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.

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.

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.

Association of kidney dysfunction with silent lacunar infarcts and white matter hyperintensity in the general population: the Ohasama study.

BACKGROUND: No previous study has investigated the association of kidney dysfunction with silent lacunar infarcts and white-matter hyperintensity (WMH) independent of ambulatory blood pressure (BP). METHODS: A cross-sectional study involving 1,008 participants (mean age 66 years) from a general population of Ohasama, Japan, was conducted. Calculated creatinine clearance (CCr) was estimated using the Cockcroft-Gault equation. In continuous and categorical analyses, the association between CCr and the prevalence of silent lacunar infarcts and WMH was investigated. Silent lacunar infarcts and WMH were detected on MRI. Multiple logistic regression analysis adjusted for 24-hour ambulatory BP, sex, age, body mass index, smoking and drinking status, antihypertensive medication, and histories of hypercholesterolemia, diabetes mellitus and heart disease was performed. RESULTS: On univariate analysis, decreased CCr (continuous variable) and CCr <60 ml/min/1.73 m(2) (categorical variable) were significantly associated with lacunar infarcts and WMH. After adjustment, each 1-standard-deviation decrease in CCr (odds ratio = 1.22; p = 0.036) and CCr <60 ml/min/1.73 m(2) (odds ratio = 1.68; p = 0.007) was significantly associated with a high prevalence of lacunar infarcts. Even when 24-hour ambulatory BP was within the normal range (<130/80 mm Hg), CCr <60 ml/min/1.73 m(2) was associated with a high prevalence of lacunar infarcts (odds ratio = 1.62; p = 0.047). CCr <60 ml/min/1.73 m(2) and 24-hour ambulatory BP had additive effects on lacunar infarcts. After the same adjustment, the association between CCr and WMH was not significant. CONCLUSIONS: CCr is closely associated with lacunar infarcts, suggesting that kidney dysfunction in the elderly is an independent risk factor or predictor for silent lacunar infarcts.

Stroke risk of blood pressure indices determined by home blood pressure measurement: the Ohasama study.

BACKGROUND AND PURPOSE: The purpose of this prospective cohort study was to investigate associations between stroke and blood pressure (BP) indices (systolic BP [SBP], diastolic BP [DBP], mean BP, and pulse pressure [PP]) determined by home BP measurement. METHODS: Associations between stroke and BP indices were examined in a rural Japanese population. Home BP data of 2369 subjects (40% men) > or =35 years of age (mean, 59 years) without a history of stroke were obtained. Associations between stroke and each index were determined using Cox proportional hazards regression and the likelihood ratio (LR) test. RESULTS: During follow-up (mean, 11.7 years), 238 strokes occurred. The LR test showed that SBP and mean BP were significantly more strongly associated with total and ischemic stroke than DBP and PP (LR chi2 > or =9.3, P<0.01 for SBP/mean BP, LR chi2 < or =3.8, P> or =0.05 for DBP/PP). SBP tended to be more strongly associated with total/ischemic stroke than mean BP (LR chi2=3.8, P=0.05 for SBP, LR chi2 < or =0.2, P>0.6 for mean BP). PP tended to be slightly more strongly associated with ischemic stroke than DBP (LR chi2=7.5, P<0.01 for DBP, LR chi(2)=9.3, P<0.01 for PP), whereas DBP was significantly more strongly associated with hemorrhagic stroke than PP (LR chi2=9.2, P<0.01 for DBP, LR chi2=2.5, P=0.01 for PP). CONCLUSIONS: PP obtained from home BP measurements was weakly associated with stroke, whereas SBP showed the strongest association. Additionally, DBP and PP may be associated with different stroke types.

Predictive value of ambulatory heart rate in the Japanese general population: the Ohasama study.

