Study of urban community survey in India: growing trend of high prevalence of hypertension in a developing country

The prevalence pattern of hypertension in developing countries is different from that in the developed countries. In India, a very large, populous and typical developing country, community surveys have documented that between three and six decades, prevalence of hypertension has increased by about 30 times among urban dwellers and by about 10 times among the rural inhabitants. Various factors might have contributed to this rising trend and among others, consequences of urbanization such as change in life style pattern, diet and stress, increased population and shrinking employment have been implicated. In this paper, we study the prevalence of hypertension in an urban community of India using the JNC VII criteria, with the aim of identifying the risk factors and suggesting intervention strategies. A total of 1609 respondents out of 1662 individuals participated in our cross-sectional survey of validated and structured questionnaire followed by blood pressure measurement. Results showed pre-hypertensive levels of blood pressures among 35.8% of the participants in systolic group (120-139mm of Hg) and 47.7% in diastolic group (80-89 mm of Hg). Systolic hypertension (140 mm of Hg) was present in 40.9% and diastolic hypertension (90 mm of Hg) in 29.3% of the participants. Age and sex-specific prevalence of hypertension showed progressive rise of systolic and diastolic hypertension in women when compared to men. Men showed progressive rise in systolic hypertension beyond fifth decade of life. Bivariate analysis showed significant relationship of hypertension with age, sedentary occupation, body mass index (BMI), diet, ischemic heart disease, and smoking. Multivariate analysis revealed age and BMI as risk factors, and non-vegetarian diet as protective factor with respect to hypertension. Prevalence of prehypertensives was high among younger subjects - particularly students and laborers who need special attention. Role of non-vegetarian diet as a protective factor might have been related to fish-eating behavior of the sample population, who also use mustard oil as cooking medium - both of which have significant level of essential polyunsaturated fatty acids. The observed prevalence of hypertension in this study and other studies suggest the need for a comprehensive national policy to control hypertension in India, and, in other similar developing countries.     

Hormone replacement therapy reduces mean 24-hour blood pressure and its variability in postmenopausal women with treated hypertension

BACKGROUND: The rate and severity of hypertension increase dramatically after menopause. Complications seem to be more frequent and marked in hypertensive patients with greater blood pressure (BP) variability, and antihypertensive treatment does not easily reduce this variability. The effect of hormone replacement therapy (HRT) on BP and its variability is not well understood in moderate to severe hypertension, but estrogen may have calcium channel-blocking properties. Cardiovascular events occur more frequently in the morning, likely in part because of a rise in BP. DESIGN: We prospectively studied 34 postmenopausal women with treated hypertension (mean age = 53 years) and receiving a cyclic combination of estradiol and norgestrel for 19 weeks with 24-h ambulatory BP monitoring. RESULTS: Mean daily BP and its variability decreased significantly with HRT (149.3 +/- 6.1 mm Hg vs. 140.3 +/- 8.5 mm Hg [p < 0.001]; diastolic: 95.4 +/- 4.7 mm Hg vs. 92.4 +/- 7.2 mm Hg [p < 0.05]). There was also a significant decrease in the early morning BP values after HRT (154.0 +/- 6.9 mm Hg vs. 145.6 +/- 11.0 mm Hg [p < 0.001]; diastolic: 98.0 +/- 4.8 mm Hg vs. 95.1 +/- 10.0 mm Hg [p < 0.05]). Subjects who were taking calcium channel blockers (n = 11) had only half the reduction in 24-h systolic BP compared with those who were not taking calcium channel blockers (5.3 mm Hg vs. 10.5 mm Hg), and the reduction in those who were taking calcium channel blockers failed to reach statistical significance. CONCLUSIONS: Our results demonstrate that HRT may have a role in decreasing the severity of hypertension, and the mechanism of its action might be through calcium channels.     

