middle-aged Japanese men without medical history of cardiovascular disease or cancer and investigated the associations of circulating tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), C-reactive protein (CRP), and adiponectin with MetS. We used the respective definitions proposed by the National Cholesterol Education Program Adult Treatment Panel III (ATP-III), the International Diabetes Federation, and the Japanese Society of Internal Medicine. Decreased serum adiponectin was observed in those with any of the ATP-III-MetS components, whereas this was not the case with increased TNF-alpha, IL-6, or CRP. Adiponectin and CRP levels linearly deteriorated with an increasing number of ATP-III-MetS components (trend P<0.001, respectively). Significantly higher CRP and lower adiponectin levels were observed in those who met any MetS criteria, whereas increased TNF-alpha was observed in only those with ATP-III-MetS. Finally, odds ratios (ORs) for MetS prevalence of a 1-SD increase/decrease in log-transformed 4 markers were calculated with multivariate logistic regression analyses. Consequently, decreased adiponectin was associated most strongly with ATP-III-MetS (adiponectin: OR, 1.90 [95% CI, 1.44 to 2.51]; P<0.001; CRP: OR, 1.33 [95% CI, 1.01 to 1.74]; P=0.03; TNF-alpha: OR, 1.25 [95% CI, 0.94 to 1.67]; P=0.12; and IL-6: OR, 0.87 [95% CI, 0.63 to 1.19]; P=0.37). This result was not altered by using the other 2 criteria.

CONCLUSIONS

The present results raise the possibility that decreased serum adiponectin might be fundamentally involved in the development of MetS.

[Epidemiology of acute coronary syndrome]

We reviewed epidemiological findings of acute coronary syndrome (ACS) in Japan. Japan has the lowest mortality and morbidity of ACS in the world. However, the crude mortality of acute myocardial infarction in 2003 increased approximately as twice as that in 1970, most likely due to an aging of population. More importantly, several Japanese prospective studies have failed to demonstrate the decline of the age-adjusted incidence of ACS despite the obvious reduction of ACS incidence caused by the intervention to the risk factors. Particularly, one study implied the increase of ACS patients aged more than 80. Given that the prevalence of dyslipidemia, diabetes, and obesity has increased in Japan, we should endeavor to modify these risk factors, especially in the elderly.

Low birth weight is associated with reduced adiponectin concentration in adult

PURPOSE

Low birth weight has been associated with metabolic and vascular diseases, but the precise mechanism is debated. Adiponectin is one of the key molecules in metabolic disease, and a decrease in level precedes the onset of type 2 diabetes and development of atherosclerosis. Our aim is to examine whether low birth weight is associated with adiponectin concentration in adult.

METHODS

We conducted a population-based cross-sectional study of 2277 subjects (1661 men and 616 women) aged 35 to 66 years who had their self-reported birth weights and adiponectin concentrations measured as adults.

RESULTS

After adjusting for potential confounders, including age, sex, current body mass index (BMI), smoking status, alcohol consumption, and exercise, geometric mean adiponectin levels were 6.63, 6.45, 6.86, 7.05, 6.75, and 7.22 microg/mL for subjects with birth weights less than 2500, 2500 to less than 2800, 2800 to less than 3000, 3000 to less than 3200, 3200 to less than 3500, and greater than 3500 g, respectively. A positive association was found between birth weight and adiponectin concentration (trend p = 0.002). Stratified by current BMI of 25 kg/m2, a positive association was not observed for subjects with a BMI less than 25 kg/m2, but was pronounced in those with a BMI of 25 kg/m2 or greater.

CONCLUSION

This study indicates that low birth weight contributes to decreased adiponectin concentrations in adult life independently of current BMI, especially for obese subjects.

Validity of self-reported height and weight in a Japanese workplace population

OBJECTIVE

To assess the validity of self-reported height and weight in a Japanese workplace population, and to examine factors associated with the validity of self-reported weight.

DESIGN

Comparison of self-reported height and weight with independent measurement.

SUBJECTS

In total, 4253 men and 1148 women aged 35-64 y (mean measured body mass index (BMI): 23.3 kg/m(2) in men, 21.9 kg/m(2) in women) were included in the study.