BACKGROUND: Resting heart rate can predict cardiovascular disease mortality or all-cause mortality. Because of the effect of the alert reaction, heart rates measured out-of-office should have better predictive power than those obtained at clinics. However, only a few studies have described the relationship between heart rate measured by ambulatory blood pressure monitoring devices and cardiovascular disease prediction. METHODS: We studied 1444 individuals from the Japanese general population who did not have a history of cardiovascular diseases including arrhythmia. We used multiple adjusted Cox proportional hazards to calculate the mortality risk of daytime heart rate, night-time heart rate, and the day-night heart rate dip ratio [day-night heart rate dip ratio = (daytime heart rate--night-time heart rate)/daytime heart rate x 100]. RESULTS: After 12 years of follow-up, 101, 195, and 296 participants died due to cardiovascular diseases, noncardiovascular diseases, and all causes, respectively. As shown by others, neither daytime nor night-time heart rate predicted cardiovascular disease mortality, whereas both predicted noncardiovascular disease mortality. The day-night heart rate dip ratio was significantly related to all-cause mortality. When night-time heart rate and day-night heart rate dip ratio were simultaneously included into the same Cox model, only night-time heart rate significantly and independently predicted all-cause mortality (relative hazard per 10 bpm increase = 1.29, 95% confidence interval, 1.07-1.54). CONCLUSION: Night-time heart rate value seems to have the most important predictor of all-cause mortality among ambulatory heart rate parameters in this population.

Optimal cutoff point of waist circumference and use of home blood pressure as a definition of metabolic syndrome: the Ohasama study.

BACKGROUND: Self-measured blood pressure (BP) at home (HBP) has a stronger predictive power for cardiovascular mortality and morbidity than casual-screening BP (CBP). No studies have evaluated the clinical significance of self-measured HBP for diagnosing metabolic syndrome (MS). Eight scientific associations recently defined MS for the Japanese population. However, this definition remains controversial, especially with respect to the cutoff value of waist circumference (WC) being higher in women than in men. METHODS: The: participants of this population-based survey were the 395 residents (> or =35 years of age) of Ohasama, a rural Japanese community. They measured HBP and underwent the oral glucose tolerance test between the years 2000 and 2006. We calculated the optimal cutoff values of WC required to diagnose MS, and examined the association of HBP with metabolic risk-factor clustering using multivariate analyses. RESULTS: Receiver operation characteristic analysis indicated that the optimal WC cutoff values for identifying clusters of metabolic risk factors were 87 and 80 cm in men and women, respectively. Elevated HBP was significantly associated with the clustering of metabolic risk factors but CBP was not. CONCLUSION: The appropriate WC cutoff value in the current MS criteria for Japanese women would be 80 cm. We suggest that HBP would be useful when considering a diagnosis of MS. The association between MS determined using HBP and the prognosis of cardiovascular diseases (CVDs) requires further investigation.

Association of microalbuminuria with brachial-ankle pulse wave velocity: the Ohasama study.

BACKGROUND: Microalbuminuria is recognized as a marker of generalized vascular dysfunction. However, the associations between microalbuminuria and pulse wave velocity (PWV), carotid intima-media thickness (IMT), and ambulatory blood pressure (ABP), respectively, have not been investigated. METHODS: Brachial-ankle PWV (baPWV), IMT, and ABP were determined in 328 individuals (mean age, 65.7 +/- 6.4 years) from the general population of Ohasama, a rural Japanese community. The participants were assigned to groups with microalbuminuria and with normoalbuminuria, and their characteristics were compared. We also examined the association between microalbuminuria and baPWV, IMT, and ABP, respectively, using multivariate analyses. RESULTS: Seventy-nine participants (24%) with microalbuminuria had significantly higher baPWV (P < 0.001) and 24-h systolic BP (SBP) (P = 0.006) than those with normoalbuminuria, although 24-h pulse pressure and mean IMT did not significantly differ between the groups. Multiple logistic regression analyses showed that baPWV, but not 24-h ABP, was independently associated with microalbuminuria (P = 0.002) when adjusted for various confounding factors. After further adjustment for 24-h SBP, the association between baPWV and microalbuminuria remained significant (P = 0.012). The trend was significant even when daytime or nighttime SBP was used instead of 24-hour SBP in this model. CONCLUSIONS: Microalbuminuria appears to be associated with baPWV more closely than with IMT and ABP, and its association with baPWV is independent of ABP and other cardiovascular risk factors.

