Multivariate analysis of the relationship of six variables to blood pressure: findings from Chicago community surveys, 1965--1971

Impaired sensitivity to thyroid hormones is associated with different grades of hypertension: A multicenter cross-sectional study

BACKGROUND AND AIM

Accumulating evidence suggests a potential link between thyroid function with hypertension. However, the research results are limited, and there is no research to explore the relationship between central and peripheral thyroid hormones (THs) sensitivity and different grades of hypertension in patients with coronary heart disease (CHD). This study aims to prove the complex interaction between thyroid system and blood pressure, and provides new ideas for the assessment of hypertension in patients with CHD.

METHODS AND RESULTS

Calculate parameters representing central and peripheral sensitivity to THs. Logistic regression analysis was used to analyze the relationship between central and peripheral THs sensitivity of CHD patients and different grades of hypertension, especially in different ages, sexes, blood glucose levels, smoking, and drinking statuses. Among the 34,310 participants, 19,610 (57.16 %) were diagnosed with hypertension. The risk of hypertension and TSHI (OR: 0.88; 95 % CI: 0.87-0.90; P < 0.001), TT4RI (OR: 0.998; 95 % CI: 0.998-0.999; P < 0.001), TFQI (OR: 0.63; 95 % CI: 0.60-0.67; P < 0.001), PTFQI (OR: 0.63; 95 % CI: 0.59-0.67; P < 0.001) was negatively associated. The risk of hypertension was positively associated with FT3/FT4 (OR: 1.20; 95 % CI: 1.17-1.22; P < 0.001). After stratified analysis, these associations remained significant at different ages, sexes, blood glucose levels, grades of hypertension, smoking, and drinking statuses (P < 0.001).

CONCLUSIONS

This study shows that the decrease in central THs sensitivity index and the increase in peripheral THs sensitivity index are associated with a higher risk of hypertension in CHD patients.

Hypertension and Diabetes Mellitus: Coprediction and Time Trajectories

Type 2 diabetes mellitus and hypertension overlap in the population. In many subjects, development of diabetes mellitus is characterized by a relatively rapid increase in plasma glucose values. Whether a similar phenomenon occurs during the development of hypertension is not known. We analyzed the pattern of blood pressure (BP) changes during the development of hypertension in patients with or without diabetes mellitus using data from the MCDS (Mexico City Diabetes Study; a population-based study of diabetes mellitus in Hispanic whites) and in the FOS (Framingham Offspring Study, a community-based study in non-Hispanic whites) during a 7-year follow-up. Diabetes mellitus at baseline was a significant predictor of incident hypertension (in FOS, odds ratio, 3.14; 95% confidence interval, 2.17-4.54) independently of sex, age, body mass index, and familial diabetes mellitus. Conversely, hypertension at baseline was an independent predictor of incident diabetes mellitus (in FOS, odds ratio, 3.33; 95% CI, 2.50-4.44). In >60% of the converters, progression from normotension to hypertension was characterized by a steep increase in BP values, averaging 20 mm Hg for systolic BP within 3.5 years (in MCDS). In comparison with the nonconverters group, hypertension and diabetes mellitus converters shared a metabolic syndrome phenotype (hyperinsulinemia, higher body mass index, waist girth, BP, heart rate and pulse pressure, and dyslipidemia). Overall, results were similar in the 2 ethnic groups. We conclude that (1) development of hypertension and diabetes mellitus track each other over time, (2) transition from normotension to hypertension is characterized by a sharp increase in BP values, and (3) insulin resistance is one common feature of both prediabetes and prehypertension and an antecedent of progression to 2 respective disease states.

The metabolic syndrome: an emerging risk state for cardiovascular disease

The common clustering of glucose intolerance, insulin resistance, abdominal adiposity, elevated blood pressure, and low HDL cholesterol is referred to as metabolic syndrome. Individuals with this syndrome have an increased risk of developing cardiovascular disease (CVD). The World Health Organisation and the National Cholesterol Education Programme’s Adult Treatment Panel III (NCEP-ATP III) have outlined specific diagnostic criteria for the diagnosis of the metabolic syndrome to help in the Identification of this syndrome in clinical practice. While the WHO criteria were specifically developed for use in research, the NCEP criteria are useful in clinical diagnosis of the metabolic syndrome. The metabolic syndrome is amenable to lifestyle modifications such as increased physical activity, weight loss, and possibly intake of low-glycemic foods. Drug therapy may be used to treat individual components of the syndrome such as elevated blood pressure and dyslipidemia. To control elevated glucose levels (when there is failure of lifestyle modification), medications such as metformin, thiazolidinedione derivatives and alpha glucosidase inhibitors may be used.

Thirty-year Survival for Black and White Hypertensive Individuals in the Evans County Heart Study and the Hypertension Detection and Follow-up Program

The Evans County Heart Study (ECHS), initiated in 1960, was one of the first major studies to document cardiovascular disease (CVD) risks for African Americans and Caucasians with elevated blood pressures. In the early 1970's, the Hypertension Detection and Follow-up Program (HDFP), with a site in Georgia (HDFP-GA) was one of the first major studies to demonstrate that treating hypertension with stepped care (SC), versus referred care (RC), has better short-term outcomes. With this background, study objectives were to evaluate 30-year survival and cardiovascular outcomes of the HDFP-GA and to compare outcomes of these patients with 1619 hypertensive individuals (30-69 years of age) from the ECHS. HDFP-GA patients included 688 individuals (black [n=267]; white [n=421]) randomized to RC (n=341) and SC (n=347). The ECHS was comprised of 733 black and 886 white hypertensives. All-cause mortality and CVD mortality were assessed in the HDFP-GA and compared to the ECHS hypertensives. After 30-years of follow-up, 65.7% of the HDFP-GA cohort had died compared with a similar 65.8% of the ECHS hypertensives. However, CVD mortality rates, while similar for the SC and RC arms, were lower than in the HDFP-GA total study group than the hypertensive participants of ECHS (32.6% vs. 40.3% p<.001). CVD survival rates for both SC and RC HDFP-GA arms were significantly better than population-based hypertensive individuals in the ECHS, with consistent benefits in all four race-sex groups. These results identify the importance of long-term follow-up of individuals in hypertension studies and trials that include CVD outcomes.

Diabetes and hypertension: the bad companions

High blood pressure is reported in over two-thirds of patients with type 2 diabetes, and its development coincides with the development of hyperglycaemia. Many pathophysiological mechanisms underlie this association. Of these mechanisms, insulin resistance in the nitric-oxide pathway; the stimulatory effect of hyperinsulinaemia on sympathetic drive, smooth muscle growth, and sodium-fluid retention; and the excitatory effect of hyperglycaemia on the renin-angiotensin-aldosterone system seem to be plausible. In patients with diabetes, hypertension confers an enhanced risk of cardiovascular disease. A blood pressure of lower than 140/85 mm Hg is a reasonable therapeutic goal in patients with type 2 diabetes according to clinical trial evidence. People with controlled diabetes have a similar cardiovascular risk to patients without diabetes but with hypertension. A renin-angiotensin system blocker combined with a thiazide-type diuretic might be the best initial antihypertensive regimen for most people with diabetes. In general, the positive effects of antihypertensive drugs on cardiovascular outcomes outweigh the negative effects of antihypertensive drugs on glucose metabolism.