An open clinical trial of benazepril--a new ACE inhibitor in mild-moderate hypertension

Benazepril hydrochloride, a new non-sulfhydryl ACE inhibitor (ACEI) was studied in a titrated dose of 10 mg-20 mg once a day for 6 weeks in 42 mild to moderate adult hypertensive patients with sitting diastolic blood pressure (SDBP) 95-114 mm Hg. The pre-drug SDBP(mean +/- SE) of 102.5 +/- 0.8 mm Hg showed a significant reduction to 87.5 +/- 0.93 mm Hg at the end of treatment. BP was controlled (SDBP < or = 90 mm Hg) in 34 (81%) patients and a drop of at least 10 mm Hg from the pre-treatment SDBP value was noted in 34 (81%) patients. Common adverse reaction was cough in 8(19%) patients. Clinically significant changes in laboratory evaluations were not seen in any patient. Study showed that benazepril in a dose range of 10 to 20 mg per day is an effective agent for treatment of mild to moderate hypertension.     

Renal hemodynamics and the renin-angiotensin-aldosterone system in normotensive subjects with hypertensive and normotensive parents

BACKGROUND AND METHODS. The kidney is important in blood-pressure regulation, but its role in the development of essential hypertension is still subject to debate. We compared renal hemodynamics, measured in terms of the clearance of para-aminohippuric acid and inulin, and the characteristics of the renin-angiotensin-aldosterone system in three groups of normotensive subjects at different degrees of risk for hypertension: 41 subjects with two normotensive parents, 52 with one normotensive and one hypertensive parent, and 61 with two hypertensive parents. The subjects ranged in age from 7 to 32 years. RESULTS. The mean renal blood flow was lower in the subjects with two hypertensive parents than in those with two normotensive parents (mean difference [+/- SE], 198 +/- 61 ml per minute per 1.73 m2 of body-surface area; P = 0.002). Moreover, both the filtration fraction and renal vascular resistance were higher in the subjects with two hypertensive parents (filtration fraction: mean difference, 3.0 +/- 1.1 percentage points; P = 0.006; renal vascular resistance: mean difference, 2.7 +/- 0.8 mm Hg per deciliter per minute per 1.73 m2; P = 0.006). The subjects with two hypertensive parents had lower plasma concentrations of renin (mean difference, 3.3 +/- 1.6 mU per liter; P = 0.03) and aldosterone (mean difference, 111 +/- 36 pmol per liter; P = 0.003) than those with two normotensive parents. The differences could not be explained by the small differences in blood pressure between the groups. The values in the subjects with one hypertensive and one normotensive parent fell between those for the other two groups. CONCLUSIONS. Renal vasoconstriction is increased and renin and aldosterone secretion is decreased in young persons at risk for hypertension. These findings support the hypothesis that alterations in renal hemodynamics occur at an early stage in the development of familial hypertension.     

Increased excretion of urinary N-acetyl-beta-glucosaminidase in essential hypertension and its decline with antihypertensive therapy

The urinary excretion of N-acetyl-beta-glucosaminidase (NAG) is increased in patients whose renal function is impaired by a variety of kidney diseases, and may provide an index of renal injury. To assess its role in essential hypertension, we measured urinary levels of NAG in 80 subjects with essential hypertension (and no evidence of renal disease) and 30 normal controls. NAG values were measured before therapy and after 3 and 12 months of treatment with diuretics. The mean urinary NAG value (+/- S.D.) for the normotensive subjects was 29 +/- 16 nmol per hour per milligram of urinary creatinine. The median value for the untreated hypertensive subjects was 53, and the mean was 65 +/- 61 (P less than 0.01). Systolic blood pressure was directly correlated with NAG levels, whereas diastolic pressure, age, sex, and race were not. Eighty patients followed for one year attained their ultimate blood-pressure reduction within three months (from a mean of 158/103 mm Hg to one of 138/91 mm Hg; P less than 0.001), whereas the urinary NAG level had not declined significantly at three months (from 60 +/- 43 to 54 +/- 54) but had changed significantly at one year (to 45 +/- 28; P less than 0.01 as compared with the initial value). These data suggest that NAG is frequently elevated in patients with high blood pressure even though there is no other evidence of renal damage, and that it can be reduced by successful antihypertensive therapy.     

Association of the renin-sodium profile with the risk of myocardial infarction in patients with hypertension.