Proposal of a risk-stratification system for the Japanese population based on blood pressure levels: the Ohasama study.

The aim of the present study was to propose a risk-stratification system based on self-measurement of home blood pressure (HBP) as well as casual-screening BP (CBP) in relation to Japanese Society of Hypertension Guidelines for the Management of Hypertension (JSH 2004). For 4 weeks, the subjects measured their HBP while seated every morning within 1 h after awaking, after having rested for at least 2 min. The subjects included 2,368 Ohasama residents aged > or = 35 years, with no history of stroke. CBP was measured twice consecutively at baseline. Among all subjects, there were 174 incidences of stroke or transient ischemic attack (TIA) observed during 9.4 years (interquartile 7.0-12.4) of follow-up. The analysis revealed statistically significant linear increases in stroke or TIA risk in both the CBP-based and HBP-based classifications. The risk for high-normal blood pressure (BP) was not significantly high according to the CBP-based classification (relative hazard [RH] 1.52; 95% confidence interval [CI] 0.89-2.60), whereas it was significantly high by the HBP-based classification (RH 1.91; 95% CI 1.04-3.51). On the basis of the data in the absolute risk table, the risks of first stroke or TIA for the 4 groups in the CBP-based and HBP-based classifications were proposed. Stroke or TIA risk increased linearly with the increase in the stage of stratified risk, regardless of BP information (trend p < 0.0001). Risks for non-hypertensive individuals should be assessed in the next version of the Japanese BP guidelines. Furthermore, the importance of HBP should be emphasized in order to accurately evaluate BP risks for individuals.

Masked hypertension determined by self-measured blood pressure at home and chronic kidney disease in the Japanese general population: the Ohasama study.

Both chronic kidney disease (CKD) and masked hypertension (MHT) are known to be linked with an increased risk of cardiovascular disease (CVD), but their relationship has remained unclear. The present study aimed to evaluate the CKD incidence in individuals with MHT in the general Japanese population. We recorded self-measured blood pressure at home (HBP) and casual blood pressure (CBP) in 1,365 individuals (mean 63.0 years old; males, 32.5%; mean creatinine clearance [CCr], 60.9 mL/min; positive proteinuria, 6.7%) and classified the subjects into four groups: sustained normal blood pressure (SNBP, 60.3%), white-coat hypertension (WCHT, 14.9%), MHT (12.8%), and sustained hypertension (SHT, 12.0%). Kidney parameter results for the respective groups (SNBP, WCHT, MHT, and SHT) were as follows: 61.7 mL/min, 61.8 mL/min, 59.6 mL/min, and 57.3 mL/min for CCr, 4.2%, 8.9%, 10.3%, and 12.8% for the prevalence of positive proteinuria, and 2.3%, 3.0%, 6.3%, and 9.8% for the proportion with CCr<60 mL/min with proteinuria. Compared with the SNBP group, the MHT and SHT groups exhibited significant differences in these parameters (p<0.05, for each). The adjusted odds ratios for CCr<60 mL/min with proteinuria were significantly higher in the MHT (2.56) and SHT (3.60) groups compared with the SNBP group (reference). MHT, like SHT, is closely related to CKD, and HBP measurement could be a useful screening strategy to detect CKD in the general population.

Plasma fibrinogen, ambulatory blood pressure, and silent cerebrovascular lesions: the Ohasama study.

