Patient characteristics and factors associated with inter-arm difference of blood pressure measurements in a general population in Ohasama, Japan

OBJECTIVES: To assess whether there is a natural difference in blood pressure (BP) measurements between the right and left arms, and to identify what factors are associated with this difference in a general population. METHODS: The study subjects were 1090 individuals who participated in a medical check-up in Ohasama, Japan. The BP was measured simultaneously in both arms, using an automated device. The inter-arm BP difference was expressed as the relative difference [right-arm BP (R) minus left-arm BP (L): R - L] and the absolute difference (|R - L|). The relationship between inter-arm difference and various factors was analyzed using univariate analysis. The characteristics of subjects in whom the absolute systolic BP (SBP) difference was greater than 10 mmHg were analyzed using multivariate logistic analysis. RESULTS: The relative differences in SBP and diastolic BP (DBP) were -0.6 +/- 6.6 (mean +/- SD) and 1.1 +/- 4.7 mmHg, while the absolute differences were 4.9 +/- 4.4 and 3.7 +/- 3.0 mmHg. The absolute SBP difference was found to correlate significantly with age, body mass index, ankle-brachial index (ABI), and hypertension. Subjects with hypertension, hypercholesterolemia, obesity, elevated hemoglobin A1c (HbA1c) and low ABI had a significant and independent increase in the risk of an absolute SBP difference greater than 10 mmHg. CONCLUSIONS: The results suggest that there is considerable difference in the measured BP in the right and left arms and that large differences in the absolute SBP are associated with risk factors for arteriosclerosis such as hypertension, hypercholesterolemia, obesity, metabolic abnormalities and low ABI.     

Haplotypes of aldosterone synthase (CYP11B2) gene in the general population of Japan: the Ohasama study.

Since the identification of a chimeric aldosterone synthase which induces mendelian hypertension, polymorphisms in aldosterone synthase (CYP11B2) has been one of major targets for molecular analyses in association with hypertension. To date, four polymorphic variants of CYP11B2, -344T/C at promoter region, a gene conversion in intron 2, 2713A/G (in exon 3) which converts from Lys to Arg at codon 173 (K173R), and 4986T/C (in exon7) which converts from Val to Ala at codon 386 (V386A), have been identified in Caucasian population. Then, linkage disequilibrium between -344T/C polymorphism and a gene conversion in intron 2 or K173R mutation has been described, suggesting the presence of genetic haplotypes in Caucasians. Since the presence of a gene conversion in intron 2 or V386A mutation was still unknown in the Japanese population, all these polymorphisms were examined together to determine the CYP11B2 haplotypes of Japanese, using DNA samples from 1290 participants of the Ohasama study, who represent the general population of a rural community of northern Japan. Molecular analyses demon- strated the presence of a gene conversion of intron 2, but the absence of V386A mutation in Japanese population. The complete linkage disequilibrium between -344T/C polymorphism and K173R mutation was noted. Although -344T allele was linked either with a gene conversion in intron 2 or with normal intron 2, -344C allele was completely linked with normal intron 2. These results indicate the presence of 3 allelic haplotypes of CYP11B2, -344C with normal intron 2 and 173R, -344T with normal intron 2 and 173K, and -344T with converted intron 2 and 173K, in the general Japanese population. The frequency (total 1.0) was 0.35, 0.53, and 0.12, respectively. The presence of allelic haplotypes is considered to be an additional genetic information to individual polymorphism of CYP11B2 to determine the linkage between CYP11B2 polymorphisms and hypertension.     

Blood pressure control assessed by home, ambulatory and conventional blood pressure measurements in the Japanese general population: the Ohasama study.

To assess blood pressure control in the Japanese population, we analyzed previously obtained measurements of conventional, home and ambulatory blood pressures in 1,174 subjects aged > or =40 in a Japanese community. On the basis of conventional blood pressure values and the use of antihypertensive medication, participants were classified as normotensive, untreated hypertensive and treated hypertensive subjects. When 140/90, 135/85 and 135/85 mmHg were used as the hypertension criteria for conventional, home and ambulatory blood pressure measurements, respectively, all three blood pressure values were higher in untreated and treated hypertensive subjects than in normotensive subjects. Among the treated hypertensive subjects, approximately half were classified as hypertensive not only by conventional blood pressure, but also by home or ambulatory measurements. Approximately 10% of the subjects defined as normotensive by conventional blood pressure measurement were classified as hypertensive by home or ambulatory measurements, whereas 60% of the untreated hypertensive subjects as defined by conventional blood pressure measurement had normal home or ambulatory blood pressure values. Therefore, we concluded that 1) the poor blood pressure control in treated hypertensive subjects was attributable not only to the white coat effect but also to inadequate control of blood pressure; and 2) a certain percentage of subjects were misclassified as hypertensive or normotensive by conventional blood pressure measurement.     

