Association between N-terminal pro B-type natriuretic peptide and day-to-day blood pressure and heart rate variability in a general population: the Ohasama study.

BACKGROUND: In addition to day-to-day variability in blood pressure (BP) or heart rate (HR), N-terminal pro B-type natriuretic peptide (NT-proBNP) has been reported to be a predictor of cardiovascular disease. Here, we tested the hypothesis that day-to-day BP or HR variability calculated as the intraindividual standard deviation (SD) of home BP or HR is associated with elevated NT-proBNP in a cross-sectional study. METHODS: Among 664 participants (mean age, 61.9 years; female, 70.5%) from a general Japanese population without a history of heart disease, 86 (13.0%) had NT-proBNP at least 125 pg/ml. RESULTS: Each 1 SD increase in the SD of home systolic BP (SBP) [odds ratio (OR), 1.82; P < .0001) and in the SD of home HR (OR, 1.44; P = 0.008) were significantly associated with the prevalence of NT-proBNP at least 125 pg/ml after adjustment for possible confounding factors including home SBP and HR. Among the four groups defined by the median SD of home SBP and of home HR, the group with higher SDs in home SBP (≥8.0 mmHg) and HR (≥5.0 bpm) had the greatest OR for the prevalence of NT-proBNP at least 125 pg/ml (OR, 4.80; P = 0007 vs. a reference group with lower SDs of home SBP and HR). CONCLUSION: These results suggest that day-to-day variability in BP and HR may be associated with target-organ damage or complications, which can lead to an elevated NT-proBNP level. An elevated NT-proBNP level may be involved in the prognostic significance of day-to-day variability in BP or HR.

Association of aldosterone-to-renin ratio with hypertension differs by sodium intake: the Ohasama study.

BACKGROUND: In cross-sectional studies, the aldosterone-to-renin ratio (ARR) has been reported to be associated with hypertension under conditions of higher sodium intake. The objective of this prospective study was to investigate the association between ARR and the development of hypertension in community residents stratified by dietary sodium intake. METHODS: From the general population of Ohasama, we obtained plasma renin activity (PRA) and plasma aldosterone concentrations (PACs) for 608 participants (mean age = 57.6 years; 71.4% women) without hypertension at baseline. Using the Cox model, we computed the adjusted hazard ratio (HR) of natural log-transformed ARR (lnARR) for the development of hypertension, defined as blood pressure ≥140/90mm Hg or start of treatment with antihypertensive drugs during follow-up. RESULTS: During a mean follow-up of 6.8 years, 298 participants developed hypertension. The median PRA, PAC, and ARR were 1.2ng/ml/hour, 6.6ng/dl, and 5.5ng/dl per ng/ml/hour, respectively. Each 1 SD increase in lnARR was associated with an increased risk for the development of hypertension in participants overall (HR = 1.18; P = 0.007). In participants with higher sodium intake (median ≥4,102mg/day), a significant association of lnARR with hypertension remained (HR = 1.25; P = 0.009), whereas no significant association was observed in participants with lower sodium intake (P = 0.18). Participants who developed hypertension had significantly lower PRA than those who did not (P = 0.003), despite no differences in PAC (P = 0.91). CONCLUSIONS: These results raise the hypothesis that relative aldosterone excess may have a deleterious effect on the development of hypertension by contributing to salt/volume-related hypertension.

Day-to-day variability in home blood pressure is associated with cognitive decline: the Ohasama study.

Although an association between high blood pressure and cognitive decline has been reported, no studies have investigated the association between home blood pressure and cognitive decline. Home blood pressure measurements can also provide day-to-day blood pressure variability calculated as the within-participant SD. The objectives of this prospective study were to clarify whether home blood pressure has a stronger predictive power for cognitive decline than conventional blood pressure and to compare the predictive power of the averaged home blood pressure with day-to-day home blood pressure variability for cognitive decline. Of 485 participants (mean age, 63 years) who did not have cognitive decline (defined as Mini-Mental State Examination score, <24) initially, 46 developed cognitive decline after a median follow-up of 7.8 years. Each 1-SD increase in the home systolic blood pressure value showed a significant association with cognitive decline (odds ratio, 1.48; P=0.03). However, conventional systolic blood pressure was not significantly associated with cognitive decline (odds ratio, 1.24; P=0.2). The day-to-day variability in systolic blood pressure was significantly associated with cognitive decline after including home systolic blood pressure in the same model (odds ratio, 1.51; P=0.02), whereas the odds ratio of home systolic blood pressure remained positive, but it was not significant. Home blood pressure measurements can be useful for predicting future cognitive decline because they can provide information not only on blood pressure values but also on day-to-day blood pressure variability.