OBJECTIVE: Twenty-four-hour ambulatory blood pressure (24-hour ABP) values are considered a powerful predictor of stroke. Silent cerebrovascular lesions are associated with an increased risk of stroke. Because fibrinogen is a major determinant of plasma viscosity, an elevated fibrinogen level might also be associated with stroke risk. We evaluated the association of 24-hour ABP and plasma fibrinogen levels with the risk of silent cerebrovascular lesions (white matter hyperintensity and lacunar infarct) detected by MRI. METHODS AND RESULTS: The study cohort comprised 958 individuals from the general population of Ohasama, a rural Japanese community. Multiple logistic regression analysis adjusted for age, sex, smoking and drinking status, use of antihypertensive medication, body mass index, 24-hour ABP, and a history of hypercholesterolemia, diabetes mellitus, and atrial fibrillation demonstrated that each 1-SD increase in fibrinogen level was associated with a significantly increased risk of silent cerebrovascular lesions (odds ratio, 1.26; P=0.001). The 24-hour ABP was also significantly and independently associated with the risk of silent cerebrovascular lesions. Even when 24-hour ABP values were within normal range (<135/80 mm Hg), elevated fibrinogen levels were associated with an increased risk of silent cerebrovascular lesions. Fibrinogen and 24-hour BP had additive effects on silent cerebrovascular lesions. CONCLUSION: The 24-hour ABP and plasma fibrinogen levels were closely and independently associated with the risk of silent cerebrovascular lesions including white matter hyperintensity and lacunar infarct.

Ambulatory arterial stiffness index and 24-hour ambulatory pulse pressure as predictors of mortality in Ohasama, Japan.

BACKGROUND AND PURPOSE: Ambulatory arterial stiffness index (AASI) and pulse pressure (PP) are indexes of arterial stiffness and can be computed from 24-hour blood pressure recordings. We investigated the prognostic value of AASI and PP in relation to fatal outcomes. METHODS: In 1542 Ohasama residents (baseline age, 40 to 93 years; 63.4% women), we applied Cox regression to relate mortality to AASI and PP while adjusting for sex, age, BMI, 24-hour MAP, smoking and drinking habits, diabetes mellitus, and a history of cardiovascular disease. RESULTS: During 13.3 years (median), 126 cardiovascular and 63 stroke deaths occurred. The sex- and age-standardized incidence rates of cardiovascular and stroke mortality across quartiles were U-shaped for AASI and J-shaped for PP. Across quartiles, the multivariate-adjusted hazard ratios for cardiovascular and stroke death significantly deviated from those in the whole population in a U-shaped fashion for AASI, whereas for PP, none of the HRs departed from the overall risk. The hazard ratios for cardiovascular mortality across ascending AASI quartiles were 1.40 (P=0.04), 0.82 (P=0.25), 0.64 (P=0.01), and 1.35 (P=0.03). Additional adjustment of AASI for PP and sensitivity analyses by sex, excluding patients on antihypertensive treatment or with a history of cardiovascular disease, or censoring deaths occurring within 2 years of enrollment, produced confirmatory results. CONCLUSIONS: In a Japanese population, AASI predicted cardiovascular and stroke mortality over and beyond PP and other risk factors, whereas in adjusted analyses, PP did not carry any prognostic information.

Ambulatory blood pressure, blood pressure variability and the prevalence of carotid artery alteration: the Ohasama study.

OBJECTIVES: To investigate the association between ambulatory blood pressure (BP) variables (level, short-term variability, circadian variation and morning pressor surge) and carotid artery alteration in a general population. METHODS: We measured ambulatory BP every 30 min in 775 participants (mean age 66.2 +/- 6.2 years, 68.8% women) from the Japanese general population. Short-term BP variability during the daytime and night-time were estimated as within-subject standard deviation of daytime and night-time BP, respectively. Circadian BP variation was calculated as the percentage decline in nocturnal BP. Morning pressor surge was defined as morning BP minus pre-waking BP. The extent of carotid artery alteration was evaluated as the average of common carotid intima-media thickness (IMT) and the presence of focal carotid plaque. RESULTS: Daytime and night-time BP values were more closely associated with carotid artery alteration than casual BP. With mutual adjustment for daytime and night-time BP, the latter (P < 0.0001) was more closely associated with IMT, which represents diffuse arterial thickening and arteriosclerosis, than daytime BP (P = 0.2). Night-time systolic BP variability was positively associated with carotid plaque (focal atherosclerotic lesions) independently of possible confounding factors, including night-time systolic BP (P = 0.01). A diminished nocturnal decline in systolic BP was associated with a greater IMT after adjustment for confounding factors (P = 0.03). A morning pressor surge was not associated with carotid artery alteration. CONCLUSION: Ambulatory BP levels and BP variability were closely associated with carotid artery alteration, suggesting that these parameters are independent risk factors or predictors of carotid artery alteration.

