Renzhe Cui

Body mass index and mortality from cardiovascular disease among Japanese men and women: the JACC study.

Background and Purpose— Although overweight is an important risk factor for cardiovascular disease in Western countries, the impact of overweight has not been well elucidated in Japan, where its prevalence is low. Methods— A total of 104 928 Japanese (43 889 men and 61 039 women) aged 40 to 79 years, free of stroke, coronary heart disease, and cancer at entry participated in the Japan Collaborative Cohort Study for Evaluation of Cancer Risk Sponsored by Monbusho (JACC Study) between 1988 and 1990. Systematic surveillance was completed until the end of 1999, with 1 042 835 person years of follow-up, and the underlying causes of death were determined based on the International Classification of Diseases. Results— There were 765 total strokes (191 intraparenchymal hemorrhages), 379 coronary heart diseases, and 1707 total cardiovascular diseases for men; and for women, there were 685 (145), 256, and 1432, respectively. Compared with persons with body mass index (BMI) 23.0 to 24.9, those with BMI ≥27.0 kg/m2 had a higher risk of coronary heart disease; for men and women, the respective multivariate relative risk (95% CI) was 2.05 (1.35 to 3.13) and 1.58 (0.95 to 2.62). Persons with BMI <18.5 kg/m2 had higher risk of total stroke and intraparenchymal hemorrhage, for men and women, the respective multivariate relative risk was 1.29 (1.01 to 1.49) and 1.92 (1.49 to 2.47) for total stroke and 1.96 (1.16 to 3.31) and 2.32 (1.36 to 3.97) for intraparenchymal hemorrhage. These excess risks did not alter materially when deaths within 5 years were excluded or when smoking status was taken into account. Conclusions— For Japanese men and women, high BMI was associated with increased risk of coronary heart disease, whereas low BMI was associated with intraparenchymal hemorrhage.

Relationships of Age at Menarche and Menopause, and Reproductive Year with Mortality from Cardiovascular Disease in Japanese Postmenopausal Women: The JACC Study

BACKGROUND Early menopause is associated with increased risk of coronary heart disease in Caucasian women. However, this association has not been examined in Asian women. METHODS We conducted a 10-year cohort study of 37,965 Japanese post-menopausal women aged 40-79 years in the Japan Collaborative Cohort (JACC) Study. Causes of death were determined based on the International Classification of Disease. RESULTS There were 487 mortality of stroke and 178 mortality of coronary heart disease. Late menarche or early menopause, or shorter duration of reproductive period was not associated with risk of mortality from coronary heart disease. However, compared with women with age at menarche ≤13 years, those with age at menarche ≥17 years tended to have increased risk of mortality from stroke: the multivariable hazard ratio was 1.32 (95% confidence interval [CI]: 0.93-1.87, p = 0.10). Compared with women with age at menopause of ≥49 years, those with age at menopause of <49 years tended to have increased risk of coronary heart disease among women aged 40-64 years; the multivariable hazard ratio was 1.85 (95% CI: 0.92-3.73, p = 0.08). CONCLUSIONS The possible association between early menopause and coronary heart disease among middle-aged women was consistent with the result of observational studies for Caucasian women, and can be explained by a protective effect of endogenous estrogen on the development of atherosclerosis.

Serum total homocysteine concentrations and risk of mortality from stroke and coronary heart disease in Japanese: The JACC study

Evidence for association between serum total homocysteine (tHcy) level and cardiovascular disease is limited in Asian populations. We conducted a nested case-control study under JACC Study. A total of 39,242 subjects aged 40-79 years provided serum samples at baseline surveys between 1988 and 1990. Control subjects were selected by matching for sex, age, community and year of serum storage. Serum tHcy levels were measured by high-performance liquid chromatography. During the 10-year follow-up, there were 444 deaths due to total cardiovascular disease, including 310 total stroke (131 hemorrhage and 101 ischemic strokes) and 134 coronary heart diseases. The risks of mortality from ischemic stroke, coronary heart disease, and total cardiovascular disease were significantly higher in individuals with the highest serum tHcy quartile (>or=15.3micromol/L) than in those with the lowest quartile (<10.5micromol/L); the respective multivariable odds ratios (95% CI) were 4.35 (1.12-16.9), 3.40 (1.17-9.86), and 1.68 (1.02-2.77). The multivariable odds ratios associated with a 5-micromol/L increase in tHcy were 1.49 (1.01-2.18), 2.01 (1.21-3.35), and 1.15 (1.00-1.32), respectively. High serum tHcy levels were associated with increased mortality from ischemic stroke, coronary heart disease and total cardiovascular disease among Japanese.