Aldosterone-to-renin ratio and nocturnal blood pressure decline assessed by self-measurement of blood pressure at home: the Ohasama Study.

Based on ambulatory blood pressure (BP) monitoring, the aldosterone-to-renin ratio (ARR) has been reported to be associated with a diminished nocturnal decline in BP, generally referred to as a "non-dipping" pattern. The objective of this cross-sectional study was to investigate the association between ARR and the non-dipping pattern based on home BP measurements. This study included 177 participants≥55 years from the general population of Ohasama (mean age: 67.2 years; 74.6% women); no patient was receiving antihypertensive treatment. The median plasma renin activity (PRA), plasma aldosterone concentration (PAC) and ARR were 0.8 ng/mL/h, 8.1 ng/dL and 9.7 ng/dL per ng/mL/h, respectively. Each 1 SD increase in log-transformed (ln) ARR was significantly associated with the prevalence of the non-dipping pattern after adjustments for possible confounding factors including home morning systolic BP (odds ratio, 1.45; p=0.049). However, no significant associations of PRA or PAC with the non-dipping pattern were observed (p≥0.2). When participants were divided into four groups according to median levels of home morning and night-time systolic BPs, the group with a higher home morning systolic BP (≥128.4 mmHg) with a higher home night-time systolic BP (≥114.4 mmHg) had the greatest ARR levels (ANCOVA p=0.01). These results support the hypothesis that relative aldosterone excess may be related to a non-dipping pattern in a general population and suggest that a non-dipping pattern can be accurately observed by home BP measurements.

Night-time blood pressure is associated with the development of chronic kidney disease in a general population: the Ohasama Study.

OBJECTIVE: Ambulatory blood pressure (BP) is reportedly associated with target organ damage. However, whether ambulatory BP carries prognostic significance for the development of chronic kidney disease (CKD) has not been confirmed. METHOD: We measured ambulatory BP in 843 participants without CKD at baseline from a general Japanese population and examined the incidence of CKD defined as positive proteinuria or an estimated glomerular filtration rate (eGFR) less than 60 ml/min per 1.73 m at health checks. The association between baseline ambulatory BP and CKD incidence was examined using the Cox proportional hazard regression model adjusted for sex, age, BMI, habitual smoking, habitual alcohol consumption, diabetes mellitus, hypercholesterolemia, a history of cardiovascular disease, antihypertensive medication, eGFR at baseline, the number of follow-up examinations, and the year of the baseline examination. RESULTS: The mean age of the participants averaged 62.9 ±â€Š8.1 years, 71.3% were women and 23.7% were under antihypertensive medication. During a median follow-up of 8.3 years, 220 participants developed CKD events. The adjusted hazard ratios for CKD in a 1-standard deviation increase in daytime and night-time SBP were 1.13 [95% confidence interval (CI) 0.97-1.30] and 1.21 (95% CI 1.04-1.39), respectively. When night-time and daytime BP was mutually adjusted into the same model, only night-time BP persisted as an independent predictor of CKD. CONCLUSION: Night-time BP is a better predictor of CKD development than daytime BP in the general population. Ambulatory BP measurement is considered useful for evaluating the risk of progression to CKD.

Home blood pressure level, blood pressure variability, smoking, and stroke risk in Japanese men: the Ohasama study.

