Trends for blood pressure and its contribution to stroke incidence in the middle-aged Japanese population: the Circulatory Risk in Communities Study (CIRCS)

Serum Albumin and High-Sensitivity C-reactive Protein are Independent Risk Factors of Chronic Kidney Disease in Middle-Aged Japanese Individuals: the Circulatory Risk in Communities Study

Aim: It is important to explore predictive markers other than conventional cardiovascular risk factors for early detection and treatment of chronic kidney disease (CKD), a major risk factor for end-stage renal failure. We hypothesized that serum albumin and high-sensitivity C-reactive protein (hs-CRP) to be independent markers, and examined their associations with the risk of CKD.

Methods: We examined the associations of serum albumin and hs-CRP levels with the risk of incident CKD, in 2535 Japanese adults aged 40–69 years without CKD at baseline during a median 9.0-year follow-up after adjustment for known cardiovascular risk factors.

Results: During the follow-up period, 367 cases of CKD developed. In multivariable analyses adjusted for known risk factors, the CKD hazard ratios (95% confidence intervals) for the highest versus lowest quartiles of serum albumin levels were 0.69 (0.40–1.17) for men and 0.42 (0.28–0.64) for women. Corresponding values for hs-CRP were 0.95 (0.54–1.67) for men and 1.85 (1.25 -2.75) for women. The association of combined serum albumin and hs-CRP with the risk of CKD was examined for women. The hazard ratio was 1.72 (1.17–2.54) for low versus higher albumin levels at lower hs-CRP levels, but such an association was not observed at high hs-CRP level. The hazard ratio was 1.96 (1.44–2.66) for high versus lower hs-CRP levels at higher serum albumin levels, but such association was not observed at low serum albumin level.

Conclusion: Both low serum albumin and high hs-CRP levels were predictive of CKD for women.

Trans-ancestry genome-wide association study identifies 12 genetic loci influencing blood pressure and implicates a role for DNA methylation

We carried out a trans-ancestry genome-wide association and replication study of blood pressure phenotypes among up to 320,251 individuals of East Asian, European and South Asian ancestry. We find genetic variants at 12 new loci to be associated with blood pressure (P = 3.9 × 10(-11) to 5.0 × 10(-21)). The sentinel blood pressure SNPs are enriched for association with DNA methylation at multiple nearby CpG sites, suggesting that, at some of the loci identified, DNA methylation may lie on the regulatory pathway linking sequence variation to blood pressure. The sentinel SNPs at the 12 new loci point to genes involved in vascular smooth muscle (IGFBP3, KCNK3, PDE3A and PRDM6) and renal (ARHGAP24, OSR1, SLC22A7 and TBX2) function. The new and known genetic variants predict increased left ventricular mass, circulating levels of NT-proBNP, and cardiovascular and all-cause mortality (P = 0.04 to 8.6 × 10(-6)). Our results provide new evidence for the role of DNA methylation in blood pressure regulation.

Relationship between the ankle-brachial index and the risk of coronary heart disease and stroke: the circulatory risk in communities study

AIM

Patients with peripheral artery disease (PAD) are at a high risk of cardiovascular disease (CVD) among Western populations. However, evidence for an elevated risk in Asian populations is limited.

METHODS

This prospective cohort study examined 939 Japanese men 60-74 years of age at the time of the baseline survey. A total of 115 cases of CVD were detected during a median 9.3 years of follow-up, and the ankle brachial blood pressure index (ABI) functioned as a surrogate measurement of PAD.

RESULTS

The age-adjusted risks of coronary heart disease, ischemic stroke and ischemic CVD (coronary heart disease and ischemic stroke) were higher among men in the lowest ABI tertile compared with that observed in the men in the highest tertile (<1.08 vs. >1.17). These associations did not change substantially after adjusting for cardiovascular risk factors. The respective multivariable hazard ratios (HRs, 95% CI) for the three conditions were as follows: 2.48 (1.08-5.71), p for trend=0.03; 1.95 (0.94-4.02), p for trend=0.04; and 2.16 (1.25-3.72), p for trend=0.004. These results did not vary based on a comparison of the three ABI categories: ≤0.90, 0.91-1.10 and >1.10. The multivariable HRs (95% CI) for an ABI ≤0.90 versus >1.10 were as follows: 2.04 (0.67-6.20), p for trend=0.14 for coronary heart disease; 3.39 (1.10-10.5), p for trend=0.006 for ischemic stroke; and 2.61 (1.19-5.76), p for trend=0.003 for ischemic CVD. There were no associations between the ABI and the risk of hemorrhagic stroke.

CONCLUSIONS

A low ABI is associated with the risk of coronary heart disease, ischemic stroke and ischemic CVD in elderly Japanese men.

Race/Ethnic Differences in the Associations of the Framingham Risk Factors with Carotid IMT and Cardiovascular Events

Background

Clinical manifestations and outcomes of atherosclerotic disease differ between ethnic groups. In addition, the prevalence of risk factors is substantially different. Primary prevention programs are based on data derived from almost exclusively White people. We investigated how race/ethnic differences modify the associations of established risk factors with atherosclerosis and cardiovascular events.

Methods

We used data from an ongoing individual participant meta-analysis involving 17 population-based cohorts worldwide. We selected 60,211 participants without cardiovascular disease at baseline with available data on ethnicity (White, Black, Asian or Hispanic). We generated a multivariable linear regression model containing risk factors and ethnicity predicting mean common carotid intima-media thickness (CIMT) and a multivariable Cox regression model predicting myocardial infarction or stroke. For each risk factor we assessed how the association with the preclinical and clinical measures of cardiovascular atherosclerotic disease was affected by ethnicity.

Results

Ethnicity appeared to significantly modify the associations between risk factors and CIMT and cardiovascular events. The association between age and CIMT was weaker in Blacks and Hispanics. Systolic blood pressure associated more strongly with CIMT in Asians. HDL cholesterol and smoking associated less with CIMT in Blacks. Furthermore, the association of age and total cholesterol levels with the occurrence of cardiovascular events differed between Blacks and Whites.

