Hyperaldosteronism among black and white subjects with resistant hypertension.
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Recent reports suggesting that the prevalence of primary hyperaldosteronism may be higher than historically thought have relied on an elevated plasma aldosterone concentration/plasma renin activity ratio to either diagnose or identify subjects at high risk of having primary hyperaldosteronism and have not included suppression testing of all evaluated subjects. In this prospective study of 88 consecutive patients referred to a university clinic for resistant hypertension, we determined the 24-hour urinary aldosterone excretion during high dietary salt ingestion, baseline plasma renin activity, and plasma aldosterone in all subjects. Primary hyperaldosteronism was confirmed if plasma renin activity was <1.0 ng/mL per hour and urinary aldosterone was >12 microg/24-hour during high urinary sodium excretion (>200 mEq/24-hour). Eighteen subjects (20%) were confirmed to have primary hyperaldosteronism. The prevalence of hyperaldosteronism was similar in black and white subjects. Of the 14 subjects with confirmed hyperaldosteronism who have been treated with spironolactone, all have manifested a significant reduction in blood pressure. In this population, an elevated plasma aldosterone/plasma renin activity ratio (>20) had a sensitivity of 89% and a specificity of 71% with a corresponding positive predictive value of 44% and a negative predictive value of 96%. These data provide strong evidence that hyperaldosteronism is a common cause of resistant hypertension in black and white subjects. The accuracy of these results is strengthened by having done suppression testing of all evaluated subjects. (+info)
Reactivity as a predictor of subsequent blood pressure: racial differences in the Coronary Artery Risk Development in Young Adults (CARDIA) Study.
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This study investigated the association between cardiovascular reactivity and subsequent ambulatory blood pressure in 316 black and white men and women in the Coronary Artery Risk Development in Young Adults (CARDIA) Study. Cardiovascular laboratory reactivity was examined in subjects 20 to 33 years old, and ambulatory blood pressure and heart rate were measured 3 years later. Average ambulatory pressure during a 24-hour period was regressed separately on stress reactivity and standard covariate risk factors in each race/gender subgroup. Blacks had higher blood pressure and heart rates than whites, men had higher blood pressure than women, and women had higher heart rates than men. After controlling for age, baseline systolic pressure, familial history of hypertension, smoking, alcohol consumption, body mass index, and exercise, systolic blood pressure reactivity to star tracing and cold pressor stress were significantly associated with systolic ambulatory pressure in black men and women 3 years later (partial r=0.24 to 0.37). Heart rate reactivity to video challenge and star tracing were also significantly predictive of subsequent ambulatory heart rate in blacks. Diastolic star tracing reactivity was significantly associated with subsequent ambulatory blood pressure in black women (r=0.23), and diastolic reactivity to video and star tracing were significantly predictive of ambulatory diastolic pressure in white men (r=0.39). We conclude that hyperresponsivity to stress may be a risk factor for subsequent blood pressure elevation in blacks and may be one pathway leading to the higher prevalence of hypertension in blacks than in whites. (+info)
Nutritional status of a population sample in Macon County, Alabama.
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A nutrition survey was conducted in Macon County, Alabama, with a population sample of 102 individuals, 76% of whom were black. Three 24-hr dietary recalls were obtained for each participant and 24 nutrients and energy were calculated for each combined 3-day intake. Serological and hematological analyses of blood were performed. Dietary calculations indicated that intakes of calcium, vitamin B12, calories, and iron were lowest within the population sample. Blood analyses did not confirm the calculated inadequacies of dietary calcium, vitamin B12, or iron. Body weight data did not support the calculated inadequate energy intakes. Serum analysis indicated a folic acid deficiency. Mean intakes of energy and macronutrients were higher in nonblacks than in blacks; for most vitamins and minerals, the same was true. The lower calcium intakes among blacks than among nonblacks in the growing years exceeded the differential in energy intakes. Higher serum vitamin B12 levels in blacks than in nonblacks were observed but not explained. (+info)
Racial differences in thoracic aorta atherosclerosis among ischemic stroke patients.
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BACKGROUND AND PURPOSE: Atherosclerosis of the thoracic aorta is an independent risk factor for stroke. There is little information on the impact of race in the prevalence of thoracic aorta atherosclerotic plaques among ischemic stroke patients. This study was an attempt to objectively assess the prevalence, thickness, and burden of thoracic aorta atherosclerotic plaques in a large population of ischemic stroke patients and to compare the differences between American blacks and whites. METHODS: This is a retrospective study of clinical data and transesophageal echocardiography (TEE) of 1553 ischemic stroke patients (664 blacks, 889 whites) over a period of 4.5 years. Atherosclerotic plaque prevalence, thickness, morphology, and burden (sum of maximum thickness in ascending aorta [AA], aortic arch [AO], and descending aorta [DA]) were assessed with TEE. Charts were reviewed for clinical information. RESULTS: Age and sex were similar among blacks and whites. Analyses of clinical data found that blacks had significantly higher hypertension (odds ratio [OR], 2.61; P<0.0001) and diabetes mellitus (OR, 1.99; P<0.0001) and significantly lower coronary artery disease (OR, 0.75; P=0.017) and carotid artery disease (OR, 0.62; P=0.0008) compared with whites. TEE showed that whites had significantly greater plaque prevalence (AA: OR, 1.37; P=0.04; AO: OR, 1.26; P=0.03; DA: OR, 1.39; P=0.002) and plaque burden (blacks, 4.28 mm; whites, 4.97 mm; P=0.007). Whites also had a trend of increased complex plaques and plaques >4 mm thick in all regions of the thoracic aorta. CONCLUSIONS: Among ischemic stroke patients, blacks had a lower prevalence of extra cranial atherosclerotic disease even though they had significantly higher hypertension and diabetes mellitus compared with whites. This difference cannot be explained by the existing risk factors in ischemic stroke patients. (+info)
An estimated prevalence of Johne's disease in a subpopulation of Alabama beef cattle.