BACKGROUND: Hypertension and smoking independently contribute to the risk of stroke. Our objective was to investigate home blood pressure (HBP) levels, day-by-day BP variability, and smoking in the prediction of stroke in Japanese men. METHODS: In this study, 902 men (mean age, 58.6 years) without a past history of stroke were evaluated. HBP was measured once every morning for 4 weeks. Day-by-day BP variability was defined as within-subject standard deviations (SD) of HBP. Smoking history was obtained from a standardized questionnaire. Hazard ratios (HRs) for stroke were examined by Cox regression model, with adjustment for possible confounders. RESULTS: During 13.1 years (median) of follow-up, 89 cerebral infarctions, 28 intracranial hemorrhages, and six other strokes occurred. Systolic HBP levels (HR = 1.59 per 14.6 mm Hg increase, P < 0.0001) and variability (HR = 1.26 per 3.1 mm Hg increase, P = 0.03) of +1 between-subject SD were significantly associated with cerebral infarction. The relationship between HBP and cerebral infarction differed with smoking status (interaction P = 0.021 and 0.017 for systolic level and variability, respectively). In analyses stratified according to smoking, systolic level (HR = 1.78, P < 0.0001) and variability (HR = 1.38, P = 0.006) were significantly associated with cerebral infarction in ever smokers (N = 511), but not in never smokers (N = 391; P ≥ 0.6 for both). No significant association was found between smoking and the risk of intracranial hemorrhage. CONCLUSIONS: In ever smokers, both HBP levels and variability are significantly associated with the risk of cerebral infarction. Our findings further validate the benefit of smoking cessation in preventing cardiovascular disease (CVD), especially cerebral infarction.

Plasma renin activity and the aldosterone-to-renin ratio are associated with the development of chronic kidney disease: the Ohasama Study.

BACKGROUND: The aldosterone-to-renin ratio (ARR) is used to screen for primary aldosteronism and could be an index for salt sensitivity. The association between ARR and the development of chronic kidney disease (CKD) is completely unknown. METHOD: A longitudinal observational study involving 689 participants from a general Japanese population (mean age 58.2 years; 68.5% women) who did not have CKD and were not receiving antihypertensive medication at baseline was conducted. The estimated glomerular filtration rate (eGFR) was calculated from serum creatinine levels, and CKD was defined as eGFR less than 60 ml/min per 1.73 m(2) and/or dipstick-positive proteinuria. The associations of baseline plasma renin activity (PRA), plasma aldosterone concentration, and ARR with the development of CKD were examined using Cox proportional hazard regression analysis adjusted for sex, age, BMI, smoking, drinking, history of hypercholesterolemia, diabetes mellitus, and cardiovascular disease, SBP, and baseline eGFR. RESULTS: During a mean 9.1-year follow-up, 118 participants developed CKD. A 1 standard deviation increment in the natural log-transformed (ln) ARR was positively associated with the incidence of CKD (hazard ratio 1.29, P = 0.012). LnPRA showed an inverse association (hazard ratio 0.76, P = 0.007). Meanwhile, plasma aldosterone concentration was not associated with CKD. Individuals who developed CKD had significantly lower baseline PRA (0.97 vs. 1.14 ng/ml per h; P = 0.03) and higher baseline ARR levels [66.6 vs. 56.8 (pg/ml)/(ng/ml per h); P = 0.02] than those who did not. CONCLUSIONS: Lower PRA and higher ARR were associated with the development of CKD in a general population, suggesting that they are independent predictors of CKD.

Aldosterone-to-renin ratio as a predictor of stroke under conditions of high sodium intake: the Ohasama study.