BACKGROUND. To test the prognostic value of plasma renin activity prospectively, we determined the pretreatment renin-sodium profile of 1717 subjects with mild-to-moderate hypertension (mean age, 53 years; 36 percent white; 67 percent men) in a systematic work-site treatment program. METHODS. Renin profiles, obtained by plotting plasma renin activity against the urinary excretion of sodium, were classified as high (12 percent of the subjects), normal (56 percent), and low (32 percent), and there were expected variations according to age, sex, and race. Modified stepped-care treatment for hypertension, prescribed without reference to the renin profile, was similar in the three renin groups. RESULTS. Mean (+/- SD) blood pressure at entry was 151 +/- 19/100 +/- 10 mm Hg in the subjects with a high renin profile, 151 +/- 19/97 +/- 10 mm Hg in those with a normal profile, and 151 +/- 20/96 +/- 11 mm Hg in those with a low profile. During 8.3 years of follow-up, there were 27 myocardial infarctions. As adjusted for age, sex, and race, the incidence of myocardial infarction per 1000 person-years was 14.7 among the subjects with a high renin profile, 5.6 among those with a normal profile, and 2.8 among those with a low profile (rate ratio for high vs. low, 5.3; 95 percent confidence interval, 3.4 to 8.3). The rate of mortality from all causes was 9.3 in the high-profile group, 5.3 in the normal-profile group, and 3.9 in the low-profile group. The independent association of a high renin profile with myocardial infarction (but not with stroke or noncardiovascular events) was affirmed by Cox analyses (rate ratio for high vs. normal plus low, 3.2; 95 percent confidence interval, 1.2 to 8.4) after adjustment for race, sex, age at entry, serum cholesterol level, smoking status, electrocardiographic evidence of left ventricular hypertrophy, blood glucose level, body-mass index, history of cardiovascular disease or treatment, blood pressure, and use of beta-blockers. CONCLUSIONS. In the study population, whose blood pressure before and during treatment was in a narrow range, and after other cardiovascular risk factors had been considered, the renin profile before treatment remained independently associated with the subsequent risk of myocardial infarction.     

Behaviour of the carotid wall in menopausal women with and without arterial hypertension

OBJECTIVE: A study was conducted on the carotid vascular wall to evaluate its behaviour in postmenopausal women suffering from arterial hypertension compared to normotensive postmenopausal women. METHOD: Intima-media thickness(IMT) of carotid artery was determined by ecoduplex scanner in 182 postmenopausal women (age range 40-60 years) divided in four age classes (40-45, 46-50, 51-55, 55-60 years). Ninety-one women presented normal arterial blood pressure (SBP 136.6+/-11.7 and DBP 82.3+/-8.9 mmHg) and 91 were hypertensive (SBP 172.6+/-11.7 and DBP 97.4+/-6.6 mmHg). RESULTS: The normotensive women presented the following IMT values: 1.19+/-0.21 mm (40-45 years), 1.21+/-0.25 mm (46-50 years), 1.25+/-0.20 mm (51-55 years), 1.25+/-0.20 mm (55-60 years). IMT values in hypertensive women were: 1.75+/-0.25 mm (40-45 years), 1.77+/-0.30 mm (45-50 years), 1.91+/-0.28 mm (51-55 years), 2.02+/-0.33 mm (55-60 years). ANOVA test was performed in both groups of women and did not show any significant difference in the four age classes of normotensive women. On the other hand it revealed a statistical significance between 40-45 and 46-50-year-old hypertensive classes (P<0.001) and between 51-55 and 55-60-year-old hypertensive clases (P<0.02). CONCLUSIONS: There was a correlation between age and IMT in the arterial hypertensives, especially in two older classes, and between the duration of menopause and IMT values. The results indicated that carotid wall thickening was constantly higher in hypertensive women compared with normotensive ones.     