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The objective of this study was to estimate the overall prevalence of animals that were infected with Mycobacterium avium ssp. paratuberculosis in a subpopulation of Alabama beef cattle. This was determined using a commercial enzyme-linked immunosorbent assay (ELISA) for the detection of M. avium ssp. paratuberculosis-specific antibodies in serum. Serum was collected from 79 herds that were participating in the Alabama Brucellosis Certification program. A total of 2,073 beef cattle were randomly tested by selecting 30 animals per herd in herds greater than 30 and selecting all animals in herds 30 and less for testing. It has been estimated that the commercial ELISA test used has a 60% sensitivity and a 97% specificity. Of the 79 herds tested, 29 herds were seronegative, 24 herds had 1-2 positive animals, and 26 herds had 3 or more seropositive animals. The average number of infected animals per positive herd was 3.3. In addition, a calculated minimum of 53.5% of the herds were identified as Johne's positive herds with a 95% confidence level. Of the total number of animals tested, 8.0% (166/2,073) of them were positive by the ELISA. After adjustments for test sensitivity and specificity and the proportion of animals sampled per herd, the true prevalence was calculated to be 8.75%. These data suggest that approximately 50% of the herds are infected with M. avium ssp. Paratuberculosis, and the overall prevalence of infection in Alabama beef cattle is approximately 8%, which correlates with other previously published regional estimates. (+info)
The efficacy of 9-cis-retinoic acid (aliretinoin) as a chemopreventive agent for cervical dysplasia: results of a randomized double-blind clinical trial.
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9-Cis-retinoic acid (aliretinoin) is a pan-retinoid receptor agonist and has been demonstrated in preclinical models to have potent chemoprevention effects. The purpose of this study was to determine the utility of using aliretinoin as a chemoprevention agent in cervical dysplasia. Patients with histological evidence of cervical intraepithelial neoplasia (CIN) 2/3 were randomized in a double-blind manner to receive high-dose aliretinoin (50 mg), low-dose of aliretinoin (25 mg), or placebo daily for 12 weeks. Compliance and side effects were monitored at various time points during therapy. At the completion of therapy, all of the patients underwent a loop procedure. Histology of pretreatment biopsies was compared with that of loop specimens. One-hundred and fourteen patients with CIN 2/3 were enrolled in the study. In the 112 patients evaluable for toxicity, headache was the most common clinical side effect and was experienced more frequently (74%) in the high-dose aliretinoin group. Eight patients withdrew from the study before completion of study medication because of unacceptable side effects. In the 104 patients evaluable for efficacy, there was no statistical difference in the rate of regression among the placebo (32%), the low-dose aliretinoin (32%), and the high-dose aliretinoin (36%) groups. (P = not significant; power 0.06). Aliretinoin at these dosages and this schedule does not appear to result in significant regression rates in CIN 2/3 patients when compared with placebo. Headache is encountered frequently and may thwart efforts to increase the dose or duration of aliretinoin in future cervical cancer chemoprevention studies. The rate of histological regression in biopsied CIN 2/3 patients is high even over a short time interval, and emphasizes the importance of having a placebo arm and an adequate sample size in cervical dysplasia chemoprevention studies. (+info)
Ascending vs descending aortic dissections.
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One hundred eight patients with spontaneously developing thoracic aortic dissection were seen between 1966-1973, 78 of whom had acute dissection and 30 chronic. The age (49 vs 60 yrs) and incidence of hypertension (32% vs 71%) were significantly lower in the 56 patients in whom dissection originated in ascending aorta than in the 52 patients in whom the dissection originated in the upper descending aorta. The mortality rate in medically treated patients with acute ascending aortic dissection was 88%. Cardiac tamponade was the major cause of death. The mortality rate was significantly lower in those who were treated surgically (24%). Fifteen (54%) of the patients with ascending aortic dissection and significant aortic incompetence did not have aortic valve replacement and only two subsequently (53 and 92 months later) required valve replacement. Although the initial mortality in patients with acute descending aortic dissection treated medically and surgically was similar, the long term survival rate was higher in the surgically treated group. We conclude that ascending aortic dissection and descending aortic dissection have different clinical profiles and prognoses. Immediate surgical intervention is indicated in patients with acute ascending aortic dissection. Patients with acute descending aortic dissection can be treated medically initially followed by early elective operation. (+info)
Rural/urban differences in access to and utilization of services among people in Alabama with sickle cell disease.
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OBJECTIVE: This study examined relationships between socioeconomic factors and the geographic distribution of 662 cases of sickle cell disease in Alabama in 1999-2001. METHODS: Measures of community distress, physical functioning, and medical problems were used in analyzing utilization differences between individuals with sickle cell disease living in urban and rural areas. RESULTS: Utilization of comprehensive sickle cells disease services was lower for individuals with sickle cell disease living in rural areas than for those living in urban areas. Rural clients reported significantly more limitations than urban clients on several measures of physical functioning. The results also suggest that utilization of services was higher for those with more medical problems and those who lived in high distress areas, although these findings did not meet the criterion for statistical significance. CONCLUSIONS: Conclusions based on statistical evidence that geographic location and socioeconomic factors relate to significantly different health care service experience bear important implications for medical and health care support systems, especially on the community level. (+info)