BACKGROUND: Aldosterone is thought to have deleterious effects on the cardiovascular system. The aldosterone-to-renin ratio (ARR) is more reproducible than aldosterone levels alone and could be an index for inappropriate aldosterone secretion or activity. We previously reported the apparent relation between ARR and hypertension in subjects with high sodium intake. This prospective study investigated the risk of ARR for a first stroke in a general population stratified by sodium intake. METHODS: We obtained plasma renin activity (PRA) and plasma aldosterone concentrations (PAC) for 883 participants aged ≥ 35 years not receiving antihypertensive treatment in the general population of Ohasama (mean age: 59.0 ± 11.3 years; 65.6% women). RESULTS: Over a mean of 10.9 follow-up years, 45 strokes occurred. The median PRA, PAC, and ARR were 1.2 ng/ml/h, 6.4 ng/dl, and 5.3 ng/dl per ng/ml/h, respectively. Using Cox regression, we computed hazard ratios adjusted for sex, age, body mass index (BMI), and systolic blood pressure. No association between logARR and stroke was observed in subjects overall. However, in subjects with high sodium intake (≥ median of 4,058 mg/day (salt equivalent, 10.5 g/day)), each 1 s.d. increase in logARR was associated with an increased hazard ratio for stroke (hazard ratio: 1.49, P = 0.04). No significant association was observed in subjects with low sodium intake (P = 0.7). When we repeated all the analyses using logPRA or logPAC, no significant associations were found. CONCLUSION: These results suggest that high ARR, that is, relative aldosterone excess, is a predictor for stroke under conditions of high sodium intake.

Pre-hypertension as a significant predictor of chronic kidney disease in a general population: the Ohasama Study.

BACKGROUND: Hypertension is associated with an increased risk of development of chronic kidney disease (CKD). However, it is unclear whether pre-hypertension is related to the incidence of CKD. METHODS: The incidence of CKD defined as positive proteinuria or estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m(2) was examined in 2150 inhabitants without pre-existing CKD from the general Japanese population. The association of blood pressure and CKD incidence was examined using a Cox regression model adjusted for age, sex, habitual smoking and drinking, obesity, history of cardiovascular disease, diabetes mellitus or hypercholesterolemia, eGFR at baseline, number of follow-up examinations and year of baseline examination. Participants were categorized according to the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure. RESULTS: Participants were categorized into normotension (n = 586, 27.3 % ), pre-hypertension (n = 815, 37.9 % ), Stage 1 hypertension (n = 386, 18.0 % ) and Stage 2 hypertension (n = 363, 16.9 % ). During a mean follow-up of 6.5 years (14 023 person-years), 461 incidences of CKD were recorded. Compared to normotension, adjusted hazard ratios of CKD were significantly higher for pre-hypertension (1.49, P < 0.003), Stage 1 (1.83, P < 0.001) and Stage 2 (2.55, P < 0.001) hypertension. The population-attributable fraction of pre-hypertension (12.1 % ) was considered to be compatible to that of Stage 1 (8.6 % ) and Stage 2 (14.9 % ) hypertension. CONCLUSION: This was the first study to demonstrate that pre-hypertension was significantly associated with an increased risk of CKD and was one of the considerable causes of CKD in the general population.

Evaluating home blood pressure in treated hypertensives in comparison with the referential value of casual screening of blood pressure: the Ohasama study.

OBJECTIVE: The target home blood pressure (BP) levels for antihypertensive treatment have not been fully investigated. We estimated home BP values that corresponded to the referential values of casual screening of BP using reduced major axis (RMA) regression for data from untreated and treated individuals in a general population. METHODS: The study included 2651 participants (778 treated) aged 20 years or above. The relationships between casual BP and home BP were examined using RMA regression to consider measurement errors. We calculated estimated home BP values that corresponded to casual BP using the regression equations. RESULTS: Although casual BPs and home BPs were significantly correlated (all: P<0.0001), the coefficients of determination in multiple regression were higher in untreated individuals than those in treated ones. When RMA regression was applied between casual BP (x) and morning home BP (y), the equations were expressed as y=0.78x+26.55 (systolic BP) and y=0.84x+14.34 (diastolic BP) in treated individuals and y=0.79x+19.29 (systolic BP) and y=0.85x+9.94 (diastolic BP) in untreated ones. The estimated home BPs corresponded to 140/90 mmHg of casual BP: 135.8/89.8 mmHg (morning), 132.2/86.6 mmHg (evening), and 133.9/87.8 mmHg (average) in treated individuals and 129.2/86.7 mmHg (morning), 127.8/84.8 mmHg (evening), and 128.2/85.2 mmHg (average) in untreated individuals. CONCLUSION: We estimated the referential values of home BP in treated hypertensives using a regression model; however, further intervention studies on home BP are needed to clarify the target treatment goals of home BP.