Detection of carotid atherosclerosis in individuals with masked hypertension and white-coat hypertension by self-measured blood pressure at home: the Ohasama study.

OBJECTIVE: To investigate carotid atherosclerosis in individuals with masked hypertension (MHT) and white-coat hypertension (WCHT) in a general population. METHODS: Self-measurement of blood pressure at home (HBP) and casual blood pressure (CBP) measurements were recorded in 812 individuals aged at least 55 years (mean 66.4 years) from the general Japanese population. The intima-media thickness (IMT) of the near and far wall of both common carotid arteries was measured and averaged. The relationships between carotid atherosclerosis (IMT and plaque) and the four blood pressure groups (sustained normal blood pressure: HBP < 135/85 mmHg, CBP < 140/90 mmHg; WCHT: HBP < 135/85 mmHg, CBP >or= 140/90 mmHg; MHT: HBP >or= 135/85 mmHg, CBP < 140/90 mmHg; sustained hypertension: HBP >or= 135/85 mmHg, CBP >or= 140/90 mmHg) were examined using multivariate analysis adjusted for possible confounding factors. RESULTS: Adjusted IMT in individuals with sustained hypertension [0.77 mm; 95% confidence interval (CI) 0.75 to 0.79 mm] and MHT (0.77 mm; 95% CI 0.73 to 0.80 mm) was significantly greater than in those with sustained normal blood pressure (0.71 mm; 95% CI 0.69 to 0.72 mm) and WCHT (0.72 mm; 95% CI 0.71 to 0.74 mm) (P < 0.0001). The odds ratios for the presence of plaques in all four groups were similar to the trends in IMT. CONCLUSIONS: Our findings imply that CBP measurements alone are insufficient to distinguish individuals at high risk of carotid atherosclerosis from those at low risk. However, these individuals do have distinct HBP measurements, suggesting that HBP measurement could become a valuable tool for predicting carotid atherosclerosis.

Stroke risk in systolic and combined systolic and diastolic hypertension determined using ambulatory blood pressure. The Ohasama study.

BACKGROUND: To investigate the risk of stroke in subjects with isolated systolic hypertension (ISH), isolated diastolic hypertension (IDH), and combined systolic and diastolic hypertension (SDH) in a Japanese general population, we used 24-h ambulatory blood pressure (ABP) and casual-screening blood-pressure (CBP) readings. METHODS: Subtypes of hypertension were defined based on systolic blood pressure (SBP) >135 mm Hg or diastolic blood pressure (DBP) >80 mm Hg for 24-h ABP, and SBP >140 mm Hg or DBP >90 mm Hg for CBP. We obtained 24-h ABP and CBP data for 1271 (40% male) subjects aged > or =40 years (mean age, 61 years) without a history of symptomatic stroke; their stroke-free survival was then determined. The prognostic significance of each subtype of hypertension was determined by Cox proportional hazard analysis. RESULTS: There were 113 symptomatic strokes during follow-up (mean time, 11 years). Compared with normotension, among the hypertension subtypes determined by 24-h ABP, the adjusted relative hazards (RHs) of stroke were 2.24 for ISH (P = .002) and 2.39 for SDH (P = .0004). The association was less marked among subtypes determined by CBP (RH = 1.40 and P = .13 for ISH; RH = 2.07 and P = .017 for SDH). The IDH group was excluded from the Cox analysis because both the prevalence and the number of events were low in this group. CONCLUSIONS: Isolated systolic hypertension, as determined by 24-h ABP measurements, was associated with a high risk of stroke, similar to that found in SDH subjects; this suggests that the prognosis of hypertensive patients would be improved by focusing treatment on 24-h systolic ABP.