Conclusion

The magnitude of associations between risk factors and the presence of atherosclerotic disease differs between race/ethnic groups. These subtle, yet significant differences provide insight in the etiology of cardiovascular disease among race/ethnic groups. These insights aid the race/ethnic-specific implementation of primary prevention.

Urinary albumin as a marker of future blood pressure and hypertension in the general population

We investigated whether urinary albumin could predict the development of hypertension and future increases in blood pressure in the normotensive general population.Normotensive subjects who visited our hospital for a physical checkup (n = 6205, men 61.8%, 53.4 ± 11.4 years old) were enrolled in this study. Urine samples were collected for the measurement of albumin concentration, expressed as the ratio of urinary albumin to creatinine concentrations (UACR [mg/g Cr]). After the baseline examination, subjects were followed up for a median of 1089 days with the endpoint being the development of hypertension.Urinary albumin was in the normal range (UACR <30 mg/g Cr) in most subjects (97.5%). During the follow-up, hypertension developed in 1184 subjects (19.1%, 69.5 per 1000 person-years), with more men than women affected. The incidence of hypertension was increased across the quartiles of UACR by Kaplan-Meier analysis (log-rank, P < 0.0001) and the hazard ratio (lowest quartile [median UACR 1.14 mg/g Cr] as reference) was 1.53 (95% confidence intervals 1.30-1.80) in the highest quartile (median UACR 8.87 mg/g Cr). Multivariate Cox hazard analysis in which UACR was taken as a continuous variable identified UACR as a significant predictor of hypertension (hazard ratio 1.37, 95% CI 1.20-1.56). UACR was also an independent predictor of future increases in systolic blood pressure (P < 0.01).Urinary albumin is an independent predictor of hypertension and increases in blood pressure in the general population even in the normal range below the threshold defined for microalbuminuria.

Heart rate variability and blood pressure among Japanese men and women: a community-based cross-sectional study

Heart rate variability (HRV) is associated with blood pressure levels; however, very few studies have correlated HRV to lifestyle in the general population. We investigated 1418 men and 2040 women aged 40-74 years and measured the HRV indices in the time and frequency domains using a 5-min R-R interval recording. Multiple linear regression analyses were used to estimate the association between HRV and blood pressure levels after adjustment for major confounders. HRV indices were not associated with systolic blood pressure levels in men, whereas in women, one-s.d. (1-s.d.) increment of s.d. of normal R-R intervals (SDNN) was associated with a 1.21-mm Hg decrease in systolic blood pressure after adjusting for several confounders (P<0.05). In addition, a 1-s.d. increment of SDNN corresponded with 1.00 and 1.10 mm Hg reductions in diastolic blood pressure in men and women, respectively (P<0.05). When stratified by the use or nonuse of antihypertensive medication, these inverse associations were more evident in the nonuser group. Furthermore, among men not using antihypertensive medication, reduced HRV was associated with increased systolic blood pressure levels in nondrinkers. The data suggest that HRV reflects diastolic blood pressure better than systolic blood pressure levels for both sexes and that alcohol intake strongly affects systolic blood pressure levels in men, which may have weakened the association with HRV.

An association between central aortic pressure and subclinical organ damage of the heart among a general Japanese cohort: Circulatory Risk in Communities Study (CIRCS)

BACKGROUND

This study aimed to investigate associations between central aortic pressure (CAP) and subclinical organ damage of the heart amongst the general population.

METHODS

We conducted a cross-sectional study in a community-based population, consisting of 3002 men and women aged between 40 and 79 years. The CAP was measured using the HEM-9000AI device, an automated tonometer. Electrocardiograms (ECG) were read according to the Minnesota Code. Subclinical organ damage in the heart was defined as measurable left high amplitude R waves (LHAR), major and minor ST-T abnormalities, and left ventricular hypertrophy (LVH).

RESULTS

Age- and sex-adjusted prevalence of LHAR, major and minor ST-T abnormalities, and LVH was higher for subjects in the highest tertile of CAP levels than those in the lowest tertile. After further adjustments for other cardiovascular risk factors, these associations did not change substantially. The multivariable odds ratios (ORs) (95% CI) of LHAR, major and minor ST-T abnormalities, and LVH for the highest tertile of CAP levels compared to the lowest tertile were 2.7(1.9-3.9), 1.8(1.1-2.9), 1.7(1.3-2.3) and 3.2(1.3-8.1), respectively. The positive associations with LHAR and minor ST-T abnormalities were observed primarily among non-hypertensive subjects. The respective corresponding ORs were 2.8(1.7-4.6) and 1.7(1.2-2.4) for non-hypertensive subjects, and 1.7(0.9-3.3) and 1.1(0.7-1.8) for hypertensive subjects.

CONCLUSION

CAP levels were associated with subclinical organ damage of the heart independent of cardiovascular risk factors, and these associations were primarily seen in non-hypertensive subjects.

High-density lipoprotein subclasses and risk of stroke and its subtypes in Japanese population: the Circulatory Risk in Communities Study

BACKGROUND AND PURPOSE

High-density lipoprotein (HDL) cholesterol is an established protective factor for ischemic stroke. However, the contribution of HDL subclasses to stroke risk and its subtypes is uncertain.

METHODS

A prospective nested case-control study of 40- to 85-year-old Japanese was undertaken using frozen serum samples collected from 5280 men and 7524 women. They participated in cardiovascular risk surveys from 1985 to 1999 (1 community) and 1989 to 1998 (2 communities) under Circulatory Risk in Communities Study. HDL cholesterol subclasses were classified by high-performance liquid chromatography into 3 subgroups: S-HDL (very small or small HDL), M-HDL (medium HDL), and L-HDL (large or very large HDL) cholesterol. One control subject per case was matched by sex, age, community, serum storage year, and fasting status.

