Atrial fibrillation is a major risk factor for stroke, especially in women: the Jichi Medical School cohort study

Background

Only a few population-based cohort studies have investigated the impact of atrial fibrillation (AF) on stroke in Japan.

Methods

A total of 10 929 participants (4147 men and 6782 women) were included in this population-based prospective cohort study. Baseline data, including electrocardiograms (ECGs) to ascertain AF status, were obtained from April 1992 through July 1995 in 12 areas in Japan. Cox proportional hazards models were used to analyze the association of AF with stroke.

Results

A total of 54 participants had AF (0.49%). The mean follow-up period was 10.7 years, during which 405 strokes were identified; 12 of these occurred in participants with AF. The crude incidence of stroke in participants with and without AF was 14.9 and 4.5 per 1000 person-years in men, respectively, and 39.3 and 2.7 per 1000 person-years in women. After adjusting for geographical area, sex, age, smoking status, drinking status, obesity, hypertension, dyslipidemia, and diabetes mellitus, the hazard ratios (95% confidence interval) of AF in all participants and in male and female participants were 4.11 (2.28–7.41), 2.12 (0.77–5.84), and 10.6 (5.01–22.4), respectively. The population attributable fraction (PAF) of stroke caused by AF was 2.2%; the PAFs were 1.0% and 3.6% in men and women, respectively.

Conclusions

The present Japanese population-based prospective cohort study showed that AF is a major risk factor for stroke, especially in women.Key words: atrial fibrillation, stroke, women, cohort study     

Low cholesterol is associated with mortality from stroke, heart disease, and cancer: the Jichi Medical School Cohort Study

Background

We investigated the relationship between low cholesterol and mortality and examined whether that relationship differs with respect to cause of death.

Methods

A community-based prospective cohort study was conducted in 12 rural areas in Japan. The study subjects were 12 334 healthy adults aged 40 to 69 years who underwent a mass screening examination. Serum total cholesterol was measured by an enzymatic method. The outcome was total mortality, by sex and cause of death. Information regarding cause of death was obtained from death certificates, and the average follow-up period was 11.9 years.

Results

As compared with a moderate cholesterol level (4.14–5.17 mmol/L), the age-adjusted hazard ratio (HR) of low cholesterol (<4.14 mmol/L) for mortality was 1.49 (95% confidence interval [CI]: 1.23–1.79) in men and 1.50 (1.10–2.04) in women. High cholesterol (≥6.21 mmol/L) was not a risk factor. This association was unchanged in analyses that excluded deaths due to liver disease, which yielded age-adjusted HRs of 1.38 (95% CI, 1.13–1.67) in men and 1.49 (1.09–2.04) in women. The multivariate-adjusted HRs and 95% CIs of the lowest cholesterol group for hemorrhagic stroke, heart failure (excluding myocardial infarction), and cancer mortality significantly higher than those of the moderate cholesterol group, for each cause of death.

Conclusions

Low cholesterol was related to high mortality even after excluding deaths due to liver disease from the analysis. High cholesterol was not a risk factor for mortality.Key words: low cholesterol, mortality, liver disease, stroke, heart disease, cohort study     

Metabolic syndrome mortality in a population-based cohort study: Jichi Medical School (JMS) Cohort Study

BACKGROUND: Metabolic syndrome is known to increase morbidity and mortality of cardiovascular disease. The National Cholesterol Education Program Adult Treatment Expert Panel III in 2001 (revised in 2005) and the Japanese definition of metabolic syndrome were launched in 2005. No study regarding the association between metabolic syndrome by Japanese definition and mortality has been performed. The aim of this study was to clarify the prevalence of metabolic syndrome and its effects to mortality in a population-based cohort study. METHODS: A total of 2,176 subjects who satisfied the necessary criteria for metabolic syndrome were examined between 1992 and 1995 as a part of Jichi Medical School Cohort Study by Japanese definition. Cox's proportional hazard models were used to analyze the association of metabolic syndrome with mortality. RESULTS: The prevalence of metabolic syndrome was 9.0% in males and 1.7% in females. There were 17 deaths (14 males), including 6 cardiovascular deaths (5 males), during a 12.5-year follow-up period among metabolic syndrome subjects. After adjusting for age, smoking status, and alcohol drinking status, the hazard ratio (95% confidence interval) for all-cause mortality was 1.13 (0.64-1.98) in males and 1.31 (0.41-4.18) in females, and HR for cardiovascular mortality was 1.84 (0.68-4.96) in males, and 1.31 (0.17-9.96) in females. CONCLUSION: No statistical significant relationship between metabolic syndrome by Japanese definition and all-cause mortality was observed in a population-based cohort study.     