Do screening blood pressure and plasma catecholamines predict development of hypertension? Twenty-year follow-up of middle-aged men

OBJECTIVES

The sympathetic nervous system is implicated in the development and maintenance of hypertension. However, the predictive impact of arterial plasma catecholamines has never been reported. We investigated arterial catecholamines and blood pressures (BPs) prospectively over 20 years in a group of well-characterized middle-aged men.

METHODS

Fifty-six of original 79 men were available for the follow-up. Multiple regression analysis was done with mean BP at follow-up as a dependent variable, and arterial plasma catecholamines and BP at baseline as independent variables.

RESULTS

Half of the originally normotensive men developed hypertension during follow-up. There were significant differences in the screening BP values measured at baseline between the new hypertensives and the sustained normotensives. Multiple regression analysis revealed arterial adrenaline at baseline as an independent predictor of mean BP at follow-up in the new hypertensives (beta = 0.646, R2 = 0.42, p = 0.007). Furthermore, arterial noradrenaline at baseline was a negative independent predictor of mean BP at follow-up in the sustained normotensives (beta = -0.578, R2 = 0.334, p = 0.020). Noradrenaline increased with age in the group as a whole (1318+/-373 vs 1534+/-505 pmol/l, p = 0.010) while adrenaline did not change.

CONCLUSION

Our data suggest that arterial adrenaline is involved in the development of hypertension over 20 years in middle-aged men. Men with sustained normotension may have an inherent protection against sympathetic overactivity. Furthermore, screening BP at baseline in normotensive men differentiated between those who developed hypertension and those who remained normotensive at follow-up.

Resting heart rate in middle age and diabetes development in older age

OBJECTIVE

Based on prior research showing inverse associations between heart rate and life expectancy, we tested the hypothesis that adults with higher resting heart rate in middle age were more likely to have diagnosed diabetes or to experience diabetes mortality in older age (>65 years).

RESEARCH DESIGN AND METHODS

Resting heart rate was measured at baseline (1967-1973) in the Chicago Heart Association Detection Project in Industry. We used Medicare billing records to identify diabetes-related hospital claims and non-hospital-based diabetes expenses from 1992 to 2002 in 14,992 participants aged 35-64 years who were free from diabetes at baseline. Diabetes-related mortality was determined from 1984 to 2002 using National Death Index codes 250.XX (ICD-8 and -9) and E10-E14 (ICD-10).

RESULTS

After age 65, 1,877 participants had diabetes-related hospital claims and 410 participants had any mention of diabetes on their death certificate. The adjusted (demographic characteristics, cigarette smoking, and years of Medicare eligibility) odds of having a diabetes-related claim was approximately 10% higher (odds ratio [OR] 1.10 [95% CI 1.05-1.16]) per 12 bpm higher baseline heart rate. Following adjustment for BMI and postload glucose at baseline, the association attenuated to nonsignificance. Higher heart rate was associated with diabetes mortality in adults aged 35-49 years at baseline following adjustment for postload glucose and BMI (1.21 [1.03-1.41]).

CONCLUSIONS

Higher resting heart rate is associated with diabetes claims and mortality in older age and is only due in part to BMI and concurrently measured glucose.

Cigarette smoking and colorectal carcinoma mortality in a cohort with long-term follow-up

BACKGROUND

Evidence suggests that colorectal carcinoma (CRC) may be a tobacco-associated malignancy.

METHODS

In the current study, the authors examined the association between cigarette smoking and CRC mortality in the Chicago Heart Association Detection Project in Industry study, a cohort of 39,299 men and women with an average of 26 years of follow-up. To assess whether the association was stronger in participants with a potentially long history of smoking, the authors also stratified the analysis using a baseline age > or = 50 years versus < 50 years.

RESULTS

Using multivariate Cox regression analysis, there was a marginally significant trend (P = 0.06) for men and women combined between smoking and CRC mortality. In the age-stratified analysis in the older participant group, there was no apparent association for men, women, or men and women combined. In the younger participant group, there appeared to be dose-response relations for women and for men and women combined (P value for trend = 0.008 and 0.03, respectively) between smoking and CRC mortality. The relative risk for women who smoked >20 cigarettes/day compared with never smokers was 2.49 (95% confidence interval [95% CI], 0.87-7.12), and was 1.87 for men and women combined (95% CI, 1.08-3.22).

CONCLUSIONS

The results of the current study support an association between cigarette smoking and CRC mortality, particularly in women age < 50 years.

Fasting blood glucose is independently associated with resting and exercise blood pressures and development of elevated blood pressure

OBJECTIVE

To assess whether fasting blood glucose is independently related to blood pressure at rest and during exercise, and to development of elevated blood pressure.

DESIGN

Cross-sectional and prospective cohort study of 2014 apparently healthy middle-aged men.

METHODS

The baseline survey included carefully standardized blood pressure measurements at rest and during exercise testing, an intravenous glucose tolerance test and a panel of fasting blood tests, including fasting blood glucose. Results from 7-years follow-up provided data on development of elevated blood pressure.

RESULTS

Strong associations were found between quartiles of fasting blood glucose and baseline resting and/or exercise levels of blood pressure, and also development of elevated blood pressure over 7 years. Physical fitness, calculated from an exercise test, had a strong modulating effect on blood pressure at all levels of fasting blood glucose. In multivariate models - after adjusting for intravenous glucose tolerance, physical fitness, age, body mass index, triglycerides and cholesterol - fasting blood glucose was strongly associated with blood pressure at rest (coefficient = 2.83, P = 0.0004) and during exercise (coefficient = 6.57, P < 0.0001), and further to development of treated hypertension and/or elevated blood pressure [odds ratio (OR), 1.17; 95% confidence interval (CI), 1.05-1.31].

CONCLUSION

In healthy non-diabetic and non-hypertensive men, strong associations were found between fasting blood glucose and blood pressure at rest and during exercise and to development of elevated blood pressure after 7-years follow-up. Fasting glucose metabolism deserves scrutiny when studying the pathogenesis of hypertension.