RESULTS

In 2005, we identified 241 strokes (155 ischemic and 86 hemorrhagic). S-HDL and M-HDL cholesterol levels were inversely associated with total stroke risk, ischemic stroke, specifically lacunar infarction, and hemorrhagic stroke. After adjustment for cardiovascular risk factors, these associations remained statistically significant. Multivariable conditional odds ratios (95% confidence interval) for 1 SD (0.12 mmol/L) increment of S-HDL cholesterol levels were 0.34 (0.23-0.52) for total stroke, 0.38 (0.23-0.63) for ischemic stroke, 0.33 (0.18-0.61) for lacunar infarction, 0.30 (0.14-0.65) for hemorrhagic stroke, and 0.30 (0.12-0.77) for intraparenchymal hemorrhage. The respective multivariable odds ratios for 1SD (0.10 mmol/L) increment of M-HDL cholesterol levels were 0.56 (0.41-0.75), 0.63 (0.45-0.88), 0.59 (0.40-0.87), 0.41 (0.21-0.80), and 0.38 (0.16-0.90). No associations were found between L-HDL cholesterol levels and risk of total stroke and its subtypes.

CONCLUSIONS

Small- to medium-sized HDL, not large HDL, cholesterol levels were inversely associated with total stroke risk.

Association between dietary behavior and risk of hypertension among Japanese male workers

Dietary behavior can worsen or prevent hypertension. However, data on the association between dietary behavior and the risk of hypertension in Asians are limited. The aim of this study was to determine these associations in Japanese male workers. We conducted a prospective study of 30-71-year-old Japanese male workers in Osaka, Japan, between 2001 and 2011. The study subjects were 3486 normotensive males who were assessed for an average of 4.6 years using an annual survey. We defined hypertension by a systolic blood pressure of ≥140 mm Hg, a diastolic blood pressure of ≥90 mm Hg and/or the use of antihypertensive medications. Dietary behavior questionnaires were included in the annual surveys. For each question on dietary behavior, we calculated the odds ratios (ORs) for the risk of hypertension using logistic regression models. We used subjects who consistently gave affirmative answers in the baseline and end-point surveys as a reference. The number of new cases of hypertension was 846 among 3486 subjects. Compared with subjects who eat meat frequently, subjects who did not eat meat frequently showed a higher risk of hypertension (OR=1.26, 95% confidence interval (CI): 1.00-1.59). Subjects who did not consume dairy products every day showed a higher risk of hypertension (OR=1.39, 95% CI: 1.13-1.71) compared with those who did. Meat and dairy product intake was associated with the prevention of hypertension among Japanese male workers.

Non-fasting blood glucose and risk of incident coronary heart disease in middle-aged general population: the Circulatory Risk in Communities Study (CIRCS)

OBJECTIVE

The objective was to determine whether non-fasting glucose concentration is a predictor for incident coronary heart disease.

METHODS

We investigated a cohort data of 9,900 40- to 69-year-old residents in four Japanese communities for 1975-1986 baseline surveys of the Circulatory Risk in Communities Study (CIRCS). Non-fasting blood glucose concentrations were available for 7,332 participants. Diabetic type was defined as a glucose level of ≥ 11.1 mmol/L and/or the use of medication for diabetes mellitus.

RESULTS

A total of 170 coronary heart disease including 113 myocardial infarctions occurred in non-fasting participants within the median 22-year follow-up period. Multivariable hazard ratios (HRs) of incident coronary heart disease for the participants with diabetic type compared with the normal type were 1.98 (0.84-4.68) for men, 3.39 (1.47-7.81) for women, and 2.47 (1.37-4.46) for total subjects. Corresponding HRs for myocardial infarction were 2.14 (0.83-5.55), 5.70 (2.21-14.67) and 3.17 (1.65-6.10), respectively. Multivariable HRs of incident coronary heart disease per one standard deviation of serum glucose levels were 1.17 (1.02-1.36), 1.19 (1.03-1.38), and 1.19 (1.08-1.32), respectively. The corresponding HRs for myocardial infarction were 1.18 (1.00-1.38), 1.27 (1.07-1.49) and 1.23 (1.10-1.37).

CONCLUSION

Non-fasting glucose concentration, either as diagnosis of diabetic type or as continuous variable, proved to be an independent predictor for incident coronary heart disease in middle-aged general population.

Risk factors for sudden cardiac death among Japanese: the Circulatory Risk in Communities Study

OBJECTIVE

There is little evidence concerning risk factors for sudden cardiac death (SCD) among Asians.

PATIENTS AND METHODS

A prospective, nested, case-control study of Japanese patients aged between 30 and 84 years was undertaken using data collected from 26 870 participants in cardiovascular risk surveys conducted in four communities between 1975 and 2005. The incidence of SCD was ascertained by systematic surveillance, with 239 cases of SCD identified over this period. For each case of SCD, three control patients were selected, matched by age, sex, examination year, follow-up time, and community.

RESULTS

Hypertension, diabetes mellitus, smoking, major ST-T abnormalities, left high amplitude R waves, and increased heart rate (≥77 beat/min) were all independently associated with a 1.5-3.2-fold increase in SCD risk, whereas no associations were observed for body mass index and hypercholesterolemia. The population-attributable fraction [95% confidence interval (CI)] was 23.0% (2.9-39.0) for hypertension, 15.3% (3.8-25.5) for current smoking, 14.5% (8.0-20.5) for major ST-T abnormalities, and 8.1% (2.2-13.7) for diabetes mellitus. The number of SCD risk factors (hypertension, diabetes, smoking, and ECG abnormalities) was positively associated with increased SCD risk. The odds ratio for increased SCD risk with three or more risk factors versus zero risk factors was 5.76 (95% CI 3.20-10.39).