Impacts of educational level and employment status on mortality for Japanese women and men: the Jichi Medical School cohort study

The objective of this study was to examine educational levels and employment status as independent determinants of overall and cause-specific mortality in a Japanese population. Participants were 4,301 men and 6,780 women in a multi-center community-based prospective study, and data of the baseline survey was collected between 1992 and 1995. The participants were followed up until December 31, 2002 (the average follow-up period was 9.17 years). Early termination of education was associated with an increased risk of mortality from all causes for both men and women. This tendency was more prominent in women aged 59 and younger (hazard ratio (HR) = 3.82, 95% confidence interval (CI): 1.18–12.34), after adjusting for confounding factors using the Cox proportional hazard models. Similar trends were shown for men; specifically, cardiovascular disease mortality for all men was increased by early termination of education (HR = 2.97, 95% CI: 1.17–7.52) compared to later termination. For employment status, unemployed men showed increased mortality from all causes compared to white-collar workers (HR = 1.51, 95% CI: 1.00–2.28). Female farmers and forestry workers showed reduced mortality from all causes compared to white-collar workers (HR = 0.55, 95% CI: 0.33–0.93). Male farmers and forestry workers also showed reduced mortality from cardiovascular diseases compared to white-collar workers (HR = 0.34, 95% CI: 0.14–0.82). Educational level and employment status may affect mortality for Japanese women and men.Funding: The Foundation for the Development of the Community, Tochigi, Japan.     

Healthy-eating attitudes and the incidence of cardiovascular disease: the SUN cohort

There is an emerging use of brief dietary questionnaires to investigate diet-health relation. We prospectively assess the association between eating attitudes (yes/no) and incident cardiovascular disease (CVD) in 19,138 participants of the Seguimiento Universidad de Navarra (SUN) Cohort. We calculated a baseline healthy-eating attitudes score (in quartiles), positively weighting answers on more fruit, vegetables, fish and fiber and less meat, sweets and pastries, fat, butter, fatty meats and added sugar in drinks. We observed 139 incident cases of CVD. A higher score was associated with a lower risk of CVD [3-5 points Hazard Ratio (HR): 0.38 (95% confidence interval: 0.18-0.81); 6-8 points: 0.57 (0.29-1.12); 9-10 points: 0.31 (0.15-0.67), compared to 0-2 points]. Key contributors were the attitude to increase fruit [HR: 0.59 (0.40-0.87)], vegetables [HR: 0.57 (0.29-1.12)] and fiber intake [HR: 0.69 (0.48-0.98)]. Brief questionnaire on attitudes towards healthy-eating may be a useful tool for the primary prevention of CVD.     

Potential factors associated with fruit and vegetable intake after premature acute coronary syndrome: a prospective cohort study

Abstract

Studies on dietary changes and their associated factors are limited, particularly with respect to younger cardiovascular patients. Our objective was to evaluate the factors associated with fruit and vegetable intake among adults with premature acute coronary syndrome (ACS) 1 year after the event. We used data from GENESIS-PRAXY, a multicentre prospective study of adults aged 18–55 years, hospitalised for ACS. Participants were 704 adults from 24 centres in Canada, 1 in USA and 1 in Switzerland. Data were collected through questionnaires and chart reviews at baseline and 1 year post-ACS. Fruit and vegetable intake was low among adults with premature ACS, and remained suboptimal at 1 year post-ACS, with only 21% meeting the minimum recommendations of at least 5 daily servings. The findings suggest that patient lifestyle characteristics, such as the number of hours spent at work and baseline intake are factors that may be associated with the intake of fruits and vegetables. More research is needed to assess effective strategies to increase fruit and vegetable intake among patients with premature ACS so that they meet dietary recommendations.     