Pulse pressure compared with other blood pressure indexes in the prediction of 25-year cardiovascular and all-cause mortality rates: The Chicago Heart Association Detection Project in Industry Study

We compared the relations of 4 blood pressure (BP) indexes (pulse pressure [PP], systolic BP [SBP], diastolic BP [DBP], and mean arterial pressure [MAP]) with 25-year mortality rates for coronary heart disease (CHD), cardiovascular disease (CVD), and all causes in younger, middle-aged, and older men and women by using data from a long-term prospective epidemiological study of employed persons who were screened between 1967 and 1973. A single supine BP measurement was obtained at baseline. Vital status was determined through 1995. We report on 5 groups (total, 28 360 participants) consisting of men age 18 to 39, 40 to 59, and 60 to 74 years and of women age 40 to 59 and 60 to 74 years who were not receiving antihypertensive treatment, had no history of CHD, and did not have diabetes. Cox proportional hazards analyses were used to determine multivariate-adjusted hazard ratios with a 1-SD higher value for each BP index; Wald chi(2) tests were used to compare the strength of relations. Relations of PP were less strong than were those of SBP for all end points in all age/gender groups. SBP or MAP showed the strongest relations to all end points in all age/gender groups (hazard ratio, 1.17 to 1.36). The relations of SBP to death were stronger than were those of DBP, except for middle-aged men and for CVD in women. DBP showed significant positive associations with death, after control for SBP, in middle-aged participants. In conclusion, these data indicate that the long-term risk of high BP should be assessed mainly on the basis of SBP or of SBP and DBP together, not on the basis of PP, in apparently healthy adults.

Longitudinal changes in body mass index and body composition over 3 years and relationship to health outcomes in Hong Kong Chinese age 70 and older

OBJECTIVES

To determine longitudinal changes in body mass index (BMI) and body composition with age and the relationship between these changes with mortality, morbidity, functional capacity, and other health outcome measures.

DESIGN

A 3-year longitudinal study of a random sample of community-living subjects.

SETTING

Older Chinese in the Hong Kong Special Administrative Region of China.

PARTICIPANTS

Two thousand and thirty-two Chinese subjects age 70 and older recruited territory-wide by proportional random sampling.

MEASUREMENTS

Baseline information collected included medical history, self-perceived health, Barthel Index, Geriatric Depression Score, time taken to complete a 16-foot walk, height, weight, mid-arm circumference, arm skin-fold thickness, and waist/hip ratio. Body composition was calculated from prediction equation. Outcome measures included mortality, development of new diseases, Barthel Index, time taken for 16-foot walk, self-perceived health, and Geriatric Depression Score.

RESULTS

All parameters, with the exception of triceps skin-fold thickness in men, decreased, regardless of presence or absence of disease. The decrease in arm circumference, triceps skin-fold thickness, and total body fat (TBF) was greater in women than in men, whereas men had a greater decrease in fat-free mass (FFM). Even in the absence of disease, three times as many subjects lost > or =5kg in weight as gained > or =5kg (15% vs. 5%), and only age could be identified as a contributing factor to this weight loss. In the absence of disease, lower anthropometric indices were associated with greater mortality, development of new disease (in women only), dependency, and poor performance measure. Waist-hip ratio was not associated with mortality or any other health outcomes. Decrease in both FFM and TBF were associated with worse outcomes, the effect being more marked in women.

CONCLUSION

In the older population, changes in weight and body composition occur even in the absence of disease and are associated with mortality and physical functioning level. Weight loss rather than weight gain appears to be more important in this population, and promotion of life-style interventions targeted at weight maintenance would be important.

Heart rate as a predictor of future blood pressure in schoolchildren

Heart rate (HR) has been shown to predict future blood pressures (BP) in studies in adults. We explored the relation of HR to future BP levels in a cohort of 344 black and 456 white schoolchildren ages 5 to 19 years, to examine the hypothesis that HR predicts subsequent BP even very early in life. After making baseline measurements, BP was assessed longitudinally 1 to 24 additional times (mean = 8.25) after the baseline period, at intervals of approximately 6 months. We found that HR was significantly related to future diastolic BP in the black boys (P = .016) after adjusting for baseline diastolic BP, age, and body mass index, but not in the black girls or in the white children. Because HR is reflective of sympathetic nervous system (SNS) activity that in turn can be related to the renin-angiotensin system (RAS), we also explored the relation of HR to the RAS by studying relationships to variants in the angiotensinogen gene and the angiotensin I-converting enzyme (ACE) gene. We found a significantly positive relationship of HR to the presence of the deletion allele of the ACE gene (P = .0015), but, again, only in the black boys. Because blacks in general appear to retain additional sodium when compared with whites, the SNS, as reflected in the HR, may influence BP more when individuals have increased sodium retention. In summary, baseline HR predicted future diastolic BP in the black boys but not in the black girls or in the white children.

Relation of high blood pressure to glucose intolerance, plasma lipids and educational status in an Arabian Gulf population

BACKGROUND

In Bahrain and other populations of the Arabian Peninsula, glucose intolerance is associated with raised plasma total cholesterol, postmenopausal status and low educational status. These associations are not generally seen in other populations with high diabetes prevalence. A study was undertaken in order to determine if hypertension in Bahrainis is associated with the same factors as those related to glucose intolerance.

METHODS

A cross-sectional survey of 2120 Bahrainis aged 40-69 years.

RESULTS

The age-adjusted prevalence of hypertension (defined as current treatment for hypertension, systolic blood pressure > or = 160 mmHg or diastolic blood pressure > or = 95 mmHg) rose with increasing degrees of glucose intolerance. Age- and sex-standardized prevalence of hypertension was 21% (95% CI: 19-24%) in those with normal glucose tolerance, 31% (95% CI: 27-36%) in those with impaired glucose tolerance, and 38% (95% CI: 34-42%) in those with diabetes. In a multivariate analysis adjusting for age and sex, raised blood pressure was independently associated with waist girth, plasma cholesterol, glucose intolerance, family history of hypertension and (in women) postmenopausal status. There was an inverse relationship between blood pressure and educational status that was independent of other variables. This association parallels the inverse relationship of diabetes to educational level and is consistent with low educational level being a marker for socioeconomic deprivation in early life in this population.

CONCLUSION

The high prevalence rates of hypertension and diabetes in Bahrainis are manifestations of a pattern of metabolic disturbances that includes raised plasma cholesterol levels. Both hypertension and diabetes are associated with low educational status, which in this population is a marker for socioeconomic deprivation in early life. This suggests that the risk of hypertension may be set by environmental factors in early life.

Heart rate and subsequent blood pressure in young adults: the CARDIA study

The objective of the present study was to examine the hypothesis that baseline heart rate (HR) predicts subsequent blood pressure (BP) independently of baseline BP. In the multicenter longitudinal Coronary Artery Risk Development in Young Adults study of black and white men and women initially aged 18 to 30 years, we studied 4762 participants who were not current users of antihypertensive drugs and had no history of heart problems at the baseline examination (1985-1986). In each race-sex subgroup, we estimated the effect of baseline HR on BP 2, 5, 7, and 10 years later by use of repeated measures regression analysis, adjusting for baseline BP, age, education, body fatness, physical fitness, fasting insulin, parental hypertension, cigarette smoking, alcohol consumption, oral contraceptive use, and change of body mass index from baseline. The association between baseline HR and subsequent systolic BP (SBP) was explained by multivariable adjustment. However, HR was an independent predictor of subsequent diastolic BP (DBP) regardless of initial BP and other confounders in white men, white women, and black men (0.7 mm Hg increase per 10 bpm). We incorporated the part of the association that was already present at baseline by not adjusting for baseline DBP: the mean increase in subsequent DBP was 1.3 mm Hg per 10 bpm in white men, white women, and black men. A high HR may be considered a risk factor for subsequent high DBP in young persons.