Reproducibility of nocturnal blood pressure assessed by self-measurement of blood pressure at home.

To assess the reproducibility of nocturnal blood pressure (BP) during sleep as measured using a self-measurement device at home, we obtained repeated nocturnal home BP at 0200 h and quality of sleep assessment from a diary in 556 subjects (71% women, 62.4+/-11.1 years) in the general population. We used an Omron device (HEM-747IC-N, Omron Healthcare Co., Ltd., Kyoto, Japan), with which the time and frequency of monitoring can be preset and the readings stored. The mean+/-SD of the difference between test-retest BP measurements was 0.7+/-15.1 mmHg systolic and 0.2+/-9.7 mmHg diastolic with a mean interval of 5.9 days. The absolute differences were greater than 10 mmHg in 261 (46.9%) subjects for systolic and 145 (26.0%) subjects for diastolic. There was no evidence of regression to the mean in nocturnal measurements over at least three nights (n=390, p>0.22). The differences (the first minus the second measurement) were large in subjects who experienced sleep disturbance only in the first (n=64, 2.3+/-13.6 mmHg and 1.6+/-9.6 mmHg for systolic and diastolic, respectively) or second sessions (n=56, -4.1+/-16.4 mmHg and -2.5+/-11.4 mmHg) compared with the subjects without sleep disturbance (n=66, 1.5+/-17.8 mmHg and 0.8+/-10.3 mmHg) and those with sleep disturbance (n=370, 0.9+/-14.5 mmHg and 0.2+/-9.3 mmHg) in both sessions. In conclusion, the reproducibility of single nocturnal BP as assessed using a self-measurement device at home was not good, especially for subjects who experienced different quality of sleep in each session. To evaluate nocturnal BP using a self-measurement device, estimation of quality of sleep is indispensable.

Incorporating self-blood pressure measurements at home in the guideline from the Ohasama study.

Recent guidelines for the treatment of hypertension have all emphasized the importance of self-blood pressure (BP) measurements at home (home BP) in clinical applications of practice, research, and epidemiology. In the Ohasama study, a cohort study based on home BP, we have demonstrated several important findings to be incorporated in those guidelines. We demonstrated that home BP more accurately and reliably reflect target organ damage and the prognosis of cardiovascular disease than conventional BP, whereas the predictive value of home BP increased progressively with the number of measurements. Even the initial-first home BP values (one measurement) showed a significantly greater relation with stroke risk than conventional BP values (mean of two measurements). Home BP in the morning (morning BP) and in the evening (evening BP) provide equally useful information for stroke risk, whereas morning hypertension, which is that specifically observed only in the morning, might be a good predicator of stroke, particularly among individuals using anti-hypertensive medication. Home BP increased the predictive power of categorizations of guidelines compared with conventional BP. Heart rate values assessed at home using a device designed for home BP measurement (home heart rate) was significantly associated with the risk of cardiovascular mortality, independent of home BP. We expect that continuous follow-up and further analysis of the Ohasama data would contribute to producing further important findings worth incorporating in future hypertension guidelines.

Prognosis of "masked" hypertension and "white-coat" hypertension detected by 24-h ambulatory blood pressure monitoring 10-year follow-up from the Ohasama study.

