Tadao Gotoh

Correlation between lipoprotein(a) and aortic valve sclerosis assessed by echocardiography (the JMS Cardiac Echo and Cohort Study)

An elevated serum level of lipoprotein(a) (Lp[a]) may be an independent risk factor for atherosclerotic disease, but the relation of Lp(a) to aortic valve (AV) sclerosis has not been determined. We measured serum concentrations of Lp(a) and investigated their relation to the presence of echocardiographic AV sclerosis in residents of a rural village in Japan. We measured serum Lp(a) levels in 347 men and 437 women aged 35 to 90 years (mean +/- SD: 62 +/- 11 years) who participated in mass screening examinations in Wara village, Gifu, Japan. AV sclerosis was assessed by long- and short-axis 2-dimensional echocardiographic views and continuous-wave Doppler echocardiography. AV sclerosis was graded as follows: 0 = normal AV; 1 = increased echo density; 2 = thickening or calcific deposits > or = 3 mm; and 3 = same as 2 with mildly restricted motion (pressure gradient < 16 mm Hg). Lp(a) levels ranged from < 1 mg/dl to 153 mg/dl. The 25th, 50th, and 75th percentile values were 7, 16, and 28 mg/dl, respectively. Lp(a) levels were significantly higher in women than in men (p < 0.01), and did not increase significantly with age. The prevalence of AV sclerosis (grades 2 and 3) increased significantly with age (p < 0.001). AV sclerosis was present in 65 (36.1%) of 180 subjects with Lp(a) levels > or = 30 mg/dl and in 77 (12.7%) of 604 subjects with Lp(a) levels < 30 mg/dl (p < 0.001). There were no significant differences in the prevalence of AV sclerosis in terms of sex, blood pressure, or levels of total cholesterol, high-density lipoprotein cholesterol, triglycerides, or blood sugar. We conclude that increased serum levels of Lp(a), as well as aging, are closely related to AV sclerosis.

Dietary patterns and levels of blood pressure and serum lipids in a Japanese population.

Background Associations between dietary patterns and cardiovascular disease risk factors remain unclear. The objective of this study was to evaluate the association between dietary patterns derived from factor analysis and the levels of blood pressure and serum lipids in a Japanese population. Methods We conducted a cross-sectional analysis among 6886 (in the analysis on blood pressure) and 7641 (in the analysis on serum lipids) Japanese subjects aged 40-69 years. Dietary patterns were identified from a food frequency questionnaire by factor analysis. Associations between dietary patterns and blood pressure and serum lipids were examined after taking potential confounders into account. Results Three dietary patterns were identified: vegetable, meat, and Western. In men, the meat pattern was associated with higher total, high-density lipoprotein (HDL), and low-density lipoprotein (LDL) cholesterol. The Western pattern was associated with higher total and LDL cholesterol. In women, the vegetable pattern was associated with lower systolic and diastolic blood pressure and pulse pressure, and higher HDL cholesterol. The meat pattern was associated with higher total and HDL cholesterol. The Western pattern was associated with higher total, HDL, and LDL cholesterol, and the least intake pattern of Western diet was associated with higher systolic and diastolic blood pressures. Conclusions Dietary patterns of a Japanese population were related to cardiovascular disease risk factors, especially in women.

Sleep Duration and Incidence of Cardiovascular Events in a Japanese Population: The Jichi Medical School Cohort Study

Background Although sleep is one of the most important health-related factors, the relationship between sleep duration and the incidence of cardiovascular events has not been fully described. Methods The present study comprised the 11 367 study subjects (4413 men and 6954 women) of the Jichi Medical School Cohort Study, a population-based prospective study. Baseline data were obtained by questionnaire and health examinations between April 1992 and July 1995 in 12 rural areas in Japan, and the main outcome measures were the incidence of cardiovascular diseases (stroke and myocardial infarction [MI]). Cox proportional hazards models were used to analyze the association between sleep duration and the incidence of cardiovascular events. Results A total of 481carciovascular events (255 men and 226 women) were observed during an average follow-up period of 10.7 years. After adjusting for age, systolic blood pressure, serum total cholesterol, body mass index, smoking habits, and alcohol drinking habits, the hazard ratios (95% confidence intervals) for the incidence of cardiovascular diseases for individuals sleeping less than 6 hours and 9 hours or longer were 2.14 (1.11–4.13) and 1.33 (0.93–1.92) in men, and 1.46 (0.70–3.04) and 1.28 (0.88–1.87) in women, respectively, relative to those who reported sleeping 7 to 7.9 hours per day. Conclusions Our data indicate that men who sleep less than 6 hours a day have a higher risk of cardiovascular events than those sleeping 7 to 7.9 hours.