CONCLUSIONS

Among the Japanese population, hypertension, smoking, major ST-T abnormalities, left high amplitude R waves, and diabetes mellitus were associated with an increased incidence of SCD, whereas there were no associations of body mass index or hypercholesterolemia with SCD incidence.

Alkaline phosphatase and risk of stroke among Japanese: the Circulatory Risk in Communities Study (CIRCS)

Although serum alkaline phosphatase (ALP) levels have been associated with mortality from all-cause and from either ischemic or hemorrhagic stroke, no study has been published of the associations between ALP and the incidence of stroke. We therefore examined the associations of ALP with risk of stroke among Japanese, stratified by drinking status because ALP is known as an enzyme affected by alcohol consumption. We conducted a prospective cohort study of 10,754 Japanese subjects (4098 men and 6656 women) aged 40-69 years and living in 4 communities under systematic surveillance for stroke incidence. During the 16-year follow-up, we documented 264 strokes (164 ischemic strokes and 69 hemorrhagic strokes) for men and 225 strokes (118 ischemic strokes and 89 hemorrhagic strokes) for women. There was a U-shaped association between ALP level and stroke incidence in both men and women, which was confined primarily to nondrinkers. For nondrinkers, higher ALP levels were associated with an elevated risk of ischemic stroke for men and of hemorrhagic stroke for women, whereas lower ALP levels were associated with elevated risks of ischemic and hemorrhagic strokes in both men and women. Our data indicate that not only higher, but also lower, serum ALP level may be a predictor for the risk of stroke in nondrinking men and women.

Self-reported snoring frequency and incidence of cardiovascular disease: the Circulatory Risk in Communities Study (CIRCS)

Background

Although associations between snoring and cardiovascular disease have been reported in several prospective studies, there is limited evidence from Asian populations. The objective of this study was to determine if there is an association between self-reported snoring frequency and the incidence of cardiovascular disease in Japanese.

Methods

The subjects were 2350 men and 4163 women aged 40 to 69 years who lived in 3 communities in Japan. All subjects were participants in the Circulatory Risk in Communities Study (CIRCS) and were followed for 6 years. Incidence of cardiovascular disease during the follow-up period comprised events of myocardial infarction, angina pectoris, sudden cardiac death and stroke.

Results

During the 6-year follow-up period, 97 participants (56 men and 41 women) had cardiovascular events. After adjustment for potential confounding factors, self-reported snoring frequency was associated with an increased risk of cardiovascular events among women but not men. The hazard ratios (95% CI) for cardiovascular events were 0.9 (0.4–2.0) for sometimes snoring and 2.5 (1.0–6.1) for everyday snoring in women and 0.7 (0.3–1.3) and 1.0 (0.5–2.1), respectively, in men. Further adjustment for body mass index attenuated the association in women; the respective hazard ratios for cardiovascular events were 0.9 (0.4–1.9) and 2.1 (0.9–5.4).

Conclusions

Self-reported habitual snoring was associated with increased risk of cardiovascular events among Japanese women. Overweight may partly mediate this association.

Trends in sudden cardiac death and its risk factors in Japan from 1981 to 2005: the Circulatory Risk in Communities Study (CIRCS)

OBJECTIVE

There is little evidence whether sudden cardiac death (SCD) is increasing in Asia, although the incidence of coronary heart disease among urban middle-aged Japanese men has increased recently. We examined trends in the incidence of SCD and its risk factors in the Circulatory Risk in Communities Study.

DESIGN AND SETTING

This was a population-based longitudinal study. Surveillance of men and women for SCD incidence and risk factors was conducted from 1981 to 2005.

SUBJECTS

The surveyed population was all men and women aged 30-84 years who lived in three rural communities and one urban community in Japan.

MAIN OUTCOME MEASURES

Trends in SCD incidence and its risk factors.

RESULTS

Age-adjusted and sex-adjusted incidence of SCD decreased from 1981-1985 to 1991-1995, and plateaued thereafter. The annual incidence per 100 000 person-years was 76.0 in 1981-1985, 57.9 in 1986-1990, 39.3 in 1991-1995, 31.6 in 1996-2000 and 36.8 in 2001-2005. The prevalence of hypertension decreased from 1981-1985 to 1991-1995, and plateaued thereafter for men and women. The age-adjusted prevalence of current smoking for men decreased while that of diabetes mellitus increased for both sexes from 1981-1985 to 2001-2005.

CONCLUSIONS

The incidence of SCD decreased from 1981 to 1995 but was unchanged from 1996 to 2005. Continuous surveillance is necessary to clarify future trends in SCD in Japan because of an increasing incidence of diabetes mellitus.

Adult mortality attributable to preventable risk factors for non-communicable diseases and injuries in Japan: a comparative risk assessment

BACKGROUND

The population of Japan has achieved the longest life expectancy in the world. To further improve population health, consistent and comparative evidence on mortality attributable to preventable risk factors is necessary for setting priorities for health policies and programs. Although several past studies have quantified the impact of individual risk factors in Japan, to our knowledge no study has assessed and compared the effects of multiple modifiable risk factors for non-communicable diseases and injuries using a standard framework. We estimated the effects of 16 risk factors on cause-specific deaths and life expectancy in Japan.

METHODS AND FINDINGS

We obtained data on risk factor exposures from the National Health and Nutrition Survey and epidemiological studies, data on the number of cause-specific deaths from vital records adjusted for ill-defined codes, and data on relative risks from epidemiological studies and meta-analyses. We applied a comparative risk assessment framework to estimate effects of excess risks on deaths and life expectancy at age 40 y. In 2007, tobacco smoking and high blood pressure accounted for 129,000 deaths (95% CI: 115,000-154,000) and 104,000 deaths (95% CI: 86,000-119,000), respectively, followed by physical inactivity (52,000 deaths, 95% CI: 47,000-58,000), high blood glucose (34,000 deaths, 95% CI: 26,000-43,000), high dietary salt intake (34,000 deaths, 95% CI: 27,000-39,000), and alcohol use (31,000 deaths, 95% CI: 28,000-35,000). In recent decades, cancer mortality attributable to tobacco smoking has increased in the elderly, while stroke mortality attributable to high blood pressure has declined. Life expectancy at age 40 y in 2007 would have been extended by 1.4 y for both sexes (men, 95% CI: 1.3-1.6; women, 95% CI: 1.2-1.7) if exposures to multiple cardiovascular risk factors had been reduced to their optimal levels as determined by a theoretical-minimum-risk exposure distribution.