Predictive value for mortality of the double product at rest obtained by home blood pressure measurement: the Ohasama study.

BACKGROUND: To clarify whether the double product (DP) (product of systolic blood pressure (SBP) and pulse rate (PR)) at rest based on home blood pressure (HBP) measurement has prognostic value for mortality. METHODS: HBP data of 2,583 participants from a Japanese general population (40% men) ≥35 years of age (mean, 59 years) without a history of cardiovascular disease (CVD) were obtained. The prognostic significance for a 1,000 mm Hg × beats/min elevation in the DP was determined by Cox proportional hazard regression analysis. The association between mortality and the DP was compared to that between mortality and the SBP or the PR using the likelihood ratio (LR) test. RESULTS: During a mean follow-up of 12.0 years, 454 total deaths, 153 CVD deaths (85 cardiac diseases, 68 strokes), and 301 non-CVD deaths occurred. The DP was positively and significantly associated with total, CVD, cardiac, stroke, and non-CVD mortality. The LR test showed that the DP was more strongly associated with total mortality, mortality from cardiac disease, and non-CVD than SBP. Similarly, the DP was more strongly associated with total death, CVD death, and death from stroke than PR. CONCLUSIONS: The home DP was significantly associated with mortality, and the LR test indicated that the association between the DP and mortality would be stronger than that between mortality and SBP or PR. These findings are preliminary, and further study is needed to confirm the usefulness of the DP in risk stratification.

Prognostic significance of home arterial stiffness index derived from self-measurement of blood pressure: the Ohasama Study.

BACKGROUND: Arterial stiffness is a stroke risk factor. The home arterial stiffness index (HASI) can be calculated from self-measured blood pressure using the same formula as the calculation of ambulatory arterial stiffness index (AASI). METHODS: In 2,377 inhabitants (baseline age, 35-96 years) without a history of stroke, home blood pressure was measured once every morning for 26 days (median). HASI was defined as 1 minus the regression slope of diastolic over systolic on home blood pressure in individual subjects. The standardized hazard ratio (HR) of HASI was computed for cerebral infarction, while adjusting for sex, age, body mass index, pulse pressure, mean arterial pressure, heart rate, day-by-day variability of systolic blood pressure, smoking and drinking habits, serum total cholesterol, diabetes mellitus, and antihypertensive treatment. RESULTS: A total of 191 (8.0%) cerebral infarctions and 75 (3.2%) hemorrhagic strokes occurred over a median of 13.8 years. Mean ± s.d. of HASI was 0.60 ± 0.23 units. An increase in HASI of 1 s.d. was associated with an increased HR for cerebral infarction in all subjects (1.19, P = 0.034), men (1.37, P = 0.002), and normotensive subjects (1.46, P = 0.006), but not in women or hypertensive patients (P > 0.56). For hemorrhagic stroke, HASI was not prognostic. CONCLUSIONS: HASI predicted cerebral infarction independent of pulse pressure and other risk factors in men and normotensive subjects. One important role of home blood pressure measurement is early recognition of onset of hypertension in normotensive subjects who are at risk of developing hypertension. HASI provides additional benefits for such subjects.

Aldosterone-to-renin ratio and nocturnal blood pressure decline in a general population: the Ohasama study.