Prediction of stroke by ambulatory blood pressure monitoring versus screening blood pressure measurements in a general population: the Ohasama study

OBJECTIVE: To investigate the association between 24 h, daytime and night-time ambulatory blood pressures and first symptomatic stroke, to compare their predictive powers for stroke with that of casual (screening) blood pressure, and to compare the predictive power for stroke between daytime and night-time blood pressures, in a general population in Ohasama, Japan. DESIGN: A prospective cohort study. SUBJECTS AND METHODS: We obtained ambulatory blood pressure on 1,464 subjects aged > or = 40 years without history of symptomatic stroke, then followed-up their stroke-free survival. There were 74 first symptomatic stroke during the follow-up period (mean = 6.4 years). The prognostic significance of blood pressure for stroke risk was examined by a Cox proportional hazards regression model adjusted for possible confounding factors. RESULTS: The non-parametric and parametric analysis indicated that 24-h, daytime and night-time ambulatory blood pressures were linearly related with stroke risk. The likelihood ratio analysis demonstrated that these ambulatory blood pressures were significantly better related to stroke risk than did screening blood pressure, and that daytime blood pressure better predicted stroke risk than did night-time blood pressure. CONCLUSIONS: The present study which prospectively investigated the relation between ambulatory blood pressure and first symptomatic stroke risk in a general population demonstrated that (i) ambulatory blood pressure values were linearly related to stroke risk; (ii) ambulatory blood pressures had the stronger predictive power for stroke risk than did screening blood pressure; and (iii) daytime blood pressure better related to stroke risk than did night-time blood pressure.     

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.     

Predictive values of automated blood pressure measurement: what can we learn from the Japanese population - the Ohasama study

BACKGROUND: Measurements of ambulatory blood pressure (ABP) and of home blood pressure (HBP) as an adjunct to casual/clinic blood pressure (CBP) measurements are currently widely used for the diagnosis and treatment of hypertension. We have monitored a rural cohort of people from the population of Ohasama, Japan, with respect to their prognosis and have previously reported that ABP and HBP are superior to CBP for the prediction of cardiovascular mortality. One reason that CBP is a poor predictor of prognosis is that it incorporates several biases, including the white-coat effect. METHODS AND RESULTS: We examined the prognostic significance of white-coat hypertension for mortality and found that the relative hazard for the overall mortality of patients with white-coat hypertension was significantly lower than that for true hypertension. Short-term blood pressure variability has recently attracted attention as a cause of target-organ damage and cardiovascular complications. Our results confirmed that short-term blood pressure variability (as measured every 30 min) was independently associated with cardiovascular mortality. In addition, research has recently focused on isolated systolic hypertension and pulse pressure as independent risk factors for poor cardiovascular prognosis. The Ohasama study also clearly demonstrated that isolated systolic hypertension and increased pulse pressure, as assessed by HBP, were associated with an increase in the risk of cardiovascular mortality. Circadian blood pressure variation is characterized by a diurnal elevation and a nocturnal decline in blood pressure. We therefore compared morbidity from stroke between dippers (subjects who show an ordinal nocturnal dipping of blood pressure) and non-dippers (those with a diminished nocturnal dipping or nocturnal elevation of blood pressure [inverted dippers]) in the Ohasama study. The incidence of stroke increased with an increased length of observation in dippers using antihypertensive medication but not in non-dippers using antihypertensive medication. In contrast, the relative hazard for mortality increased in non-dippers and inverted dippers. These results suggest a cause-and-effect relationship for both dippers and non-dippers. CONCLUSION: The Ohasama study showed that the level and variability of hypertension as assessed by ABP and HBP are independent predictors of cardiovascular mortality. It also demonstrated an independent association between the prognosis of hypertension and each component of ABP and HBP, indicating the prognostic significance of these blood pressure measurements.     