MEASUREMENTS

Self-reported height and weight were obtained by a self-administered questionnaire. Measured height and weight were based on annual health checkups. Sex, age, measured BMI, and the presence of hypertension, diabetes, and hyperlipidemia were examined as potential factors associated with the accuracy of self-reported weight.

RESULTS

Self-reported height and weight were highly correlated with measured height and weight for men and women (Pearson's r for men and women: 0.979 and 0.988 in height, 0.961 and 0.959 in weight, 0.943 and 0.950 in BMI, respectively). For men, mean differences+/-2 s.d. of height and weight were 0.078+/-2.324 cm and -0.034+/-5.012 kg, respectively, and for women 0.029+/-1.652 cm and 0.024+/-4.192 kg, respectively. The prevalence of obesity with BMI > or =25 kg/m(2) based on self-reported data (23.6 and 11.5% for men and women, respectively) was slightly smaller than that based on measured data (24.9 and 12.4%, respectively). Specificity and sensitivity, however, were quite high for both men and women (sensitivity was 85.8 and 85.2%, and specificity was 97.0 and 98.9%, respectively). The subjects with higher measured BMI significantly underestimated their weight compared with those with smaller BMI after adjustments for age in men and women. Furthermore, the presence of diabetes in men and age in women affected self-reported weight. Neither the presence of hypertension nor hyperlipidemia was associated with reporting bias.

CONCLUSION

The self-reported height and weight were generally reliable in the middle-aged employed Japanese men and women. However, it should be remembered that self-reported weight was biased by actual BMI and affected by age and the presence of diabetes.

Methods for myometrium closure and other factors impacting effects on cesarean section scars of the uterine segment detected by the ultrasonography

OBJECTIVE

Ultrasound examination is an objective method for assessment of uterine scar defects. The present study was conducted to compare single-layer interrupted sutures (Group A) with double-layer interrupted sutures (Group B) and our new method (Group C) as well as other perioperative parameters in relation to risk of wedge defects in scars.

METHODS

We have introduced a new myometrium closure procedure consisting of continuous suture with decidual closure followed by interrupted myometrium suture. In this prospective study, women undergoing cesarean operation (n = 137) were examined by transvaginal ultrasound one month after surgery to assess the appearance of lower uterine scars. Multivariate logistic regression analysis was performed to identify associations of perioperative parameters and methods for lower myometrium closure with abnormal wedge formation.

RESULTS

Wedge defects were observed in a total of 27 patients (19.7%). The analysis revealed Groups B and C to have reduced risks with odds ratios of 0.28 and 0.077, respectively, as compared to Group A. Furthermore, increasing gestational week at delivery, plural fetal pregnancies, premature rupture of membranes and pre-eclampsia were also linked with an increased risk, with odds ratios of 1.4-8.9.

CONCLUSION

The incidence of uterine scar defects 1 month after cesarean sections varies with the method applied for myometrial suture and perioperative variables. The data suggest that methods for myometrium closure as well as other factors influence the condition of myometrial healing.

Birth Weight and Adult Hypertension Cross-Sectional Study in a Japanese Workplace Population

BACKGROUND

Low birth weight has been associated with adult hypertension in several Western populations. This association needs to be evaluated in Japanese people.

METHODS AND RESULTS

A population-based cross-sectional study of 3,107 subjects (2,303 males and 804 females) aged 35-66 years was conducted. The participants responded to a questionnaire about their birth weights, blood pressure, medical history, parental history, and lifestyle factors. Hypertension was defined as systolic blood pressure > or =140 mmHg and/or diastolic blood pressure > or =90 mmHg and/or under treatment by anti-hypertensives. Multiple logistic regression analysis adjusted for age, sex, body mass index, parental history, and lifestyle revealed the adjusted odds ratios for hypertension were 1.26 (95% confidence interval: 0.88-1.80), 1.00 (reference), 0.89 (0.73-1.08) and 0.70 (0.49-1.00) in subjects in birth weight categories of <2,500 g, 2,500-<3,000 g, 3,000-<3,500 g, 3,500- g, respectively (p-value for trend =0.009). Furthermore, this inverse association was clearly pronounced in normal-weight subjects.