BACKGROUND: Aldosterone-to-renin ratio (ARR) is an index for inappropriate aldosterone activity and salt sensitivity. We previously reported that elevated ARR might be associated with salt-sensitive hypertension. Because salt-sensitive hypertensive patients are reported to show a diminished nocturnal decline in blood pressure, we hypothesized that high ARR may be associated with diminished nocturnal decline in blood pressure (generally referred to as a 'nondipping' pattern), especially in individuals with high sodium intake. METHODS: This study tested this hypothesis in 184 participants aged at least 55 years not receiving antihypertensive treatment in a general Japanese population (age: 67.6 ±â€Š6.9 years; 71.7% women). RESULTS: Ambulatory blood pressure monitoring identified 63 (34.2%) participants with a nondipping pattern (nocturnal decline of SBP <10%). The median plasma renin activity (PRA), plasma aldosterone concentration (PAC), and ARR were 0.8 ng/ml per h, 8.3 ng/dl, and 8.7 ng/dl per (ng/ml per h), respectively. After adjustment for possible confounding factors, each 1 SD increase in logARR was associated with the prevalence of nondipping pattern (odds ratio, 1.95; P = 0.002). This association was observed in individuals in the highest tertile of 24-h urinary sodium excretion estimated from spot urine data (e24-hUNa; ≥179.6 mEq/day; P = 0.01) but disappeared in those in the lowest tertile of e24-hUNa (<147.9 mEq/day; P = 0.6). In those in the highest tertile of e24-hUNa, PRA was significantly lower in nondippers than in dippers (0.49 vs. 0.85 ng/ml per h) despite no differences in PAC. CONCLUSION: These results suggest that relative aldosterone excess might be related to a nondipping pattern of blood pressure, especially in individuals with high sodium intake.

Associated factors of home versus ambulatory heart rate variability in the general population: the Ohasama study.

We previously demonstrated that heart rate (HR) variability obtained by daytime ambulatory monitoring and that of daily home measurement associated differently with cardiovascular mortality risk; cardiovascular mortality was linked with decreased daytime ambulatory HR variability and increased day-by-day home HR variability. The aim of this study was to identify factors contributing to each variability, clarifying possible reasons for their different predictive values. We obtained daytime ambulatory HR and home HR in 538 individuals of a general Japanese population aged ≥55 years. Daytime ambulatory HR variability and day-by-day home HR variability were estimated as a standard deviation measured every 30 min by daytime ambulatory monitoring and day-by-day home measurements once in the morning for 4 weeks, respectively. There was only weak correlation between daytime ambulatory HR variability and day-by-day home HR variability (r = 0.08∼0.14). In a multiple regression model, daytime ambulatory HR variability was associated with daytime ambulatory HR (P < 0.0001), daytime ambulatory blood pressure (BP) variability (P < 0.0001), and male sex (P = 0.003), while negatively associated with daytime ambulatory systolic blood pressure (SBP) (P < 0.0001) and smoking (P = 0.038). Meanwhile, day-by-day home HR variability was positively associated with home HR (P < 0.0001), day-by-day home BP variability (P < 0.0001), and male sex (P = 0.018). Associated factors of daytime ambulatory HR variability and day-by-day home HR variability were different. Our findings suggest that HR variabilities by different intervals of measurements might be mediated by different mechanisms.

How many measurements are needed to provide reliable information in terms of the ambulatory arterial stiffness index? The Ohasama study.

The aim of this study was to investigate how frequent ambulatory blood pressure (ABP) readings need to be obtained to reproduce the ambulatory arterial stiffness index (AASI) and pulse pressure (PP) without loss of information. We compared concordance from full and reduced ABP recordings. We recorded 24-h ABP at 30-min intervals in 1542 residents of Ohasama, Japan (baseline age, 40-93 years; 63.4% women). We randomly excluded up to 16 readings per recording or we selected readings at fixed 1- or 2-h intervals. Using full recordings as reference, we computed for the reduced recordings repeatability coefficient by Bland and Altman's approach. By Cox regression, we also calculated multivariate-adjusted hazard ratios for cardiovascular mortality. The median number of ABP readings per recording was 46. Randomly excluding more readings reduced the concordance of AASI, but not PP. Selecting blood pressure readings at 1- or 2-h intervals produced mean values of AASI and PP, which significantly differed from those in full recordings. During follow-up (median, 13.3 years) 126 cardiovascular deaths occurred. Across quartiles, AASI significantly predicted cardiovascular mortality in a U-shaped manner. AASI lost its prognostic significance when the number of randomly excluded readings increased from 8 to 16 or when the interval between readings was 1 h or longer. Compared with PP, AASI is less reproducible when the number of readings in ABP decreases, but this does not affect the predictive accuracy of AASI for cardiovascular mortality, until the median number of readings per ABP recording is less than ∼35.