Association of Trp64Arg beta 3-adrenergic-receptor gene polymorphism with essential hypertension in the Sardinian population

OBJECTIVE

To evaluate the possible association of three candidate gene polymorphisms with essential hypertension in the genetically homogeneous Sardinian population.

SUBJECTS AND METHODS

We studied 494 unrelated, nondiabetic subjects, 213 (43.2%) with essential hypertension. All subjects underwent a 75 g oral glucose tolerance test with determination of glycemia and insulinemia and serum lipids. The polymorphisms evaluated comprised Trp64Arg of the beta 3-adrenergic receptor, Gly40Ser of the glucagon receptor gene and the insertion/deletion polymorphism of the angiotensin converting enzyme (ACE) gene.

RESULTS

Among the overall population studied, 48 (9.7%) were heterozygous carriers of the Trp64Arg polymorphism. The frequency of the Trp64Arg variant was significantly higher in hypertensives (13.6%) than normotensives (6.8%; chi 2 5.73, P = 0.017). The 48 subjects with the Trp64Arg variant had significantly higher (P < 0.049) serum triglyceride levels than the 446 with the Trp64Trp variant, while no significant differences were observed, either fasting or during the 75 g oral glucose tolerance test, in glycemia and insulinemia. No differences were found between hypertensive and normotensive subjects for ACE gene insertion/deletion polymorphism nor in the frequency of the Gly40Ser coding change in exon 2 of the glucagon receptor gene.

CONCLUSIONS

Our results are consistent with the thesis that the Trp64Arg polymorphism of the beta 3-adrenergic receptor gene is associated more often with the condition of high blood pressure than with normal blood pressure.

Influence of heart rate on mortality in a French population: role of age, gender, and blood pressure

-The aim of the present study was to assess the effects of high heart rate on mortality in different subgroups in a French population according to age, gender, and blood pressure levels. We studied 19 386 subjects (12 123 men, 7263 women), aged 40 to 69 years, who had a routine health examination at the Centre d'Investigations Préventives et Cliniques (IPC) between 1974 and 1977. Heart rate (HR) measured by ECG was classified into 4 groups: HR1, <60; HR2, 60 to 80; HR3, 81 to 100; and HR4, >100 bpm. Mortality data were recorded for the period of 1974 through 1994. In both sexes, HR was a significant predictor of noncardiovascular mortality. In men, the relative risk (95% confidence interval) for cardiovascular death after adjustment for age and other risk factors in the HR2, HR3, and HR4 groups was 1.35 (1.01 to 1.80), 1.44 (1.04 to 2.00), and 2.18 (1.37 to 3.47), respectively, when compared with HR1. In women, HR did not influence cardiovascular mortality. The association of HR with cardiovascular mortality in men was (1) related to a strong association with coronary but not cerebrovascular mortality, (2) independent of age and hypertension, and (3) influenced by the level of pulse pressure; in patients with high pulse pressure (>65 mm Hg), accelerated HR was not associated with increased cardiovascular mortality. In conclusion, in a large French population, accelerated resting HR represents an independent predictor of noncardiovascular mortality in both genders, and of cardiovascular mortality in men, independent of age and the presence of hypertension. Further investigations are needed to explain the complex interactions between HR, pulse pressure, and cardiovascular complications.

Glucose-induced alterations of cytosolic free calcium in cultured rat tail artery vascular smooth muscle cells

We have previously suggested that hyperglycemia per se may contribute to diabetic hypertensive and vascular disease by altering cellular ion content. To more directly investigate the potential role of glucose in this process, we measured cytosolic free calcium in primary cultures of vascular smooth muscle cells isolated from Sprague-Dawley rat tail artery before and after incubation with 5 (basal), 10, 15, and 20 mM glucose. Glucose significantly elevated cytosolic free calcium in a dose- and time-dependent manner, from 110.0 +/- 5.4 to 124.5 +/- 9.0, 192.7 +/- 20.4, and 228.4 +/- 21.9 nM at 5, 10, 15, and 20 mM glucose concentrations, respectively. This glucose-induced cytosolic free calcium elevation was also specific, no change being observed after incubation with equivalent concentrations of L-glucose or mannitol. This glucose effect was also dependent on extracellular calcium and pH, since these calcium changes were inhibited in an acidotic or a calcium-free medium, or by the competitive calcium antagonist lanthanum. We conclude that ambient glucose concentrations within clinically observed limits may alter cellular calcium ion homeostasis in vascular smooth muscle cells. We suggest that these cellular ionic effects of hyperglycemia may underlie the predisposition to hypertension and vascular diseases among diabetic subjects and/or those with impaired glucose tolerance.

Casual blood pressure in a general Danish population. Relation to age, sex, weight, height, diabetes, serum lipids and consumption of coffee, tobacco and alcohol

A population survey was conducted on 3608 randomly selected Danes aged 30, 40, 50 and 60 years respectively. Of these, 3400 were not in medical treatment for arterial hypertension. The following parameters were investigated: sex, age, serum lipid levels (total cholesterol, HDL cholesterol, triglycerides), presence of diabetes mellitus, height, body mass index (BMI), and average daily consumption of coffee, tobacco and alcohol. Analysis with multiple linear regression showed that all variables with the exception of triglycerides, HDL cholesterol and height were significantly associated with systolic blood pressure. Likewise all factors except diabetes, triglycerides and height were significantly associated with diastolic blood pressure. Further analysis in which the effect of each parameter was corrected for by the effects of the remaining variables, demonstrated that apart from age and sex only BMI and high alcohol consumption were positively associated with differences in blood pressure greater than a few mmHg. However, the variation in both systolic and diastolic blood pressures was only partly accounted for by the parameters studied--in the covariates analysis R2 for systolic blood pressure was 0.28 and R2 for diastolic blood pressure was 0.30. In conclusion, this investigation demonstrated that blood pressure is relatively independent of other factors important in the development of cardiovascular disease. Of the above-mentioned factors with some influence on blood pressure only age, BMI and high alcohol consumption have potential clinical importance.