CONCLUSIONS

Tobacco smoking and high blood pressure are the two major risk factors for adult mortality from non-communicable diseases and injuries in Japan. There is a large potential population health gain if multiple risk factors are jointly controlled.

Risk factors for snoring among Japanese men and women: a community-based cross-sectional study

PURPOSE

This study seeks to examine risk factors for snoring, a major symptom of sleep-disordered breathing (SDB) because the evidence is limited in Asian populations.

METHODS

Subjects for the present cross-sectional study were 3,138 men and 5,345 women aged 35–79 years from three communities in Japan who participated in the Circulatory Risk in Communities Study. The data on snoring frequency and cardiovascular health were obtained during annual cardiovascular surveys between 2000 and 2005. The logistic regression model was used to estimate the odds ratios (ORs) for snoring associated with body mass index (BMI), alcohol consumption, and other cardiovascular risk factors.

RESULTS

The prevalence of almost everyday snoring was 24% among men and 10% among women. After adjustments for age, community, cigarette smoking, alcohol consumption, and for women, menopausal status, the multivariable-adjusted ORs for everyday snoring in the highest versus lowest quartiles of BMI categories were 3.4 (95% confidence interval (CI): 2.6–4.4) for men and 3.9 (2.8–5.4) for women. The respective ORs in ≥23 g ethanol per day versus never-drinkers categories were 1.4 (1.1–1.8) and 3.1 (1.8–5.3) and those in ≥20 cigarettes versus never-smokers categories were 1.4 (1.0–1.8) and 1.9 (0.9–3.7). The associations of alcohol consumption and cigarette smoking with everyday snoring were stronger for BMI<25 kg/m2 than BMI≥25 kg/m2 in both sexes.

CONCLUSION

BMI, alcohol consumption, and cigarette smoking were positively associated with habitual snoring for both men and women, especially in nonoverweight persons.

Chronic kidney disease and drinking status in relation to risks of stroke and its subtypes: the Circulatory Risk in Communities Study (CIRCS)

BACKGROUND AND PURPOSE

Several epidemiological studies have established an association between chronic kidney disease (CKD), based on estimated glomerular filtration rate (GFR), and risk of stroke. However, sex-specific evidence for the relationship between CKD and risk of stroke and its subtypes is still limited.

METHODS

We conducted a prospective cohort study of 12 222 Japanese men and women age 40 to 69 years living in 4 communities under systematic surveillance of stroke incidence to determine the relationship between CKD and risk of stroke and its subtypes.

RESULTS

During the 17-year follow-up, there were 566 strokes (327 ischemic and 186 hemorrhagic strokes). GFR was inversely associated with age- and community-adjusted risk of total stroke for both men and women. Compared with the reference group without CKD (GFR ≥60 mL/min per 1.73m(2)), the adjusted risks of total stroke for subjects with CKD (GFR <60 mL/min per 1.73m(2)) were 1.63 (1.22-2.17) for men and 1.51 (1.13-2.02) for women. Excess risk of stroke associated with CKD was identified primarily for hemorrhagic stroke among men and for ischemic stroke among women. After adjustment for traditional cardiovascular risk factors, associations remained statistically significant. When stratified by drinking status, excess risk of hemorrhagic stroke with CKD was confined to drinkers; adjusted risks were 4.18 (2.31-7.57) for men and 7.00 (1.92-25.56) for women.

CONCLUSIONS

CKD was associated with increased risk of hemorrhagic stroke for men, and of ischemic stroke for women. This sex difference may partly be explained by the difference in prevalence of drinkers between men and women.

Low-density lipoprotein cholesterol and risk of coronary heart disease among Japanese men and women: the Circulatory Risk in Communities Study (CIRCS)

OBJECTIVE

The objective of this study was to assess the association between serum LDL-cholesterol levels and risk of coronary heart disease (CHD) among Japanese who have lower means of LDL-cholesterol than Western populations.

METHODS

The predictive power of estimated serum LDL-cholesterol levels in casual blood samples for risk of CHD was evaluated among residents from four Japanese communities participating in the Circulatory Risk in Communities Study (CIRCS). A total of 8131 men and women, aged 40 to 69 years with no history of stroke or CHD, completed baseline risk factor surveys between 1975 and 1987. By 2003, 155 cases of incident CHD (myocardial infarction, angina pectoris and sudden cardiac death) had been identified.

RESULTS

Mean LDL-cholesterol values were 99.4 mg/dL for men and 109.4 mg/dL for women. The crude incidence rate (per 100,000 person-years) of CHD was 152.0 for men and 51.9 for women. The respective multivariable hazard ratios for ≥ 140 mg/dL versus <80mg/dL LDL-cholesterol were 2.80 (95% confidence interval: 1.59 to 4.92) for total CHD, 3.83 (1.78-8.23) for myocardial infarction, 4.07 (2.02-8.20) for non-fatal CHD, and 1.24 (0.44-3.47) for fatal CHD.

CONCLUSION

Serum LDL-cholesterol levels ranging from around 80 mg/dL to 200mg/dL were positively associated with risk of CHD in a Japanese population.