Usual dietary isoflavone intake is associated with cardiovascular disease risk factors in postmenopausal women

Intervention data suggest a cardioprotective role for supplemental isoflavones; however, few studies have examined the cardiovascular disease (CVD) benefit of usual dietary isoflavone intake. This cross-sectional study examined the association between usual dietary isoflavone intake and CVD risk factors, including lipids and lipoproteins, body mass index (BMI) and fat distribution, blood pressure, glucose and insulin. Subjects were postmenopausal women (n = 208) aged 45-74 y, who attended screening and baseline visits for a randomized, double-blind, placebo-controlled trial examining the effects of isoflavone use. At screening, total cholesterol, triglycerides, HDL cholesterol and LDL cholesterol were measured, and demographic, behavioral and menopausal characteristics were assessed. One month later, dietary intake over the past year was assessed with a standardized questionnaire. Anthropometric measurements and blood pressure were obtained, and a 75-g oral glucose tolerance test was administered. Isoflavone consumption did not vary by age, exercise, smoking, education or years postmenopausal. Women with high genistein intake had a significantly lower BMI (P-trend = 0.05), waist circumference (P-trend = 0.05) and fasting insulin (P-trend = 0.07) than those with no daily genistein consumption. In adjusted analyses, genistein, daidzein and total isoflavone intake were each positively associated with HDL cholesterol (P = 0.05) and inversely associated with postchallenge insulin (P = 0.05). These data suggest a protective role for dietary soy intake against CVD in postmenopausal women.     

Fish intake is positively associated with breast cancer incidence rate

Animal studies have, in general, been supportive of a protective effect of fish and fish (n-3) PUFA against breast cancer risk; but the epidemiologic evidence of such a relationship is limited. Case-control and cohort studies have rarely shown significant associations. The association between total fish intake and the effect of fat content and preparation method of the fish, in relation to the incidence rate ratios of breast cancer, were investigated among postmenopausal women. We also investigated the effect of fish intake with respect to estrogen receptor expression of breast cancer tumors. A total of 23,693 postmenopausal women from the prospective study "Diet, Cancer and Health" were included in the study. During follow-up, 424 women were diagnosed with breast cancer. The incidence rate ratio (IRR) and 95% CI per each additional 25 g of mean daily intake of fish were 1.13 (CI, 1.03-1.23). Analysis of fatty fish gave IRR of 1.11 (CI, 0.91-1.34), and the result for lean fish was 1.13 (CI, 0.99-1.29). When fish intake was stratified into three types of preparation methods, the IRR for fried fish was 1.09 (CI, 0.95-1.25), for boiled fish 1.09 (CI, 0.85-1.42), and for processed fish 1.12 (CI, 0.93-1.34). The IRR per additional 25 g of mean daily intake of fish was 1.14 (CI, 1.03-1.26) for estrogen receptor-positive (ER+) and 1.00 (CI, 0.81-1.24) for estrogen receptor-negative (ER-) breast cancer. In conclusion, this study showed that higher intakes of fish were significantly associated with higher incidence rates of breast cancer. The association was present only for development of ER+ breast cancer.     

Vegetable protein intake is associated with lower gallbladder disease risk: Findings from the Women's Health Initiative prospective cohort

ObjectiveThis study aimed to measure associations between gallbladder disease and protein intake patterns, separated by quantity and type (vegetable vs. animal), among postmenopausal women.MethodsAnalyses were based on 130,859 postmenopausal women enrolled from 1993 to 1998 at 40 U.S. clinical centers in the Women's Health Initiative clinical trials and observational study. Women were excluded if they reported a history of gallbladder disease prior to baseline. Cox proportional hazards regression models, adjusted for gallbladder disease risk factors, were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for associations between energy-adjusted protein intake and gallbladder disease.ResultsIn this study sample, 8.1% of postmenopausal women self-reported incident gallbladder disease. In multivariate analysis, women in the highest quintile of energy-adjusted vegetable protein intake (> 24.0 g/d) had a lower risk of gallbladder disease (HR, 0.87; 95% CI, 0.81–0.93) as compared to women in the lowest quintile (< 16.3 g/d) (P_trend < 0.001). Total protein intake was modestly protective against gallbladder disease (P_trend < 0.021). Animal protein intake was not associated with gallbladder disease risk. The protective effect of vegetable protein held stable only for women without history of diabetes (HR, 0.86; 95% CI, 0.80–0.92) and without recent weight loss (HR, 0.88; 95% CI, 0.80–0.97).ConclusionsVegetable protein intake is inversely associated with gallbladder disease risk in our sample of postmenopausal women. In addition to weight management, healthcare providers could emphasize vegetable protein as an additional dietary modality to promote lower risk for gallbladder disease.     