Body Fat Distribution and the Risk of Hypertension and Diabetes among Japanese Men and Women

To identify anthropometrical indices of body fat distribution for predicting the risk of hypertension and diabetes, a population-based prospective study was designed. Subjects in two communities (n=2,422 and 3,195), who were free of hypertension and diabetes, respectively, were followed-up. The area and gender-specific risk of hypertension and diabetes were compared among tertiles of body mass index (BMI) and body fat distribution, including waist circumference (WC), waist-to-hip ratio (WHR), waist-to-height ratio (WHtR), and subscapular skinfold-thickness (SSF). During the 10-year follow-up for hypertension and diabetes, the incident cases of hypertension were 72 for Yao men, 125 for Kyowa men, 160 for Yao women and 193 for Kyowa women and those of diabetes were 27, 64, 37 and 77, respectively. One SD differences in BMI and WC were associated with 1.2 to1.6-fold higher risk of hypertension, and that of SSF was associated with 1.4 to 1.6-fold higher risk of diabetes for both men and women in Yao and for women, but not men, in Kyowa. One SD differences of BMI, WC and WHtR were also associated with 1.4 to 2.0-fold higher risk of diabetes for Yao and Kyowa women. In conclusion, the significant predictors for hypertension were BMI and WC and those for diabetes were BMI and SSF in both genders in both communities, except for men in Kyowa. WC and WHtR were also predictors for diabetes in women but not in men.

Associations of Sleep-Disordered Breathing with Excessive Daytime Sleepiness and Blood Pressure in Japanese Women

Sleep-disordered breathing (SDB) is a recognized risk factor for excessive daytime sleepiness (EDS) and hypertension, but evidence of this association in Asian women is limited. We conducted a cross-sectional study of 3,568 women aged 30–69 years living in three Japanese communities. The 3% oxygen desaturation index (ODI) was selected as the indicator of SDB, and blood oxygen fall was estimated by overnight pulse oximetry. The prevalence of SDB was 20.2% for 3% ODI ≥5, 6.4% for 3% ODI ≥10, and 2.8% for 3% ODI ≥15 among Japanese women aged 30–69 years. The 3% ODI was positively associated with the prevalence of self-reported EDS and mean values of systolic and diastolic blood pressure levels. The multivariate odds ratios for 3% ODI of 5–9, 10–14, and ≥15 in reference to 3% ODI <5 were 1.9 (1.2–3.0), 2.2 (1.0–4.6), and 1.8 (0.7–4.4) (p for trend =0.01), respectively, for EDS and 1.1 (0.9–1.4), 1.2 (0.8–1.8), and 2.2 (1.4–3.4) (p for trend <0.001), respectively, for hypertension. The severity of SDB was significantly associated with EDS and hypertension among Japanese women.

Cigarette Smoking and Risk of Disabling Dementia in a Japanese Rural Community: A Nested Case-Control Study

Background: Previous prospective cohort studies have examined the association between smoking and the risk of dementia, but the results were inconsistent. Methods: A prospective, nested, case-control study was conducted to examine the association between cigarette smoking and risk of disabling dementia within the cohort of 6,343 men and women aged 35–85 years. Incident dementia was documented in 208 men and women (95 cases with and 113 cases without a history of stroke). Two control subjects per case were selected by matching for sex, age and year of examination. Results: The multivariable odds ratios (95% CI) for current versus never smokers were 2.3 (1.1–4.7) for total dementia, 2.6 (0.8–8.2) for dementia with a history of stroke and 2.2 (0.8–5.7) for dementia without it, yielding no effect of stroke history on the smoking-dementia association. A dose-response relationship was noted between the years of cigarette smoking and the risk of total dementia, and a significant excess risk was found for smoking duration of ≧45 years. Conclusions: The present prospective study suggests that long-term cigarette smoking may raise the risk of disabling dementia.

Relationship of smoking and smoking cessation with ankle-to-arm blood pressure index in elderly Japanese men

Background Cigarette smoking is associated with an increased risk of peripheral arterial disease, but the relationship between smoking cessation and preclinical peripheral atherosclerosis is uncertain. Design and methods A cross-sectional, population-based study to examine the effect of smoking and smoking cessation on the prevalence of peripheral arterial disease among 1215 men aged 60–79 years in two Japanese communities in 1999–2000. The ankle-to-arm systolic blood pressure index (AAI) was used as an estimate of the presence of peripheral atherosclerosis. Results The mean AAI correlated inversely and linearly with smoking status and pack-years of smoking. The multivariate prevalence odds ratio [95% confidence interval (CI)] of low AAI (<0.90) compared with never-smokers was 3.7 (95% CI 1.1–12.7) for current smokers and 4.2 (95% CI 1.2–14.6) for men with 45 or more pack-years of smoking. In men who have quit smoking for 20 years or more, the mean AAI was higher and the prevalence of low AAI (<0.90) was lower than those of current smokers, but similar to those of never-smokers. Conclusions Our results confirm that current smoking and pack-years of smoking correlate with the presence of peripheral artery disease. The results suggest that smoking cessation for 20 years or more is associated with the regression of atherosclerosis in peripheral arteries. This finding needs to be confirmed by a prospective study.