Hypertension prevalence and age-related changes of blood-pressure in semi-nomadic and urban Oromos of Ethiopia

We evaluated the prevalence of hypertension and the age-related behaviour of systolic blood pressure (SBP) and diastolic blood pressure (DBP) in a wide sample of male and female Ethiopian Oromos living in rural or pre-industrial urbanized settings. Blood pressure (BP) was measured in the sitting position after 5 min rest in 5277 Oromos. In the group, 4928 were semi-nomadic shepherds, while 349 came from a town of 60,000 inhabitants where they were involved in low-technology jobs. The first subgroup was composed of 2482 men and 2446 women. All subjects were divided into 3 age groups: 15-44, 45-64, and > or = 65 years. Body weight (BW) and the Quetelet index (QI) were matched to BP levels using Pearson's method. In semi-nomadic men, SBP was 121.4 +/- 8.4 mmHg versus 132.4 +/- 10.4 mmHg in urban men (p < 0.001). In women, SBP was 120.5 +/- 7.9 mmHg versus 128.1 +/- 10.1 mmHg (p < 0.001). The prevalence of hypertension was 0.40% in the semi-nomadic and 3.15% in the urban population. In the latter, significant increases in BW and QI were found, which were significantly correlated to both SBP and DBP. In semi-nomadic men, a 5.33% increase in SBP and a 5.22% in DBP was found between age groups 1 and 2 (p < 0.001 in both). In urban men the increase was 4.77% and 3.41% respectively (p < 0.001). In both male populations no difference in SBP and DBP was observed between age groups 2 and 3.(ABSTRACT TRUNCATED AT 250 WORDS)

Correlates of blood pressure in community-dwelling older adults. The Cardiovascular Health Study. Cardiovascular Health Study (CHS) Collaborative Research Group

Although elevated blood pressure is an important predictor of cardiovascular disease and stroke in the elderly, little information exists on the distribution and risk factor correlates of blood pressure in this group. As part of the Cardiovascular Health Study, a population-based cohort study of 5201 men and women aged 65 to 101 years, we investigated correlates of systolic and diastolic blood pressure. Multiple regression analyses were conducted for all participants and a subgroup of 2482 without coronary heart disease and not on antihypertensive therapy (the "healthier" subgroup). In the total group, independent predictors of diastolic blood pressure included heart rate, aortic root dimension, creatinine, hematocrit, alcohol use, and black race (positive associations) and internal carotid artery wall thickness, mitral early/late peak flow velocity, white blood cell count, cigarette smoking, and age (negative associations). Positive predictors of systolic blood pressure included mitral late peak flow velocity, left ventricular mass, common carotid artery wall thickness, serum albumin, factor VII, diabetes, alcohol use, and age; negative predictors were coronary heart disease, uric acid, height, and smoking. In the healthier subgroup, positive predictors of diastolic blood pressure included heart rate, hematocrit, serum albumin, creatinine, and body weight, whereas mitral early/late peak flow velocity, serum potassium, smoking, and age inversely related to diastolic pressure. For the same group, common carotid artery wall thickness, left ventricular mass, serum albumin, factor VII, high-density lipoprotein cholesterol, and age were directly related to systolic blood pressure, whereas serum potassium was inversely related. Both systolic and diastolic pressures varied considerably by geographic site.(ABSTRACT TRUNCATED AT 250 WORDS)

Plasma triglycerides and 24 hour urinary sodium excretion in elderly hypertensives. A pathogenetic connection?

Hypertension among the elderly generally represents a salt- sensitive state. However this salt-sensitivity does not appear to result from age-related increase in either sodium or salt intake. Since 20 years new trends seem to relate the role of sodium in the genesis of hypertension to a primary abnormality of electrolyte transport of cell membrane. Lipid abnormalities have also been described in untreated patients with high blood pressure. Plasma triglycerides were considerably higher (p < 0.01) in the hypertensives than in the controls. 24 hour sodium excretion was significantly lower (p < 0.0001) in hypertensives than in the controls. We have found a strong correlation among reduced sodium excretion, higher triglycerides and elevated blood pressure in the elderly. The blood pressure correlated negatively with 24 hour sodium excretion (p < 0.0001 for systolic and p < 0.002 for diastolic) and positively with plasma triglycerides (p < 0.0001 for systolic and p < 0.001 for diastolic). The poor literature regarding an association of these two alterations in human hypertensives makes our results provocative. We speculated that these alterations may be a facet of the insulin resistance commonly detectable in human hypertensives. However, further investigations are required to answer to this intriguing hypothesis.

Secular blood pressure trends in normotensive persons: the Framingham Study

Trends in hypertension prevalence are difficult to assess because of a massive increase in the prevalence of antihypertensive treatment. Over the past three decades mean blood pressure levels among the 5209 members of the Framingham Study cohort have declined, and elevated blood pressure is only one third as prevalent. However, if those receiving treatment who have normalized blood pressures are defined as hypertensive, in addition to those with elevated blood pressure, the prevalence of hypertension has increased. No consistent secular trend in the incidence of hypertension was noted over three decades, but high blood pressure eventually developed in two thirds of the study cohort. To determine whether untreated blood pressure levels are changing over time, trends in mean blood pressure were examined in normotensive subjects over three decades. Only a 1 mm Hg decline in mean systolic and diastolic pressure over each 10-year interval was noted (p < 0.001). Thus blood pressure in the normotensive segment of the population has been quite stable. Because the incidence of hypertension is very high and future hypertension arises from the upper end of the normal blood pressure distribution, there is an urgent need for primary prevention. Preventive measures such as exercise, avoidance of salt and alcohol, and especially weight control deserve a high priority.

Serum lipids, neuroendocrine and cardiovascular responses to stress in healthy Type A men

This study examined the relationship between serum lipid activity in healthy Type A men and cardiovascular and neuroendocrine responses to a behavioral stressor, mental arithmetic. Assessment of blood lipids included measures of total cholesterol (TC), low density lipoprotein cholesterol (LDLC), high density lipoprotein cholesterol (HDLC), and serum triglycerides. Cardiovascular (blood pressure and heart rate) and neuroendocrine (epinephrine, norepinephrine and cortisol) responses were recorded before (rest), during (stress) and after (recovery) the mental arithmetic test. Diastolic blood pressure, mean arterial pressure and, to a lesser extent, systolic blood pressure levels at rest, during stress, and at recovery correlated positively with TC levels. In addition, both diastolic and mean arterial pressure were positively correlated with the ratio of TC to HDLC and with triglycerides during stress and recovery. Heart rate did not correlate with any lipid measure. Cardiovascular stress-reactivity calculated as change from rest to stress did not correlate significantly with any lipid measure. Plasma norepinephrine during stress correlated positively with triglycerides; a similar trend was observed for the TC/HDLC ratio. Plasma cortisol at rest and during stress correlated positively with the TC/HDLC ratio and serum triglycerides, and negatively with HDLC. Plasma norepinephrine reactivity calculated as change from rest to stress correlated negatively with HDLC and positively with triglycerides. In addition, cortisol reactivity was positively correlated with triglycerides. It is suggested that the mechanisms mediating Type A behavior and coronary heart disease may include increased cardiovascular and neuroendocrine responses as well as unfavorable lipid profiles.

Clustering of cardiovascular risk factors in confirmed prehypertensive individuals

Numerous studies have indicated that hypertensive subjects have an atherogenic lipoprotein pattern, hyperinsulinemia, and impaired glucose tolerance relative to normotensive individuals. These abnormalities could be due to adverse effects of certain antihypertensive agents, to pathophysiological concomitants of the hypertensive state itself, or to both. In this report, we describe the cardiovascular risk factor profile of 1,440 subjects who were normotensive and were not taking any antihypertensive medications when first examined and who subsequently participated in the 8-year follow-up of the San Antonio Heart Study. Hypertension developed in 130 subjects during the follow-up period. At baseline these prehypertensive individuals had significantly higher levels of blood pressure, fasting total and low density lipoprotein cholesterol, triglyceride, glucose, and insulin, and 2-hour glucose than those who remained free of hypertension. In addition, they had higher body mass indexes, a less favorable body fat distribution, and lower levels of high density lipoprotein cholesterol. In multiple linear regression analyses, baseline levels of triglyceride and blood pressure remained significantly higher and high density lipoprotein cholesterol remained significantly lower in the subjects who later converted to hypertension than in those who remained normotensive. Although baseline insulin levels were also higher in the prehypertensive subjects, this difference was not statistically significant. In nonobese subjects, however, those with high baseline insulin concentrations had an increased incidence of hypertension compared with those with low insulin concentrations. The present results suggest that the cluster of atherogenic changes associated with hypertension actually precede the development of the hypertensive state.