Obstructive sleep apnea: its prevention and screening may contribute to the prevention of hypertension, diabetes and cardiovascular diseases

Relationships between obstructive sleep apnea and cardiovascular diseases have been reported by both clinical and epidemiological studies. To investigate whether nocturnal intermittent hypoxia (NIH), a surrogate marker for obstructive sleep apnea in the general population, is associated with cardiovascular risk factors, we have conducted epidemiological studies in Japan. The Circulatory Risk in Communities Study (CIRCS) is a cohort study conducted across Japan to examine the risk factors for cardiovascular diseases. In CIRCS participants, NIH was estimated by the hourly occurrences of oxygen desaturation ≥3% (3% oxygen desaturation index [3% ODI]) measured during sleep using a pulse-oximeter. Our studies showed that among middle-aged Japanese, 3% ODI levels were associated with hypertension, elevated serum CRP levels, accumulation of metabolic risk factors, and increased risk of developing type 2 diabetes. Screening for obstructive sleep apnea in the general population is a promising and widely broadly applicable strategy for predictive, preventive and personalized medicine.

Adiposity and risk of cardiovascular diseases in Japan: secular trend, individual level associations and causal pathway - implications for the prevention of cardiovascular diseases in societies with rapid economic development

In Japan, overweight/obesity in adults defined as a body mass index of 25 kg/m² or over has roughly doubled among middle-aged men over the past few decades. In parallel with a population rightward shift in the degree of obesity, the proportion of hypertension attributed to overweight has increased. There is an indication that the incidence of ischemic stroke and coronary heart disease remains stable or has been increasing among men. These facts indicate that the relative importance of cardiovascular diseases (CVD) risk factors may have changed. Although it was confirmed at an individual level that the degree of obesity was positively associated with CVD incidence, there is a sizeable proportion of individuals who are at an increased CVD risk state without being overweight/obese in today’s Japan. Thus, further implementation and promotion of activities are needed to bring about meaningful changes in the obesity trend in communities that are harmonized with other domains of CVD prevention activities.

Lifetime risk of stroke and impact of hypertension: estimates from the adult health study in Hiroshima and Nagasaki

Very few reports have been published on lifetime risk (LTR) of stroke by blood pressure (BP) group. This study included participants in the Radiation Effects Research Foundation Adult Health Study who have been followed up by biennial health examinations since 1958. We calculated the LTR of stroke for various BP-based groups among 7847 subjects who had not been diagnosed with stroke before the index age of 55 years using cumulative incidence analysis adjusting for competing risks. By 2003, 868 subjects had suffered stroke (512 (58.9%) were women and 542 (62.4%) experienced ischemic stroke). BP was a significant factor in determining risk of stroke for men and women, with distributions of cumulative risk for stroke significantly different across BP groups. The LTR of all-stroke for normotension (systolic BP/diastolic BP < 120/80 mm Hg), prehypertension (120-139/80-89 mm Hg), stage 1 hypertension (140-159/90-99 mm Hg) and stage 2 hypertension (> 160/100 mm Hg) were 13.8-16.9-25.8-25.8% in men and 16.0-19.9-24.0-30.5% in women, respectively (P < 0.001 among BP groups in both sexes). The estimates did not differ significantly (P = 0.16) between normotensive and prehypertensive subjects. One in five Japanese atomic bomb survivor subjects experienced stroke over their lifetime from the age of 55 years. Long-term stroke risks were elevated in those with hypertension (> 140/90 mm Hg) at any of the index ages of 45, 55, 65 and 75 years.

Lifestyle and cardiovascular disease in Japan

The aim was to give on overview of the profile of cardiovascular disease, vascular pathology and the relationships between lifestyle and cardiovascular disease in Japanese. Compared with the United States and Europe, the higher mortality from stroke and lower mortality from coronary heart disease constitute a unique cardiovascular profile for Japan. A selective review of population-based pathology, trend and prospective cohort studies was performed to clarify the characteristics of cardiovascular disease and vascular pathology, trends in the incidence and mortality of cardiovascular disease, and the relationships between lifestyle and cardiovascular disease among Japanese adults. Since the 1970s, mortality from coronary heart disease as well as stroke has declined substantially in Japan, probably due to a major decline in blood pressure levels and for men a more recent decline in smoking, in spite of an increase in body mass index and total cholesterol levels. However, the decline in mortality was smaller and plateaued in middle-aged men aged 30-49 in the metropolitan cities of Tokyo and Osaka. The incidence of coronary heart disease has increased among middle-aged men residing in the suburbs of Osaka. As for the associations between lifestyle and cardiovascular disease, higher sodium, lower calcium and lower animal protein content in the diet and for men higher alcohol consumption may account for the higher prevalence of hypertension and higher risk of stroke for Japanese than for western populations. On the other hand, lower saturated fat (meat) and higher n3 polyunsaturated fat (fish) in the Japanese diet may contribute to the lower prevalence of hypercholesterolemia and lower risk of coronary heart disease among Japanese. Japan is unique among developed countries in that coronary heart disease mortality has been low and has continued to decline, while stroke mortality has declined substantially. However, a recent trend for coronary heart disease incidence to increase among urban men is a cause for concern as a potential source of future problems for public health and clinical practice in Japan.

Associations between alcohol consumption and sleep-disordered breathing among Japanese women

BACKGROUND

The associations between alcohol consumption and sleep-disordered breathing in women are uncertain.

METHODS

We conducted a cross-sectional study of 3113 women aged 30-69 years. The 3% oxygen desaturation index (3% ODI), based on overnight pulse oximetry findings, was selected as an indicator of sleep-disordered breathing.

RESULTS

3% ODI frequencies of ≥5 were higher for drinking women with ethanol intakes of ≥23.0 g/d than for never drinkers: the respective multivariable odds ratios and 95% confidence intervals was 1.8(1.0-3.4). The corresponding odds ratio was 3.0(1.6-5.8) for habitual snoring. The associations of ethanol intakes of ≥23.0 g/d with 3% ODI ≥ 5 was more evident among women with BMI <23.0 kg/m(2) (median) than those with higher BMI but did not vary by habitual snoring. The multivariable odds ratios of 3%ODI ≥ 5 for women with ethanol intakes of ≥23.0 g/d versus never drinkers were 2.7(1.0-6.7) for lower BMI and 1.5(0.6-3.3) for higher BMI and the corresponding odds ratio were 2.8(1.6-7.2) and 3.2(1.3-7.9) for habitual snoring, respectively.