Relationships between sleep-disordered breathing and blood pressure and excessive daytime sleepiness among truck drivers

Sleep-disordered breathing is a risk factor for hypertension, cardiovascular disease and accidents in the general population, but little is known about this correlation among professional truck drivers. To examine the relationships of sleep-disordered breathing with blood pressure levels and excessive daytime sleepiness among truck drivers, we conducted a population-based cross-sectional study of 1,313 subjects aged 20–69 years registered in the Japanese Trucking Association. The 3% oxygen desaturation index was selected as an indicator of sleep-disordered breathing, representing the number of desaturation events per hour of recording time in which blood oxygen fell by ≥3% by overnight pulse oximetry. The Epworth Sleepiness Scale was used to estimate excessive daytime sleepiness. There were significant positive associations between the 3% oxygen desaturation index levels and both diastolic blood pressure levels and Epworth Sleepiness Scale scores. The multivariate odds ratio of hypertension was 2.0 (1.1–3.6) for a 3% oxygen desaturation index of ≥15 in reference with a 3% oxygen desaturation index of <5. This association was more evident among those aged ≥40 years and overweight subjects. Further, the multivariate odds ratio of an Epworth Sleepiness Scale of ≥11 was 2.3 (1.1–4.9) for a 3% oxygen desaturation index of ≥15 in reference with a 3% oxygen desaturation index of <5. This association was more evident among those aged ≥40 years. The associations of sleep-disordered breathing severity with diastolic blood pressure levels and excessive daytime sleepiness suggest the need for sleep-disordered breathing screening among truck drivers for prevention of hypertension and potential traffic accidents.

Aldosterone Synthase Gene T−344C Polymorphism, Sodium and Blood Pressure in a Free-Living Population: A Community-Based Study

There have been few epidemiological studies on the gene-environmental interaction between the aldosterone synthase gene (CYP11B2) T−344C polymorphism and sodium in relation to blood pressure in a free-living general population. We hypothesized a priori that persons with the T allele of CYP11B2 would have elevated blood pressure levels in response to a higher sodium intake, and thus the association between the T−344C polymorphism and blood pressure would be more evident among persons with a high sodium intake than among those with a low sodium intake. Study subjects were 2,823 men and women aged 30–74 in a Japanese community. We examined the associations between the T−344C polymorphism and blood pressure levels, stratified by sodium variables estimated by 24-h urinary sodium excretion and a dietary questionnaire. There was no significant difference in blood pressure levels among the CC, TC and TT groups for either or both sexes. However, among persons with higher sodium excretion, mean systolic blood pressure levels tended to be higher in those with the TC (+3.0 mmHg, p=0.06) and TT (+2.9 mmHg, p=0.07) genotypes than in those with the CC genotype, but this tendency was not seen among those with lower sodium excretion (−4.0 mmHg, p=0.03 for TC vs. CC; −3.0 mmHg, p=0.11 for TT vs. CC; p for interaction =0.006). In conclusion, we found no association between CYP11B2 and blood pressure for total subjects or for persons with a higher sodium intake. However, a possible gene–blood pressure association among persons with higher sodium intake needs to be explored further.

G-Protein β-3 Subunit C825T Polymorphism, Sodium and Arterial Blood Pressure: A Community-Based Study of Japanese Men and Women

Epidemiological evidence on gene‐environment effects of the G‐protein β‐3 subunit C825T polymorphisms and sodium on blood pressure in the free‐living general population is limited. We examined the associations between the C825T polymorphism and blood pressure levels, stratified by the sodium variables estimated by 24‐h urinary sodium excretion and a dietary questionnaire, among 1,471 men and women aged 30‐74 from a community in Japan. Our a priori hypothesis was that individuals with the 825T allele have elevated blood pressure among subjects with a high sodium intake. Among the whole group, the systolic blood pressure level was +2.2 mmHg (p = 0.10) higher in TT than CC genotype individuals after adjustment for sex, age, antihypertensive medication use, body mass index, and alcohol consumption. This difference was more evident among individuals with low sodium excretion (+4.5 mmHg, p = 0.01), low present sodium intake (+3.2 mmHg, p = 0.11), and low past sodium intake (+4.8 mmHg, p = 0.02). No associations were observed among those with high sodium variables. Our results indicate that the G‐protein β‐3 subunit C825T polymorphism is associated with higher systolic blood pressure levels in a large free‐living Japanese population, and more specifically in women with a low sodium intake. This finding helps to explain part of the discrepancy between the previously reported genetic association among different ethnic groups.