Aldosterone-to-renin ratio and home blood pressure in subjects with higher and lower sodium intake: the Ohasama study.

Aldosterone-to-renin ratio (ARR) is used to screen primary hyperaldosteronism. We investigated the association between ARR and the prevalence of hypertension using home blood pressure (HBP) measurements in community residents stratified for long-term habitual dietary sodium intake. We obtained HBP and conventional blood pressure (CBP) data for 514 participants aged ≥35 years not receiving antihypertensive treatment in the general population of Ohasama (mean age: 59.7±10.8 years; 71.2% women). A standardized method was used to calculate habitual sodium intake from a food-frequency questionnaire. The prevalence of HBP hypertension (≥135/85 mmHg) and CBP hypertension (≥140/90 mmHg) were 12.6 and 20.2%, respectively. The median plasma renin activity (PRA), plasma aldosterone concentration (PAC) and ARR were 1.1 ngml(-1)h(-1), 6.4 ng per 100 ml and 5.5 ng per 100 ml per ngml(-1)h(-1), respectively. After adjustment for possible confounding factors, each 1 s.d. increase in logARR was associated with the prevalence of HBP hypertension (odds ratio 1.37; P=0.04), but not with the prevalence of CBP hypertension (P=0.2). The association of ARR with HBP hypertension was strengthened for subjects with high sodium intake (greater than or equal to the median of 4822 mgday(-1)), whereas it became nonsignificant for those with low sodium intake (interaction P=0.03). Among subjects with high sodium intake, HBP hypertensives had significantly lower PRA than normotensives, despite no differences in PAC. In conclusion, relative aldosterone excess or low-renin hypertension may have an important role in HBP hypertension in the general population with high sodium intake.

Serum magnesium, ambulatory blood pressure, and carotid artery alteration: the Ohasama study.

BACKGROUND: To investigate the associations of 24-h ambulatory blood pressure (ABP) and serum magnesium level (sMg) with risk of carotid artery alteration in a general population. METHODS: sMg and ABP, monitored every 30 min, were measured in 728 subjects (mean age, 67 years) from the Japanese general population. The extent of carotid artery alteration was evaluated according to mean common carotid intima-media thickness (IMT) and the presence of focal carotid plaque. To determine the association of sMg and carotid artery alteration, analysis of covariance (ANCOVA) (for adjusted mean IMT) or multiple logistic regression analysis (for odds ratio (OR) for the presence of carotid plaques) was used. RESULTS: Lower sMg was significantly associated with mean IMT (P = 0.004) and risk of ≥2 carotid plaques (P = 0.03) after adjusting for possible confounding factors, including 24-h ABP (systolic), creatinine clearance (Ccr) (estimated using the Cockcroft-Gault equation), and serum minerals (sodium, potassium, calcium, and inorganic phosphorus). Even when 24-h ABP values were within normal range (<130/80 mm Hg), lower sMg levels (<2.2 mg/dl) were significantly associated with mean IMT (P = 0.007) and risk of ≥2 carotid plaques (OR, 2.14; 95% confidence interval, 1.18-3.85; P = 0.01). CONCLUSIONS: Both 24-h ABP and lower sMg were closely and independently associated with risk of carotid artery alteration. Further investigations are needed to examine the relationship between sMg levels and the incidence of cardiovascular disease.

Relationship of dysregulation of glucose metabolism with white-coat hypertension: the Ohasama study.