Consequences of renal morphologic damage induced by inhibition of converting enzyme in rat renovascular hypertension

The consequences of morphologic changes in the kidney distal to a stenosis induced by chronic administration of a converting enzyme inhibitor were determined after induction of experimental renovascular hypertension in rats. The relationship between changes in morphology in the clipped kidney and diuresis, creatinine, and mortality was studied by converting a two-kidney, one-clip model into a one-kidney, one-clip model after 1 month of converting enzyme inhibition. The right renal artery was constricted with a clip of 0.2 mm diameter to increase blood pressure, the left kidney was left untouched. After 1 month, systolic blood pressure had increased to 173 +/- 27 mm Hg in the clipped animals (n = 47) compared with 139 +/- 8 mm Hg in sham-operated animals (n = 15; group 1). An inhibitor of angiotensin-converting enzyme, MK421 (2 mg/kg, po), or an equivalent volume of vehicle was then administered daily for 1 month. After treatment with the converting enzyme inhibitor, blood pressure (148 +/- 28 mm Hg) was virtually identical with that of a sham-operated, vehicle-treated control group (145 +/- 16 mm Hg, n = 15), and was significantly lower than that of untreated hypertensive rats (186 +/- 30 mm Hg, n = 17) (group 2). The weight of the left kidney was increased in the untreated hypertensive animals as compared with sham-operated controls (1260 +/- 168 mg for group 2 versus 1075 +/- 100 mg for group 1). After treatment with MK421, the weight of the contralateral kidney (1472 +/- 190 mg) was further increased. After 1 month of treatment with MK421 or vehicle, the unclipped left kidney was removed from all animals. The treated animals were then randomly divided into two groups: one in which treatment with MK421 was stopped (treated/untreated, n = 24; group 3) and a second in which the treatment was continued (treated/treated, n = 23; group 4). The ability of the rats to excrete a water load of 15 ml was then examined 12 hours after removal of the unclipped left kidney. In the two groups of treated rats, the urinary excretion of the water load was decreased and frequency of oliguria was increased as compared with controls and hypertensive untreated rats. Survival rates were affected by the treatment: 3 deaths occurred in the hypertensive untreated group 2, 10 in the treated/untreated group 3, and 12 in the treated/treated group 4. The majority of these deaths could be attributed to renal insufficiency.(ABSTRACT TRUNCATED AT 400 WORDS)     

Strategy for the treatment of noncompliant hypertensive hemodialysis patients

Hypertensive hemodialysis patients noncompliant for their medications do not benefit from pharmacologic advances in the treatment of high blood pressure, and increase their already high risk of cardiovascular complications. The medical staff often becomes frustrated by severe hypertension in those who refuse to take medicines at home, drink excessive fluids, miss multiple dialysis sessions and sign-off dialysis early. In addition to addressing the psychosocial, financial, educational and substance abuse problems which contribute to noncompliance, we have developed a medication strategy to serve as an at least interim means of lowering blood pressure. Antihypertensive agents which have long half-lives in renal failure (lisinopril) and/or are intrinsically long acting (transdermal clonidine and amlodipine) were administered on dialysis days by the unit personnel to those patients who did not or would not take that or any dose on their own. The lisinopril and amlodipine were assured to have been taken on at least the dialysis days (thrice weekly), and the clonidine patch replaced weekly. Sixteen patients were thus treated when they failed to reliably self-administer medications. They had a significant decline in the predialysis systolic pressure of 15 mm Hg (175 +/- 6 to 160 +/- 5 mm Hg), diastolic of 12 mm Hg (103 +/- 3 to 91 +/- 3 mm Hg), and mean pressure of 13 mm Hg (127 +/- 4 to 114 +/- 4 mm Hg). There was an improvement in post-dialysis bood pressures, with the mean pressure declining 13 mm Hg from 110 +/- 4 to 97 +/- 4 mm Hg. Many individuals had erratic blood pressure control, having intermittently missed dialysis and hence unit-administered medicine, as well as continued fluid or drug abuse. The patients had uniformly excellent acceptance of this regimen, even spontaneously requesting it, and had no appreciable adverse effects. In summary while noncompliance is being addressed by the entire medical team, dialysis unit administration of long-acting medicines helps many hypertensive dialysis patients who would otherwise be at increased risk for severe cardiovascular complications.     