Association between job characteristics and health behaviors in Japanese rural workers

Associations between job characteristics defined by the Karasek’s job demand-control model and health behaviors were investigated in a cross-sectional analysis of 6,759 Japanese rural workers. High psychological demands were associated with heavy smoking, exaggerated prevalence of alcohol drinking, and high work-related physical activity. Low job control was associated with lower consumption of vegetables, a smaller quantity number of cigarettes smoked, and a low level of work-related physical activity. Job strain, a combined measure obtained from the ratio of demands to control, was associated with lower vegetable consumption, low prevalence of smoking, and high prevalence of current alcohol drinking. Stratified analyses by occupations and gender provided some but not allof the explanations for the unexpected findings. The results indicate a possible association between psychosocial job characteristics and health behaviors. A few unexpected findings prevent complete support to one of the hypothetical pathways that the job characteristics lead to cardiovascular disease through behaviors.

Frequency of Citrus Fruit Intake Is Associated With the Incidence of Cardiovascular Disease: The Jichi Medical School Cohort Study

Background It has been reported that fruit intake protects against cardiovascular disease (CVD). However, most of the relevant studies were conducted in Western countries, and only a few investigated Japanese populations. The present cohort study assessed the effect of citrus fruit intake on the incidence of CVD and its subtypes in a Japanese population. Methods A baseline examination consisting of physical and blood examinations and a self-administered questionnaire was conducted during the period from April 1992 through July 1995. Dietary habits were assessed using a food frequency questionnaire that was divided into 5 categories. Citrus fruit was examined separately due to its frequent consumption by the general Japanese population. Using the Cox proportional hazards model, data from 10 623 participants (4147 men, 6476 women) who had no history of CVD or carcinoma were analyzed to assess the association between frequency of citrus fruit intake and CVD incidence. Results Frequent intake of citrus fruit was associated with a lower incidence of CVD: the hazard ratio for almost daily intake versus infrequent intake of citrus fruit was 0.57 (95% confidence interval: 0.33–1.01, P for trend = 0.04) in men and 0.51 (0.29–0.88, P for trend = 0.02) in women. Frequent intake of citrus fruit was also associated with lower incidences of both all stroke and cerebral infarction, but not hemorrhagic stroke or myocardial infarction. Conclusions Frequent intake of citrus fruit may reduce the incidence of CVD, especially cerebral infarction, in men and women.

Incidence of total stroke, stroke subtypes, and myocardial infarction in the Japanese population: the JMS Cohort Study.

Background Previous reports indicated that the incidence rate of stroke was higher in Japan than in Western countries, but the converse was true in the case of myocardial infarction (MI). However, few population-based studies on the incidence rates of stroke and MI have been conducted in Japan. Methods The Jichi Medical School (JMS) Cohort Study is a multicenter population-based cohort study that was conducted in 12 districts in Japan. Baseline data were collected between April 1992 and July 1995. We examined samples from 4,869 men and 7,519 women, whose mean ages were 55.2 and 55.3 years, respectively. The incidence of stroke, stroke subtypes, and MI were monitored. Results The mean follow-up duration was 10.7 years. A total of 229 strokes and 64 MIs occurred in men, and 221 strokes and 28 MIs occurred in women. The age-adjusted incidence rates (per 100,000 person-years) of stroke were 332 and 221 and those of MI were 84 and 31 in men and women, respectively. In the case of both sexes, the incidence rates of stroke and MI were the highest in the group of subjects aged > 70 years. Conclusion We reported current data on the incidence rates of stroke and MI in Japan. The incidence rate of stroke remains high, considerably higher than that of MI, in both men and women. The incidence rates of both stroke and MI were higher in men than in women.