OBJECTIVES: We sought to investigate the prognosis in subjects with "white-coat" hypertension (WCHT) and "masked" hypertension (MHT), in which blood pressure (BP) is lower in clinical measurements than during ambulatory monitoring. BACKGROUND: The prognostic significance of WCHT remains controversial, and little is known about MHT. METHODS: We obtained 24-h ambulatory BP and "casual" BP (i.e., obtained in clinical scenarios) values from 1,332 subjects (872 women, 460 men) > or =40 years old in a representative sample of the general population of a Japanese community. Survival and stroke morbidity were then followed up for a mean duration of 10 years. RESULTS: Composite risk of cardiovascular mortality and stroke morbidity examined using a Cox proportional hazards regression model for subjects with WCHT (casual BP > or =140/90 mm Hg, daytime BP <135/85 mm Hg; relative hazards [RH])1.28; 95% confidence interval [CI] 0.76 to 2.14) was no different from risk for subjects with sustained normal BP (casual BP <140/90 mm Hg, daytime BP <135/85 mm Hg). However, risk was significantly higher for subjects with MHT (casual BP <140/90 mm Hg, daytime BP > or =135/85 mm Hg; RH 2.13; 95% CI 1.38 to 3.29) or sustained hypertension (casual BP > or =140/90 mm Hg, daytime BP > or =135/85 mm Hg; RH 2.26; 95% CI 1.49 to 3.41) than for subjects with sustained normal BP. Similar findings were observed for cardiovascular mortality and stroke morbidity among subgroups by gender, use of antihypertensive medication, and risk factor level (all p for heterogeneity >0.2). CONCLUSIONS: Conventional BP measurements may not identify some individuals at high or low risk, but these people may be identifiable by the use of ambulatory BP.

Prognostic significance of night-time, early morning, and daytime blood pressures on the risk of cerebrovascular and cardiovascular mortality: the Ohasama Study.

OBJECTIVE: To clarify whether high blood pressure (BP) at a particular time of day is associated with cerebrovascular and cardiovascular mortality risk. METHODS: Cerebrovascular and cardiovascular mortality in 1360 individuals aged 40 years and older in Ohasama, Japan, was followed for an average of 10.6 years. We used 2-h moving averages of the BP (a total of 24 average BP measurements for two consecutive hours based on four BP readings taken every 30 min) to compare the predictive power of BP taken during a 24-h period given the same number of measurements. The associations between cerebrovascular and cardiovascular mortality risk and the 2-h moving averages of systolic blood pressure (2 h-SBP) recorded over 24 h were analysed using a Cox proportional hazards model after adjusting for possible confounding factors. RESULTS: The total cerebrovascular and cardiovascular mortality risk was significantly associated with elevated 2 h-SBP recorded during the night and early morning periods. Haemorrhagic stroke mortality was significantly associated with elevated daytime 2 h-SBP. Cerebral infarction mortality and heart disease mortality were significantly associated with elevated night-time 2 h-SBP. CONCLUSION: High BP at different times of day were associated with different subtypes of cerebrovascular and cardiovascular mortality risk.

Introversion associated with large differences between screening blood pressure and home blood pressure measurement: The Ohasama study.

OBJECTIVE: To explore the effect of personality on screening blood pressures measured in clinical settings and home blood pressure measurements. METHODS: From 1997 to 1999, 699 participants underwent screening and home blood pressure measurements and completed the Japanese version of the short-form Eysenck personality questionnaire. An increased screening blood pressure was defined as screening blood pressure > or = 140/90 mmHg and an increased home blood pressure was defined as home blood pressure > or = 135/85 mmHg. RESULTS: Participants with lower extroversion scores (i.e., introversion) showed a greater difference between screening and home systolic blood pressure. The association between introversion and differences was statistically significant, even after adjustment for other possible factors (younger age, female, wide screening pulse pressure, never smoked, and no antihypertensive medication). The adjusted means of SBP differences were 7.3 and 4.4 mmHg among the lowest and highest extroversion quartiles, respectively (P for trend = 0.02). Other personality scores (psychoticism or neuroticism) were not associated with screening and home blood pressure differences. The incorporation of an extroversion score in the basic model consisting of the above factors that affected the difference between screening and home blood pressure slightly improved the prediction of a high home blood pressure. The area under the receiver operating characteristic curve increased by 0.037 among participants with high screening blood pressure and 0.006 for those with normal screening blood pressure compared with the basic model. CONCLUSION: Physicians may need to be aware of 'introverted' patients who have high blood pressure in clinic settings, because they have the potential for 'white-coat' hypertension.