Knowledge and awareness of hypertension among patients with systemic hypertension

BACKGROUND: In Nigeria, systemic hypertension is the commonest noncommunicable disease, and public awareness about hypertension and its determinants is poor. This study aims to assess the knowledge and level of awareness of the disease among hypertensive patients attending the medical outpatient clinic of Olabisi Onabanjo University Teaching Hospital (OOUTH). METHODOLOGY: Hypertensive patients who attended the medical outpatient clinic during the one-year study period and gave their consent were recruited into the study. Response to a questionnaire on various aspects of hypertension was analyzed using the STATA for Windows software. RESULTS: There were 254 hypertensive patients, of which 111 were males and 143 were females, giving a male: female ratio of 1:1.3. The mean age (SD) of the patients was 51 years +/- 12.2; 52.4% of the participants were aware that hypertension was the commonest noncommunicable disease in Nigeria. About one in 10 patients (11.4%) was aware that "nil symptom" is the commonest symptom of hypertension, while 37% were not aware that hypertension could cause renal failure. Only about one-third (35.4%) of the patients knew that hypertension should ideally be treated for life, while 58.3% believed that antihypertensive drugs should be used only when there are symptoms. The remaining 6.3% believed that the treatment of hypertension should be for periods ranging from two weeks to five years but not for life. CONCLUSION: This study has demonstrated inadequate knowledge of hypertension in patients with hypertension in our study population. Conscious efforts should be made and time set aside to health educate hypertensive patients. Organization of "hypertensive club or society" could be encouraged. These will reduce dissemination of false or inaccurate information by hypertensive patients to the public and its attendant dangers.     

Diverse cardiovascular responses to aortic constriction in normotensive Sprague-Dawley versus spontaneously hypertensive rats.

Normotensive, Sprague-Dawley (S-D) and spontaneously hypertensive (SH) rats were subjected to aortic ligature. The systolic blood pressure of S-D rats was increased by +/- 80 mm Hg, whereas the blood pressure of SH rats with pre-existent hypertension increased only slightly, +/- 9 mm Hg. The S-D rats developed myocardial and renal infarcts as well as polyarteritis nodosa; the SH rats developed testicular and microadrenocortical infarcts only. Aortic-ligated S-D rats had elevated creatine phosphokinase, serum glutamic-oxaloacetic transaminase, serum glutamic-pyruvic transaminase, and lactic hydrogenase levels and manifested hyperglycemia, hypercholesterolemia, and elevated blood urea nitrogen (BUN) levels. Corticosterone levels increased in aortic-ligated S-D rats but decreased in SH rats. Collateralization about the site of aortic ligature appeared to be the same in both strains. It is suggested that the acutely induced hypertension in S-D rats rather than SH rats and differences in adrenal steroidogenesis between the two strains would best account for the dichotomous cardiovascular response to aortic constriction.     

Elevated arterial blood pressure in cardiac tamponade.

BACKGROUND. In cardiac tamponade cardiac output falls, but peripheral vascular resistance increases, so that systemic blood pressure may be maintained at normal or near-normal levels. We recently observed a patient with cardiac tamponade whose blood pressure was markedly elevated. METHODS. To determine the frequency of elevated blood pressure in patients with cardiac tamponade and their hemodynamic characteristics, we studied 18 consecutive patients with cardiac tamponade from a variety of causes using right heart catheterization. RESULTS. Six of the 18 patients had systolic arterial blood pressures ranging from 150 to 210 mm Hg (mean [+/- SD], 176 +/- 26) and diastolic pressures ranging from 100 to 130 mm Hg (mean, 113 +/- 14). All six had previously been hypertensive. After pericardiocentesis there was a significant decrease in blood pressure (to 139 +/- 13 mm Hg systolic, P less than 0.05; and 83 +/- 6 mm Hg diastolic, P less than 0.01) and peripheral vascular resistance (from 2150 +/- 588 to 1207 +/- 345 dyn.sec.cm-5, P less than 0.01). Cardiac output increased in all six. The other 12 patients, 3 of whom had a history of hypertension, had significant increases in cardiac output and systolic blood pressure (from 119 +/- 13 to 127 +/- 7 mm Hg, P less than 0.05) after pericardiocentesis, whereas peripheral vascular resistance decreased. Both groups had similar degrees of cardiac tamponade, as indicated by measurements of cardiac output and intrapericardial, right atrial, and pulmonary-artery wedge pressures. CONCLUSIONS. Elevated blood pressure may occur in some patients with cardiac tamponade who have preexisting hypertension. Moreover, blood pressure may fall after pericardiocentesis in patients who have elevated blood pressure associated with tamponade.     