Exercise-loaded blood pressure and Li-Na countertransport system in the erythrocyte membrane as predictors of mild essential hypertension prognosis

1. The blood pressure response to exercise loading, Na concentration in the erythrocyte and Li-Na countertransport (Li-Na CT) system in the erythrocyte membrane in 40 male volunteers and 98 patients with mild essential hypertension were investigated. Subjects were divided into a juvenile group (less than 36 years) and a middle-aged (greater than 36 years and less than 65 years) group. Exercise-loaded blood pressure in patients with mild essential hypertension was followed up for more than 5 years. 2. Systolic blood pressure (SBP) at 6 min during exercise loading was significantly higher in the mild hypertension group compared with the control group. 3. Patients with high SBP at exercise loading in the mild hypertension group transferred more often to the moderate hypertension group within 5 years. 4. No difference in the haemodynamic parameter at rest was noted in the transferred group for moderate hypertension and the non-transferred group. 5. A higher blood pressure response to noradrenaline was noted in the transferred group compared with the non-transferred group of the juvenile group. 6. High Na concentration in the erythrocyte and acceleration of the Li-Na CT system in the erythrocyte membrane were noted in the mild hypertension group compared with the volunteer group. 7. A correlation between SBP at exercise loading and Li-Na CT system in the erythrocyte membrane was noted. This correlation was strongly noted in subjects less than 50 years old. 8. From these results it was concluded that SBP at exercise loading and Li-Na CT system in the erythrocyte membrane are useful as indicators for the prognosis of mild essential hypertension.

Renal haemodynamic and sympathetic responses to head-up tilt in essential hypertension

Nine mild-to-moderate hypertensive patients (HT), aged 41 +/- 0.6 years (mean +/- SEM) and nine age-matched normotensive control subjects (NT) were tilted to 60 degrees for 10 min. During tilt, both systolic (S) blood pressure (BP) (p less than 0.01) and diastolic (D) BP (p less than 0.05) increased in HT, but not in NT. At supine rest renal blood flow was higher in HT than in NT and increased by 17% in HT during tilt, while a decrease of 13% was observed in NT (p less than 0.05). Renal vascular resistance was unchanged in HT during tilt, while a significant increase (p less than 0.01) was observed in NT. Arterial plasma noradrenaline increased in both groups (p less than 0.05) during tilt, significantly more in HT than in NT (p less than 0.05). No statistically significant difference was observed between the groups in renal catecholamine uptake or release. Our data indicate enhanced general sympathetic and circulatory responses to tilt in subjects with mild-to-moderate essential hypertension. However, the enhanced haemodynamic and sympathetic responses were not shared by hypertensive kidneys and renovascular resistance remained unaffected by tilt.

Cardiovascular diseases in Chinese, Malays, and Indians in Singapore. II. Differences in risk factor levels

STUDY OBJECTIVE

The aim of the study was to examine cardiovascular risk factors to see how these might explain differences in cardiovascular disease mortality among Chinese, Malays, and Indians in the Republic of Singapore.

DESIGN

The study was a population based cross sectional survey. Stratified systematic sampling of census districts, reticulated units, and houses was used. The proportions of Malay and Indian households were increased to improve statistical efficiency, since about 75% of the population is Chinese.

SETTING

Subjects were recruited from all parts of the Republic of Singapore.

SUBJECTS

2143 subjects aged 18 to 69 years were recruited (representing 60.3% of persons approached). There were no differences in response rate between the sexes and ethnic groups.

MEASUREMENTS AND MAIN RESULTS

Data on cardiovascular risk factors were collected by questionnaire. Measurements were made of blood pressure, serum cholesterol, low and high density lipoprotein cholesterol, fasting triglycerides and plasma glucose. In males the age adjusted cigarette smoking rate was higher in Malays (53.3%) than in Chinese (37.4%) or Indians (44.5%). In both sexes, Malays had higher age adjusted mean systolic blood pressure: males 124.6 mm Hg v 121.2 mm Hg (Chinese) and 121.2 mm Hg (Indians); females 122.8 mm Hg v 117.3 mm Hg (Chinese) and 118.4 mm Hg (Indians). Serum cholesterol, low density lipoprotein cholesterol and triglyceride showed no ethnic differences. Mean high density lipoprotein cholesterol in males (age adjusted) was lower in Indians (0.69 mmol/litre) than in Chinese (0.87 mmol/litre) and Malays (0.82 mmol/litre); in females the mean value of 0.95 mmol/litre in Indians was lower than in Chinese (1.05 mmol/litre) and Malays (1.03 mmol/litre). Rank prevalence of diabetes for males was Indians (highest), Malays and then Chinese; for females it was Malays, Indians, Chinese.

CONCLUSIONS

The higher mortality from ischaemic heart disease found in Indians in Singapore cannot be explained by the major risk factors of cigarette smoking, blood pressure and serum cholesterol; lower high density lipoprotein cholesterol and higher rates of diabetes may be part of the explanation. The higher systolic blood pressures in Malays may explain their higher hypertensive disease mortality.

Anthropometric determinants of resting blood pressure and heart rate of Nigerian school children

Blood pressure, heart rate and anthropometric parameters were measured in 807 Nigerian school-age children. There was no significant difference between the blood pressure and heart rate of boys and girls after adjusting for differences in age and anthropometric parameters. The stepwise regression analysis revealed that the strong determinants of blood pressure levels were weight, Quetelet index and triceps skinfold thickness. Based on our findings, we recommend that body weight norms rather than age should be used in evaluating abnormal blood pressure levels in Nigerian children.

Blood lipids as related to cardiovascular and neuroendocrine functions under different conditions in healthy males and females

Correlations were calculated between, on the one hand, total serum cholesterol, low-density (LDL) and high-density (HDL) lipoprotein cholesterol, and triglycerides, and, on the other hand, systolic (SBP) and diastolic blood pressure (DBP), heart rate (HR), urinary epinephrine, norepinephrine, and cortisol in 30 healthy males and 30 healthy females, aged 30-50. The cardiovascular and neuroendocrine measurements were obtained under different real-life and laboratory conditions. The most striking finding was that, in men, but not in women, total serum cholesterol was significantly positively correlated with SBP in all conditions (LDL and HDL cholesterol followed the same pattern). In women, but not in men, epinephrine and norepinephrine during laboratory-induced mental stress were significantly positively correlated with total cholesterol, LDL and triglycerides.