Sleep duration and mortality in Japan: the Jichi Medical School Cohort Study

BACKGROUND: Although sleep is one of the most important health-related factors, relationship between sleep duration and mortality has not been fully discussed. METHODS: Study subjects were 11,325 participants (4,419 males and 6,906 females) in the Jichi Medical School Cohort Study, a population-based prospective study. Baseline data were obtained by questionnaire and health checkups between April 1992 and July 1995 in 12 rural areas in Japan. Main outcome measures were all-cause and cause-specific mortality derived from death certificates up to December 31, 2001. Cox's proportional hazard models were applied to analyze the association of sleep duration with mortality. RESULTS: A total of 495 deaths (289 males and 206 females) were observed during the average of 8.2-year follow-up period. After adjusting for age, systolic blood pressure, serum total cholesterol, body mass index, smoking habits, alcohol drinking habits, education, and marital status, the hazard ratios (95% confidence intervals) of all-cause mortality for individuals sleeping shorter than 6 hours and 9 hours or longer were 2.4 (1.3-4.2) and 1.1 (0.8-1.6) in males, and 0.7 (0.2-2.3) and 1.5 (1.0-2.4) in females, respectively, relative to those with 7-7.9 hours sleep. CONCLUSION: Our data suggest that males with short sleep and females with long sleep were at an elevated risk of death.     

Body mass index and stroke incidence in Japanese community residents: The Jichi Medical School (JMS) Cohort Study

Background

High body mass index (BMI) has been reported as a risk factor for cardiovascular events in Western countries, while low BMI has been reported as a risk factor for cardiovascular death in Asian countries, including Japan. Although stroke is a major cause of death and disability in Japan, few cohort studies have examined the association between BMI and stroke incidence in Japan. This study aimed to examine the association between BMI and stroke incidence using prospective data from Japanese community residents.

Age at menopause and mortality in Japan: the Jichi Medical School Cohort Study

BACKGROUND: Although several studies have reported increased mortality risk with early menopause, there were no studies examining the relationship between age at menopause and mortality in Japan. The goal of this analysis is to investigate the relationship between age at menopause and all-cause mortality among the Japanese. METHODS: Study subjects were 4,683 postmenopausal females in the Jichi Medical School Cohort Study, a population-based prospective study. Baseline data were obtained by questionnaire and health checkups between April 1992 and July 1995 in 12 rural areas in Japan. Main outcome measures were all-cause mortality derived from death certificates up to December 31, 2002. Cox's proportional hazard models were used to analyze the association of age at menopause with mortality. RESULTS: A total of 215 deaths were observed during the average of 9.2 year follow-up period. After adjusting for age, systolic blood pressure, serum total cholesterol level, serum high density lipoprotein cholesterol level, history of diabetes mellitus, body mass index, smoking habits, alcohol drinking habits, marital status, study area, and types of menopause, the hazard ratios (95% confidence intervals) of all-cause mortality were 2.10 (1.07-4.11), 0.68 (0.36-1.26), 0.94 (0.68-1.30), and 1.17 (0.63-2.20) for females with a menopause at ages younger than 40 years, 40-44, 50-54, and 55 or older, respectively, relative to those with menopause at age 45-49 years. CONCLUSIONS: Our data suggest that menopause aged younger than 40 years increases the risk of death from all causes among the Japanese.     

alpha-Linolenic acid intake is not beneficially associated with 10-y risk of coronary artery disease incidence: the Zutphen Elderly Study