CONCLUSION

Alcohol consumption was associated with higher prevalence of sleep-disordered breathing among Japanese women.

Premature mortality due to stroke and trend in stroke mortality in Japan (1980-2005)

BACKGROUND

Although a downward trend in stroke mortality over the last decades has been observed in many countries, stroke remains an important contributor to the total burden of disease. In the present study, we provided additional measures, namely years of life lost (YLLs) and average years of life lost (AYLLs) to reflect the burden of this condition in Japan.

METHODS

We obtained stroke mortality data for Japan from the World Health Organization mortality database for the period 1980-2005 to analyze trends of age-standardized rates (ASRs) per 100,000 of stroke mortality. YLLs and AYLLs were also estimated according to Japanese life tables.

RESULTS

Decreases in ASRs by 68% in men and by 74% in women were observed at the end of this study period. In men, there were total of 1,684,482 YLLs in 1980; 776,350 in 1995 and 745,636 in 2005, corresponding to an overall AYLLs for all stroke deaths of 20.6; 11.2 and 11.7 years earlier than expected, respectively. In women, the respective numbers were 1,567,817 YLLs in 1980; 810,135 in 1995 and 726,650 in 2005, corresponding to an overall AYLLs for all stroke deaths of 19.4; 10.5 and 10.5 years.

CONCLUSIONS

The findings showed shorter AYLLs due to stroke in Japan, suggesting that stroke patients died from this condition at older age at the end of the study period. This change in premature mortality was consistent with decreased trend in the stroke mortality.

The combined impact of blood pressure category and glucose abnormality on the incidence of cardiovascular diseases in a Japanese urban cohort: the Suita Study

Few prospective studies have examined the combined impact of blood pressure (BP) categories and glucose abnormalities on the incidence of cardiovascular disease (CVD) in the general Asian population. This study aimed to examine the effect of the combined risks of these factors on the incidence of CVD in a general Japanese population. We studied 5321 Japanese individuals (aged 30-79 years), without CVD at baseline, who received follow-up for an average of 11.7 years. Serum fasting glucose categories were defined according to the 2003 American Diabetes Association recommendations. BP categories were defined by the 2009 Japanese Society of Hypertension Guidelines for the Management of Hypertension. The Cox proportional hazard ratios (HRs) for CVD according to the serum glucose and BP categories were calculated. In 62,036 person-years of follow-up, we documented 364 CVD events (198 stroke and 166 coronary heart disease (CHD)). Compared with normoglycemic subjects, the multivariable HRs (95% confidence intervals (CIs)) for CVD, CHD and stroke were 1.25 (1.00-1.58), 1.46 (1.04-2.04) and 1.11 (0.81-1.52), respectively, in individuals with impaired fasting glucose (IFG), whereas these values were 2.13 (1.50-3.03), 2.28 (1.34-3.88) and 2.08 (1.29-3.35), respectively, in individuals with diabetes mellitus (DM). Compared with normoglycemic and optimal blood pressure (BP) subjects, increased risks of CVD were observed in the normoglycemic subjects with high-normal BP or hypertension, the IFG subjects with normal or higher BP, and the DM subjects regardless of BP category (P-value for interaction=0.046). In conclusion, the high-normal BP subjects in all glucose categories and the normal BP subjects with IFG showed increased risk of CVD in this Japanese population. Further investigation of larger cohorts of DM subjects should be conducted to better understand this phenomenon.

Psychological distress and cardiovascular disease: the Circulatory Risk in Communities Study (CIRCS)

Although a number of epidemiological studies have reported that psychological factors are associated with increased risk of cardiovascular morbidity and mortality, the relevant epidemiological data are mostly limited to Western populations. The present study sought to examine associations of depressive symptoms, anger expression, and tension with the incidence of cardiovascular disease in the Circulatory Risk in Communities Study (CIRCS). Depressive symptoms were measured in 901 men and women by using the Zung Self-Rating Depression Scale (SDS); anger expression and tension were measured in 6292 men and women by using the Anger Expression Scale and Framingham Tension Scale. As compared with the participants with SDS scores in the lowest tertile, those with scores in the highest tertile had twice the age- and sex-adjusted hazard ratio of total stroke. However, this excess risk was present only for ischemic stroke. Participants in the highest tertile also had a 7-fold adjusted hazard ratio of coronary heart disease, as compared with those in the lowest tertile. These associations were virtually unchanged after further adjustment for covariates. Men with “anger-in” scores in the highest tertile had a 1.5-fold age-adjusted relative risk of hypertension as compared with those in the lowest tertile; anger-in score was not associated with hypertension in women. In men and women, there were no associations between hypertension and either “anger-out” or tension scores. These findings generally support the hypothesis that—as is the case in Western populations—anger suppression and depression increase the risk of cardiovascular disease among Japanese.

Nocturnal intermittent hypoxia and the development of type 2 diabetes: the Circulatory Risk in Communities Study (CIRCS)

AIMS/HYPOTHESIS

Although the associations between obstructive sleep apnoea and type 2 diabetes mellitus have been reported in cross-sectional design studies, findings on the prospective association between the two conditions are limited. We examined prospectively the association between nocturnal intermittent hypoxia as a surrogate marker of obstructive sleep apnoea and risk of type 2 diabetes.