Ethnic differences in female overweight: data from the 1985 National Health Interview Survey

Ethnic differences in female overweight were analyzed using data from the 1985 National Health Interview Survey. The sample consisted of approximately 17,000 women, ages 18 and over. After adjusting for age and poverty status, there were clear differences in the proportions of women 20 per cent or more overweight among Black, Hispanic and other White women (35, 26 and 20 per cent, respectively). Black women were less likely than White women to perceive themselves as overweight when categorized by actual weight relative to ideal weight; however, within categories of weight relative to other women of the same ethnic group, all women not Hispanic were equally likely to consider themselves overweight. There was no difference by ethnicity in the proportion of women trying to lose weight among those who perceived themselves as overweight. These findings have implications for programs designed to modify weight, since they suggest that women use ethnic-specific standards in assessing overweight.

Age and blood pressure changes. A 20-year follow-up study in nuns in a secluded order

In a prospective study, 144 white nuns belonging to a secluded monastic order and 138 white control laywomen were followed for 20 years to investigate whether living for a long time in a stress-free environment influences the effect of aging on blood pressure. Silence, meditation, and isolation from society are the distinctive features of the life-style examined. At study entry, blood pressure was not dissimilar in the nuns and the control group, but it increased over time only in the controls, with a mean slope of the regression line (beta coefficient) of 0.089 in the nuns (NS) and 2.171 in the controls (p less than 0.0001) for systolic blood pressure and of 0.054 in the nuns (NS) and 0.742 in the controls (p less than 0.0001) for diastolic blood pressure. Weight and body mass index increased similarly over time in the two groups. Family history of hypertension was not dissimilar between the groups. Serum cholesterol and triglycerides, higher at study entry in the nuns, increased similarly over time in the two groups. Twenty-four-hour urinary sodium excretion, collected randomly in both groups, did not differ over time between nuns and controls. None of the women smoked or used oral contraceptives. Educational level was higher in the control group, but subgroups of 48 nuns and 52 laywomen of comparable educational level maintained the same difference in the blood pressure trend over time as in the main cohort. Parity affected the increase of systolic, but not of diastolic, blood pressure with age among the laywomen, but nuns and no-childbirth controls maintained a significantly different blood pressure trend over time.(ABSTRACT TRUNCATED AT 250 WORDS)

Correlates of systolic and diastolic blood pressure in men 40 to 59 years of age sampled from United States of America and Union of Soviet Socialist Republics Lipid Research Clinics populations

The correlates of blood pressure (BP) were investigated in 2 samples using common protocols, one from a Union of Soviet Socialist Republics study in 2 locations and one from a United States of America study in 9 locations. Age, heart rate, Quetelet index, high density lipoprotein cholesterol, natural logarithm of triglycerides and fasting glucose were positively related to systolic BP in both samples. In diastolic BP, alcohol consumption, heart rate, Quetelet index and natural logarithm of triglycerides were positively associated, and number of cigarettes smoked was negatively related in both samples.

Race and sex differences in the correlates of blood pressure change

Potential predictors of systolic and diastolic blood pressure change between 1960 and 1967 in the biracial population of Evans County, Georgia, were investigated. An all possible regressions multiple linear regression analysis was used. For systolic blood pressure change, the level of systolic blood pressure, age, and change in Quetelet index were significant (p less than 0.05) correlates in white men. The level of systolic blood pressure, the level and change of socioeconomic status, change in Quetelet index, and change in cholesterol were significant correlates for white women. The level of Quetelet index was of borderline significance (p less than 0.055) when the other significant variables were included in the model for white women. The change in Quetelet index was the only significant correlate of systolic blood pressure change in blacks. For diastolic blood pressure change, age, change in hematocrit, and change in Quetelet index were significant correlates for white men. Age, level and change of socioeconomic status, level and change of Quetelet index, and change in hematocrit were the significant correlates in white women. In black men, change in Quetelet index and age were significant. In black women, only age was a significant correlate of diastolic blood pressure change. These results indicate that there may be important differences in these correlates between race-sex groups and thus in the mechanism of blood pressure change for different race-sex groups. groups.

Preventing heart disease: is treating the high risk sufficient?

Monte Carlo simulation was used to assess the effects of several intervention strategies on coronary heart disease mortality rates in a Finnish and a North American cohort. Lowering total serum cholesterol by 4%, smoking by 15%, and diastolic blood pressure by 3% for the whole cohort would be expected to reduce the incidence of non-fatal myocardial infarction by at least 13% and coronary heart disease deaths by at least 18%. Lowering serum cholesterol by 34%, diastolic blood pressure to 90 mmHg, and reducing smoking by 20% in the subset of the population with all three risk factors in the highest quartile would result in a 6-8% reduction in non-fatal myocardial infarction and a 2-9% reduction in deaths from coronary heart disease in these cohorts. These data demonstrate that in populations with a relatively high incidence of heart disease, treating the entire population will produce larger effects than focusing only on high-risk populations.

Relationship between blood pressure and plasma insulin in non-obese and obese non-diabetic subjects

In this study, we have measured plasma insulin at fasting and following an oral glucose load and blood pressure after glucose load in 367 (247 non-obese, 120 obese) normotensive and untreated mildly hypertensive subjects. Overall, there was no independent association between fasting plasma insulin levels and blood pressure values. After controlling for age and body weight, a significant relationship between postglucose plasma insulin levels and diastolic blood pressure was found. When non-obese and obese subjects were examined separately, significant relationships were identified between postglucose plasma insulin levels and both systolic and diastolic blood pressure values in the former but not in the latter. A comparison of sex-, age-, and weight-matched hyperinsulinaemic vs normoinsulinaemic subjects showed that the former had significantly higher values of blood pressure only if not obese. These results demonstrate that the plasma insulin response to glucose is independently correlated with blood pressure.

Potential mechanisms explaining the risk of left ventricular hypertrophy

Major risk factors have been identified that enhance the chances of cardiovascular morbidity and mortality. These include such modifiable factors as hypertension, hyperlipidemia, obesity, diabetes mellitus, smoking and hyperuricemia. Other factors that also increase risk are not modifiable and include advancing age, male gender and black race. The development of left ventricular (LV) hypertrophy imposes another significant risk for increased morbidity and mortality. Development of LV hypertrophy may be produced by hemodynamic as well as nonhemodynamic mechanisms. Included in the latter group are some of the same factors that in and of themselves participate in the production of increased LV mass (i.e., aging, gender and race, obesity, coronary disease, diabetes and the underlying mechanisms that subserve the hypertensive disease). This article discusses the concept, drawn from clinical and experimental studies, that demonstrate that the additional increased risk of LV hypertrophy may be ascribed to loss of reserve cardiac function, accelerated atherosclerosis, development of abnormal cardiac rhythm secondary to ischemia, fibrosis or drug-induced hypokalemia, inherent predisposition to ventricular dysrhythmias and sudden death, risks directly or coincidentally related to associated diseases or perhaps even the paradoxical risk of beneficial antihypertensive therapy.