Characteristics of glucose metabolism in subjects with white-coat hypertension (WCHT) have not been fully investigated. The purpose of this study was to determine the relationship between glucose metabolism and WCHT on the basis of blood pressure (BP) at home (HBP) in the general population. Participants were from Ohasama, a rural Japanese community, and included 466 residents (mean age, 61.0 years) who had no history of diabetes mellitus. HBP and oral glucose tolerance test values were measured. Participants were classified into four groups on the basis of their HBP and casual-screening BP (CBP) values: normotension (NT) (HBP<135/85 mm Hg, CBP<140/90 mm Hg); WCHT (HBP<135/85 mm Hg, CBP>/=140/90 mm Hg); masked hypertension (HBP>/=135/85 mm Hg, CBP<140/90 mm Hg); or sustained hypertension (SHT) (HBP>/=135/85 mm Hg, CBP>/=140/90 mm Hg). The relationships between glucose metabolism and BP among the four groups were examined using multivariate analysis adjusted for possible confounding factors. Factors in relation to glucose metabolism, such as fasting glucose level, 2-h postchallenge glucose level and homeostasis model assessment-insulin resistance index, were significantly higher in subjects with WCHT and SHT than in those with NT (all P<0.03). When men and women were analyzed separately, these relationships were more pronounced in women. Our results suggest that dysregulation of glucose metabolism in WCHT might contribute to the increase in the long-term cardiovascular risk among the general population.

Association of environmental tobacco smoke exposure with elevated home blood pressure in Japanese women: the Ohasama study.

OBJECTIVE: Only a few of numerous epidemiological studies have demonstrated a positive association between environmental tobacco smoke (ETS) exposure and blood pressure (BP), despite experimental studies showing such a positive association. The association between home blood pressure (HBP) and ETS exposure was investigated in the general population. METHODS: Five hundred and seventy-nine nonsmoking Japanese women were enrolled. The participants were classified into four categories according to their responses to a self-administered questionnaire: unexposed women (non-ETS), women exposed at home [ETS(home)], at the workplace/other places [ETS(work/other)] and at home and at the workplace/other places [ETS(both)]. Variables were compared using analysis of covariance adjusted for age, marital status, body mass index, diabetes mellitus, stroke, heart disease, hyperlipidemia, alcohol intake, salt intake and activity levels. RESULTS: In participants without antihypertensive medication, systolic morning HBP in ETS(both) was 4 mmHg higher than that in non-ETS (116.8 +/- 1.01 vs. 113.1 +/- 1.08 mmHg, P = 0.02) and systolic morning HBP in ETS(home) and systolic evening HBP in ETS(both) were 3 mmHg higher than those in non-ETS (116.2 +/- 1.07 vs. 113.1 +/- 1.08 mmHg, P = 0.04; and 115.3 +/- 1.02 vs. 111.9 +/- 1.09 mmHg, P = 0.03, respectively). In participants with antihypertensive medication, ETS exposure status was not significantly associated with increased HBP levels. CONCLUSIONS: A positive association between HBP levels and ETS exposure was confirmed. HBP measurement is recommended in population-based studies investigating the effects of ETS exposure. ETS exposure may increase BP, thereby synergistically contributing to unfavorable cardiovascular outcomes along with other deleterious effects of ETS.

Factors associated with day-by-day variability of self-measured blood pressure at home: the Ohasama study.

BACKGROUND: We previously reported that high day-by-day blood pressure (BP) variability derived from self-measured BP at home (home BP) predicted cardiovascular mortality over and beyond other risk factors. The objective of this study is to clarify the determinants of the day-by-day home-BP variability. METHODS: We conducted a cross-sectional community survey in 1,215 inhabitants (female gender 59%, mean age 62 years) of Ohasama, Japan. The subjects measured their BP and heart rate once every morning and once every evening for 4 weeks. The day-by-day BP variability and heart rate variability were defined as within individual standard deviation of all home BP and heart rate, respectively. We also considered coefficient of variation (CV). These parameters in the morning and those in the evening were calculated separately. RESULTS: The level and standard deviation of home systolic/diastolic BP (SBP/DBP) in the morning were 123.4 +/- 15.1/75.7 +/- 9.0 mm Hg and 8.6 +/- 3.1/5.8 +/- 2.0 mm Hg. Multivariate linear regression analysis demonstrated that older age, female gender, elevated home BP, low home heart rate, and elevated home heart rate variability were significant determinants of elevated home-BP variability. In addition to these factors, alcohol intake and sedentary lifestyle were also determinants of elevated home-BP variability in the evening. CONCLUSIONS: Day-by-day home-BP variability was associated with home BP, alcohol intake or sedentary lifestyle. Whether modifying these factors would reduce BP variability and whether such reduction would lead to better outcomes needs further study.