Water intake during the development of renal hypertension (2K-1C) in mice

For both practical and methodological reasons, mice have been the most widely employed species for development of transgenic and gene knockin and knockout animals. However, basic behavioral and physiology control and regulatory mechanisms in mice are not well characterized. To broaden our understanding of the processes maintaining body fluid and blood pressure homeostasis in the mouse, the objectives of this study were to evaluate voluntary water, and sodium intakes during the development of renal hypertension and to examine the relationship between hypertension and the quantities of water and salt ingested. In male, C57BL/6J mice, two-kidney, one-clip renal hypertension (2K-1C) was induced, and water and 1.8% NaCl intakes were monitored for 2 weeks. At the end of this period, all animals received arterial catheters for direct recording of blood pressure. The mice that received renal artery clips were sorted into hypertensive (152+/-4 mm Hg) and normotensive (122+/-2 mm Hg) groups and were compared to control (117+/-4 mm Hg) animals that underwent a sham renal clipping procedure. Hypertensive 2K-1C animals had significantly elevated water intake compared to control animals. On most of the postsurgical days, the normotensive 2K-1C animals did not display increased water intake in comparison to the control group. No significant effect was detected for 1.8% saline intake between any of the pairs of groups. In summary, the reduction of blood flow to a single kidney in the 2K-1C model of renal hypertension induces high blood pressure accompanied by sustained hyperdipsia in the mouse.     

Sleep-disordered breathing in a middle-aged and older Polish urban population

Obstructive sleep apnoea syndrome (OSAS) is a frequent disorder; however, the prevalence of sleep-disordered breathing is not well known in many countries. The aim of our investigation was to assess the prevalence of sleep-disordered breathing (SDB) in a representative sample of the population of Warsaw. We studied 676 subjects (57.1% of the randomised cohort from the Monica II study). The sample comprised 356 males (52.7%) and 320 females (47.3%), whose mean age was 56.6 +/- 8.2 years (range 41-72 years). Mean number of apnoeas and hypopnoeas per hour of time in bed (AH) in males was 7 +/- 9.5 and in females 3.9 +/- 6.6 (P < 0.001). SDB (cut-off point AH > 5 or >10) was identified in 188 subjects (27.8%) and 97 subjects (14.3%), respectively. SDB was established twice as frequently in males as in females (respectively 36.5 versus 18.5%; P < 0.001 for AH > 5 and 19.8 versus 8.5%; P < 0.001 for AH > 10). A diagnosis of OSAS AH > 10 and Epworth Sleepiness Score > or =11 points was established in 51 subjects (7.5%). The prevalence of OSAS was nearly four times higher in males (40 subjects, 11.2%) than in females (11 subjects, 3.4%; P < 0.001). The severity of OSAS was similar in both sexes (AH: males 32.3 +/- 14.9 and females 31.4.1 +/- 15.4). Older age and male sex were predictors of SDB. SDB and OSAS were independent predictors of coronary artery disease after adjusting for age, sex, body mass index, neck circumference and smoking habit.     

Accentuated vascular and endocrine response to SQ 20881 in hypertension.

We assessed vascular and hormonal responses to inhibition of peptidyldipeptide hydrolase, which converts angiotensin I to angiotensin II (converting enzyme) and degrades bradykinin (kininase II), in subjects given 10 meq of sodium to activate both systems. In nine normal subjects a threshold dose of 30 MICROgram per kilogram of the inhibitor, SQ 20881, modestly influenced mean blood pressure (-5 +/- 1 mm Hg, P less than 0.05), and renal blood flow (+50+/-8 ml per 100 g per minute), plasma renin activity (+ 2.3 +/- 0.6 ng per milliliter per hour), and angiotensin II (-11 +/- 3 pg per milliliter) more strikingly (P less than 0.01). In six patients with essential hypertension the threshold inhibitor dose was reduced to 10 microgram per kilogram; 30 kilogram per kilogram had an enhanced (P less than 0.01) effect on mean blood pressure (-11 +/- 2 mm Hg), renal blood flow (137 +/- 20 ml per 100 g per minute), and angiotensin II concentration (-29 +/- 12 pg per milliliter). SQ 20881 elevated plasma bradykinin concentration (7.4 +/- 2.6 ng per milliliter, P less than 0.02) only in the hypertensive patients. Because both renin-angiotensin and kallikrein-bradykinin systems are influenced, vascular responses to SQ 20881 must be interpreted cautiously, but this agent has excellent antihypertensive characteristics.     