A method for combining results from several prospective epidemiologic studies

An approach to the problem of a single study lacking adequate power to examine an important question is to combine the data from several studies to allow a more powerful test of the hypothesis in question. The present paper describes a method used by the International Collaborative Group to pool data on 54,492 men aged 40-69 from 10 population studies in 7 countries to examine the association between cholesterol level and risk of death from cancer. Furthermore, there was a suggestion that the inverse association observed in some studies might be the result of an effect of undetected cancer on cholesterol level, rather than an increase in cancer risk resulting from low cholesterol levels. This paper describes the process for selection of the method used to evaluate this possibility over other potential approaches and the results obtained in the analysis of the International Collaborative Group data that support this hypothesis. This report also indicates how one might expect some of the analyses described to compare with analyses based on a discrete version of the Cox proportional hazards model.

Insulin and blood pressure in obesity

To assess factors in overweight persons that account for a tendency toward hypertension, 33 very obese women, 26 to 77 years of age, were studied. Blood pressures in these 33 women varied from low normal to mildly hypertensive. None of them had taken medication for high blood pressure, and none had diabetes mellitus. The effect of independent variables--age, body mass index (weight/height2), fasting serum glucose levels, fasting serum insulin levels, and 24-hour urinary sodium excretion--on systolic and diastolic blood pressure was assessed. There was no correlation between sodium excretion and blood pressure. Age did not correlate with diastolic blood pressure but did correlate with systolic blood pressure when body mass index, serum glucose level, and insulin level were controlled. Diastolic blood pressure correlated with body mass index and serum glucose level, but only the latter remained significant when all independent variables were considered together. Both systolic and diastolic blood pressure were found to be significantly related to fasting serum insulin level (r = 0.47, p = 0.005 and r = 0.68, p less than 0.001) even when age, weight, and serum glucose level were controlled (r = 0.41, p = 0.025 and r = 0.62, p less than 0.001 respectively). The relation between serum insulin and blood pressure was more pronounced in those women with a family history of hypertension. These data indicate that insulin may play a major role in the regulation of blood pressure in obesity and that the previously accepted relation of weight to blood pressure may depend on blood levels of insulin.

Prevalence of hypertension in white, black and Asian diabetics in a district hospital diabetic clinic

In a District General Hospital Diabetic Clinic 40.0% of a random sample of diabetics under the age of 65 years of age were hypertensive. Black patients (48.9%) had greater (p less than 0.05) prevalence of hypertension than Whites (37.5%) and Asians (35.4%). Hypertension was more prevalent in females (49.1%) than males (33.0%) (p less than 0.001) in each ethnic group except Asians, and patients not receiving insulin had greater prevalence (45.6%) than those on insulin (30.7%) (p less than 0.001), except black diabetics where the reverse was found. There was a positive relationship between age and systolic (p less than 0.00001) and diastolic blood pressure (p less than 0.00001) and a negative association between duration of diabetes and diastolic blood pressure (p less than 0.004) on multiple regression analysis but no relationship was noted between blood pressure and either weight or blood glucose. Forty-six percent of all hypertensives were receiving conventional anti-hypertensive drug therapy; 38.7% were normotensive with similar results in each ethnic group and between the sexes. Isolated systolic hypertension was the commonest form of hypertension (48.3%) with isolated diastolic hypertension (4.9%) the rarest. These findings were observed regardless of the ethnic group or gender. Although in the majority of cases hypertension was mild these data confirm the importance of routine blood pressure measurement in diabetic patients.

Blood pressure in survivors of myocardial infarction. The Coronary Drug Project Research Group

The prognostic significance of blood pressure elevation and its associated characteristics in patients recovered from myocardial infarction was studied in the placebo group (n = 2,789) of the Coronary Drug Project. Age, relative body weight, heart rate and ST depression on the electrocardiogram were important positive correlates of hypertension measured at baseline. The relation of uric acid and elevated plasma glucose levels to increased blood pressure could be partially explained as side effects of thiazide diuretic therapy. A "high normal" baseline blood pressure best predicted the development of hypertension among survivors of myocardial infarction. Both combined systolic and diastolic hypertension and isolated systolic hypertension were adverse prognostic factors. Changes in blood pressure, including the prognostic implications of a decrease in pressure, were also analyzed in the subset of patients who sustained a recurrent nonfatal myocardial infarction. Decreases in systolic (mean 7.9 mm Hg) and diastolic (mean 3.6 mm Hg) blood pressure were sustained in this subset. Patients whose blood pressure decreased after recurrent myocardial infarction tended to have higher mortality rates than those of comparable patients whose blood pressure increased or remained unchanged.

The ethnic prevalence of hypertension in a diabetic clinic

Using the WHO criteria of hypertension, we have demonstrated that 40% of randomly selected diabetic clinic attenders under the age of 65 were hypertensive. Black diabetics had a significantly greater prevalence (P less than 0.001) of hypertension than either white or Asian diabetics. Hypertension was commoner in black and white females compared with males (P less than 0.001); in Asians this difference was not statistically significant. Systolic hypertension was the most common form in all ethnic groups. Only 38.7% of diabetics receiving antihypertensive therapy had normal blood pressure readings. Blood pressure measurement should therefore be routinely performed in all diabetic patients under the age of 65, particularly in females of all ethnic groups and in black males.

Blood pressure in young adults as influenced by copper and zinc intake

The relationship of copper and zinc status with blood pressure in young adults was studied (N=59). Copper and zinc status was assessed through analysis of serum, urine, hair, and diet records. Males (N=27) had greater systolic and pulse pressures than females (N=32). Multiple regression analysis suggested that males and higher caloric and dietary copper intakes were the predominant factors associated with higher systolic and diastolic pressures, whereas higher dietary zinc intakes were associated with lower pressures. Higher urine zinc excretion rates and serum zinc concentrations were associated with higher diastolic pressures. The sex variable was the strongest factor affecting pulse pressures, with males having higher pulse pressures. Serum zinc concentrations had an inverse relationship to pulse pressures. The data suggest that the weight/height index and age had a low association with blood pressure in this normotensive sample.

Achievements in hypertension: a 25 year overview

Only 25 years ago, the field of hypertension was challenged by retrospective clinical data and epidemiologic information suggesting that an elevated arterial pressure is a major risk factor for enhanced cardiovascular morbidity and mortality. Not only was antihypertensive therapy looked on by many as dangerous and fraught with severe and undesirable side effects, but its validity in reversing the course of disease was not yet demonstrated. This review discusses the dramatic new information amassed over the past 25 years that points to the new physiologic and clinical concepts concerning hypertension. It considers impressive new diagnostic techniques and methods designed to identify secondary forms of hypertension and target organ involvement. In summary, it outlines the feasibility of reversing overall (and cardiovascular) morbidity and mortality with an array of antihypertensive agents that provide the therapeutic ability to suppress most pathophysiologic pressor mechanisms of hypertensive disease. The lesson is clear: hypertension provides the greatest available challenge to the new era of preventive cardiology in the 21st century.