METHODS

A total of 4,398 community residents aged 40 to 69 years who had participated in sleep investigation studies between 2001 and 2005 were enrolled. Nocturnal intermittent hypoxia was assessed by pulse-oximetry and defined by the number of oxygen desaturation measurements < or =3% per h, with five to <15 per h corresponding to mild and 15 events or more per h corresponding to moderate-to-severe nocturnal intermittent hypoxia, respectively. The development of type 2 diabetes was defined by: (1) fasting serum glucose > or =7.00 mmol/l (126 mg/dl); (2) non-fasting serum glucose > or =11.1 mmol/l (200 mg/dl); and/or (3) initiation of glucose-lowering medication or insulin therapy. Multivariable model accounted for age, sex, BMI, smoking status, current alcohol intake, community, borderline type 2 diabetes, habitual snoring, excessive daytime sleepiness, sleep duration and (for women) menopausal status.

RESULTS

By the end of 2007, 92.2% of participants had been followed up (median follow-up duration [interquartile range] 3.0 [2.9-4.0] years) and 210 persons identified as having developed diabetes. The multivariable-adjusted hazard ratio (95% CI) for developing type 2 diabetes was 1.26 (0.91-1.76) among those with mild nocturnal intermittent hypoxia and 1.69 (1.04-2.76) among those with moderate-to-severe nocturnal intermittent hypoxia (p = 0.03 for trend).

CONCLUSIONS/INTERPRETATION

Nocturnal intermittent hypoxia was associated with increased risk of developing type 2 diabetes among middle-aged Japanese.

Nocturnal intermittent hypoxia and metabolic syndrome; the effect of being overweight: the CIRCS study

AIM

We investigated whether nocturnal intermittent hypoxia, a surrogate marker for obstructive sleep apnea, is associated with metabolic syndrome and its components among Japanese.

METHODS

We examined 1,710 male and 2,896 female community-dwelling Japanese aged 40 to 69, who participated in annual cardiovascular examinations and investigations of sleep. Nocturnal intermittent hypoxia was estimated based on a 3% oxygen desaturation index measured with pulse-oximetry during sleep. No, mild and moderate-to-severe nocturnal intermittent hypoxia were defined by <5, 5 to <15 and >or=15 events/hour, respectively. Metabolic syndrome was defined by modified criteria of the Adult Treatment Panel III guidelines.

RESULTS

Compared with no nocturnal intermittent hypoxia, the multivariable odds ratio of metabolic syndrome was 1.9 (95% confidence interval: 1.6-2.4) for mild and 3.2 (2.2-4.7) for moderate-to-severe nocturnal intermittent hypoxia among men; 2.6 (2.1-3.4) and 5.8 (3.4-9.8) among women, respectively. When stratified by overweight status (body mass index >or=25 kg/m(2)), the multivariable odds ratio of two or more metabolic risk factors (other than overweight) associated with moderate-to-severe nocturnal intermittent hypoxia was 1.9 (1.2-3.1) among non-overweight subjects and 1.4 (0.9-2.1) among overweight subjects (p for interaction=0.002).

CONCLUSIONS

Nocturnal intermittent hypoxia was associated with the accumulation of metabolic risk factors, especially among non-overweight individuals.

Relations between protein intake and blood pressure in Japanese men and women: the Circulatory Risk in Communities Study (CIRCS)

BACKGROUND

An inverse association between protein intake and blood pressure has been reported in Western countries. However, the evidence is limited for Asians, whose protein sources are different from those in Western populations.

OBJECTIVES

The objective was to examine the association between protein intake and blood pressure in Japanese adults.

METHODS

We conducted a population-based, cross-sectional study of 7585 subjects (3499 men and 4086 women) from 40 to 69 y of age living in 5 communities in Japan. Dietary intakes of total, animal, and plant protein were estimated by a single 24-h dietary recall. We then examined the associations between dietary intake of those proteins and blood pressure after adjustment for age, sex, community, body mass index, antihypertensive medication use, ethanol intake, smoking, and dietary intakes of sodium, potassium, and calcium.

RESULTS

After adjustment for cardiovascular disease risk factors, a 25.5-g/d increment in total protein intake was associated with a decrease in systolic blood pressure of 1.14 mm Hg (P < 0.001) and in diastolic blood pressure of 0.65 mm Hg (P < 0.001), and a 19.9-g/d increment in animal protein intake was associated with a decrease in systolic blood pressure of 1.09 mm Hg (P < 0.001) and in diastolic blood pressure of 0.41 mm Hg (P = 0.003). A 13.1-g/d increment in plant protein intake was associated with a decrease in diastolic blood pressure of 0.57 mm Hg (P < 0.001). Further adjustment for nutritional factors weakened these associations, but the inverse associations of total protein intake with diastolic blood pressure and of animal protein intake with systolic blood pressure remained statistically significant.

CONCLUSION

Total and animal protein intakes were inversely associated with blood pressure in Japanese adults.

High-normal blood pressure and the risk of cardiovascular disease

The guidelines of the Joint National Committee 7 from the USA on hypertension have unified the normal and high-normal blood pressure categories into a single entity termed ;prehypertension'. In contrast, The European Guidelines for the management of hypertension in 2007 considered ;prehypertensive' to be divided into normal and high-normal blood pressure. These patients with high-normal blood pressure or prehypertension might progress to hypertension over time. Previous studies have shown that high-normal blood pressure is a risk factor for cardiovascular disease (CVD) in Western countries and Japan. The combination of high-normal blood pressure and other cardiovascular risk factors increases the risks of CVD. Recently, metabolic syndrome has also been shown to be a risk factor for CVD. In Japan, the association between metabolic syndrome and CVD was also found to be significant. The risks for CVD incidence were similar among participants who had the same number of components, regardless of the presence of abdominal obesity. In the Japanese guidelines for the management of hypertension published in 2009, patients are considered to be in a high-risk group if they have diabetes, chronic kidney disease, 3 or more risk factors, target organ damage or CVD, even if they have only high-normal blood pressure, and appropriate antihypertensive therapy should be initiated.