BACKGROUND: Data on the relation between alpha-linolenic acid intake and coronary artery disease (CAD) are limited. Other dietary components appear to modify the reported relation between alpha-linolenic acid intake and CAD. OBJECTIVE: We examined whether dietary alpha-linolenic acid intake was inversely associated with risk of CAD. DESIGN: We prospectively studied 667 men aged 64-84 y from the Zutphen Elderly Study who were free of CAD at baseline. Dietary intake was assessed by using a cross-check dietary history method. RESULTS: During the 10-y follow-up, we documented 98 cases of CAD. After adjustment for age, standard coronary risk factors, and intake of trans fatty acids and other nutrients, alpha-linolenic acid intake was not significantly associated with CAD risk. The relative risk of CAD for the highest compared with the lowest tertile of alpha-linolenic acid intake was 1.68 (95% CI: 0.86, 3.29). alpha-Linolenic acid intake from sources containing trans fatty acids was also nonsignificantly, yet positively, associated with CAD risk. alpha-Linolenic acid intake from foods that did not contain trans fatty acids was not associated with CAD risk, the relative risk of CAD for the highest compared with the lowest tertile was 1.15 (95% CI: 0.63, 2.11). CONCLUSION: We did not observe a beneficial effect of dietary alpha-linolenic acid intake on the risk of 10-y CAD incidence. Investigating this hypothesis was complicated by the association between intakes of alpha-linolenic acid and trans fatty acids. Given the results of current prospective studies, a protective cardiac effect of alpha-linolenic acid is questionable.     

Association between job strain and prevalence of hypertension: a cross sectional analysis in a Japanese working population with a wide range of occupations: the Jichi Medical School cohort study

OBJECTIVES—To explore the association between the prevalence of hypertension in a Japanese working population and job strain (a combination of low control over work and high psychological demands), and to estimate this association in different sociodemographic strata.METHODS—From a multicentre community based cohort study of Japanese people, sex specific cross sectional analyses were performed on 3187 men and 3400 women under 65 years of age, all of whom were actively engaged in various occupations throughout Japan. The baseline period was 1992-4. The association between job characteristics—measured with a Japanese version of the Karasek demand-control questionnaire—and the prevalence of hypertension defined by blood pressure and from clinical diagnoses were examined. Adjustments were made for possible confounders. The analyses were repeated for stratified categories of occupational class, educational attainment, and age group.RESULTS—In men, the level of job strain (the ratio of psychological job demands to job control) correlated with the prevalence of hypertension. In a multiple logistic regression model, job strain was significantly related to hypertension (odds ratio 1.18; 95% confidence interval 1.05 to 1.32), after adjustment for age, employment (white collar v blue collar), marital status, family history of hypertension, cigarette smoking, alcohol intake, physical activity, and body mass index. The stratified analyses showed significant excess risks in the subordinate groups compared with managers, blue collar workers, less educated workers, and the older age groups. This association was not significant in women. Multiple linear regression analyses, with systolic and diastolic blood pressures as dependent variables, did not show any significant association.CONCLUSIONS—The findings provided limited proof that job strain is related to hypertension in Japanese working men. Older men in a lower social class may be more vulnerable to the hypertensive effects of job strain.     

Hemorrhoid is associated with increased risk of peripheral artery occlusive disease: A nationwide cohort study

Background

This study was conducted to evaluate the association between hemorrhoid and risk of incident peripheral artery occlusive disease (PAOD).

Coffee Consumption and Incidence of Subarachnoid Hemorrhage: The Jichi Medical School Cohort Study

Background

Previous studies on the association between coffee consumption and subarachnoid hemorrhage (SAH) have provided inconsistent results. We examine the risk of SAH from coffee consumption in a Japanese population.

Methods

Our analyses were based on the Jichi Medical School Cohort Study, a large-scale population-based prospective cohort study. A total of 9941 participants (3868 men and 6073 women; mean age 55 years) with no history of cardiovascular disease or carcinoma were examined. Participants were asked to choose one of five options to indicate their daily coffee consumption: none, less than 1 cup a day, 1–2 cups a day, 3–4 cups a day, or 5 or more cups a day. The incidence of SAH was assessed independently by a diagnostic committee. Cox proportional hazards models were used to calculate hazard ratios (HRs) and their 95% confidence intervals (CI) after adjustment for age and sex (HR1) and for additional potential confounders (HR2).

Results

During 10.7 years of follow-up, SAH occurred in 47 participants. When compared with the participants who consumed less than 1 cup of coffee a day, the HR of SAH was significantly higher in the group who consumed 5 or more cups a day in both models (HR1 4.49; 95% CI, 1.44–14.00; HR2 3.79; 95% CI, 1.19–12.05).

Conclusions

The present community-based cohort study showed that heavy coffee consumption was associated with an increased incidence of SAH after adjusting for age, sex, and multiple potential cardiovascular confounders.Key words: coffee consumption, subarachnoid hemorrhage, community-based cohort study