Cornell Product Left Ventricular Hypertrophy in Electrocardiogram and the Risk of Stroke in a General Population

Left ventricular hypertrophy (LVH), assessed by ECG, is associated with an increased risk for cardiovascular events among hypertensive subjects. We evaluated the risks of LVH in a Japanese general population including normotensive and prehypertensive subjects. We measured ECG and blood pressure in 10 755 subjects at baseline. The Cornell product (CP) and Sokolow-Lyon (SL) voltage were calculated as markers of LVH (CP ≥2440 mm×ms and SL voltage ≥38 mm). Follow-up was performed for 10 years, and the incidence of stroke and myocardial infarction was evaluated. The prevalence of CP-LVH was 2.7% for normotensives, 5.2% for prehypertensives, and 11.0% for hypertensives, and the prevalence of SL-LVH was 5.0%, 8.2%, and 15.2%, respectively. In all of the subjects, CP-LVH and SL-LVH were both predictors of stroke (CP-LVH: hazard risk: 1.62, 95% CI: 1.19 to 2.20, P=0.002; SL-LVH: hazard risk: 1.29, 95% CI: 0.98 to 1.71, P=0.07) after adjustment for confounding factors but were not predictors of myocardial infarction. The adjusted hazard ratio of CP-LVH predicting stroke was especially high in the normotensives (hazard risk: 7.53; 95% CI: 3.39 to 16.77). In the normotensives, diabetes mellitus and hyperlipidemia were significant determinants of CP-LVH but not of SL-LVH. In all of the hypertensive subgroups (normotensives, prehypertensives, and hypertensives), the c-statistic for the equation predicting stroke increased when CP-LVH was added to the model but not when SL-LVH was added. In conclusion, both CP-LVH and SL-LVH are risk factors for stroke in the Japanese general population. CP-LVH is related to glucose abnormality, and its predictive value for stroke is seen even in normotensives and prehypertensives.

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.

Premature menopause is associated with increased risk of cerebral infarction in Japanese women.

Objective: Few epidemiological studies have examined the relationship between age at menopause and stroke incidence, and none have done so in Japanese women. Here, we investigated the relationship between age at menopause and stroke incidence in a large group of Japanese women. Methods: The study participants were 4,790 postmenopausal women aged 36 to 89 years enrolled 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. The incidence of all strokes and stroke subtypes was monitored. Results: Mean (SD) participant age was 61.0 (6.7) years, and mean (SD) age at menopause was 48.3 (4.8) years. A total of 185 strokes were observed during a mean follow-up of 10.8 years. On adjustment for age, systolic blood pressure, total cholesterol, body mass index, smoking habits, and alcohol drinking habits, hazard ratios (95% CIs) of stroke for women who underwent menopause before age 40 years, at 40 to 44 years, at 45 to 49 years, and at 55 years or after relative to those who underwent menopause at age 50 to 54 years were 1.56 (0.78-3.12), 1.59 (1.00-2.51), 1.28 (0.92-1.78), and 0.83 (0.38-1.81), respectively. However, hazard ratios (95% CI) of cerebral infarction for women who underwent menopause before age 40 years, at 40 to 44 years, at 45 to 49 years, and at 55 years or after relative to those who underwent menopause at age 50 to 54 years were 2.57 (1.20-5.49), 1.49 (0.80-2.78), 1.06 (0.67-1.68), and 1.08 (0.43-2.74), respectively. Conclusions: Our data suggest that Japanese women who undergo menopause before age 40 years are at an increased risk of cerebral infarction. Premature menopause should be considered an indicator of the need for more aggressive medical intervention aimed at the prevention of cerebral infarction.

Comparison of C-reactive protein levels between serum and plasma samples on long-term frozen storage after a 13.8 year interval: the JMS Cohort Study.

BACKGROUND C-reactive protein (CRP) is an acute phase reactant, and has been reported as a predictor of cardiovascular diseases. Measurements of high sensitive CRP in thawed samples are possible and the values are thought to remain stable even after frozen storage. However, the long-term stability of CRP values has not been documented. We measured the values of CRP before and after long-term storage, and examined the difference in determined values. METHODS High sensitive CRP was measured before and after long-term storage of samples from 99 men and women among the JMS Cohort Study subjects. We selected subjects who underwent measurement of high sensitive CRP at the baseline by stratified sampling methods using baseline CRP values. CRP was measured in serum samples at the baseline and in thawed plasma samples after an average storage period of 13.8 years. RESULTS Geometric means of CRP were 0.25 mg/L and 0.59 mg/L before and after storage, respectively. The CRP values were significantly higher after long-term frozen storage than at the baseline (p<0.0001). The both values of logarithm CRP were significantly correlated using Pearsons correlation (r = 0.920, 95% confidence interval: 0.883-0.945). CONCLUSION CRP values increased after long-term frozen storage. The CRP values showed a high correlation between before and after long-term storage.