Systemic hypertension after kidney transplantation: associated risk factors and influence on graft survival

Systemic hypertension after kidney transplant (HAPT) has been associated with a reduction in graft survival and increased morbidity and mortality of kidney transplant recipients. With the use of calcinuerin inhibitors, prevalence of HAPT has increased to 60-80%. The purpose of this study was to document the prevalence of HAPT in kidney transplant recipients attending the Instituto Nacional de Ciencias Médicas y Nutrición "Salvador Zubirán" associated risk factors and the effect of hypertension in long term graft survival. We retrospectively reviewed the clinical charts of all the patients that underwent kidney transplant from 1984 to 1994. The following risk factors were studied: age, gender, cause of renal failure, presence of hypertension before kidney transplant, histocompatibility, acute rejection episodes, chronic rejection, serum creatinine values and use of cyclosporine. We divided subjects in two groups: normotensive (NT) and hypertensive (HT). HAPT included 3140/90 mmHg blood pressure level observed at least during two consecutive evaluations or the use of antihypertensive medication. We analyzed 215 grafts from 205 patients (10 patients had two kidney transplants); mean age at transplant of 30 +/- 9 years, 131 subjects were female and 84 male. One hundred and eighty eight patients (88%) displayed pretransplant hypertension. The mean follow up was 56+/-32 months. In the postransplant period 152 (71%) were HT and 63 (29%) NT. The HT group had significantly higher blood pressure and serum creatinine values than the NT group (P < 0.001), in spite of an adequate blood pressure control in 65% of the patients from the HT group. The NT group displayed a higher graft survival than the HT group; 60 +/- 30 months vs. 51 +/- 32 months respectively (p<0.01). Multivariate analysis did not show any risk factors independently associated with the development of HAPT. The prevalence of HAPT in our series is similar to the one reported in the literature. During the postransplant period there was a reduction of hypertensive patients (88% pretransplant vs. 71% postransplant). HAPT is a significant risk factor associated with long term survival of the graft.     

Snoring and systemic hypertension--an epidemiological study

The prevalence of snoring, overweight and systemic hypertension was estimated in a random sample of 4,064 Swedish men, aged 30-69 years. Of the responders, 15.5% complained of habitual snoring and 29.6% of occasional snoring. Although there was an age-related increase in the prevalence of snoring up to 60 years, habitual snoring was found to be mainly related to body mass index (BMI) (p less than 0.0001) but not to age. Altogether 299 men (9.3%) reported hypertension, 21.5% of whom were habitual snorers, compared with 14.9% of the non-hypertensives (p less than 0.01). The hypertensives were also more often overweight. Logistic multiple regression analyses showed that among subjects 40-49 years old there was an average increase in the predicted prevalence of hypertension from 6.5% among non-snorers to 10.5% of habitual snorers in the same weight group. For the whole study population, however, the increase was mainly dependent on age and BMI. Thus, the importance of habitual snoring for the prevalence of hypertension differs in various age groups.     