CONCLUSION

Low birth weight was independently associated with adult hypertension in the Japanese workplace population. Our results support the inverse association observed previously in Western populations and suggest that intrauterine environmental insults might lead to permanent changes in the metabolism and structure of the fetal organs influencing the regulation of blood pressure.

A Positive Association between Leptin and Blood Pressure of Normal Range in Japanese Men

The results of previous studies on the relationship between leptin and blood pressure are discordant. We investigated to what extent the serum leptin level was related to blood pressure independent of the degree of insulin resistance. The subjects were 1916 men aged 34-69 years whose mean body mass index (BMI) was 23.0 kg/m2. Blood pressure was regressed by leptin concentrations with adjustments for age, BMI, insulin resistance, triglyceride, high density lipoprotein cholesterol, low density lipoprotein cholesterol, physical activity, drinking habits and smoking status. Leptin was associated with diastolic blood pressure (DBP) (standardized beta: 0.092, p = 0.003), but not with systolic blood pressure (SBP) (standardized beta: 0.035, p = 0.25), although insulin resistance was positively associated with both SBP and DBP (standardized beta: 0.175 for SBP, p < 0.001 and 0.114 for DBP, p < 0.001) among all subjects. After subjects were divided into those with normal blood pressure (SBP <130 mmHg and DBP <85 mmHg) and those with higher blood pressure, leptin was positively and significantly associated with DBP (standardized beta: 0.106, p = 0.012) independent of the degree of insulin resistance, but not with SBP (standardized beta: 0.064, p = 0.13) among subjects in the normal blood pressure range. Among the subjects with higher blood pressure, however, neither the association of leptin with SBP nor that of leptin with DBP was statistically significant. These findings suggest that leptin may maintain and increase arterial tone, resulting in the elevation of DBP only within normal blood pressure range. It is also likely that leptin is a physiological mediator--or at least a marker--of some degree of DBP elevation in obesity.

Inverse association between adiponectin and C-reactive protein in substantially healthy Japanese men

OBJECTIVE

An inverse association between adiponectin and C-reactive protein (CRP) has been shown in certain pathological states including obesity, diabetes, and coronary artery disease, which themselves might have confounded this association. This study investigated the association between adiponectin and CRP among substantially healthy subjects.

METHODS AND RESULTS

A population of 2347 middle-aged Japanese men with no medical history of cardiovascular disease, cancer, diabetes, hypertension, or hyperlipidemia was evaluated. Those with some metabolic syndrome components from serological and anthropometric tests were excluded, leaving 714 men for analysis. Serum adiponectin and CRP were significantly correlated (r = -0.21, P < 0.001). After categorization into quartiles from the lowest to the highest adiponectin concentration (Q1 to Q4), the CRP level was found to be significantly higher in Q1 than in Q2, Q3 and Q4 (0.41 mg/L versus 0.30, 0.25 and 0.24 mg/L, P = 0.043, P < 0.001 and P < 0.001, respectively). These associations remained significant even after adjustment for covariates. Moreover, multiple linear regression analysis revealed that adiponectin contributed more strongly to CRP than other factors, including the index of insulin resistance.

CONCLUSIONS

An inverse and strong association between adiponectin and CRP in substantially healthy subjects implies that decreased serum adiponectin might be fundamentally associated with the early stage of low-grade inflammation.

Alcohol consumption and colorectal cancer risk: findings from the JACC Study

BACKGROUND: Because alcohol drinking is a potential risk factor for colorectal cancer, the trend in alcohol consumption in Japan may partly explain the increase in incidence and mortality rates of this malignancy until 1990-1995.

METHODS: We analyzed data from the Japan Collaborative Cohort Study. From 1988 to 1990, 23,708 men and 34,028 women, aged 40-79 years, completed a questionnaire on lifestyle factors including drinking habits. Incidence rate ratios (IRR) were estimated by using proportional hazards models.