Availability and use of home blood pressure measurement in the Czech general population

BackgroundHome blood pressure monitoring (HBPM) is recommended for hypertensive patients as a tool to improve both blood pressure (BP) control and compliance with treatment.MethodsWe evaluated the use of HBPM in hypertensive subjects examined during a cross-sectional general population survey (Czech post-MONICA). Models predicting the availability and use of HBPM were constructed using univariate and multivariate logistic regression.ResultsOf 449 treated hypertensive patients (mean age 63.2 years, 52.1% women), 250 (55.7%) reported that they had a device for BP monitoring available at home. The factors associated with HBPM availability were older age, university education, marital status, longer duration of hypertension and nonsmoking. Of the 250 subjects with HBPM available, 40% used HBPM regularly (at least once a week), and this ratio increased with the number of antihypertensive drugs taken (monotherapy 30%, dual combination 43%, combination of ≥3 drugs 48%; p_trend = 0.028). BP control was similar in those using HBPM regularly and those who used HBPM irregularly or did not use it at all (54.5 vs. 49.7%; p = 0.52).ConclusionHBPM is available to more than a half of treated hypertensive patients from the general population. However, only minority of the patients perform home blood pressure measurement regularly.     

Factors explaining the intention to give blood among the general population

BACKGROUND AND OBJECTIVES: The aim of this study was to identify factors explaining the intention to donate blood. MATERIALS AND METHODS: A random sample of 4000 respondents drawn from the general population received a questionnaire by mail. This questionnaire assessed variables as defined by the most prominent social cognitive theories. RESULTS: Overall, the respondents expressed a neutral mean level of intention to give blood in the next 6 months (2.84 on a five-point scale); 56.2% had never given blood in the past. The variables explaining 74% of the variance of intention were: perceived behavioural control (beta = 0.39; P < 0.001); factors facilitating taking action (beta = 0.25; P < 0.001); anticipated regret (beta = 0.16; P < 0.001); moral norm (beta = 0.11; P < 0.001); attitude (beta = 0.08; P < 0.01); level of education (beta = -0.03; P < 0.05); and past experience in giving blood (beta = 0.09; P < 0.001). Nonetheless, the predictive power of perceived behavioural control and moral norm was higher among the ever donors (both at P < 0.01) compared to the never donors, whereas the reverse was observed for attitude (P < 0.05). CONCLUSIONS: People's intentions are mainly determined by perceived barriers and obstacles regarding blood donations. This suggests that promotional strategies should focus on the elimination of barriers to action as well as the development of a higher perception of control. Also, messages should be adapted to the targeted population, based on their previous blood donation behaviour (i.e. never donors vs. ever donors).     

Aldosterone synthase gene (CYP11B2) C-334T polymorphism, ambulatory blood pressure and nocturnal decline in blood pressure in the general Japanese population: the Ohasama Study.

OBJECTIVE: The C-344T polymorphism in the 5'-flanking region of the aldosterone synthase (CYP11B2) gene has been suggested to be associated with hypertension and disturbed circadian blood pressure (BP) rhythm through its effect on aldosterone synthesis. However, previous findings on this topic have been inconsistent. DESIGN: A cross-sectional study. SUBJECTS AND METHODS: We investigated the CYP11B2 C-344T genotype in 802 subjects, aged 40 and over, in a Japanese community, who gave written informed consent and were monitored for 24 h ambulatory BP. RESULTS: The frequencies of the CC, CT, and TT genotypes in these Japanese subjects were 0.14, 0.44, and 0.42, showing a higher frequency of the T allele (0.64) than in Caucasians. Although there was no significant difference in 24 h ambulatory BP levels among the genotypes, the nocturnal decline in BP was significantly greater in the CC homozygous subjects than in other subjects (P = 0.0065 for systolic and P = 0.031 for diastolic decline in nocturnal BP). Detailed analyses demonstrated that this association was significant only in aged (60 years and over) or male subjects. The prevalence of previous cardiovascular disease was significantly less in these subjects with the CC genotype than in those with the TC and TT genotypes, although age, body mass index, male gender, smoking, use of alcohol and antihypertensive medication did not differ among the three genotypes. There was no significant difference among the three genotypes in biochemical and hormonal parameters. CONCLUSION: Although the C-344 T polymorphism of CYP11B2 did not directly influence the level of 24 h BP, the CC genotype was associated with decreased nocturnal BP in elderly or male Japanese. Since prevalence of previous cardiovascular disease was significantly less in homozygous CC subjects, greater nocturnal BP decline in this genotype appears to be beneficial in the circadian BP rhythm.     

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.     