Blood pressure perturbations caused by subclinical sleep-disordered breathing

We studied the acute effects of apneas and hypopneas on blood pressure in a nonclinic population of middle-aged adults. Arterial pressure was measured noninvasively (photoelectric plethysmography) during an overnight, in-laboratory polysomnographic study in 72 men and 23 women enrolled in the Wisconsin Sleep Cohort Study, a population-based study of sleep-disordered breathing. Sleep-disordered breathing events (272 apneas and 1469 hypopneas) were observed in 92% of subjects. The across-subject mean decreases in arterial O2 saturation were 9+/-8% (SD) for apneas (17+/-8 seconds duration) and 4+/-3% for hypopneas (21+/-6 seconds duration; 41+/-17% of baseline ventilation). In both apneas and hypopneas, even those with only 1% to 3% O2 desaturations, blood pressure decreased during the event, followed by an abrupt increase in the postevent recovery period. Mean values for peak changes in blood pressure (difference between the maximum during the recovery period and the minimum during the event) were 23+/-10 mm Hg for systolic and 13+/-6 mm Hg for diastolic pressure. The strongest predictors of the pressor responses to apneas and hypopneas were (in order of importance): magnitude of the ventilatory overshoot, length of the event, magnitude of changes in heart rate and arterial O2 saturation, and presence or absence of electroencephalographic arousal. We speculate that these fluctuations may play a role in the pathogenesis of hypertension in individuals with subclinical sleep-disordered breathing.     

Human renin gene BglI dimorphism associated with hypertension in two independent populations

The renin (REN) gene is a good candidate that could underlie an individual's genetic susceptibility to human essential hypertension (EHT). We describe here a polymerase chain reaction-based assay for detection of a BglI dimorphic site located in the first intron of the REN gene. In this retrospective, case-control, association study, we investigated BglI allele and genotype distributions in 554 subjects (280 hypertensives and 274 normotensives) from the United Arab Emirates (UAE) - a genetically homogeneous ethnic population with no history of smoking or alcohol consumption - and in 485 hypercholesterolemic, US Caucasian subjects (250 hypertensives and 235 normotensives). A statistically significant association was found between alleles on which the BglI site is present [BglI(+)] and clinical diagnosis of EHT in the UAE sample group (odds ratio = 2.69, p = 0.0006), and a similar trend was observed in the US group (odds ratio = 1.97, p = 0.01). BglI(+) homozygous status was also investigated in the US group and found to be associated with elevated systolic and diastolic blood pressure values (respectively, 144.8+/-26.1 vs. 134.1+/-23.0 mm Hg, p = 0.04; and 91.0+/-12.5 vs. 82.2+/-12.7 mm Hg, p = 0.009). In conclusion, variations of the REN (or of a nearby) gene that may be in linkage disequilibrium with the REN BglI(+) marker could play a role in contributing to an increased individual's genetic susceptibility to EHT in the UAE population and amongst US hypercholesterolemic Caucasians. Such a genetic influence, which seems to show a recessive mode of inheritance, could also be implicated in raising both systolic and diastolic blood pressures.     

Cardiovascular risk: initial estimation in the study cohort "CDC of the Canary Islands in Venezuela"

In Venezuela as in the Canary Islands (Spain), cardiovascular disease is a major cause of morbidity and mortality. The purpose of this research is to estimate the cardiovascular risk in the Canary Islands migrants living in Venezuela and participating in the study cohort "CDC of the Canary Islands in Venezuela". 452 individuals, aged 18 to 93 years (54.9% women), were enrolled between June 2008 and August 2009. A data survey was performed and their weight, height, abdomen and hip circumferences, and blood pressure were measured. After a 12-hour fasting period, a blood sample was obtained for glucose and lipid profile determinations. 40.5% of the subjects were over 65 years of age and 8% corresponded to the younger group (18-30 years). In men, the average age was 57.69 +/- 18.17 years and the body mass index 29.39 +/- 5.71 kg/m2, whereas women were 56.50 +/- 16.91 years and 28.20 +/- 5.57 kg/m2, respectively. The prevalence of metabolic syndrome was 49.1%, overweight and obesity together 75,2%, abdominal obesity 85.4%, diabetes 17.4%, impaired fasting glucose (IFG) 12.2%, elevated blood pressure 52.9%, low HDL-cholesterol 53,8% and elevated serum triglycerides 31%. Among subjects without diabetes or IFG, a third showed a high triglycerides/HDL-cholesterol ratio, indicating insulin resistance. We conclude that the Canarian-Venezuelan community suffers high prevalence of cardiovascular risk factors (obesity, abdominal obesity, dyslipidemia, diabetes). In relation to the current population of the Canary Islands, they show a lower frequency of IFG and a higher frequency of low HDL-cholesterol. In comparison to the Venezuelan population (Zulia), they showed to have lower prevalence of IFG, low HDL cholesterol and elevated triglycerides.