RESULTS: During the mean follow-up of 7.6 years through December 1997, we documented 418 incidents of colon cancer and 211 of rectal cancer. Male ex- or current drinkers demonstrated a twofold risk for colon cancer compared with nondrinkers: the multivariate-adjusted IRR was 2.01 (95% confidence interval [CI] 1.09-3.68) for ex-drinkers and 1.97 (95% CI: 1.28-3.03) for current drinkers. The dose-response relationship between alcohol consumption and the risk, however, was not clear. Female ex-drinkers were at an increased risk without statistical significance. For rectal cancer, we found a slightly lower risk in light current drinkers who consumed less than 22 g ethanol per day: the multivariate IRR was 0.61 (95% CI: 0.33-1.13) for men and 0.69 (95% CI: 0.27-1.74) for women. Although the IRR for all current drinkers was almost unity in men, an increasing trend in risk was detected with increasing alcohol consumption in current drinkers (trend p = 0.027).

CONCLUSIONS: Taking the findings from our study and other prospective investigations into consideration, more attention should be paid to alcohol consumption in the prevention of colon cancer in Japan.

Glucose intolerance and colorectal cancer risk in a nested case-control study among Japanese People

BACKGROUND

Glucose intolerance may increase the risk of developing colorectal cancer.

METHODS

In a sero-epidemiological nested case-control study, conducted as part of the Japan Collaborative Cohort Study (JACC Study) for Evaluation of Cancer Risk, we measured serum glycoalbumin in 123 patients with colorectal cancer and 279 controls. Conditional logistic regression was used to evaluate the risk of colorectal cancer.

RESULTS

There were trends towards an association between high levels of glycoalbumin and an increased risk of colorectal cancer in men (odds ratio [OR]=2.39; 95% confidence interval [CI]; 0.89- 6.36) and between high levels of glycoalbumin and a decreased risk of colorectal cancer in women (OR=0.41; 95% CI, 0.14-1.04).

CONCLUSIONS

A high level of glycoalbumin may increase the risk of colorectal cancer in men. The finding that high levels of glycoalbumin in women decreased their risk of colorectal cancer was inconsistent with previous reports, and may have been the result of limitations in the procedure in selecting samples and statistical power.

Medical history of circulatory diseases and colorectal cancer death in the JACC Study

BACKGROUND: Host factors expressed by individual past medical history of hypertension, stroke, and myocardial infarction may have a relationship with colorectal cancer.

METHODS: As part of the Japan Collaborative Cohort Study (JACC Study) for the Evaluation of Cancer Risk sponsored by the Ministry of Education, Science, Sports and Culture of Japan (Monbusho), we conducted a follow-up study of 110,792 Japanese inhabitants aged 40-79 years to reveal the relationship of past medical history of hypertension, stroke, and myocardial infarction at the baseline in 1988-1990 with colorectal cancer death for about 10 years up to the end of 1999.

RESULTS: Past medical history of hypertension associated with an increased risk of female rectal cancer when analyzing all cancer cases with adjustment for age, body mass index, and exercise (hazard ratio [HR] = 1.97, 95% confidence interval [CI]; 1.13-3.43). Past medical history of myocardial infarction was also an increased risk for female rectal cancer (HR = 3.05, 95% CI; 1.28-7.28). Females who had a medical history of stroke had increased risk of rectal cancer without statistical significance.

CONCLUSION: There was a positive association of past medical history of hypertension and myocardial infarction and an increased risk of rectal cancer in women.

Relationship between body mass index and the risk of ovarian cancer in the Japanese population: Findings from the Japanese Collaborate Cohort (JACC) study

AIM

The incidence of ovarian cancer in Japan has increased since the 1970s. The many studies that have assessed the relationship between body mass index (BMI) and the risk of ovarian cancer have produced contradictory results. Here we investigated this relation using data from the Japan Collaborative Cohort Study for the Evaluation of Cancer Risk, which was initiated in 1988.

METHODS

A self-administered questionnaire on dietary habits and other risk factors for cancer was completed by 36,456 Japanese women. After 7.6 years of follow up, 38 cases of ovarian cancer were available for analysis. Cox proportional-hazards models were used to compute relative risks and to adjust for confounders.

RESULTS

Compared to women with BMI of 18.5-24.9 kg/m2, the relative risk of ovarian cancer was 2.24 (95% CI = 1.10-4.21) for BMI of 25.0-29.9 and 1.78 (95% CI = 0.24-13.34) for BMI of > or = 30 kg/m2. A test for trend revealed that this finding was statistically significant (P = 0.014).

CONCLUSION

The results of this study suggest that being overweight is independently associated with a higher risk of developing ovarian cancer in the Japanese population.