Relationships between residual blood pressure variability and cognitive function in the general population of the PAMELA study

The present study was aimed at assessing the relationships between absolute and individual residual blood pressure (BP) variability and cognitive function in a general population. This cross‐sectional study evaluated cognitive function using minimental state evaluation (MMSE) in 471 subjects enrolled in the PAMELA study. MMSE was calculated 10 years after initial enrollment of the subjects in the PAMELA study. Measurements included office, home, and 24‐hour ambulatory BP monitoring. BP variability was obtained by calculating: (a) 24‐hour standard deviation (SD) for systolic and diastolic BP and (b) individual residual BP variability. Mean age (±SD) of the subjects enrolled was 63 ± 5.7 years at the initial evaluation, with a 10‐year increase when MMSE was performed. There was no significant difference in BP or heart rate values measured at office, home, or during 24‐h BP monitoring between subjects with MMSE < 24 and those with ≥24. BP variability measured by SBP and DBP SD was also similar between these two groups. However, individual residual BP variability was significantly greater in subjects with lower MMSE and this difference became more pronounced when the study population was divided in three groups according to MMSE score (10‐20, 21‐23, 24‐30). Individual residual SBP and DBP variability gradually decreased with the increase in MMSE score. Our data show that a sensitive parameter for the development of cognitive impairment is not BP or absolute BP variability but rather its short‐term erratic component, which has been previously shown to be an important prognostic marker for organ damage, cardiovascular, and all‐cause mortality.     

T+31C polymorphism (M235T) of the angiotensinogen gene and home blood pressure in the Japanese general population: the Ohasama Study.

The angiotensinogen (AGT) gene polymorphism M235T (a methionine to threonine amino acid substitution) has been investigated in association with essential hypertension (EHT) based on conventional measurement of blood pressure (BP); however, the results have been inconsistent. Recently, we have been conducting lines of genetic analysis on a general population of Ohasama Town in Iwate Prefecture, Japan, who measured their BP at home (Ohasama genetic analysis and home BP project). We here assessed the association between AGT M235T polymorphism and hypertension within the same population (1,245 subjects aged 40 years and over). AGT M235T polymorphism was determined by genotyping the AGT T+31C polymorphism, which has complete disequilibrium with the AGT M235T polymorphism. We defined subjects as hypertensive if they were being treated with antihypertensive medication and/or had home BP values of more than 135 mmHg in systole and/or 85 mmHg in diastole. The genotype frequencies were similar to those in previous Japanese studies. There was no significant difference among the genotypes in home BP values (p = 0.63/0.74 for systolic/diastolic blood pressure) or in prevalence of hypertension (MM: 44.7%; MT: 42.3%; TT: 39.6%; p = 0.61). No difference was noted in the frequency of familial history of hypertension. Pulse pressure, however, was significantly different among the genotypes (p = 0.049), and this association was prominent in the older (age260) population (p = 0.0018), but not noted in the younger population (60 > age > or = 40). In conclusion, the present analysis confirmed the lack of a significant effect of AGT M235T polymorphism on blood pressure level, but the difference in pulse pressure in the older population suggests that further investigations of this polymorphism should be made in the Japanese population.     

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.     

Detection of HCV RNA in subjects with antibody to hepatitis C virus among the general population of Fukuoka,Japan

Volunteer blood donors and aged people who came to hospitals for a thorough physical checkup were surveyed to evaluated the exact prevalence of hepatitis C virus (HCV) infection in the general population of Fukuoka, Japan. We tested for antibody to HCV (anti-HCV) by second-generation assay and, to distinguish active HCV infection from past resolved infection, we tested for HCV RNA in reactive serum samples by polymerase chain reaction. The prevalence of anti-HCV was 286 (2.0%) of 14341 subjects, increasing with advancing age, from 0.4% in the under-29 age group to 12.0% in the over-70 age group. There were no differences between sexes. HCV RNA was detected in 170 of 286 (59.4%) anti-HCV-positive subjects. The ratio of HCV RNA-positive to anti-HCV-positive subjects was higher in males than in females (P<0.05) and decreased with advancing age, from 72.2% to 46.5%. The prevalence of elevated alanine aminotransferase (ALT) was only 15.9% in subjects with HCV RNA, higher in males (21.4%) than in females (8.3%) (P<0.05). This study revealed that the prevalence of anti-HCV was high in the aged population, but that the ratio of HCV RNA-positive to anti-HCV-positive subjects was low, and most of the HCV RNA-positive subjects had normal ALT levels.     

Comparison of different methods of measurement of aspirin resistance: using the appropriate statistic.

We have read with interest the recent article by Lordkipanidzéet al.¹ on the comparison of six different assays of platelet